aarroyo87

The problem came back after I just got back the exhaust shop. I have an old opti that I had from before I rebuilt the engine. It was working fine before so I'm going to see if my ebay opti is the problem. This is driving me nuts.

aarroyo87

just pulled the opti out in an hour and 1:15 minutes. It really is a f'd design to have thewater pumpover the distributor. The plug wires are tough to pull off causeof the slime thecoolantleaves behind.

aarroyo87

Got theold opti in, I'm waiting for the rain to stop for a test drive.

aarroyo87

Even the old opti is giving me the same symptoms. Can anyone recommend a great LT1 mechanic in the San Francisco Bay Area?

aarroyo87

I drove the car over and over to kind of get a better feel for the problem. I noticed the old opti smoothed out the motor, I kind of feels like the motor lost compression. The new opti gave me a feeling that I could feel every combustion in every cylinder. Anyways, I was reading about vacuum leaks and I think I have conducted my test incorrectly. From what I hear, fuel injected engines need to be tested with the IAC disconnected. Makes sense so i going to retest for vacuum leaks.

ss.slp.ls1

iTrader: (36)

I would see how the car runs after you readjust the rockers and get those AC Delco o2's installed.

A new opti harness might be worth a shot.

Also if you are concerned about compression, you can perform a compression and leak down test.

Also if you are concerned with compression, you can perform a compression and leak down test. (after you readjust the valves)

aarroyo87

I put the new AC delcom O2 in and it did not help.
I changed the Opti harness and no helpy neither.
I'm not concerned about compression. The motor is rebuilt and runs strong while the RPMs are up. I'm datalogging today and noticed the car runs stumblesand evetually dies once it goes into closed loop. The INT go down to the 70's on both sides right before the car dies. I can smell the raw gas fumes. I'm wondering why it would run rich in closed loop.

quik95lt1

iTrader: (7)

Like I said earlier I am leaning to a problem in the tune. I have seen alot of mail order tunes that run decent on the throttle but idle like absolute garbage. If you are cammed you are idleing in a different region of the VE table and the BLM's are going to respond differently to the vacuum change. You could also be in some type of engine protection/cat overtemp mode which will default to 11.7 AFR. I'd call your tuner back.

aarroyo87

I just emailed my tuner and attached the data log. I refered him to the records that show exactly what happens and when it happens. I'm going to anohter tuner on Thursday.

aarroyo87

I dropped the car off at NextGen Auto Sports in Hayward CA. They are going to Dyno diagnose the car. The bummer is that they can't touch it for a week or 2 because they are swamped with work. I'll get back to the forum as soon as I have some more info.

Tic Tock, Tic Tock...

aarroyo87

quik95lt1 - you were right, it was the mail order tune. I had the car dyno tuned and now it run great. ($450) I could not really get any street time cause it was raining and i would just spin my tires. I pulled a 310 rwhp and I'm 50 hp short of my goal. I'm running a b body maf and 3 inch intake tubing. The tuner said that to go with a f body maf and 3.5 inch intake tubing. Thanks everyone for the help. I'm going to try to get my money back from the mail order tuner.