2G Idles for a few seconds then dies?

[eclipsed123]

I blew a intercooler coupler on my way home last night. I couldn't get it to crank back up it would just turn over. I replaced the coupler this morning and was able to get it to crank it idled fine for a few seconds then died. I thought maybe it was fuel related because I couldn't hear my fuel pump so I swapped it with the one off my other dsm and same thing. I also changed the power transistor with a known working one. I'm kinda stumped because it does idle fine for a few seconds

 

[Vegas Smith]

Probably a big boost leak.

 

[eclipsed123]

It was the coupler on the j-pipe but that was the coupler I replaced I can do a blt to make sure but I did did try to run it with the maf unhooked as well to no avail.

 

[Vegas Smith]

If your car still has a mas/maf then any problem you have should start with a blt. Sometimes you'll develop a tear on the backside of a coupler and you'd never know it by just looking around.

 

[curt-s]

Does it struggle and die or just die as if the ignition was turned off? Two totally different scenarios. Can you keep it running with minimal throttle and, if so, what are your afr and trims when doing so? Before that, BLT as indicated.

 

[eclipsed123]

It just dies as if the ignition was turned off. It doesn't idle long enough for the heater on the wideband to warm up and give a afr. Won't stay running even with a little throttle. I'm at work now but I will do another blt when i get off and see what I got. I always thought that even with a massive boost leak it would still idle if the maf was unplugged?

 

[curt-s]

Should still run. I blew a hole in a coupler nearest the exhaust manifold when I was still on mass air and it caused the car to die during the pull but it fired up fine and still drove the entire way across the city (mind with whacked out CombinedFT). thought I windowed the block.

A sudden death makes me think more timing or ignition failure than boost leaks. When you start it, you are in open loop. It changes to closed loop after the o2 starts cycling. Usually the wbo2 is warmed up before that but Does it die at that point? Can you present us a video or log?

 

[Dsmkauai]

Make sure all your sensors are connected properly still. Maybe something came loose when it blew off.

 

[eclipsed123]

I don't see any loose connectors. I did a blt and it was fine except for a minor leak around the throttle body but that one has been there just haven't gotten around to rebuilding the throttle body. I swapped out the ecu and the cas (one mounted on the side of the valve cover) with another one but still the same thing. I'm thinking its something fuel related because after cranking it for awhile idleing for a few seconds then dying it will get to where it won't start anymore unless I let it sit for awhile or apply 12 volts to the fuel pump test connector beside the battery.

 

[eclipsed123]

I'm trying to avoid taking all the pulleys and covers off to check the timing unless someone thinks that could be the cause. Like I said before though it runs perfectly fine for the few seconds it does idle. I let it sit overnight last night and applied 12 volts to the fuel test pump this morning and it idled for a few minutes before it cut back off. After that it went back to only idleing for a few seconds before dying.

 

[pauleyman]

Since its dying like it was turned off it sounds electrical. Something isn't getting


A power or feeding info to ecu.

 

[curt-s]

I'm trying to avoid taking all the pulleys and covers off to check the timing unless someone thinks that could be the cause. Like I said before though it runs perfectly fine for the few seconds it does idle. I let it sit overnight last night and applied 12 volts to the fuel test pump this morning and it idled for a few minutes before it cut back off. After that it went back to only idleing for a few seconds before dying.

I meant ignition timing rather than mechanical. Either way, most it would be is upper timing cover for mechanical and nothing removed for ignition. I was referring more to a failed cas or wiring to it.. sudden death syndrome hit me when the PTU wasnt grounded well enough.
Even a sputtering fuel pump would cause a slower turn-off because of latent fuel vapour and ultra lean mixture.. sudden-off screams something is causing a sudden lack of spark pulse, usually wiring related or a bad ecu.

 

[eclipsed123]

I rotated the engine to tdc and the timing marks lined up on the lower timing cover. I tried something else today I unhooked the return line from the fpr and applied 12 volts to the fuel pump and nothing came out. I tried the same thing with my other dsm and fuel poured out. If I remove the fpr gas pours out so I thought maybe the fpr was bad so I swapped it out and nothing.

 

[99ECLIPSEGSXDSM]

M car would run for a few seconds like this when my CAS went out.

 

[Bleakley]

I rotated the engine to tdc and the timing marks lined up on the lower timing cover. I tried something else today I unhooked the return line from the fpr and applied 12 volts to the fuel pump and nothing came out. I tried the same thing with my other dsm and fuel poured out. If I remove the fpr gas pours out so I thought maybe the fpr was bad so I swapped it out and nothing.

Pump could be bad.
I had a pump in a car that would supply SOME fuel free flow, but under pressure it couldn't do it.
Sounds like you're getting somewhere. Look into it.

 

[eclipsed123]

Figured I would update this in case someone experiences something similar it ended up being 2 things. The nozzle at the end of my fuel pump had came loose and wedged itself sideways in the fuel pump housing and the crank sensor was bad.

 

[curt-s]

Well, I did say it sounded ignition timing related.. but I would not have seen the nozzle issue. Though that would cause more of a sustained lean issue as it was still flowing fuel (obviously enough to start and since there is enrichment at startup via link or fps, more than enough volume).
Good catch on the nozzle.. damn weird considering its pressed over.

 

[Jay 97 GSX]

check the sensor on the intake side where the upper intercooler piping goes, unplug it and see if it runs.

 

[pauleyman]

Crank sensor bad? Why? Did you check crank endplay?