hey i'm back again for more update. after the car got running and such, i decided to pull a plug and see how it was running. for the plugs to be completely black, no color at all. running super rich. tore down where the injectors sit and found that the plastic piece that snaps onto the brass fitting, some of them had cracks and the seals right there also were bad(remember i had machine work done a while ago). needless to say they should have fix that portion of the head also so i wouldn't have to do this. so i got new plastic inserts and all new injectors(cause of age) and all seals and tonight i will install to see if that will eliminate and air leak at the injectors since it seems like that might have been part of the problem why it was running like junk. also i have the tt race header on it and had to extend the o2 sensor wire with a butt connector. i will solder this tonight also. any input would be great in solving this massive headache
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85 jetta running rich
- Thread starter jetta87
- Start date
Bill Miller
New member
If the injector cups/seals are bad/leaking, I'd expect the car to run lean (extra air) rather than rich. Replacing them is a good thing, but I don't think that's the source of your running rich problem. New injectors may clear up the problem, but did you check the spray pattern on the old injectors? They may have been leaky, or had a poor spray pattern, which could cause a rich condition.
i did not get a chance to check them before i pulled them out, but when i oput them in i took the best out of 8 injectors cause i have 2 motors. i again shouldnt have done that in the begining,yes they could have been leaking. and i hardly dought the fuel box would be out of adj since it hasnt been touched since 85 and i daily drove this car for a while.
If the injector cups/seals are bad/leaking, I'd expect the car to run lean (extra air) rather than rich.
True, until the ECU corrects for the extra air, when it sees constant lean O2 sensor reading, and starts dumping in fuel to maintain stoich when in closed loop. One reported telltale for unmetered air leaks is the MFA fuel economy not matching up to actual fuel economy.