| What's new? Rev 19 added stock air / fuel meters to "not included parts" list. Rev 18 listed "not included parts", section 8 (@ the end), better stock fuel tanks, 4-15-02 Rev 17 clarified thermotime wiring, added fuel accumilator , 4-1-02 Rev 16 added Probst book, bulkhead fittings, 1-15-02 Rev 15, tweak to tuning section, 1-15-01 Rev 14, Oxy sensor (troubleshooting)7-2-00 Rev 13 Troubleshooting, replacement parts, air bypass direction, Type 4 warmup reg mount, T1 single throttle return spring, fuel pump relay notes (vague at best) 5-25-00 Rev 12 Injector line flush, fitting torque notes 1-20-00 Rev 11 Updates on main fuel line assembly. 11-15-99 Rev 10 Note on banjo fittings in fuel plumbing . 5-3-99 I suggest anyone who wants a better basic understanding of Bosch FI, CIS and combustion fundamentals buy "Bosch FI and Engine Management" by Charles O. Probst, ISBN 0-8376-03000-5, Bentley publishing. I have specialized into CIS modification somewhat deeper than Mr. Probst, but he has a wide ranging understanding of all Bosch FI systems. Contents: 1. Unpacking and part identification 2. Engine assembly A. Type 1 center plenum B. Type 1 &4 dual plenum C. Type 4 stock plenum D. Type 4 top center plenum 3. Meter placement, mounting and air ducting 4. Fuel plumbing 5. Wiring 6. Startup and tuning 7. Troubleshooting 8. Replacement parts 1. Unpacking and Part Identification Basic systems are for Type 1 center plenum stock airfilter. This manual willl cover those most completely, apologies in advance to heavily optioned systems. The large steel plate is the airmeter mount. It can be cut, bent, welded, and bolted to the chassis to mount this heavy, bulky metering assembly. The aluminum airmeter mounts on the plastic airfilter assembly, with the cast iron fuel distributor on top. A large rubber boot directs air to the throttle, through plastic and rubber duct assemblies. 914 and Early Type 2 brackets are custom designed. Remote air filter systems have an aluminum milled mounting assembly with lower airflow casting and inlet boot and duct. The air filter is not supplied. The center plenum is the magnesium alternator mount assembly, with steel strap for alternator or 12V generator. The aluminum oil filler adaptor plate bolts to the right side, with the oil filler bolted to it. Aftermarket or stock cap assemblies fit the fill neck (not included). The throttle mounts on top, direct or with an adaptor. Single round throttles use a stock linkage bolted on the left side of the plenum, with the cable to the left of the doghouse cooler. 1975 on beetle shrouds have this cable location stock. Left and right manifolds use fabric/rubber boots to the plenum tubes, with insulating gaskets under the manifolds. Injectors pop into the machined boss near each port with o-ring seals. Aluminum manifolds use short steel adaptor tubes, with rubber clamped boots. Longer studs are required in the head for aluminum manifolds. All seals are stock VW parts. Only dual port engines can be converted to MFI. Steel manifolds are powder coated satin black, some color options are available for extra cost or parts can be unpainted with $20 credit. To clear the injectors and lines for safety, exhaust pipes from front cylinders must be below the top of the boss on the cylinder head for upper tin, if Tri- Mill type exhaust is used. Bugpack 2004-11 is a 1-5/8 S&S rear collector off-road exhaust with adequate clearance, if MFI heat shields are used. If a cold start injector is used, the fuel pump blockoff is drilled for the thermotime switch, which controls priming time on the cold start injector. If a fast idle throttle bypass is used, air is ducted to the unit from above the throttle plate and released below it, with an electric heater closing the passage after minutes. All systems have fuel prefilter, electric pump, high pressure line , main fuel filter, short line to fuel distributor, distributor, and low pressure return line to tank. The return port into the tank can be anywhere, top or bottom. The fuel pump should be close to and below the main tank. The output lines from the pump see 80 PSI, and must be crimped or compression fittings. Custom length injector lines (measure for build and shipment) go from the 4 outlet ports on top of fuel distributor to injectors located at the intake ports. Copper o-rings seal all banjo type connections, other compresion types are self sealing. All systems have warmup regulators fed from the center top of the fuel distributor, with a low pressure return line to the return port area of the fuel distributor. Electric heat changes the fuel mixture from rich at startup to lean after minutes. With full flow oil filter mount option, the warmup regulator senses the oil temp and does not enrich hot restarts. This warmup regulator unit is mounted on the engine block of watercooled cars using CIS, difficult on air cooled VWs. Optional altitude compensated warmup regulators correct mixture by sensing outside air pressure through a vent. If a cold start injector is used, a high pressure line from inlet side of fuel distributor is routed to the injector. If a fuel sump is used, the FI system pulls from and returns to it. The sump is fed from the bottom of the main tank, and air vented from the top of the sump to the top of the main tank. If gravity cannot be used to feed the sump, a second fuel pump can force fuel to the sump, bleeding excess back to the main tank. 2. Engine Assembly 2.A. Type 1 center plenum Long block should have upper cylinder tin and oil cooler installed. Cover openings with tape before removing studs. Front left (closest to the driver) stud should be removed from generator stand area. Both fuel pump studs should be removed to allow for center plenum installation. If aluminum manifolds are being used, longer studs (supplied) need to be