hey, so I have kind of a weird issue. I read up on all the common opti symptoms and I'm not sure that mine fits in there.

Background - Just put this 93 383 into my 94 this spring and have about 5000 miles on it...about 1500 miles ago the SES light started coming on when I got up to highway speeds (it would NEVER come on if i didn't go about ~45) so I tried to get the codes but it never worked and i just got an error. I talked to someone about it and was told it was prolly something to do with the AIR delete (not sure).
Also, since the motor swap @ WOT there is a ton of black smoke...assuming I am running rich, I am hooking up a wide band to check A/F and then get a good tune.

Problem - So now, the first time I start my car in the day it will run perfect. No stalls, idle is good and it pulls w/o hesitation all the way through. I can drive it for 3 hours in the city and on the highway w/o any problems. Once I shut the car off and let it sit for about an hour and start it back up, all hell breaks loose. It dies at stop lights, backfires under load and the idle varies from 900-1100 rpms.

So with this being a new problem, so far I have only changed the plugs and wires. After looking, the water pump is leaking for sure (onto the opti obviously) and that seems to be the only leak I have and that is being replaced. I just don't understand how it can work perfect and then once it sits it breaks.

I want to get the car tuned within a few weeks but I need it to be running good for that. I understand that its hard to diagnose an untuned car, but I just want some input for ideas on where to start to fix/find this issue.

Thanks in advance and I'm sure I have forgetting important information that you guys need to help me so just ask and I will do my best to answer it.

GM847 Cam, Eagle Crank, Eagle Rods, SRP Forged Pistons, 1.6 Roller Rockers, Comp Srings, 42lb Injectors, LPE CAI, Full Exhaust, PCM tune

 

Are you running the 93 engine speed-density on the 93 ECM, or are you using an MAF sensor with the 94 PCM? You need to get the code(s) and which computer you are using determines how you pull them.

 

MAF Sensor w/ the PCM. Yeah, before the motor swap I was able to get codes and now I can't.

 

94 PCM, right?

How did you try and pull the codes? What worked in the past?

 

I would just go to ORielys and plug it in. It worked great...but now its like it doesn't recognize the car.

I guess Im curious to know why it would run fine forever, but then if you shut it off and let it sit it gets really ****ty

 

So I think that the water pump may be leaking on the opti after I shut it off and then when i try to start it again...the opti is wet and there is a misfire. Can an opti cause a backfire like that tho?