I've got a 4.8l engine in my project truck. I just finished wiring it back up Friday and it fired right up. I started it for about 30 seconds maybe 4 times on Saturday. It now will not start. It will crank and every now and then a partial fire but will not run. I added some new fuel to my fuel cell because what was in there was kind of old (last sept). This has been a cab off build and i just put the cab on the other day. Its got me confused because it was running and now will not. Its show fuel pressure on the gauge (around 60) and i can hear the external pump working.

Last year i but a cam, headers, ls1 intake manifold, blackbear tune, exhaust, slp valve springs etc and had it running. Then tore it apart and now trying to get it back together. Please help if you have any ideas / suggestions!

 

do you have a tune for the cam?

 

Sounds like you're getting fuel, how's the spark? Plugs fouled, coils plugged in, crank sensor, cam sensor plugged in?

Check and make sure that you don't have any blown fuses too...

 

Yes i do.

The truck ran and drove last year but hasnt been started since september 09. I put it all back together and started it about 4 times but now it wont start.

 

Might have bad gas...9/09 isn't that long, but if it was crappy gas to begin with, sitting around may have allowed the bad stuff that's in it to separate, and that may be what the fuel pump pickup is sucking in...

 

possible vats issue?

 

I'm not sure. I remember last year when i was firing the motor up for the first time i had these issues and forget how i solved it lol. I did send the computer out to get a blackbear tune last year. I had him remove everything i didnt need (egr, evap, rear o2 sensors, cats, plus add the cam, headers, etc etc.)

I'm not even sure if my truck ever had the vats issues. I need to double check my grounds again tonight. I think thats what it was the last time. Does anyone know if there are any other grounds other than the on on the drivers side front of the block and then the strap coming off the back of the engine to the cab?

How should i check to see if its a VATS issue?

 

I pulled a plug this morning and noticed its a little bit wet and has some black crud build up on it. I'm gonna pull all the plugs and clean them off this evening. Hopefully this helps!

 

Also i noticed the MAP sensor was broke yesterday. I had another one laying around and put it in but it still didnt fire.

 

so you cleaned the plugs but are they firing?