installed at intake ports. Do not drop loose objects into engine. Experience is what you get when you do not get what you wanted. Right plenum half (alternator stand) fits over the three remaining studs after gasket - metal louver thingie - gasket. M8 nuts and lockwashers go on the studs. The long M8 hex bolt goes into the engine case from inside the plenum, with lockwasher. Tighten all 4. The flat aluminum milled oil filler adaptor bolts to the right side of the right plenum half with 3 M6 allen bolts, with a gasket or sealer underneath. The oil filler bolts to it with 3 M8 hex bolts, with lockwashers underneath. Aftermarket or stock cap assemblies fit the fill neck (not included). Breather ports can be drilled into the right face of oil filler, just below neck. Pipe threads have over 1/4 inch thickness for sealing at this area. The left plenum side bolts to the right side with sealer at the joint. Factory gaskets are obsolete. 3 M6 nuts/LW are at top and rear, with 1 long M6 allen bolt with LW at upper front from left side. 2 shorter M6 allen bolts with LW are at center and lower front from left side. The throttle mounts on top, direct or with an adaptor for progressive units. Sealer should be used at all flanges. Single round throttles use a stock linkage bolted on the left side of the plenum, with the cable to the left of the doghouse cooler. 1975 on beetle shrouds have this cable location stock. A second extension spring below the throttle shaft pulling forward may be required for positive throttle return. Bracket under development. Sand or off-road throttles should have torsion return springs removed, and extension spring return plates and springs installed. For single throttles, the spring should hook to the top corner of the shroud above and in front of the spring return plate. Progressive throttles have self-contained return spring assemblies, and can use either the stock throttle pull location with the bellcrank or a high direct pull requiring more cable travel. Test your throttle for safe return-to-idle performance when engine is installed in vehicle and all covers, etc are installed. Stock cable tubes tend to pack with sand, consider open cable and pulleys or quality sealed cables in good condition. If a fast idle throttle bypass is used, air is ducted to the unit from above the throttle plate and released below it, with an electric heater closing the passage after minutes. Air is plumbed from the rear of single throttles with reworked EGR pipe, to the bypass valve and into plenum at 3/8 NPT boss on right side rear surface. The bypass unit must be connected so the electrical conector is on the engine side of the central disc, so the internal plate will seal correctly. If inverted, the hot idle will be as fast as cold idle. Any location in the duicts and manifold is ok for these connections, due to the small passage size and low manifold air density at idle. The shroud and alt/generator assembly bolts down with the strap and M8 nuts with LW. For single throttles, a 1975 on beetle shroud has the throttle cable location pre-drilled. Other shroulds need to be drilled before installtion for the cable and housing, to the left of the doghouse cooler. If a cold start injector is used, the fuel pump blockoff is drilled for the thermotime switch, which controls priming time on the cold start injector. The switch seals with a copper O-ring, with a gasket under the blockoff plate. The cold start injector screws down to the plenum or throttle adaptor with cork gasket underneath using M6 bolts with LW. Test fit injectors into intake manifold bosses. Slip clean fat o-ring over clean injector about 1-1/2 inch from unthreaded end. Push into intake manifold bosses, rolling the o-ring along exterior of the injector. Oils will make o-ring slide, not allowing rolling. O-ring should pop into groove on injector and groove in manifold. Remove injectors by pulling on injector, as they will be flow tested out of manifold to purge injector lines of air at start-up. Intake manifold fabric/rubber seals boots are slipped over plenum spuds, and the sealing gaskets installed over the head studs at intake ports. Aluminum manifolds use short steel adaptor tubes, with standard DP rubber clamped boots. Left and right steel or aluminum manifolds are fitted into the seal boots at plenum end, and twisted over the studs. M8 nuts and LW are used to secure. Clamps are not used on these fabric boots. Engine assembly is done. 2.B. Type 1 &4 dual plenum Not documented at this time 2.C. Type 4 stock plenum Long block should have all cylinder tin and oil cooler installed. The plenum and throttle assembly bolts to the case flange at 2 locations, near the flywheel flange and under the plenum. Flat washers should be used on the plenum tabs, and lockwashers on the nuts. The throttle linkage is identical to stock EFI Type 4 engines from '75 to '79. Sand or off-road throttles should have torsion return springs removed, and extension spring return plates and springs installed. Test your throttle for safe return-to-idle performance, when engine is installed in vehicle and all covers, etc are installed. If a fast idle throttle bypass is used, air is ducted to the unit from above the throttle plate and released below it, with an electric heater closing the passage after minutes. Air is plumbed from the air inlet duct to the bypass valve, under the runners and into plenum at boss. The bypass unit must be connected so the electrical conector is on the engine side of the central disc, so the internal plate will seal correctly. If inverted, the hot idle will be as fast as cold idle. Any location in the duicts and manifold is ok for these connections, due to the small passage size and low manifold air density at idle. If a cold start injector is used, it is controlled by the thermotime