89PalermoSHP Posted April 27, 2008 Report Share Posted April 27, 2008 After getting my wideband installed Im noticing some issues with AFR and rough running. Some factors: 1. New bosch O2(single wire installed in downpipe, wideband further down) 2. Ive tried 1G mas and the stock mas- not really any difference 3. Injectors were nice to begin with but sent to RC engineering to clean and flow 4. Checked for vac leaks, double checked, triple..... 5. Checked and rechecked intake pipe leaks. 6. Original fuel pump- I dont have a fp gauge, the clowns at the shop ran 2 year old gas through it. I have the walbro and all filters(the inner fender was replaced) but have yet to install. From a cold start it starts nice. AF of high 11' to mid 12's. Ive got the ecu checker light going and getting one blip(O2) untill full solid once warm. Once the led goes solid, the AF goes to high 14'2 to mid 15's. The motor will surge(kind of a strong word for the symptom) in the higher AF readings sounding worse than at startup. So once the ecu decides the motor is warm it runs worse. Also when revving, it will have a bit of rumble on decel. I havent taken it on the road as the last time it was hitting 16-17's on the AFR gauge. Mike C. has suggested a narrowband gauge or check the o2 sensor with a multimeter. I have 2 good O2 sensors and have the same issue with both so I suspect its not the issue. I am also not getting any ecu error codes from it. Is the fuel pump the first logical step? Other things I should be looking at? Thank you Link to comment Share on other sites More sharing options...
emagdnim Posted April 27, 2008 Report Share Posted April 27, 2008 It would either be the pump or the fuel filter... I'd try them first. Link to comment Share on other sites More sharing options...
scott87star Posted April 28, 2008 Report Share Posted April 28, 2008 I had similar issues with my '87. A also have a wide band further down the system and while most of the time the AFR's cycled around 14.7 like they should every once in awhile the motor would stumble and I could see the AFR's in the 16-17 range on the wide band. We have to smog here in Houston and when I took it in for its annual it passed low but not at a higher RPM and it barely passed on the low end, all for HC. The owner suggested the problem was a vacuum leak, which I doubted since I had recently rebuilt the throttle body and had gone through the hoses but to humor him I bought 10 feet of new line and replaced them all between the throttle body and any device or check valve. Bingo! Must have been a crack or something in the old hose 'cause it passed smog easily and never stumbles any more. My cruise control works better too. Scott Link to comment Share on other sites More sharing options...
89PalermoSHP Posted April 28, 2008 Author Report Share Posted April 28, 2008 I will go through them again. It would sure be nice if it was as easy as that. Link to comment Share on other sites More sharing options...
patra_is_here Posted April 28, 2008 Report Share Posted April 28, 2008 hey man, just a couple of simple things to check, because i've had similar issues: check the ground on the intake manifold. check the narrowband with a multimeter if you still have some smog equipment all hooked up, then that could be contributing, especially if you're getting a sticking EGR. some of the smog items on these cars are temperature referenced. also, check to see if your BOV is cracking at idle. Link to comment Share on other sites More sharing options...
89PalermoSHP Posted April 29, 2008 Author Report Share Posted April 29, 2008 Im going to post a few pics hopefully by the weekend and see what items I can/should get rid of. As of the moment I dont have the fresh air box, I have the charcoal canister disconnected at the turbo(and plugged) but still hooked up to the things on the intake. There probably a good chance one or more of those things could be contributing. Link to comment Share on other sites More sharing options...
patra_is_here Posted April 29, 2008 Report Share Posted April 29, 2008 well, a malfunction EGR valve would cause similar issues Link to comment Share on other sites More sharing options...
Recommended Posts