sunsetorange

iTrader: (1)

Like I stated, the motor will fire but not run. Shuts down as soon as it fires. I know the common thing is VATs but that should have been shut down. Key word, should. I have power everywhere, good grounding, cleaned my injectors last night.... After cleaning the injectors I can now hear the cylinders firing.

Any help would be very much appreciated.

Thanks,
Nick

severous01

check signal from crank sensor. no crank signal, no fire.

sunsetorange

iTrader: (1)

Not the crank sensor because it fires. I unplugged it to verify.

busta9876

iTrader: (3)

check for vacuum leaks, back of intake is port for power booster..if open , could cause issue after startup. Try unplugging the mass airflow sensor, see if it will run...

sunsetorange

iTrader: (1)

Vacuum is all hooked up. When I tried firing the first time I did not have a MAF wired up because the guy I got the motor from cut out a chunk of wires. I do have one hooked up now though.

sunsetorange

iTrader: (1)

From what I have been reading it almost sounds like VATS but like I said, it SHOULD have been disabled. Is there anything else that would give it similar symptoms where it fires for a second but won't continue to run? Any sensor that that would prevent it from running? Besides crank sensor... thanks

57 Black Widow

iTrader: (1)

I just read a post where some injectors that had been sitting for a while caused this kind of behavior. Might try soaking them in injector cleaner for a bit and try again.

Jake

LS1MCSS

iTrader: (18)

I think you're right about SHOULD being the key word. I don't think vats is turned off.

65panel5.3

check power etc to the coils or injectors while somebody else tries to start it. see if your losing power when the vehicle shuts down. if not possibly a fuel pressure issue or the pump not running when key is on or in the crank position

fmowry

iTrader: (14)

That's what I was going to say. FP relay not firing after the car starts, killing the pump.

Do you have a simple Bosch relay wired as posted in the swap wiring diagrams in the stickies (somewhere)?

Old Geezer

iTrader: (3)

PCM power is on both start and run circuits?? If not, it'll start and then die as soon as the key is released....

sunsetorange

iTrader: (1)

I have power in both run and start for my coils and injectors. PCM has constant power. Fuel pump turns on when in run and pressures up then kicks on again as it starts. Fuel pump signal is coming from PCM. It is firing on all cylinders when it does start but just wont stay running. For a second it sounds damn healthy without any exhaust on it

ghettocruiser

iTrader: (17)

I had vats "tuned out" while the motor was in the original car. It was supposedly all turned off and ready to go. But my first start was plagued by the run/shut off issue. I wanted to confirm it was VATs because I had checked a bunch of other stuff out with no conclusion.

I didnt feel like waiting for a VATS bypass box to check, so I went to radioshack and bought everything I need to make one for less than $20. Bout 20 minutes to put it together, hooked it up, and viola. She fired and ran. So then I KNEW it was VATs.

I chose to buy a pre-made, smaller bypass. Mine was hacked together because I was in a hurry. Later I had the VATs tuned out again and this time it stuck. Funny thing with my car...sometimes it would run without the bypass...sometimes it wouldnt. It was weird. Until I got it tuned then it stayed off.

Here's the thread I made about building the bypass if you want to give it a try. Should have all the info you need.

https://ls1tech.com/forums/conversio...ypass-box.html

Justin