switch, which controls priming time on the cold start injector. The switch mounts to the bracket and to the engine centerline clamp bolts. The cold start injector screws down to the plenum with cork gasket underneath using M6 bolts with LW. Test fit injectors into intake manifold bosses. Slip clean fat o-ring over clean injector about 1-1/2 inch from unthreaded end. Push into intake manifold bosses, rolling the o-ring along exterior of the injector. Oils will make o-ring slide, not allowing rolling. O-ring should pop into groove on injector and groove in manifold. Remove injectors by pulling on injector, as they will be flow tested out of manifold to purge injector lines of air at start-up. Two intake manifold fabric/rubber seals boots per runner seal the manifolds to short tubes to the plenum spuds, and the sealing gaskets installed over the head studs at intake ports. M8 nuts and LW are used to secure. Clamps are not used on these fabric boots. These higher flowing intake manifolds do not exactly line up with the large plenum for good throttle response, so the second boot and flex tube is used. Engine assembly is done. 2.D. Type 4 top center plenum. Not documented at this time. 3. Meter placement, mounting and air ducting This step requires more thinking than any other, except if MFI has already done it for you. If so, the mount plate is pre-cut and bent for your application. 914 and Early Type 2 brackets are custom designed. Check for your application with MFI. The airflow meter must be securely mounted, because of the weight of the unit. The heavy fuel distributor and the air outlet cone point upward, although they can be tilted up to 30 degrees from vertical. All engine covers need to miss the unit, when closed. The air duct to the engine throttle should be as short as possible, for good fuel delivery response to throttle opening. Typically, the stock rubber large banjo boot and molded plastic duct can be mated directly to the rubber 90 degree bend for single throttle units. 2 inch ABS DVW pipe, elbows and rubber clamp-on connectors all are legal for inlet ducts. Engine mount flex requires some degree of duct flex, make sure your mounts are in good condition. CIS engines have brute low end torque, making engine and driveline health critical. One broken ring gear, several loosened engine mounts and failed cylinder head sealing have already resulted from CIS power increases. The fuel connections should all be accessible, so the outlet boot cannot cover the connections. The air filter should be able to be changed, without excessive dissasembly. The idle mixture adjust screw and plug (center of meter top) needs to accessible while the engine is running. To try out your design, temporarily block of clamp the meter with or without the plate in place and check access. The plate is sandwiched under the aluminum casting and over the airbox upper half. Welding, preferrably mig or tig, is the best means to secure the mount plate to the vehicle structure. Bolts with adequate washers will work as a second choice. Sheet metal screws are not reccomended. The steel plate can be folded to create a strong flange or two to stiffen the plate, so think about it before trimming the excess material off. The heavy end with the fuel distributor needs to be stronger, as most of the load will be taken there. The sandwich effect makes the narrow area of the mount plate very stiff and strong, and that is the light end of the meter. Extra steel can be added on to the plate outside the meter assembly, and notice the large tab on the plate can point ot the left of right of the meter assembly. Cut off the excess, fold your tabs, grind away paint from chassis areas and tack weld the plate in place. Check the fit, and redo until satisfied. Extra mounting plates can be ordered from MFI if you would like another try. This is the most difficult step of the entire process. Take your time, and be proud of real hands on labor! After securing the mount plate to chassis, mount the meter assembly with upper and lower gaskets on the plate with 6 M6 bolts and lockwashers. These gaskets seal outside air from clean air above the air filter. The tubes protruding from the plastic upper air box are for crankcase breather, if desired. Plug any unused holes. Short bolts siliconed into place are fine plugs. The air filter fits inbetween the two air box halves, and the metal clips secure the two. The clips can be repositioned for better access, and the lower air box can have additional holes cut for increased air flow, or the air can be ducted form fresh air if desired. Most closed body air cooled VWs have cool air over the engine because of the cooling fan inflow. No preheating is required on inlet air, and carb icing is not a concern. Test your mount with adequate force to ensure suspension bottoming will not dislodge the meter assembly. Pushing down on the cast iron fuel distributor with 50 lbs. is a safe test for the mounting. If it flexes down more than 1/8 inch, add more braces, or move the meter assembly closer to the chassis. The large fuel filter mounts to the distributor assembly, or to a convenient nearby surface. The stock formed mount fits on the end of the meter casting, or the bare steel mount can be welded or bolted down where convenient. Two bare mounts are included, the thicker one for the pump and thinner one for this use. Both ends of the filter need wrench access during filter install or change. Always use 2 wrenches on the end being connected. The filter is M14 banjo at inlet, and M12 banjo at exit. The inlet port of the fuel distributor is also M12 banjo, so the filter-distrib line can go either way. The blue Airequip line is the feed to the distributor from filter, assembled by the installer (no tools required). 