I installed a LS3 in my impala. she turned off fine with no problem the first time i crunk her. now that i have put her all the way together she had no fuel pressor and she wouldnt stay running. so i disconnected the MAF and she runs like a champ. so i went and bought a new MAF ancd still had the same problem with the new as well as the last one. has anybody ran into this problem before? what should i do?

 

Might want to re-read what you wrote and word it so people can understand it.
It turned off fine? Or do you mean it fired up fine?


How do you have the fuel system wired? through a LS1 PCM? Need some more details.

 

sorry about that. no through an LS3 PCM. she runs fine without the MAF connected but once i connect the MAF it wants to cut off. so i disconnected it and she runs strong.

 

Last time I had this problem it was because the MAF was installed backwards.

 

MAF is in right. anything else you can think of?

 

The explanation doesn't make sense to me. Why would
the MAF affect fuel pressure? Or did it, even?

Maybe MAF faulted, speed density mode simply plays
better with the whacked fuel pressure situation. Get
to where you -know- the fuel pressure is right, and
then worry about sensor accuracy.

 

What is your fuel pressure when it runs fine (without the MAF)...?

Does your fuel pressure regulator have a manifold hose...? If so, pull it off the FPR and see if it is wet with gas in there.

 

a friend of mine came by today and pluged up its laptop and checked the ecm and he told me that its running an open loop somewhere. when the car is turned on it should have a closed loop. he said it could be an O2. he thinking that the ecm is looking for 4 and it only 2 im running. and that the timing is going crazy. he going to look more into it. but he said that the MAF is working fine nothings wrong with it.

 

Engines will always run OL initially until you get some heat into the exhaust where the o2's can operate accuratly.

 

Any way you can have him pull the codes it is throwing and post them. They will give us a better idea of what the problem might be. Is the PCM you are using the one that was origianlly used to run the motor or did you buy it seperate?

 

its throwing out alot of codes. here they go P0102, P0113, P0352, P0354, P0356, P0358, P0650, P1516, P2101 & P0300.