help!!! new problem w 1999 chevy suburban

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moparmat2000

moparmat2000

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Ok,

I got all the water leaks fixed on the 1999 chevy shitburban, now im having a fuel problem. Truck will start when i dribble a little gas in the throttle body, and run for a moment then it dies. I put a brand new GM ac delco fuel pump in the tank a few months ago when it went bad. The pump makes a whirring noise in the tank so i know its working.i swapped a new fuel filter into it last night and it started up. This morning its back to cranking but not starting. A little gas in the air horn will bring it to life again. Just like yesterday.

Does this truck have a return line. Im thinking mebbe its s bad pressure regulator.im thinkingof pinching off the return line to see if its the regulator. This truck uses a multiport spider setup under the intake manifold. Where would the fuel press regulator be located?

Any other ideas?

Thanks in advance
Matt
 
We had to do a "clear flood mode" on my. Wife's jimmy. Not sure if that's the technical term or not, it's just what I heard it called. Move the floor mat out of the way and put the pedal on the floor board as far as it will go and turn the key. Again, this is just how I was told they did it, but the bastard fired right up after a second.
 
I'll see about the regulator in a minute, have to go to the garage computer, but does the pump stay on? I just fought a similar issue on an 89, Chevy tied the fuel pump into the oil pressure sending unit, no pressure no fuel. In my case was a fuse.
 
the regulator is inside the intake, on the side of the "spider"
 
Also, you need to check fuel pressure on the supply line, should be around 55LBS. the pump can run and still not build pressure, and the line from the pump to the top of the sending unit inside the tank can sometimes leak/rupture also, causing this problem. just cause you hear the pump, doesn't mean you have fuel pressure!
 
As replicaracer43 said, check the pressure.

Pressure with ignition on and idle are the same, 60-66. With the return briefly restricted 66.

edit, pulled wrong diagram.
 
Hm, never seen THAT particular setup on one before, is that a natural gas deal????
 
replicaracer43 said:
Hm, never seen THAT particular setup on one before, is that a natural gas deal????
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Yeah, thinking it was looking at it. Was in a rush to help the wife and pulled the wrong image. Sorry about that.
 
ducter said:
Yeah, thinking it was looking at it. Was in a rush to help the wife and pulled the wrong image. Sorry about that.
Click to expand...
hahaha, no problem, thought it looked odd!
anyway, the fuel supply and return come up on the driver side of the engine, and go into the top of the injection unit. They are metal lines. There will be a Schrader valve located near the back of the engine, more or less to the side of the distributor location...
 
ducter said:
I'll see about the regulator in a minute, have to go to the garage computer, but does the pump stay on? I just fought a similar issue on an 89, Chevy tied the fuel pump into the oil pressure sending unit, no pressure no fuel. In my case was a fuse.
Click to expand...

turn the key to the run position pump comes on and runs for about 15 seconds. then shuts off. it has always worked this way. I remove cap from fuel pressure manifold, got a good solid squirt of fuel when I pushed down on the valve.

truck runs for short. Of time when you put fuel in the throttle body. is there a low oil pressure relay somewhere?
 
Is there any chance that you might have water in the gas?

Loosen your fuel cap and make sure it hasn't gotten a vapor lock for some reason.
 
moparmat2000 said:
turn the key to the run position pump comes on and runs for about 15 seconds. then shuts off. it has always worked this way. I remove cap from fuel pressure manifold, got a good solid squirt of fuel when I pushed down on the valve.

truck runs for short. Of time when you put fuel in the throttle body. is there a low oil pressure relay somewhere?
Click to expand...
No oil pressure relay. Check fuel pressure..... a squirt can be 10 lbs.... these things need high fuel pressure to run..... If your pressure is good, we can continue diagnosing, till then, your shotgunning
 
You can rent a fuel pressure gauge from auto zone if you don't have one and don't want to tie money up in one. Depending on my finances I buy or rent, you can never have to many tools but sometimes budget out weighs it all. I would start with the fuel pressure as will. Your not getting a cel right?
 
Just another thought, you have passlock on that suburban I believe? Do you have any security lights on the dash that aren't going off while trying to start it? Or that flash when it dies? Might be killing the injectors?
 
ducter said:
Just another thought, you have passlock on that suburban I believe? Do you have any security lights on the dash that aren't going off while trying to start it? Or that flash when it dies? Might be killing the injectors?
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No security setup in it, i dont even bother to lock the doors on this piece o **** , partly because 2 of em dont lock anyways. I am going to rent a fuel pressure gage tester from autozone today. Thought about doing that last night.

Old timey carbs and points **** is much easier and simpler to work on.
 
ok i put a gage on it, i get 50 to 55 PSI. truck will barely idle and runs shitty. no throttle response. there is a new fuel filter.
 
Odd that your not getting any codes. I know egr issues will not normally keep it from starting but can make for crap idle and make it seem like a misfire, even stall the engine, your ICM will also do as your saying but again not normally prevent it from starting. Without it throwing a code makes it tricky. Sorry I am not more help.
 
moparmat2000 said:
turn the key to the run position pump comes on and runs for about 15 seconds. then shuts off. it has always worked this way. I remove cap from fuel pressure manifold, got a good solid squirt of fuel when I pushed down on the valve.

truck runs for short. Of time when you put fuel in the throttle body. is there a low oil pressure relay somewhere?
Click to expand...

Yes, though I have no idea where.

If you bypass the factory wiring and run the pump directly off a battery, will it run?
 
ducter said:
Just another thought, you have passlock on that suburban I believe? Do you have any security lights on the dash that aren't going off while trying to start it? Or that flash when it dies? Might be killing the injectors?
Click to expand...

IIRC, Pass-Lock will prevent it from cranking...it did on my Caprice.
 
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