4. Fuel plumbing All systems have fuel prefilter, electric pump, high pressure main feed line (built by installer), main fuel filter, short line to fuel distributor (built by installer), distributor, and low pressure return line to tank. The return port into the tank should consider fuel slosh and anti-slosh sump requirements. Injector lines are custom sized, measure for build and shipment. Torque all fuel connections snug with wrenches, tighten if leaks occur during testing. The fuel pump should be close to and below the main tank. Feed lines from main tank to pre-filter or fuel sump should be 3/8 id.. Replacement 3/8 fuel bungs for VW and 914 tanks are available from MFI. Revision 18 update: Stock VW EFI tanks have fuel retrun ports and fuel sumps internal to the tank, and make excellent tanks for early carb vehicles being injected. 75-79 bus tanks fit back to '65 at least, and beetle tanks fit back to ????. No external sump is required for normal use. Fuel sump details: If an external fuel sump is used, the FI system pulls from and returns to it. The sump is fed from the bottom of the main tank, and air vented from the top of the sump to the top of the main tank. If gravity cannot be used to feed the sump, a second fuel pump can force fuel to the sump, bleeding excess back to the main tank. 5 - 1/4 inch pipe threaded ports are on the end of MFI sump tank. Orientation is typically high noon, 1, 5 and 6 oclock, with a center port. The 1 and 5 ports can also be at 7 and 11, if the tank is rotated 180 in the mount. A supplied steel bracket can be welded or bolted to the chassis, with 1 band clamp at each end of the bracket. The rubber cushion goes between the mount and sump, protecting the sump from rubbing. Top is always air vent from sump to top of main tank, 1/4 id. Bottom is ideally a drain port with shutoff valve. Next up from bottom is feed to the pump, 3/8 id.Either remaining hole is fine for the 2 lines that feed fuel into the sump. Return from FI is 1/4 id if under 4feet, 5/16 id if over 4feet. Feed from tank is 3/8id. 914 notes. Fuel sumps are suggested, due to cornering starvation problems. Due to cramped space, no drain is used. Feed the tank to bottom port of the sump, connecting after tank and rubber line is lowered in place. Pump pickup still should be 2nd lowest. Plug the unused port with pipe plug. See photos on this website (under "fitting it in") for details on sheet metal surgery to simplify access. 914 pumps are installed unde the tank, to the left of the sump. Vent the sump to the top small vent line to the charcoal filter. Main feed line from pump to engine runs under carpet to rear of car, details forthcoming. Low pressure return line (5/16") bundles with feed line. Mount the warmup regulator on supplied bracket boltes to case centerline clamp bolt. Rising heat from engine will keep regulator temperature and fuel mixture correct for hot restarts. Pump mounting. The pump mounts the thicker smallest steel brackets, welded, bolted or screwed to the chassis. A band clamp secures the pump to the bracket. The 3/8 prefilter plumbs into the aluminum adaptor, with a short section of 1/2 inch line into the pump. Band clamps are used on all connections, because they are low pressure. All connections downstream of the pump in this system are high (80 psi) pressure. They need to be tested and inspected before the engine will be started. If a leak occurs, fix it before continuing. The banjo fittings can take significant torque before stripping. Contact MFI before starting a fire. Parts can be replaced, humans cannot be. The short hex block mounts the output check valve where wrenches can be used during dissassembly. The hex block mounts onto the pump with a 12mm banjo and copper washers on each side. Align the block between the electrical terminals on the pump, checking during torqueing. The check valve threads directly into the hex block with a copper washer. The block is 3/4 inch hex, use 2 wrenches to torque the check valve in place. Rev 11 update: The high pressure output lines from the check valve to main fuel filter and fiter to fuel distributor are 250 psi / 250 degree fuel rated push-on Airequip 1/4" blue line, with barbed banjo fittings. Install all components and doublecheck your measurements, the first length of line is included in initial purchase. Oil the hose and barb before pushing the hose on all the way to the stop washer. The hose can spin until the oil washes out, even when under pressure. Note: the line will not pull off the barbs (good), so do not make a mistake and push on the wrong pieces. Note the 14 mm bigger banjo goes on the fuel filter inlet side, with 12 mm on outlet of pump and outlet of filter and inlet of fuel distributor. Rev 17 update: Fuel accumilator fittings for the Airequip pushon line are avaialble from MFI. The Accumilator has two sizes of compression fitting, larger is outlet inlet. This accumilator piece is intended to maintain fuel pressure after the pump shuts off to prevent any vapor locking or fuel boiling in the injection lines. Systems with htis will spurt fuel after pump shutdown if a fitting is released. The capnut seals the output line banjo to the check valve with 2 copper washers. Make sure to use 2 wrenches on the capnut and check valve when removing the capnut, for any reason. With the check valve screwed into the pump body, dissassembly is very difficult. My biggest beef with Bosch engineers! Rev 10 update: Note about banjo fittings: Always check that the copper washers are the only part of the line in contact with the fitting. Any contact between the line crimp and other component will cause a leak, either from the seal or lead to line failure at some later date. Extra washers can be stacked under the banjo fitting to space crimps away from the solid component. The output lines from the pump see 80 PSI, and must be