Car shuts off and won't start back up.

**Dozier** · 02-17-2010, 04:13 PM

Ok, so I have an ls1 with ls6 heads and intake manifold. Lots of bolt one and a good tune. Also have bigger injectors and 255 fuel pump.

Was driving down the road day before yesterday when the car sputtered a little bit. I kept driving and though...that was funny. I get another half mile down the road and it sputtered again. I down shifted and hit the gas and it was fine. So I continue driving and get another half mile and the car started to sputter bad like it was out of gas, then it shut off. I pull over and tried to start it up and it cranked right back up. So i start driving to the nearest autoparts store which was oreillys. Before I get there the car shut off again and I had enough momentum to coast in. So I parked and went in to borrow a obdii code reader. I tested and it pulled 14 trouble codes. Most were there from the motor being originally auto and it was switched to manual, and also going fro
a chevy car to Nissan 240sx. So I cleared the codes out and tried to start the car. It fires up for about five seconds and shuts off. I checked the codes again...nohing wrong. I turn the key on to listen for the fuel pump. I can hear it. I took off the fuel filter to check for clogs. Everything fine. There is pressure too. I got the car towed to myocal shop and the next day, they had a chance to look at it. He cranked it up and it ran fine. I said no way. Asked if he drove it and he said no. So I came down there and drove the car down the road and back. I was just about to leave while the car was idling, when it started to sputter again and it fell on it's face and shut off again. I have no clue what is going on. Someone said that the fuel pump could be going out. They said to check the pressure with a gauge because ls motors need 60-70 psi of fuel pressure to run or something. Supposedly it could be dropping to around 20 or so when it shuts off. Because you can still hear the pump running when the car shuts off.

Today I tested with a fuel gauge on the fuel rail to check the pressure. It stays at 56-57 psi. When it dies, it goes up to 60 psi. I have no clue what is going on. Pressure is fine.

Any input or suggestions are greatly appreciated as this is my daily driver and need to get it back on the road. Thanks.

Adam

**0rion** · 02-17-2010, 04:27 PM

man....that really sounded like a fuel pump failing after it heats up until I saw your pressures. Pressure should be around ~58psi so it sounds like you're fine there. This is a transplant motor I take it. Might be tough to nail down if it's a loose wire or something like that but just start trouble shooting the car. Sounds like you've verified fuel pressure and that the pressure stays up even as it's dying? Check your spark next to make sure it has spark when it dies and won't start. I'm assuming vats has all been taken care of on it?

**Cutlass** · 02-17-2010, 06:58 PM

crank position sensor?

**0rion** · 02-17-2010, 07:23 PM

Originally Posted by Cutlass

crank position sensor?

I was kinda thinking that too or the camshaft position sensor. Could be the ignition relay too I guess. Checking for spark should at least start him on a path.

**Dozier** · 02-18-2010, 05:13 AM

Ok...I will check for spark today. I will post up results in a little while.

Yes it is a transplant into a 91 Nissan 240sx. Car has run problem free for about three months now. VATS has been disabled. Fuel pressure is pretty much the same when it dies.

**KP1** · 02-18-2010, 05:27 AM

If you have a problem with the oil pressure sending unit signal to the computer I believe it will cut fuel & shut down.

**SteveC** · 02-18-2010, 06:01 AM

Originally Posted by Cutlass

crank position sensor?

Nope, the vehicle will still run with this sensor going bad, you will just be in "limp mode" firing left bank and right bank. You will get a flashing SES light on this one, and throw a P1336.

Originally Posted by 0rion

I was kinda thinking that too or the camshaft position sensor.

A bad camshaft sensor will still let the engine run, however in my case the tach not working was the first sign of this. I had a solid SES light and I threw a P0343, and was running in limp mode.

SteveC

**Danger731** · 02-18-2010, 06:14 AM

Originally Posted by SteveC

Nope, the vehicle will still run with this sensor going bad, you will just be in "limp mode" firing left bank and right bank. You will get a flashing SES light on this one, and throw a P1336.

