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    Thread: Project Run-an-8v-with-no-ecu

    1. Junior Member
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      86 Jetta Diesel N/A
      10-05-2012 11:32 AM #1
      So as the title states I've got my hands on a 1.8 from an 86 GTI (cis+knock sensor). The goal is to swap it into my car (86 jetta diesel N/A) with as little wiring as possible. I have sourced a Dodge omni manifold from the 1.7 with a holley 5200 carb (weber 32/36) because all of the CIS stuff is not there/functioning anymore. My plan is to rip off all remaining CIS components and install omni intake and carb. Only question I had was about ignition. I assume, since it's knock sensing, that it has some sort of ECU so i would need an earlier distributor and coil? Will one from a CIS+Lambda car work? So that would leave me with providing switched 12v to the + term on the coil and the choke on the carb. Then just the wire from the dist to the - side of the coil? Only sensors left should hook to my diesel harness...correct? Any/all help is appreciated

    2. Member ps2375's Avatar
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      80 Rabbit(DEAD), 94 Golf
      10-05-2012 12:19 PM #2
      My 1980 Rabbit which had a points distributor and CIS basic never had any "ECU". Not a hard thing to do. For many years I always said that the radio was the "smartest" component on the entire car. Now it is on MS and runs as good as it ever has.

      As for what ign you can use, a system from an '81 will be the "breakerless" dizzy and will work. I had a "Cali" car from the 1980 model year that also had the same ign, but I think it was made "50 state" in '81.
      Tradition is the art of making the same mistake repeatedly, on purpose.

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      86 Jetta Diesel N/A
      10-05-2012 01:57 PM #3
      If i could find something like that, i would definitely snag it but early cars are hard to come by around here. Would CIS+lambda ignition work? To my understanding, lambda is just a crude o2 sensor with an ecu to control fuel. No ignition brains to my knowledge.

      On a side note, what fuel pump setup should work. I'll use the GTI's tank and pump if i can, but if not, do i just remove the pump and wire an inline electric pump (high vol, low pres)?

    4. Member ps2375's Avatar
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      10-05-2012 02:10 PM #4
      Both of the "breakerless" ones I mentioned were on CIS-Lambda cars.

      And as for a fuel pump, I would think any low press pump for a carb setup will work, you may want to think about a regulator also.
      Tradition is the art of making the same mistake repeatedly, on purpose.

    5. 10-05-2012 07:54 PM #5
      You can cut the ignition part of harness out of a junk car. harness plug from icm in rain tray 6-7 wires
      or so. dizzy w/ vacuum advance, icm, coil, ect

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      10-06-2012 02:08 PM #6
      Never having owned or worked on a Dodge Omni I can only take your word that the Volkswagen parts do match. I have seen pictures and the engine does look to use the same parts, more or less, but I will not bet my life on it. Yes, I know VW made the engines for these cars but that does not mean the “everything” is the same or will fit/work.

      Lets start from the rear and work forward. The fuel tank can be used but you will need to clean it out good due to the diesel. I don’t know what the difference is between the diesel tank level sender and the one used here on carburettor models but I’m thinking it should also work. If it turns out that it will not then either get one from Europe or use the current one. If you use the current one you will have to remove the transfer pump and extend the down pipe, plus add a strainer. The fuel return nipple on top is no problem as with some set-ups I did the carburettor had a fuel return on it (DGV may or may not) or the tube can be capped for use maybe later.

      The under car main pump is much too strong. You can get regulators which cut it down but then there is the “why”, when there are other ways which require less overstressing things and are more simple. Just ditch the entire under car pump unit and save it to sell or use later. Install a low pressure electric pump in its place, many brands out there, or install a mechanical one on the front of the engine block like the factory. The factory style mechanical pumps are about 0.25bar which is good for use with almost any carburettor. There are really a few ways to pump the fuel from the tank to the engine, cost and function will make it up to you to pick.

      The cylinder head will have to have the injector ports blocked off. The thread is 22mm if you want to look for a plug. I did find a plug that VW sold but don’t have the part number anymore or even remember just where I discovered it. There is an old trick which works just fine. Remove the brass injector insert, snap a penny into the lower plastic insert and reinstall the brass insert good and tight. Then just cap off the air shroud nipple to be sure and you’re done.

      Ignition is like the fuel pump, there are a few ways to go depending on taste, money, skills or desire. Without going into expensive set ups I figure there are three basic factory ways you can go. A point type ignition with vacuum/mechanical advance, an electronic type also with vacuum/mechanical advance or the knock sensor system. There are some European electronic systems that do not use knock sensors which are good too but would be hard to come by. Points I just can’t see anyone wanting to use, just extra work for nothing. That leaves the two electronic types which both have their good and bad sides. For 90% of the people out there I would say use the knock sensor system. It is easy to install, carefree and flexible. Mechanical is OK for the engine the distributor was set for, but most people really don’t know how to or how to correctly set a vacuum/mechanical distributor up for a particular engine. But as stated, there are more than one way to skin that cat but it depends on just what you want.

