Posts like a 4 Banger
Join Date: Aug 2007
Location: South Jersey/NYC
Running lean after overhaul
So, after three months of on and off, I got my 3.8 NA '99 Bonne SLE put back together.
The problem began after the car blew out a radiator hose and then started misfiring and kicking out white smoke.
I was unsure if it was blown head gasket or LIM/UIM, but at the advice here, I started off on a voyage to replace the LIM/UIM. Here'* what was replaced...
Fuel regulator, PVC valve, MAP, LIM/UIM gaskets, Dorman upper intake manifold with ZZP HV3 insert, ZZP stage 1 throttle body and sensors, air filter, ECT, water pump, radiator hoses, coolant elbows, serpentine belt, front and rear transmission mounts, fuel filter, spark plugs, spark plug wires, front and rear O2 sensors, oil filter, oil, antifreeze (non-dex Prestone mix-with-anything), tranny filter, tranny fluid, engine oil pan gasket, tie rod end and a starter.
The starter, serp belt and radiator hoses were actually replaced right before the misfire started. The car had gone a LONG time without a full tuneup, as I was unable to get the spark plug wires and fuel filter off. The spark plugs had 193K on them, and looked brand new. The O2 sensors also had 193K on them... but they were toast, even though they still functioned. Many of the other parts (water pump, MAP, ECT) were replaced proactively, as I was right there. The oil and pan needed removal since I dumped a pint of coolant into the pan while removing the intake. My oil pan gasket was toast, anyway.
During the overhaul, I discovered fuel in the fuel regulator vacuum line, which is what I suspected was causing the misfires... in any case, it was obvious that the fuel regulator had to go.
During the overhaul, my old intake and throttle body were completely gummed up. Seeking a little upgrade, I got the ZZP HV3 intake insert and a stage 1 throttle body, which is hogged out slightly... and more importantly, was not full of tar. While replacing the LIM/UIM, I blocked off the throttle body intake passages with plugs and JB Weld.
Due to the HUGE pile of parts coming and going, I did bonehead a thing or two... I forgot to replace the EGR stovepipe... but I am not too worried about this at this point, since I blocked off the coolant. I also neglected to use the included fuel injector sleeves and O rings. These must have slipped under the box flaps, so I bought my own O-rings and reused the sleeves. I also didn't replace the rear vacuum port (to the power brakes) on the UIM, reusing the old.
So, once starting the car, I immediately got a P0336 and a CEL. Also, the car wouldn't idle below 800 rpm. I thought these were related, so I traced the wires from the crank sensor to the ICM and finally found I had accidentally crushed a pin in a connector. Once fixed, the CEL went away... but the car still stalls below 800 rpm. While idling the car, I got a P0171 pending... but it hasn't triggered the CEL yet. I did notice the fuel trim being highish.
This has led me to suspect a vacuum leak... but using propane to search for a leak came up with nothing... so I'm stumped. I thought the HV3 or stage 1 throttle body might have something to do with it, but they aren't introducing more unmetered air, so I can't imagine they are the problem.
Otherwise, the car runs nice. It'* a LOT more responsive... and I would say that there is a 5-8% power increase using the seat-of-your-pants dyno. It idles once the car warms up, and I suppose it will idle once it gets warmer (it has been fairly cold at the Jersey Shore). It'* almost as if the choke was broken... _if_ the car had a choke.
I would normally accept this kind of behavior from a '74 Nova... but not a fuel injected '99 Bonne.
Any ideas would be appreciated.