correctly crimped hydraulic style lines, correct push-on hose (supplied) or compression fittings. No band clamps allowed. Steel lines with compression fittings with flared ends are ok for 914 / Ghia / Thing front tank vehicles. Front pump mounting near a front tank keep heat vapor lock issues to a minimum, but requires good forethought on feed and return fuel line routing. Rev 16 update: Note about bulkhead fittings: If a flexible high pressure line is to go thru a steel bulkhead, the best practice is to use a metal bulkhead fitting tighened to the sheet metal with correct barbs in each end. The Airequip 1/4" blue line is a standard for such fittings, the barbs have the yellow plastic washer for assembly checking. This hose also works for oil lines. The large fuel filter mounts to the distributor assembly, or to a convenient nearby surface. The stock formed mount fits on the end of the meter casting, or the bare steel mount can be welded down where convenient. Both ends of the filter need wrench access during filter install or change. Always use 2 wrenches on the end being connected. The filter is M14 banjo with 2 copper washers at inlet, and M12 banjo with 2 copper washers at exit. The inlet port of the fuel distributor is also M12 banjo, so the filter-distrib line can go either way. Fuel distributor port identification: Several generations of 4 cylinder distributors are in use, with similar connection functions. To identify, view from the 4 port side. Point the center outlet up, to 12 oclock. Ports at 10 and 1 are earliest generation. G1 Ports at 7,8,9 and 11 are middle generation. G2 Ports at 7,8,9, 11 and 4 are latest generation. G3 These 4 vertical ports go to injectors, with M8 banjo and 2 copper washers at distributor end. No firing order exists, as all 4 injectors squirt all the time. G1: 10 o’clock is inlet from filter, 1 o’clock is return to tank. Center is feed to warmup regulator. Return from regulator screws into center of 1 o’clock port, with concentric banjo screw. Cold starts can be fed from center of 10 o’clock, with concentric banjo screw. G2: 11 o’clock is inlet from filter, 8 oclock is return to tank. Center is feed to warmup regulator. Return from regulator to 9 o’clock. Cold starts can be fed from 7 oclock. This fitting must be plugged if cold start not used. M8 x 1 fine threaded bolt with copper washer is adequate. G3: 11 o’clock is inlet from filter, 8 o’clock is return to tank. Center is feed to warmup regulator. Return from regulator to 9 o’clock. Cold starts can be fed from 7 o’clock. 4 o’clock is blocked lambda port. These units have been reconfigured and do not operate with lambda closed loop control. All systems have warmup regulators fed from the center top of the fuel distributor, with compression fitting at distibutor end and M10 (unique) banjo with 2 copper washers at warmup regulator. Regulator does not function if plumbed backwards. Low pressure return line to the return port area of the fuel distributor, with M8 banjos and 2 copper washers at each end. Electric heat changes the fuel mixture from rich at startup to lean after minutes. With full flow oil filter mount option, the warmup regulator senses the oil temp and does not enrich hot restarts. This warmup regulator unit is mounted on the engine block of watercooled cars using CIS, difficult on air cooled VWs. Optional altitude compensated warmup regulators correct mixture by sensing outside air pressure through a vent. If a cold start injector is used, a high pressure line from inlet side of fuel distributor is routed to the injector with M8 banjos and 2 copper washers at each end. Custom length injector lines will be built to your specifications. Stock injector lines only exist to 32 inch, custom lines can be built to 180 inch, and injector line length does not affect performance. Install all components and double check your measurements, the first set of lines is included in initial purchase. These lines can be formed over a human thumb for tighter bends without risk. Care should be taken to avoid sharp edges, rotating parts, exhaust systems, etc... when routing injector lines. The return line from the fuel distributor to the tank is M12 banjo with 2 copper washers at distributor, although it is low pressure. Band clamps and rubber hose can be used for this line. Return from FI to tank is 1/4 id if under 4 feet , 5/16 id if over 4 feet . The return port into the tank can be anywhere, top or bottom. An aluminum weld-in 1/4 inch NPT bung is available from MFI for vent ports on spun aluminum buggy tanks. The fuel sump is designed as an anti-slosh device, to ensure fuel is present at the pump pickup with lower fuel levels during cornering or tilt situations. Pump pressure drives engine operation, no fuel, no go. Recirculating into the sump ensures best operation until the main tank can refill the sump, during straight and level flight. Bolt the engine in, measure the injector lines, and call or e-mail MFI to order the custom lines. Overnight shipping service available at extra cost. At this time you should only need wiring, custom fuel lines and testing to get operational. Rev12. When the lines arrive, install the banjo fitting onto the fuel distributor output ports with copper washers above and below using 8mm hollow bolts. Do not install the injectors until flushing is completed. 