    7. Member
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      92 Jetta GLI 1.6TD Ripper (VNT20 Turbo), 86 GTI (Wolfsburg Golf), 86 Audi Coupe GT
      10-06-2012 03:34 PM #7
      Quote Originally Posted by WaterWheels View Post
      Never having owned or worked on a Dodge Omni I can only take your word that the Volkswagen parts do match. I have seen pictures and the engine does look to use the same parts, more or less, but I will not bet my life on it. Yes, I know VW made the engines for these cars but that does not mean the “everything” is the same or will fit/work.

      Lets start from the rear and work forward. The fuel tank can be used but you will need to clean it out good due to the diesel. I don’t know what the difference is between the diesel tank level sender and the one used here on carburettor models but I’m thinking it should also work. If it turns out that it will not then either get one from Europe or use the current one. If you use the current one you will have to remove the transfer pump and extend the down pipe, plus add a strainer. The fuel return nipple on top is no problem as with some set-ups I did the carburettor had a fuel return on it (DGV may or may not) or the tube can be capped for use maybe later.

      The under car main pump is much too strong. You can get regulators which cut it down but then there is the “why”, when there are other ways which require less overstressing things and are more simple. Just ditch the entire under car pump unit and save it to sell or use later. Install a low pressure electric pump in its place, many brands out there, or install a mechanical one on the front of the engine block like the factory. The factory style mechanical pumps are about 0.25bar which is good for use with almost any carburettor. There are really a few ways to pump the fuel from the tank to the engine, cost and function will make it up to you to pick.


      The cylinder head will have to have the injector ports blocked off. The thread is 22mm if you want to look for a plug. I did find a plug that VW sold but don’t have the part number anymore or even remember just where I discovered it. There is an old trick which works just fine. Remove the brass injector insert, snap a penny into the lower plastic insert and reinstall the brass insert good and tight. Then just cap off the air shroud nipple to be sure and you’re done.

      Ignition is like the fuel pump, there are a few ways to go depending on taste, money, skills or desire. Without going into expensive set ups I figure there are three basic factory ways you can go. A point type ignition with vacuum/mechanical advance, an electronic type also with vacuum/mechanical advance or the knock sensor system. There are some European electronic systems that do not use knock sensors which are good too but would be hard to come by. Points I just can’t see anyone wanting to use, just extra work for nothing. That leaves the two electronic types which both have their good and bad sides. For 90% of the people out there I would say use the knock sensor system. It is easy to install, carefree and flexible. Mechanical is OK for the engine the distributor was set for, but most people really don’t know how to or how to correctly set a vacuum/mechanical distributor up for a particular engine. But as stated, there are more than one way to skin that cat but it depends on just what you want.
      you dont ned to do squat with the fuel pickup in the tank, the diesel one is what you want when you have a carb..

      and all electronic ignitions have an ICM, even if they dont have a knock box..

      the only dizzy you can wire up with a wire from it, directly to the coil, is a points style dizzy..

      the electronic dizzys have a hall effect sensor, and need a ign module to operate..

    8. Junior Member
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      86 Jetta Diesel N/A
      10-09-2012 01:25 PM #8
      After looking at the wiring diagrams for the GTI I'll probably end up keeping the stock ignition with the knockbox. I plan on raising compression down the road so its probably best anyway. So I can just ditch the return line and run an electric pump from the engine compartment? As far as the intake manifold goes, the only issue I see is MAYBE clearance with the exhaust mani but I'm running a header anyway. As for plugging the injector holes, I'll find something with the same thread. I don't trust pennies.

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      86 Jetta Diesel N/A
      10-10-2012 09:37 PM #9
      Who makes a good, cheap (oxymoron, I know) AFR gauge and sensor? I want one that fits in the factory o2 bung.

    10. Member ps2375's Avatar
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      10-11-2012 12:01 AM #10
      Tradition is the art of making the same mistake repeatedly, on purpose.

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      86 Jetta Diesel N/A
      10-11-2012 10:26 PM #11
      Good call. Will that solid AFR gauge hook up to the factory o2?

    12. Member ps2375's Avatar
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      80 Rabbit(DEAD), 94 Golf
      10-11-2012 11:02 PM #12
      Not without a controller and it must have a wideband sensor. Get the Spartan sensor/controller to go with the gauge.
      Tradition is the art of making the same mistake repeatedly, on purpose.

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