1996 Chevy Truck My truck seems like it's not getting fuel

Tiny
KNIGHTNYTE2
  • MEMBER
  • 1996 CHEVROLET TRUCK
  • V8
  • 2WD
  • MANUAL
  • 180,000 MILES
My truck was difficult to start the last few times, but once it starts, its fine. This morning, I sprayed some starter fluid in the carb, (first time to try that) and it fired right up. I had to stop for a few minutes, and it would not start. I sprayed starter spray and it would start, then die. I thought it was a fuel feed problem. Changed the inline filter, still would not start. I changed the mass airflow sensor (expensive booger) on the air filter line. Still trouble starting without starter fluid. But this time it would not die, it idled ok. I drove it back home, turned it off, and restarted it fine. Waited 10 min, and it wouldn't start. The service engine light is on. Currently, there is no way to get it to an auto zone to put it on the computer. Any help would be appreciated.
Tuesday, July 7th, 2009 AT 4:11 PM

10 Replies

Tiny
DR LOOT
  • MECHANIC
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You failed to mention if you had checked the fuel pressure? That is where I would start considering you used start fluid and she fired right it sounds like you got a weak fuel pump that will not hold the pressure and bleeding back into the tank.
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Friday, July 10th, 2009 AT 9:19 PM
Tiny
KNIGHTNYTE2
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I do not have the gages to test the pressure, but I hear the fuel pump come on when I turn the ignition switch to on. Today, I removed the fuel supply line coming into the throttle body, and had someone try to start it. It pushed about 1/2 cup of gas into a cup I had under it. From what I understand, that starts the feed to start the motor. When the motor starts, the fuel pump starts again.
I hope to get a hint before I pull the top throttle body off and check the fuel pressure regulator, fuel injector. Etc. It was late afternoon when I started, and by 4 PM the temps went over 100 in Houston. I'll start again in the morning.
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Friday, July 10th, 2009 AT 9:29 PM
Tiny
DR LOOT
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I understand your position, and I also understand even though the fuel comes on it still doesn't mean that you have correct fuel pressure, even though it pumps out a lot of fuel, you could do a volume check, but I'm not sure how much fuel needs to be pumped out in 15 seconds, but I guarantee you it is more than a cup. The fuel pressure regulator should have a vacuum line going to it, if you remove the vacuum line it will have full pressure.
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Friday, July 10th, 2009 AT 11:05 PM
Tiny
KNIGHTNYTE2
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Thanks for the help. My bud only hit the starter for a second or two. My truck usually starts with just bumping the starter. From what the autozone, I know, but at the moment that's all the suggestions I have gotten, they tell me the fuel pump dumps a little fuel into the throttle body, and when the motor starts, the pump kicks on full.
My problem seems now that fuel is not getting to the plugs to fire. If the initial bump gets fuel through the line, then the fuel pressure regulator is bad, or possibly the fuel injector stages open making it lose pressure.

Thanks again for the answer.
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Friday, July 10th, 2009 AT 11:30 PM
Tiny
KNIGHTNYTE2
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I finally found a fuel gage that I purchased this morning. I put it inline just after the inline filter. The fuel pressure shows constant 45 lbs, and goes to 50 when trying to crank.
I dropped a little gas inside the throttle butterfly. I attempted to crank it, and it caught for a second. I do not seem to have fuel getting into the throttle chamber.

Thanks for any help.
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Saturday, July 11th, 2009 AT 3:44 PM
Tiny
DR LOOT
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Those fuel pressure readings sound to be within the specifications so that's not the problem, you're making me have to think now, with 180,000 miles have you ever rebuilt the throttle body? The kit runs about $21 they just consists of gaskets and O-rings, I'm just wondering now if you have a vacuum leak at the throttle body, it just not making any sense to me that you have proper fuel pressure and it will not start, a vacuum leak will cause the engine to run lean therefore not getting enough fuel on start up. Either that or we are having some ignition problems, after clanking and letting the key off, does it want to start? And may just pop once? Check that out and let me know.
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Saturday, July 11th, 2009 AT 4:39 PM
Tiny
KNIGHTNYTE2
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I pulled the upper throttle body, put in a new pressure regulator. Cleaned every thing up. Pulled the injectors out one by one to make sure each tip was clean. It has the octopus type injector.
Put it all back together, made sure gaskets were in place & tight, reconnected everything. Kicked it over to start and it was trying. It caught for a min, but died. Sprayed starter fluid and it catches, but when it burns up, it dies.
I'm still getting 45 lbs of fuel pressure. The autozone folks said I needed 60-66. Anyone heard of that high? The fuel pressure gauge doesn't even go that high. It stops at 60 lbs.

Any more ideas or thoughts?
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Sunday, July 12th, 2009 AT 4:06 PM
Tiny
DR LOOT
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I checked my manual online and AutoZone is correct 60-66 psi, if you have only 45 it will not start, you need a minimum of 60, I told you that in the beginning that I thought it had fuel problems, dropped the fuel tank replaced the pump and don't forget about the in-line filter, and also replace the filter on the pump which is called the Sock
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Sunday, July 12th, 2009 AT 5:26 PM
Tiny
KNIGHTNYTE2
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The final solution was the fuel pump. 60+ lbs are required to trip the fuel pressure regulator with the octopus injectors. I was getting answers that 45 was enough, and it should have been to crank. It should have run rough, according to chevy, but it should have cranked.

I tried giving Dr Loot a couple gold stars, but for some reason I can't upload photos or post positive reviews. Thanks, Doc, for your help.

I have a vacuum leak and it will not run with the filter body off. It hums or whistles while running, but it runs. I hate to have to pull off the upper throttle body, and make sure the throttle kit gaskets are all straight and none crimped when I put the body back on, but that's where I expect the problem is.

Great site, thanks for your help.
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Sunday, July 12th, 2009 AT 8:09 PM
Tiny
DR LOOT
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I'm glad I could help! Most people do not appreciate that they do not realize that this is my job and it is a very hard job and I only get paid $0.25 per response. And the more you respond the more money I make and donations are critical that's how we keep this site up and running so tell all your friends you know where to get answers for their automotive needs.
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Tuesday, July 14th, 2009 AT 11:47 AM

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