5. Wiring Simplest pump wiring is ON whenever ignition is on. Off-road cars use this method. The pump draws up to 8 amps, 20 amp fuse would be smallest to use, due to turnon spikes. The downside is: if the vehicle is wrecked AND if fuel line(s) are broken The pump will run, fuel will leak (up to 1 gal/minute) until tank is empty or switch is turned off. The upside is: simpest possible system. THINK about very safe line routing. Protect your tank as if it were a human. It has feelings, too. Safer /more complex possibility: Pump is ON if started is engaged OR ignition on AND oil pressure OK. Special switch or relay arrangement can be used. Use the VW rabbit relay to control the fuel pump in this manner. I do not have parts or documentation at this time on this. The upside is: Most wrecks kill the engine or invert the vehicle, in either case killing oil pressure, stopping the fuel pump. The downsides are: 1. Losing oil pressure flying over whoop-de-doos, hard cornering or severe tilt will stop the pump, and engine. 2. Electronics to think about if pump does not ever run. Other wiring: Warmup regulator gets ignition switch voltage and is grounded under one of the mounting bolts. No polarity, either way is fine. Cold start and thermo time wiring: Either cold start injector terminal gets +12 from starter solenoid control wire from switch. . The heater terminal of the Thermotime switch (brass hex with snout and connector) also gets same starter "on" +12v. This terminal (30 ohm to the switch case) is the LEFT prong when looking at the switch with the locking tang for the electrical connector on the up side of the switch.The other terminal of the cold start and RIGHT (grounded to the switch case) prong of TT switch are conected together. Injector grounding is internal on this circuit, through the thermo time switch. The thermo time switch opens, limits priming time on the cold start injector based on engine case temperature and cranking time. If a fast idle throttle bypass is used, air is ducted to the unit from above the throttle plate and released below it, with an electric heater closing the passage after minutes. This device gets ignition switch voltage and is grounded under one of the mounting bolts. No polarity, either way is fine. 6. Startup and tuning Fuel line flushing, and system test is the next priority. Get catch basins for injector testing. 12 oz glass bottles (empty and clean) are not affected by fuel, and allow clear view of spray pattern, while containing mist. Check area to ensure no open flames, pilot lights, smoking, etc. during testing. Injector mist is very volatile. Put 1 gallon of fuel (gasoline only) into the main tank. Check for drips. If a leak occurs, fix it before continuing. If no leaks are found, disconnect coil output lead and set ignition to run position. All connections downstream of the pump in this system are high (80 psi) pressure. Pump should prime itself, and slow down to a steady hum. Run for 5 seconds, and look for leaks at all connections. If a leak occurs, fix it before continuing. There should be no fuel dripping from the injector lines at this time. If so, unscrew the adjuster screw with long M3 allen key in the hole at top center of air meter assembly until the drip stops. Contact MFI before starting a fire. Parts can be replaced, humans cannot be. If no leaks are present, remove the air filter or boots to allow hand access to the air metering plate. With pump on, engine off, and injector lines pointing into catch basins, lift the air metering plate. Injector lines will need to be purged of air, and any assembly debris will be flushed out. Install the injectors, torqueing with 12 and 14 mm wrenches hand tight and repeat lifting the plate. One by one, you will hear the sound of power, the screeching of the injector valves. This squealing is atomizing the fuel, and the spray patterns should be short , even and misty. Long streams are not acceptable, continute to test for 2 minutes with the air metering plate at full up stop. Injector mist is very volatile, and is a fire hazard. Dispensed fuel can be recycled into the tank. Idle adjustment (under wire and rubber plug) sets intial plunger position within fuel distributor. If injectors dribble when plate is released, turn setscrew with long M3 allen key counterclockwise 1 turn past no dribble. If no dribble is present, turn clockwise to create dribble, and back off counterclockwise 1 turn past no dribble. If all 4 injectors are squealing correctly, insert into intake manifold bosses. No firing order exists, as all 4 injectors squirt all the time. The fat rubber o-rings slide up the injector shaft to within 1/2" of the groove. Clean the injector of any gas or oil, to ensure the o-ring will roll, not slide on the injector. Push the injector in until the o-ring pops into the groove in mount and injector. The hot idle speed is controlled on all systems with large air bypass screw on throttle, near base. Unscrew leads to more air and faster hot idle, screw in leads to slower idle. If a fast idle throttle bypass is used, air is ducted to the unit from above the throttle plate and released below it, with an electric heater closing the passage after minutes. Reconnect the coil output lead, and start the engine. Check immediately again for leaks, fix any that are found. Systems without a fast idle throttle bypass need additional throttle opening to idle cold, or the air bypass screw can be artificially opened. Allow the engine to warm up for 10 minutes before tweaking mixture, if possible. Richening mixture is achieved by screwing mix adjust setscrew with long M3 allen clockwise, leaning CCW. If in doubt try richer. CIS can run very lean and confusing to the ear. Adjust for smoothest idle, similiar to a one barrel carb. 7. Troubleshooting Mixture verification with oxygen sensor: Mount an oxy sensor in the exhaust pipe between collector and muffler to ensure only ex. gas will be present. Get a single wire oxy sensor (about $20 from Napa), and an 18mm (non-tapered seat) spark plug anti-fowl adaptor. Cut off the external threads, make sure the sensor screws into this completely (correct thread size) and file off the plating so you can weld the round smooth zone into the ex. pipe without zincing yourself to death. Connect any voltmeter with 0-1V DC scale to ground and the oxy sensor wire, and warm up the vehicle. Here are some rough voltage to a/f mixture numbers: 0.45V = 14.7:1, ideal for smog and cat converters. 