I'm about 1600 miles into my rebuild so I decided to check the spark plugs for the first time after the rebuild. They were very black and sooty (but not wet) with carbon buildup as thick as a fingernail.

The oil was changed at 500 mile intervals after the rebuild.

I know I was running rich before the rebuild because the car literally burned off the mufflers and when I was driving around without mufflers there was the pop on shifts.

Now after the rebuild it seems I am still running rich. I checked the timing and it was right, for stock at least. I have a small streetport on my rebuid so I don't know how much that would effect timing. I checked my TPS and it was at 1.5k so I readjusted it to 1k. I drove around and adjusted it again. Few days later I checked it and made a minor adjustment to get it closer to 1k. I also checked the oxygen sensor and it was within spec.

When I start it up after the engine has cooled down it will go down to 200 or 300 rpm and bounce around and it seems like its trying to get itself going but it will die. I can hit the gas and it will be fine. Sometimes it will jump around idling between 1000-1500 and then gradually come down as it warms. Once its warm the idle is pretty steady, but if I'm coming up to a stop light and push in the clutch the rpms will drop to 400 or 500 and the car will shake a little. When I'm driving the car I can just feel that it is not operating as efficiently as it should. It runs like all the descriptions I've read of an engine running rich.

I can't think of anything else to check to prevent against running rich since I have the timing and TPS set right. I don't want to keep running rich because I'm almost certain that's what caused me to have to get a rebuild in the first place. Any help would be greatly appreciated.

 

No check codes?

Many possibilities - a bad temp sensor comes to mind.

 

S5 NA. Only time I see the check engine light come on is when I put the key in.

 

Stock pump, injectors? Were the injectors serviced at the rebuild? Have you played with the idle adjust screw at all? Is the BAC system still installed? Have you played with the idle mixture adjustment at all? What's the compression #'s now after 1600 miles?

 

Stock pump and injectors. Injectors not serviced. I don't know the condition of the injectors. I've never looked at them since I've had the car. I've changed the adjust screw on top of the throttlebody if that's what you're talking about but not since the rebuild. Pretty sure BAC system is still installed. I had some emissions removed during rebuild but it was never really specified what was removed. I just said remove whatever to supplement the streetport. I'm not sure about the idle mixture adjustment, unless that's what you turn to tune the TPS. I haven't checked compression numbers.

 

Any more ideas on this?

 

Could this be a thermo wax problem? Stuck injector? Help me out here

 

if it were a stuck injector the car would be running on 1 rotor. it oculd be slightly clogged, but i doubt thats the case.

actually my rebuild was doing this and i found several small vacuum leaks which i am currently fixing (lim, uim gaskets) also, i would do the throttle body mod while you're troubleshooting just to rule out the whole thermowax deal.

just my 2cents

 

Running rich will foul plugs, but shouldn't kill the motor.

The BAC is your main electronic idle control.
I'd start with a search on "BAC + test + clean"
Also check the fuel & emmissions section in the on-line manuals at the link in my sig below.

 

As just a temporary patch, you can wire a ground wire & switch to the AWS solenoid o kick up the idle.

 

Running extraordinarily rich (like being WAY over rich on a standalone) will shorten engine life. I don't think there is anyway to do this with the stock fuel system/management.

 

not to hijack this thread but is there anyway to run too lean on stock injection? my motor is now toast, I believe in part to not having functioning secondaries. The car would rev up to around3800 ~ 4000rpm and depending on load, it would just studder and not rev, bucking all the way. now the car doesn't start hot and I am rebuilding this weekend. the car also has no emissions of any kind, straight exhaust with only one muffler, header, slightly ported intake manifold, K&N, throttle body mod/porting, and 5th & 6th tied open/ soon to be gone. Do I ever need MORE fuel?