Timing seems really off, need help!

[86LT1]

Ok so I've had my engine built for a good while now and I took it to bryan from pcm's for less to have it tuned and the computer reprogrammed because i believed the reason it was running like crap was because I had a bunk computer tuning.... but he said thats prob not the case and the reason my engine sounds like its running so shitty is because the mechanical timing is so off, which it does sound like the timing is way off. So I took off my delteq coil packs like he recommended I did, went back to my opti and ran all new wires, re-installed my ignition module, MSD coil, and fired it back up.

...Same shit, still running like garbage... it sounds like the timing is still way off, there's back pressure coming through the manifold and out of the intake, and will not idle... i have to rev it to kind of keep it going, but i immediatly wants to die. Its driving me nuts, I know I liked up the cam and the timing chain correctly... when I degreed the cam it was 1 degree retard so i left it.. the lashing on the rockers, i made snug then went a quarter turn because I planned on going back to adjust them later on.. so i didnt make them really tight. I mean I have no clue what is going on???? can anyone help me??? Um... the only parts that are not NEW are the ignition module, which came with the engine when i originally bought it.... And the opti-spark distributor( i didn't purchase new becuase I only needed it to send signal to my delteq coil pack system) But I thought if the opti wasnt working the car just wouldnt work, not make the timing go completely out of wack? I just don't know right now... i've hit a dead end. Any help, or suggestions on what I can do to figure out my problem would be awesome!! Thanks!

[MEAN LT1]

What year LT1 are you running?. If its 93-94 with the pin drive. You may have installed it incorrectly. Its not supposed to happen but its been done many times if your not cafeful.

[hempkat94z]

Shoot a video and post it on here so we can hear it. Is it throwing any codes? If you are pushing back through the intake then you sound like you are 180* out of timing. What size cam are you running? I would seriously tear it down and install the cam dot to dot and put it back together to make sure it is going to run.

[86LT1]

I'm running a 97LT1 with the 97 wiring harness and a 94 computer. The cam I installed was the LT4hotcam, and my timing chain is the LT4 heavy duty... when I installed those I made sure that the dots where lined up correctly, so I'm pretty confident that I did that correctly... but your prob right, i should tear it down and check it out. But before I go through all of that is there any sequence of things that I could check that could be causing it to go way out of timing?? the opti wouldn't be doing this would it? or the ignition module?? I mean I really don't know, this is my first LT1 / EFI motor build. But now since its running the same as it did when I had my coil packs on it leads me to believe that the coil packs weren't the problem >:-/ I spent a good bit of money on those, and now another decent amount on wires and coil.... I was shooting for the shootout in the end of may but they way things keep going for me its prob not going to happen. But if the info i just gave helps diagnose any more problems please share what you think it may be! I'll def try to get a vid on here also, and thanks for the info.

[hempkat94z]

The only other thing that I could think of would be either a vacuum line not being attached or the opti harness or the ICM. I had a strange problem when I did my most recent cam swap and it ended up being my O2 sensor. Some how I had shorted out my drivers side O2 during the cam swap and I couldn't figure out what the hell was causing the problem. It would idle but any slight throttle and it would just stumble. This went on for 2 days and damn near tore it back down but my ride didn't show up to pick me up for work so I drove the damn thing to his house spitting and sputtering all the way there. Finally it threw a code and it ended up being the O2.

Here is what I would do! Not in any special order.
Call Bryan and have him send me another computer and send yours back. just to make sure that is not the problem
Since you did the OBD II to OBD I swap make sure all is good there. If all checks out good.
Check all vacuum lines. If all checks out good.
Check all sensors by hooking it up to a good scanner that reads all the voltages of each sensor. And if that checks out good.
Tear it down and start over. I hate to tell you that but if all the sensors and computer are reading fine then it has to be mechanical so you would need to do it again.

[JAKEJR]

One of the easiest things to check is the routing of the spark plug wires. Since the numbers are on the backside of the Opti, it's pretty easy to cross two wires.

I remember a long while back, I crossed 2 and 4 and had the same back-firing through the intake. I knew as soon as it popped what the problem was and swapping those two wires fixed it.

I recall reading some other posts recently on another Forum where the original poster had the same problem and was pulling out his hair. Turned out he had routed one of his plug wires near the ignition module which caused his problem. Voltage from the plug wire was screwing up the module's function.

Hope this helps.

Jake

West Point ROCKS!

[86LT1]

well thanks a lot for the your help, I'm gonna go through everything like you guys mentioned, call bryan get another pcm and then if all else fails start taking apart the motor... I hope i screwed up a wire haha, but thanks again for your thoughts.