0.7V = 13:1, ideal for HP and exhaust valve cooling. 0.3V = 16:1, ideal for economy and melting air cooled engines. Oxy sensors need heat to work, do not try to read them for a minute or so from a start-up. An 18mm spark plug in the test port is a good conversation piece, and keeps the more expensive oxy sensor safe for another day, or testing something else. Idle mixture is adjusted with 3mm Allen wrench supplied , I usually peak the rpm with the mix screw at any air setting. CIS motors can idle incredibly lean (and very ratty) if misadjusted. Richen it up if you are unsure. Warm idle speed is simple screw bypass at throttle. Lean at hi rpm: If you get 0.8 v up to some rpm wide open then the voltage drops to below 0.5 V, DO NOT rev the engine above the 0.5 V rpm, to ensure long happy lives (your engines, yours, and mine). Either the fuel filter system is plugged or your motor needs a larger CIS meter assembly. Stock CIS meters are good for "about" 100 crank hp, give or take 20%. Rear wheel hp will be 15-30% below crank hp, if you are doing chassis dyno tests. My "180 hp" (130#/hr) system should satisfy most aspirated engines, and some mild turbos. Contact MFI if you have this lean hi rev condition. Hot starts can be difficult, generally this is a lean condition from vapor lock in injector lines. Plumbing for stock accumilators is avaialble to maintain system pressure after pump shutdown during heat soak. A manual priming switch that grounds out the cold start terminal connected only to the TT switch will crudely awake any hot sleeping beast. CIS can start ratty, until all injector lines are purged. The other 2 or 3 cyls work perfect, and driving is the best cure to fill all lines. 30 seconds max. Water is bad for any gasoline fuel sys. CIS gets cylinder "dropouts" from water, not as bad as carbs that lose all cylinders fed by a jet. Bouncing can move water from a low spot to the fuel distributor, but the recirculating pressure regulator helps to move the water back to the tank. Check the fuel in the sump for water, add some alcohol fuel additive (absorbs water) and burn the fuel up. New fuel filters are $10, Fram, Purolator, etc. are all good. Don't change in sandstorm. Flow tests require 4 bottles (12 oz about right), and lift the airflow plate. The injectors scream (like a Ferrari) when they are healthy, and delivery is usually within 5% cyl-cyl. Swap injectors and lines to hunt down cause. Very rare to go this deep, still better than carb jets where you can't dry run the carb. Fuel distributor plunger can be removed and cleaned (do NOT drop). Tuning and Troubleshooting Tuning:High power mixture can be adjusted to 6% CO for good HP with my modified airflow meter, cooling and robust insensitivity to mixture variance. .8 v oxy sensor is also good, easy to install and check. A small scale wind tunnel is useful for basic calibration. Aviation gas not recommended due to different octane rating system, unleaded premium suggested. Troubleshooting:CIS can start ratty, until all injector lines are purged. The other 2 or 3 cyls work perfect, and driving is the best cure to fill all lines. 30 seconds max. Water is bad for any gasoline fuel sys. CIS gets cylinder "dropouts" from water, not as bad as carbs that lose all cylinders fed by a jet. Bouncing can move water from a low spot to the fuel distributor, but the recirculating pressure regulator helps to move the water back to the tank. Check the fuel in the sump for water, add some alcohol fuel treatment to dissolve the water and burn the fuel up. New fuel filters are $10, Fram, Purolator, etc. are all good. Don't change in sandstorm. THINK BEFORE DOING THIS TEST: "Beer Bottle" flow tests require a running pump, 4 bottles (12 oz about right), and lift the airflow plate. The injectors scream (like a Ferrari) when they are healthy, and delivery is usually within 5% cyl-cyl. Swap injectors and lines to hunt down cause. Very rare to go this deep, still better than carb jets where you can't dry run the carb. Fuel distributor plunger can be removed and cleaned (do NOT drop). 8. I am deciding to ship kits without the following items. I cannot devote the time to find enough to maintain and grow the business, or I provide little to no value by handling them. They are all used in unmodified condition, and if used parts, testing is trivial and shows most are usable. I can test pieces if they are shipped to the MFI shop. Not included in kits: Bosch: Air / fuel meter: Usually good used if all fuel lines still connected. The pre’80 factory installations used G1 or G2 type (see below) cast iron meters, and do not require computers. The G3 lamdba style units require computers, or extensive modification. I hot rod some G3’s into my hi fuel flow kit. I can modify aluminum airflow castings for tuning “wide open” mixture, e-mail if this interests you. CIS-E is more complex than the Space Shuttle. Fuel distributor port identification: Several generations of 4 cylinder distributors are in use, with similar connection functions. To identify, view from the 4 port side. Point the center outlet up, to 12 oclock. Ports at 10 and 1 are earliest generation. G1 Ports at 7,8,9 and 11 are middle generation. G2 Ports at 7,8,9, 11 and 4 are latest generation. G3 These 4 vertical ports go to injectors, with M8 banjo and 2 copper washers at distributor end. No firing order exists, as all 4 injectors squirt all the time. G1: 10 o’clock is inlet from filter, 1 o’clock is return to tank. Center is feed to warmup regulator. Return from regulator screws into center of 1 o’clock port, with concentric banjo screw. Cold starts can be fed from center of 10 o’clock, with concentric banjo screw. G2: 11 o’clock is inlet from filter, 8 oclock is return to tank. Center is feed to warmup regulator. Return from regulator to 9 o’clock. Cold starts can be fed from 7 oclock. This fitting must be plugged if cold start not used. M8 x 1 fine threaded bolt with copper washer is adequate. G3: 11 o’clock is inlet from filter, 8 o’clock is return to tank. Center is feed to warmup regulator. Return from regulator to 9 o’clock. Cold starts feed from 7 o’clock. 