A bad camshaft sensor will still let the engine run, however in my case the tach not working was the first sign of this. I had a solid SES light and I threw a P0343, and was running in limp mode.

SteveC

INCORRECT !

If the CPS goes out it will not run, been there ! 60 dollar part 20 minutes of work.

http://www.ls1.com/forums/showthread.php?t=127798

**NoscamaroSS** · 02-18-2010, 08:19 AM

^^^I might run like crap but it will run with a bad crankshaft position sensor.

**Danger731** · 02-18-2010, 08:31 AM

So if you disconnect it the car will start ? hmmm...

**Dozier** · 02-18-2010, 03:23 PM

I checked for spark today and once the car died, there is no more spark. When trying to crank, there is nothing. I pulled a few codes the first time the car stopped running and wrote them down. Then I cleared them all and the only one that keeps popping up is this one...

P0452
Evaporative Emission Control System Pressure Sensor

I know that will have nothing to do with the car running though. However there were about 14 total trouble codes. Most of them were related to the transmission, fans, 02 sensors. The car was originally automatic. 02s were tuned out, and fans are hard wired to a switch.

It did bring up the Crankshaft position sensor P0336. So today I replaced that sensor, and the problem is still the same. No difference. I am baffled.

**Dozier** · 02-18-2010, 03:25 PM

Ok, so I should probably check the oil pressure sending unit?

**knappbunch** · 02-18-2010, 03:54 PM

Mine did the same thing and it was the holley wanna be Chinese walbro that failed when it got warm put in a new walbro! An actual walbro been fine ever since!

**cammed goat** · 02-18-2010, 04:04 PM

This sounds like my old Beretta. My car would run fine cold but when it got warm, it would die. Turned out I had a broken ignition module harness that would wiggle loose and cause the car to die.

**Cutlass** · 02-18-2010, 05:10 PM

Originally Posted by Dozier

I am baffled.

Don't give up yet. We're making progress, we're chasing a no spark. One quick, easy check is to check for power and ground to the ignition coils on both
banks. Its the pink and black wires. Mostly likely thats not it but its gotta be checked.
Essentially all you need for spark is a crank position sensor, pcm, ign coil power and ground, and the wiring in between all this stuff.
What year and model is this LS1, wiring harness, and computer out of?

**Dozier** · 02-18-2010, 07:54 PM

The block is 98. Heads and intake along with other parts are 99-02 model stuff. I think the PCM is a 98 also. Not sure though. I will find out tomorrow.

**0rion** · 02-18-2010, 09:14 PM

I'm going ignition relay Regis.......final answer.

The only thing that worries me is the transplant part of it.....huge chance for a loose or chaffed wire but I'm still saying ignition relay because it's common and cheap.

**Dozier** · 02-19-2010, 06:18 AM

I will check today and post up the results.

**Hi-Po** · 02-19-2010, 08:37 AM

Im going to throw this out there, someone correct me as/if needed.

That P0336 code being thrown most likely has something to do with your problem.

You have a block/crank out of a 98 correct? But your not sure what year PCM you have? When replacing the CKP sensor, is a relearn not a necessity? Does anyone else here think a crank relearn would be a good idea? I suppose try the easy things first that have been stated already, but to me it seems a CASE relearn is needed or might help.

Yay or nay?

**0rion** · 02-19-2010, 10:02 AM

Originally Posted by Hi-Po

Im going to throw this out there, someone correct me as/if needed.

That P0336 code being thrown most likely has something to do with your problem.

You have a block/crank out of a 98 correct? But your not sure what year PCM you have? When replacing the CKP sensor, is a relearn not a necessity? Does anyone else here think a crank relearn would be a good idea? I suppose try the easy things first that have been stated already, but to me it seems a CASE relearn is needed or might help.

Yay or nay?

I guess I was assuming a case learn had been done with the swap and to be honest with you I have no experience with case learn or what conditions call for it other than what I've read HERE
Frost is who I'd probably ask about that relearn as I'm sure he's been there/done that a few times.
I do believe you could be right though.