Hi all, this is in regards to my post on the LT1 Tech Section:

http://web.camaross.com/forums/showthread.php?t=488986

I'm a complete noob with this ECU programming stuff but sure would like to know if my computer is trying to tell me something. The Datamaster file can be found here:

http://www.autoresto.com/Files/Z28file.htm

Thanks guys!

 

Not a lot of data in there..... a couple minutes of idling, and a couple revs of the throttle. You need to log data with the engine under load - e.g actually driving it.

You still have DTC 48 for the MAF. It may be a "stored" code, because the MAF afgs numbers look relatively normal for idle RPM. You have constant knock retard of 1.0-1.5 degrees. The only time it goes away is when you opened the throttle. Is it possible you have something rattling under the engine? There is also a mysterious increase in the knock retard with it jumping up to 5.0deg around record 826. Nothing changes, but all of a sudden, the retard blips up. Can you relate that to anything you did during the data log?

You have the LT4 HOT cam, as I recall, and that would explain the MAP being 50-55kPA. Maybe a little higher than it should be.... might want to check the valve adjustment. The IAC counts are a bit high at 70+. TPS looks good for closed throttle.

One thing that is odd.... left BLM in Cell 16 is 135, but both the right BLM (long terms) and INT (short terms) seem to be locked at 128. Shouldn't happen. Both O2's seems a bit "lazy" at times. Sometimes they are cycling high and low like you would expect them to do in closed loop. But other times they just settle around a single value (+/-) and stay there for several seconds.

Again, the kind of log you made is not going to tell you much. Letting it idle and blipping the throttle doesn't really show too much.

 

Injuneer, thanks so much at taking a look at it. Do you think it would be OK to drive for a short distance? Several folks in the other thread have mentioned the valves being out of adjustment as well. I'll try and check those out over the weekend.

Oh, the blip on the retard going to 5, could it be caused by me shutting the door? If so, that might have been what happened. One more thing on the retard being at 1.0 constantly is that my exhaust (both ends of the Y-pipe) is not secure, just slipped on. I was waiting to get it running correctly before welding or clamping things tight.

Also, if I read your reply correctly you don't think my O2s are causing the popping problem?

 

Are you saying the Y-pipe is loose at the header collectors? That would be allowing air into the exhaust, which will cause the O2 sensors to indicate a false lean, and the PCM to start adding fuel the engine doesn't need. May explain why the BLM's are adding about 5% extra fuel on the left side.

 

Yes, I have a set of Pacesetter's and they just slip onto the Y. The Y also slips on the catback pipe. Nothing is clamped or welded. My O2s are before these slip on points though... that would still cause a leak? Maybe sucking air into the system?