LS1 starts but wont run....
Thread Starter
Teching In
Joined: Feb 2019
Posts: 8
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LS1 starts but wont run.... Aloha folks,
I know this is not a new subject..but here I am brining it up again. I have a LS1 put into my 56' chevy truck. I had a wiring harness built for it from a builder down south. I have a brand new fuel tank and pump, which seems to be working just fine. I've tested the fuel pump relay and it appears to be working as it should. ( although i did read someone suggesting its meant to be 5v from the pcm, it looks like I have 12v being sent from the computer). I have the battery ground to body, body ground to engine, engine ground to frame, harness ground to engine and PCM ground to battery.
One thing of note is that I do not currently have my MAF connected. I bent a pin connecting it, and I can't get a 150.2 terminal here in town. Its on its way but i've read it should still be able to start fine without it for the time being. I also do not have my O2 sensors connected, as its still just headers. All other sensors are connected and the engine has coolant and oil.
The fuel pump primes, then clicks off the relay until i crank it. Starts right up, sounds smooth but dies out anywhere from 1-3 seconds afterwards. Its an abrupt stop. I don't have a node light or a fuel pressure gauge at the moment...
Do you guys think have the MAF unplugged would cause this issue? I believe VATS has been turned off from the tuner who built the harness but I'm going to send him and email to confirm. I've checked the cam and crank sensors, to be sure they were connected...any thoughts?
Thanks. Matt
I know this is not a new subject..but here I am brining it up again. I have a LS1 put into my 56' chevy truck. I had a wiring harness built for it from a builder down south. I have a brand new fuel tank and pump, which seems to be working just fine. I've tested the fuel pump relay and it appears to be working as it should. ( although i did read someone suggesting its meant to be 5v from the pcm, it looks like I have 12v being sent from the computer). I have the battery ground to body, body ground to engine, engine ground to frame, harness ground to engine and PCM ground to battery.
One thing of note is that I do not currently have my MAF connected. I bent a pin connecting it, and I can't get a 150.2 terminal here in town. Its on its way but i've read it should still be able to start fine without it for the time being. I also do not have my O2 sensors connected, as its still just headers. All other sensors are connected and the engine has coolant and oil.
The fuel pump primes, then clicks off the relay until i crank it. Starts right up, sounds smooth but dies out anywhere from 1-3 seconds afterwards. Its an abrupt stop. I don't have a node light or a fuel pressure gauge at the moment...
Do you guys think have the MAF unplugged would cause this issue? I believe VATS has been turned off from the tuner who built the harness but I'm going to send him and email to confirm. I've checked the cam and crank sensors, to be sure they were connected...any thoughts?
Thanks. Matt
Thread Starter
Teching In
Joined: Feb 2019
Posts: 8
Likes: 0
Have you tried using a different vehicle to swap PCM's to reset the VATS system? Or do you suggest sending it out to get it tuned out? There are a few videos around of folks using donor vehicles or disarm the security key..
TECH Senior Member
Joined: Jun 2016
Posts: 22,295
Likes: 3,617
From: Central Cal.
In a swap situation like yours, unless you are using the same key and ignition switch that came with the car the engine came out of, you have to program it out. Call LSX Power Tuning for help on this.
Aloha folks,
I
One thing of note is that I do not currently have my MAF connected. I bent a pin connecting it, and I can't get a 150.2 terminal here in town. Its on its way but i've read it should still be able to start fine without it for the time being. I also do not have my O2 sensors connected, as its still just headers.
I
One thing of note is that I do not currently have my MAF connected. I bent a pin connecting it, and I can't get a 150.2 terminal here in town. Its on its way but i've read it should still be able to start fine without it for the time being. I also do not have my O2 sensors connected, as its still just headers.
Sounds like vats. If you never had it happen... You can't hands down say it is. Its happened to me. It'll crank up and stay running for 3 seconds and cut off like a bad pump. Everytime, instant crank and run, but cutoff in 3 seconds. Have your tuner delete the vats out asap. I suggest hiding a cutoff switch tho just for insurance.