4 o’clock is lambda port. These units in stock form operate with lambda closed loop control, using simple computer and oxy sensor. I am not familiar with these systems. Fuel pump: All CIS vehicles have equivalent fuel pumps, larger than EFI vehicles (approx 2.4" round x 4.7" long body). Most are located under the chassis in front of RR wheel on watercooled VW, Audi. Audi pumps (4315-6091D143 typ marking) have unique electrical connections, nicely sealed but connectors must be scavenged from vehicle harness. VW pumps (171-906-A343 typ marking) have 4 and 5 mm studs for the two terminals. Saw off the fuel nipple before removing the check valve / cap / dead nipple, save the cap and check valve for use on my adapter block for easy servicing. I ship an adaptor from the 3/8 fuel prefilter lines to the 1/2" pump inlet. Some GTI have a "filter bottom" pump in a plastic sump, this whole thing makes me nervous. Bosch: warmup regulator: This is mounted on the front of the engine block on watercooled VW, with 6mm bolts requiring 5mm long Allen key and some leverage (locking pliers). 14mm and 13mm wrenches are required to loosen the fuel fittings. Two types are common. Altitude compensated "special" ones have a black plastic mushroom cap on the face away from mount surface, normal ones (0438-140-011) do not. All are compatible, if you go more than +3000' you may notice a difference in performance. Usually good used if both fuel lines still connected. Bosch: injectors (cylinder inj. not included, cold start yes at this time) Normal HP (<25 hp/cyl) cylinder injectors are 0437-502-015 or -023 with compatible (early ('77-'79) rabbit) mounting (single fat O-ring(063-133-557), no aluminum shrouds on injector). -007 are not recommended. New ones are $25 or so, you can test $1 used ones by doing the "beer bottle test". They are buried in rabbits heads, pliers are useful to yank them out. Bosch: Hi HP injectors: "180 hp kits" use new hi flow 0437-502-017 injectors, slightly longer with a unique threaded mounting. The fat seal o-rings can be used directly on the injector shaft, but cracking does occur. For better o-ring life or for boosted applications, I can groove tham in the o-ring area to the same profile as -015 injectors, and sell new for only a few dollars more each from the parts store. If you are planning on more than 100hp, these 930 turbo injectors are a good choice. I have a stash of tested cold start "5th" injectors at this time. Bosch: thermotime switch for cold start injector kits. These brass or bronze 15/16" hex pieces with electrical connector out the end, are mounted in the water outlet neck to radiator. I supply new similar electrical connectors with the kits. Usually good used. Filters: Air: '77-'79 Rabbit air filter boxes use 5.25" x 10.7" flat filter, fine for 99% of street cars. K&N makes an element for this. Fuel prefilter (before the fuel pump) 3/8" line steel can, Purolator 211111 is a good one. I supply 3/8 to 1/2 adaptor for the pump inlet. There is a plastic prefilter with 1/2" out, I do not use this piece, nor do I know a p/n. Fuel high pressure filter '77-'79 Rabbit is 2.2" dia x 4.5" long, fine for all uses. Fram G3713 is one possibility. Rabbit/Jetta/Scirroco: lower plastic airbox / air filter housing. Watch for cracks. Get the metal clips too. I have many upper airboxes that bolt to the airflow meter, I will still include them. Rabbit/Jetta/Scirroco: airflow duct from meter to throttle. VW 067-133-373. Plastic molding, oval at each bent end and smaller round diameter in the middle. Only one end is usually used at airflow meter, saw off to length and deburr. Rubber clamping connectors will go over the round area to assemble the inlet air duct. Always good used. Rabbit/Jetta/Scirroco: rubber boot from airflow meter to boot. VW 067-133-357 (early part) does NOT have "extra" small holes plugged with yellow plugs. My favorite. VW 067-133-357A late part has extra holes. Check for through cracks in the bellows area. Usually good used. Get the round and oval screw clamps also. Audi/VW Fox fuel sumps (some applications) This is a white to clear plastic box with 4 spigots molded in, the nicest factory piece I've seen, small but usable for street cars. Look for cracks, test for leaks. I do not know p/n at this time. Volvo 242 air meter mount castings (for some remote air filter applications). This is under the unique mounting stack used in 4 cyl 242 Volvos (early 80's), with the flat top "2x4" intake manifold on top, this casting is on the bottom. Always good used. I do not know p/n at this time. Replacement parts for pieces included in kits: idle bypasses, gaskets, seals are typically unmodified VW or Bosch part numbers from stock vehicles, Hi HP Fuel distributors are custom hot rodded, no factory application. Crimped injector lines are available for $25 each, any length. The main fuel supply line in the kit is Airequip 1/4" blue pushon, part number FC-332-04 AQP 1/4. 250 psi 250 degrees working rating, fuel compatible. There are many fittings for use with this line, including T and bulkhead fittings (go with1/4 pushon to 1/8 pipe fittings at each end and use 1/8 pipe T or bulkhead fitting). All compatible barb fittings have the yellow ring that the line is pushed on until the ring is touched. |
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