1990 Pontiac 6000, Starts then stalls

elmo1945 · 04-20-2006, 08:57 AM

I have a 1990 Pontiac 6000, 3.1. After sitting for a few weeks, I went to start it. It started immediately as it always did, but then stalled immediately and then no matter how long I cranked, it wouldn't even sputter. After sitting for an hour or two it will do the same thing. Start then stall.I beleive It is a fuel problem of some sort, because if I squirt starting fluid in the air intake while someone hits the starter, it starts right up, then stalls as soon as I stop spraying. I've worked on cars for years but nothing newer than the 80's. If it has fuel injection and a computer, I'm lost. It's an old junker, but 4 wheel drive so I would like to save it if I can get out cheap. I'm guessing fuel pump, but don't want to spend the money if that isn't it.
Thanks for your help.

raffiican · 04-20-2006, 03:00 PM

Quote:

Originally Posted by elmo1945

I have a 1990 Pontiac 6000, 3.1. After sitting for a few weeks, I went to start it. It started immediately as it always did, but then stalled immediately and then no matter how long I cranked, it wouldn't even sputter. After sitting for an hour or two it will do the same thing. Start then stall.I beleive It is a fuel problem of some sort, because if I squirt starting fluid in the air intake while someone hits the starter, it starts right up, then stalls as soon as I stop spraying. I've worked on cars for years but nothing newer than the 80's. If it has fuel injection and a computer, I'm lost. It's an old junker, but 4 wheel drive so I would like to save it if I can get out cheap. I'm guessing fuel pump, but don't want to spend the money if that isn't it.
Thanks for your help.

Can you hear the fuel pump run for 2 seconds when you turn the key to the on position (without cranking the engine)? You may need a second person to listen near the tank while you turn on the key, and keep in mind that once you try it, you will have to turn the key off again for at least 10 seconds before you can try again.

elmo1945 · 04-21-2006, 08:49 AM

Thanks, I'll try it this weekend and let you know.
Lee

elmo1945 · 04-26-2006, 11:06 AM

I can hear the fuel pump for a few seconds before the car starts. After it stalls, when I try to restart I do not here the pump again.

raffiican · 04-26-2006, 02:10 PM

The pump won't run again after the initial "prime pulse" when the key is turned on untill the computer sees a reference pulse from the ignition module, or untill the contacts in the oil pressure switch close. I think you may need to test the fuel pressure, there is a pressure test port on the fuel rail, but you will need a pressure gauge.

elmo1945 · 04-26-2006, 03:10 PM

Thanks, I'll give it a try. I have a guage, Do you know where the test port is located, and what the pressure is supposed to be??
Thanks again.

richtazz · 04-28-2006, 05:52 AM

the port is on the drivers side near the throttle body. The pressure should be 31-35 psi, key on engine off, and should drop only a couple of pounds when the car is started. If the fuel pump is shutting down after it's initial prime, you have either a bad oil pressure switch (the relay shuts the pump off if no oil pressure signal is received once the car is started), or no spark reference is getting to the ECM from the ICM (the pump shuts off because the ECM doesn't "think" the car is running). Since you obviously have spark, I'd start with the oil pressure switch. It's relatively cheap and fairly easy to replace. A friend of mine had a 90 6000-STE AWD with a 5-speed in it, quite a sleeper back in the day, and a lot of fun.

dcjredline · 04-12-2007, 12:47 PM

Quote:

Originally Posted by richtazz

A friend of mine had a 90 6000-STE AWD with a 5-speed in it, quite a sleeper back in the day, and a lot of fun.

1989 Was the last year for the STE! And I have never heard of an AWD with 5 speed. Pontiac made these cars with the T125C transmission and I WOULD LOVE to see pictures of his AWD 5speed transmission and transfercase setup. I highly doubt Pontiac did 6 or so SPECIAL, SPECIAL cars. Lets see some pics or some other proof of this cars exsistance. That would be awesome.

raffiican · 04-12-2007, 01:05 PM

Just a quick note/correction. I know GM did NOT make a 5-speed AWD ANYTHING....and also, the oil pressure switch does NOT shut off power to the fuel pump if there is no oil pressure. In fact it is the opposite; once oil pressure rises to the threshold of the switch it supplies power to the pump to keep it running in case the fuel pump relay fails. If the fuel pump relay is operating correctly, you could have 0 psi oil pressure and still have fuel pressure. This is a common misconception (oil pressure switch as a fuel pump shut-off) that can be de-bunked by a quick inspection of the wiring diagrams (assuming basic electrical knowledge).

Mike.

My Sixth Gear · 04-28-2007, 04:21 PM

I encountered a similar problem with the 3100 where the cylinder six fuel injector was shorted and only had a 1 ohm resistance value, this caused all the current to go this injector and the other two injectors on the same bank weren't firing causing the engine to stall. Try checking the resistance values of the injectors, all should be around 6 or so ohms.

wagonman76 · 06-06-2007, 11:14 AM

Ive had 2 a-bodies with this same problem. Both times it was the wiring to the fuel pump relay, the orange wire, about an inch from the relay connector. The wire had broken and corroded inside the insulation.

Stan King · 04-17-2011, 06:27 AM

I had this problem with my 90 pontiac. The fuel pump operated ok to pressurize the fuel delivery sys to 40 psi when ignition sw is on for 2 sec.. But the oil pressure sw. was intermintent open on the fuel pump pwr side. Defect Found: faulty oil pressure switch.....

royengle · 06-30-2013, 12:45 AM

Same problem with my 89 Pontiac 6000LE. Runs, then stalls

, won't start until a few days later.

Fuel pump delivers gasoline to injector rail, tested release value has pressure squirting gas. Poured gas into the air filter, then engine starts and runs til the fuel is used up. So ignition is OK too. It seems that the fuel injectors are not working, because of the Computer Module may not be turning them on?

Also Oil Pressure gauge/light is also working OK. Replaced Oxygen Sensor too, no change.

Problem may involve engine temperature, hence the cool down the next day

.

royengle · 06-30-2013, 12:48 AM

Quote:

Originally Posted by Stan King

I had this problem with my 90 pontiac. The fuel pump operated ok to pressurize the fuel delivery sys to 40 psi when ignition sw is on for 2 sec.. But the oil pressure sw. was intermintent open on the fuel pump pwr side. Defect Found: faulty oil pressure switch.....

You didn't mention here if your Oil Pressure gauge/light was working all the time?

royengle · 06-30-2013, 12:52 AM

Originally Posted by My Sixth Gear

I encountered a similar problem with the 3100 where the cylinder six fuel injector was shorted and only had a 1 ohm resistance value, this caused all the current to go this injector and the other two injectors on the same bank weren't firing causing the engine to stall. Try checking the resistance values of the injectors, all should be around 6 or so ohms.

This sounds like a good possibility, sense it appears to be my fuel injectors that are not working now.

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