Engine dies immediately when starting

[kaspr]

Hi all,

Here's my problem: The car was working fine until this problem occurred - it was sudden. Went to start one day, and it starts right away, then dies the instant that it starts. When I give it gas while starting, I can get it to run for a few seconds, but it is really flaky. If I give it too much gas, it'll backfire sometimes. While giving it gas, the rpm's fluctuate alot, even when I'm holding the gas pedal somewhat steady. It's super hard to keep it at a certain rpm level. I cannot get the car to run ever since a couple of days ago when this problem occurred. The fuel pump does work when I turn the key to the "on" position. Any thoughts?

I'm guessing it could be any one of the following issues, could somebody make a recommendation as to what they think it is or isn't?

throttle position sensor
mass air flow sensor
fuel pump
fuel pump relay
fuel pressure regulator
crankshaft position sensor
ecm

Whatever it is, remember the problem happened suddenly.

Thank you!

[deadring]

i think you can take out the throttle position sensor, because if i unplug mine on my pa the car will still run ok.

the best thing you can do is go in diagnosis mode and get the codes out.

i hope you have a pre 95 model so you can get out the codes yourself and see whats wrong.

but from what it looks like, i' suspct the crank position sensor... or MAYBE fuel pump.. which would be a rare and a long shot.

but first, get the codes out

Deadring

[Gocart879]

i can pretty much say i think its your fuel pump. get a pressure testing kit and test the fuel pressure. you may hear it running, but something can be wrong internally. i had the same problem exact description. but i didnt hear my fuel pump.

[kaspr]

One other note is that upon starting (without pushing the gas pedal), it surges right up to 2000 rpm's, then dies right away. Could it be that it's getting too much gas and that's making it go up to 2000 rpm's? I'll try to find a fuel pressure gauge. Tried removing the connectors for the Throttle position sensor, MAF sensor, and IAC valve, and no difference.

[deadring]

lack of fuel can mak an engine surge at higher rpm

check your fuel pressure

[HotZ28]

With the engine off, and looking at the throttle position sensor, open the throttle to see if the lever on the TPS is moving with the throttle (opening and closing). I just replaced one today that had a broken spring and would not return to the home position. It caused the car to idle at 2000 rpm and shut off when it stuck wide open.

[kaspr]

I checked the TPS; it's moving with the throttle. I've narrowed it down to the following:

Crankshaft position sensor
Fuel pump
Fuel pump relay
Fuel pressure regulator
ecm

I'll check the fuel pressure, as that will further narrow it down. I just have to find one at a store. I'll try Napa.

[HotZ28]

I assume by now you have checked you codes from the check engine light (PCM). What codes are you getting.

[kaspr]

Actually, regarding the diagnostic codes, I have a '94, which is a hybrid OBDI/OBDII system, so the equipment is quite expensive compared to '93< & '96> models. So no, I have not scanned the codes.

[HotZ28]

It might be cheaper to have a mechanic scan it for you rather than change parts. I know how it feels not to have the right tools to stay pace with new technology, you have to pay one way or the other.
Fortunately I have a scaner that will scan all cars from 1985 to 2002 and above. If you were close by I would be glad to do it for you free.

[kaspr]

HotZ28, what kind of scanner is that, and where did you get it? That sounds pretty nice! Well, I checked the fuel system, and everything was right - 42 psi fuel pressure. So now I'm pretty sure it's either the crankshaft pos. sensor, camshaft pos. sens., ecm, or ignition module. Any other advice would help a lot.

[HotZ28]

I use Genisys Pathfinder 2004 Deluxe Kit w/ Asian 2003 and ABS/Air Bag 2002 Software - 3484ABS

http://www.toolsource.com/ost/produc...PQQ89RRTNH72A5

You could go buy Auto Zone to have your codes read for free, if you have a store nearby.

My scanner has a cable adapter for the OB11 ADL and you select the 95 model Buick and it knows that it is an OB1 ECM based on the preloaded pathfinder software.

[kaspr]

Wow! that's nice, but expensive. I'm going to replace the crankshaft position sensor today, and I'll let you all know if that fixes it.

[HotZ28]

Going back to the bad TPS I had to replace the other day, it would move up with the throttle, but would not return to the home position all the way. That made the ECM think that the throttle was partially open, when in fact the throttle body butterfly was closed. When you have that condition, the ECM thinks it needs more fuel, however it can not get the air it needs.

[Opps123]

i think ive had the same problem....i replaced the camshaft sensor and still the same problem...i replaced the magnet on the gear and it so far is working very welll...the only downside to that is that it is almost 6-8 hours to replace....for a little magnet...