I have never had a problem getting an ls1 to run but this one has just got me whipped! The car will start on the first or second hit and rev to about 1700 or 1800 rpm from my log and then just shut off. And it does this every time. Everything is always the same about where it idles to and where it shuts off at. The car is getting fuel and fire %100 positive. Ive checked every fuse in the car, changed the tps (because last time it did this same exact thing I replaced it and it fired rite up) no misfires or nothing. It acts like something just shuts the car off after it fires. Ive even done a full write on the computer just to make sure the tune was in it and nothing changed. I just had the car running perfect two weeks ago and then I come back to trim on my hood and work on it some and then I go to start the car and this happens. Just dont make sense to me. Could a cam or crank sensor cause this? Any suggestions would be great because I have no clue where to go from here.

 

wow, that sounds like the same issue with my ls1 ta. It idles fine for about 10 secs then shuts off. cranks up fie every time, but shuts off. I was told to check the crankshaft sensor. But it is also just got the pcm reflashed so i'm assuming the tuning would have been deleted. probably didn't help you much..

 

Well mine won't even idle for 2 seconds. It just hits enough to rev to about 1700 rpm and then just shuts off. No matter how much gas I give it to keep it going changes nothing. So idk. Really starting to frustrate me!

 

I have a couple of questions about your tune

What tuning software are you using?
Are you running a SD Tune or are you using the MAF sensor?

I ran into a similar problem and it turned out to be that the DTC for the MAF was set not to report. The ECU will try to use the MAF even though it was not plugged in.

 

Had a car (today actually) that did this after a cam swap and did exactly the same thing... turned out to be the ignition relay.

 

Im using hptuners and it is a SD tune. None of the MAF codes are set to not report, Just set for no MIL light.

 

I def need to check that because that is one thing I havent checked. Ill be back in town on tuesday and will check this and let you all know. Thanks

Darren

 

set to fail on first error, uncheck the SES. Goto the MAF table and zero the whole thing. In the BOTTOM cell (1500Hz) and put in like 12.5 to 13g (not lbs). That will keep the car running until it fails the MAF and rule out that issue. It's good practice for SD in general... some GTOs in particular can be a little slow to fail their MAFs.

 

Going to the shop tomorrow and already changed what you told me and saved it and getting a ignition relay. Thanks again for all the help and ill let you know what happens.

 

Ok so Frost I done what you told me with the MAF set to fail on first error and unchecked the ses and then put 12.5 in the maf table under 1500hz and it fired rite up. So my question to you is why did it fire when I done this? I have ran the car the previous way it was set up for 2 years and no problems so why now all of a sudden did I have to do this?

 

Every now and then some OS's decide that they don't want to fail the MAF as they should or either the MAF should be failed but the DTC's don't set and it is still referenced. Setting up the DTC's like that make it fail pretty quickly. Putting 12.5g in the bottom of the MAF table is so that if it doesn't fail the MAF right away as it should, the car gets enough fueling to idle (from that 12.5g 0Hz cell) until it will properly fail the MAF as it should.