xomega

oh lt1 gods. move this to where this post needs to be. i did a project swap. a lt1 in a thirdgen w/ 4l60e. the harness was for a 4l60e also. i sent the pcm to be programed due to it having vats on it. so i recieved it back. put it in. car starts. sounds awesome in neutral. idles good. soon as i drop it into gear it goes awall. the car miss's looses power and shakes the whole car for exactly 30 seconds. then it picks back up. then ill give it gas while in gear and it falls on its face again for another 30 seconds. i tried to wire up the obd2 port. took a scanner and scanned it. <cannot communicate with vehicle> i checked 4 times i have everything wired right. all the way down to the obd2 port. ive also pulled the fuelrail. all injectors are pulsing. i saw a mist and noid lights dont lie i have 42 psi of gas pressure in drive and neutral. help guys. really i need help here btw. there is no 02 sensors in the car. but i have been ready the car will run fine w/o o2s on a cold start up. and even on a cold start up it does the same thing. the guy doing the tuning said he programed it for a 700r4 instead of a 4l60e. dont know why. but i unplugged the 12/13 plug and same deal. he said it ran perfect in his lt1/6speed. ive been searching for 3 days for someone with a lt1/4l60e car to plug it into <pcm> but icant find one. and im not about to stand outside autozone flashing a pcm in the air until someone stops

imnotplutonium

iTrader: (4)

wow that sucks man, hope you can find some help

crAzy95Z28

iTrader: (3)

maybe ur MAP sensor is out. I notice that when i put the car in drive it would start to bog and do like ur saying, then in nuetral nothing would happen.

Check out ur MAP though and take it to autozone and have them test it.

xomega

its odd. now i start the car and put it into gear and can drive it without problems. then sometimes it still acts up. its like something was stuck and its slowly working loose. the engine hadnt been started in a while for it was a project car. im going to check the iac. would i iac cause this issue too?

96SCTA

does not seem to sound like an iac problem. If it was the iac ur idel would be messed all up and not recover properly from a rev. Maybe map sensor.

sevanseriesta

iTrader: (34)

Sounds like a PCM ground. If it is not grounder properly it will act like that. What I would do is attach a wire to the pcm and the attach it to the body. Take it out and see if all is good. Easy quick fix, if this is the case

xomega

ive read posts on other sites where when they did a lt1 swap <into a non stock lt1car>the car ran like crap until the pcm was properly tuned. does this sound true?.

sevanseriesta

iTrader: (34)

The only way that would be the case is if the pcm was for a auto on a stick car or vice versa. Automatic pcm's run on a different frequency and will not run 100%. Could be the case. Try the ground thing first will be a much cheaper fix just to try it.

TwoFast4Lv

iTrader: (8)

You NEED to get it programed for a A4. I have not done many conversions. The M6 uses different sensors and solenoids. it may be getting screwed up signals and causing the issues. I would also get the O2s in.

Gotta take care of the little stuff first and then see what you are left with. until all that is right it is a guessing game

BTW make SURE all the proper grounds are installed or you will have lots of problems!

xomega

thanks for the support i have a pcm pinout from shbox.com and ive took my voltmeter. from the battery + to each ground on the harness's that plug into the pcm each ground wire has 12.4 volts on them
also. i just purchased my ypipe. ill be using my hedman shortys and well the hedman y pipe for it. if you run a lt1 with just shorty headers will it do anything to the knock sensor? like make your timing retard?

gnomee

iTrader: (16)

I had a friend who did the same thing except he kept the 700r4. He had the same issue and it had to do with the shifter not telling the pcm it was in gear. I don't know much more than that, but when he fixed that it worked fine.