96Formula6spd

iTrader: (7)

Hey guys I got my car running and it is running pig rich but the wideband in my car says it is leaning out. I took it up to a buddies shop and we are trying to figure out what is causing it to be dumping fuel into the engine. To start off we pulled all the plugs and they are covered in gas. All 8 not just a few. At the same time we ran a compression test. Cold test had everything around 170-180psi on all cylinders. Fuel pressure was 43.5psi. The regulator is dry and when we removed the vacuum line it jumps about 8psi. Smoke comes in puffs at idle. Smells super rich. I have an aem wideband and it says at idle its running 15-17afr. So here is a list of everything we tried and changed.

Car Specs
355 Stock Pistons, CC503 on 1.6 roller rockers, Tuned by PCM For less, Stock Injectors, Stock heads. Newer opti,new tr55 plugs and .044 gap due to the milled heads and thinner gasket.

First we thought tune so we swapped in a stock ecu. Ran a little off but the same results. Same black smoke out the back. Same afr. Ran like an untuned cc503. Pulled plugs afterwards and they had gas on them once again.

Second we tried different sensors. So we swapped mafs to a good known one. No change. We swapped maps. No change. We unplugged the coolant temp sensor. No change. Unplugged the oxygen sensors. No change. We checked all the vacuum lines and everything is good.

So we had a scan gauge on the car while we did this. Idle is set to 850 and the car idles around that. It free revs and drives fine it just keeps dumping fuel out the back. Car smells super rich. At some points you can not even stand behind it. My buddy and I are stumped. The car should not run this good and be this rich.

So I have another set of injectors and spare Fuel pressure regulator. But other than that I have no idea what could be causing the issue.

Anybody got any ideas?

IllusionalTA

iTrader: (9)

fresh build? WB02 is giving a false lean, since it can't read the unburned fuel falling out the exhaust...

tonskiguy

iTrader: (3)

If you unplugged the O2s, and there was no change, it could be that they are not doing anything. Can you monitor them with a scan tool and verify voltage fluctuations?

FAD2BLK93

Stock injectors...not enough for the 503. PCMFORLESS tuned it for them? What 24#'ers?

Rodinator1234

I had a PCM for less tune for my car 97 Camaro with a CC502, lots of other stuff but stock heads and stock injectors, car was rich as well. I went to a local shop with LT1 experience Redline in Festus MO for help, to make a long story short I ended up with 32lb bosch gen 3 injectors and a fresh new tune on there dyno. Needless to say the car runs much much better. My old Multitech's were not up to the demand. They were old and wore out. If they were new they may have been ok, but since I need to get new injectors anyway I upgraded. I don't know if this will help or not, but this is my experience. What gets me is the wide band reading lean. Is it callibrated right? Where are you putting it? Any place in the exhaust system that could be leaking could also be sucking air, which will cause it to read lean, which will make the ecm want to fatten it up. Header gaskets good? EGR blocked off, or leaking or open?

96Formula6spd

iTrader: (7)

It is fresh rebuild. Wideband is 18 inches after the y-pipe merger.

We had it on a scan gauge. They were reading between 150-800. Will try to get what that number means. Brand new GM units.

Yep stock 24lb injectors. Been sitting on and off for 3.5 years.

Brand new header gaskets. Dont hear any exhaust leaks. Egr is deleted and it has a nice gasket. I was thinking of going to 30lb injectors but the budget would not allow it. I may try swapping in a spare set or a third spare set. May try an new fpr. Bad news for lt1 tuners in the area. There is Hawks Third Gen but I have started hearing bad things from a few buddies. Other than that I don't know of anyone around who is good with lt1 cars. PCM For less had their guy move to Ohio.

FAD2BLK93

ECT reading correctly?

96Formula6spd

iTrader: (7)

If you mean Engine Coolant Temp then yes. Was sitting right around where it needed to be. Well warmed up just idling it was saying 210 on the scan gauge.

96Formula6spd

iTrader: (7)

Well after some more playing with the car it seems the rings are taking a long time to seat. We have been driving it in break in mode with lots of rpm change and engine brake. Smoke is almost gone after 150 miles. Going to keep driving it and see if it all goes away. Buddy has had this happen before on a ls1 in his race car. He went and took his car to a hill climb. Hopefully after another few miles it will be running like a champ. Need a new set of plugs tho.

matt_paco2010

iTrader: (3)

Ya don't let it load up too much or you'll wash your bores and have to start from scratch.

It almost sounds like a misfire issue, a wideband will always read lean in the event of a misfire regardless of what your fuel is doing.

If you have the tuning software try turning the o2 sensors off by setting the closed loop enable temps way high. Big cams like to fool stock o2 sensors at idle because the mixture is way off, lots of reversion in the cylinder causes plenty of fresh air and raw fuel in the exhaust. The computer tries to compensate for the false lean condition by dumping more fuel which makes it run worse. I tune with a wideband and leave the stock o2's on the shelf.

Let me know how it works out for ya

shbox

The rings are taking a long time because of the excess fuel. It is conceivable that the time for them to seat properly has passed as a result. If you are lucky, some more break-in will work it out.

96Formula6spd

iTrader: (7)

Yeah ring seating time failed but it seems to be cleaning up. My buddy had this happen to his stock ls1 car. He took it to a hill climb and beat on it all weekend. It cleaned up and has been running 2-3 years now. Hopefully it will run. All else fails I just sell it blown up.