GM car starts then dies immediatly

[SuperCab]

asking for a friend as I have no particular interest in cars... Here it goes.


It's a 91 IIRC Olds or Buick or something. 3.3L V6. Starts when cold, runs for ~2 minutes but only at idle, dies if you try to rev it up. after ~2minutes, dies. Restarts, runs ~5 seconds, dies. Restarts, runs ~5 seconds, dies. Repeat laast two steps until battery dies, if you are so inclined. hits right off every time, than immediatly dies...

Fuel pressure is ~45psi, regulator is good...

Trying to help the guy out but I'm more or less out of ideas...


EDIT: one more thing tht may be important: I unplugged the MAF and had him start it... ran bad, typical of unplugged maf, but still died on schedule...

Has me pretty damn stumped. Appreciate the help as you guys always seem to solve my problems...

 

[polarbear]

Owned one. You know it's an issue when the tech has the part # of the ECU memorized. Car did something similiar- died randomly and without warning. Not consistent like that, though. After about three trips to the shop and two ECU's later, I had one of our guys (Chevy shop) replace the coil pack, and that fixed the problem. I'd look there first.

 

[SuperCab]

Hmm... Just got done putzin with it with him (lives right down the street from me) It'll run on ether and seem to run pretty well, too. If you have enough coordination between your ether can hand and your move the throttle valve hand you can get it to rev right up, so I'm back to a fuel problem, but it has fuel (45psi+) at the injector rail...

Bad injectors? All of them though? That IMHO seems unlikely, so is it the ECU not pulsing the injectors?

 

[polarbear]

Let me walk over to the Buick shop tomorrow and talk with one of the techs. The coil packs on those cars are wierd. normally, when a coil pack fails, it just dies and that's all she wrote. Not on those cars.

 

[SuperCab]

Ok, I'd appreciate that alot!

 

[Fellro]

Crank sensor is a possible suspect, as it sounds like it is turning off the fuel. That is where a scan tool is helpful, takes a lot of the guesswork out. Possible to be the ignition module as well.

 

[polarbear]

Yup. Per Buick Tech- cam or crank sensor, in that order, most likely suspect. They had "buttons" on them that would break off. From that point on, it's a coin toss. Aforementioned ignition module or ECU would be next in line. You really need a scanner before you start throwing parts at it.

 

[SuperCab]

Thanks alot Ernie... We ll chek for codes next time im over there.

 

[SuperCab]

Well, spent a little time workin on this dudes car the other evening... He swore he's checked for vacuum leaks, but it turns out he'd knocked a big vacuum line loose in his messing around with it. The old ether can trick found it in a second...

So now it runs indefinitely, however the original problem remains... It wont rev up at all, and he says it was consuming fuel excessivly before/as it was happening...

I told him it's likely to be the ECM... though Im also thinking maybe the coil packs??? Any input would be appreciated...

And I am sorry I got into this mess, but too late to worry about it now...

 

[blacksnapon]

Just as a suggestion, theres a small wire coming off of the positive battery cable. If I remember right, theres a connector in that wire. Take it apart and clean it. That wire powers the PCM.