96 1500 cold starting problem - The 1947 - Present Chevrolet & GMC Truck Message Board Network

1971LT1SWBPOSI373 · 12-05-2007, 10:07 AM

My 96 is difficult to start after it sits a few days. When I crank it the fuel pump runs as it should, and then it will crank for a bit, and then I will get some mild backfiring through the airhorn. It almost acts as if the distrubutor cap was faulty and it was cross firing between the teminals...
The backiring through the airhorn will continue, then I will stop cranking and try it again and it will fire once or twice. Eventually it will fire, and catch, and run as if nothing was wrong.... The longer i crank it the more it fires as it should.
Obviuosly the airhorn doesn't have a cold weather choke, but is there something I should check or look for that would cue me in to the problem? It once spit out a code for engine misfiring but that was it. I put in a new crank position sensor, and I thought that got it until the cold weather started setting in, then the hard starting began again. Once the truck has been started, it is fine for the rest of the day no matter how long it sits. The engine has new plugs, wires, cap, rotor, and fuel filters, air filter, pvc valve, all GM OEM parts. Also has the new Felpro intake manifold gasket set installed. Runs great once started, but it does hesitate slightly from a dead idle when stepping on the gas. Any ideas? It has the 5.0 (305) V-8 with automatic transmission, no modifications.

hgs_notes · 12-05-2007, 11:37 AM

Might be the fuel pressure regulator. When they go bad it leaks and loses fuel pressure. Which explains the starting issue. The regulator may still function though to maintain enough pressure for normal operation. This is a very common issue on these trucks. Did mine right after I went through the trouble of replacing the intake gaskets, guess what, the rgulator was under the intake!

Hope this helps.

1971LT1SWBPOSI373 · 12-05-2007, 12:06 PM

the fuel pump will run about 10 seconds or so when i first turn on the key. Is the regulator part of the spider assy? As I believe that is all that is under my intake from memory.

hgs_notes · 12-05-2007, 09:37 PM

Yeah, its a small part on the spider.

1971LT1SWBPOSI373 · 12-06-2007, 11:54 AM

I'm not liking this....
OK, so if I gain access through the airhorn and go into the plenum area with a fiber optic borescope I should be able to see fuel dripping from the regulator at the end of the intial fuel pump 10 second run up cycle when first turning on the key correct???? I need to confirm this somehow before tearing it back down again, and this would seem like an easy way to do it.
If this is the case, maybe I should just change the entire spider assy...

1971LT1SWBPOSI373 · 12-07-2007, 09:33 AM

The borescope may not work as I forgot about the plastic cover that goes over the spider assy.
What about sensors???? Is there a sensor that could be causing this???

12-05-2007, 10:07 AM	#1
1971LT1SWBPOSI373 Registered User Join Date: Mar 2002 Location: Springfield, VA Posts: 460	96 1500 cold starting problem My 96 is difficult to start after it sits a few days. When I crank it the fuel pump runs as it should, and then it will crank for a bit, and then I will get some mild backfiring through the airhorn. It almost acts as if the distrubutor cap was faulty and it was cross firing between the teminals... The backiring through the airhorn will continue, then I will stop cranking and try it again and it will fire once or twice. Eventually it will fire, and catch, and run as if nothing was wrong.... The longer i crank it the more it fires as it should. Obviuosly the airhorn doesn't have a cold weather choke, but is there something I should check or look for that would cue me in to the problem? It once spit out a code for engine misfiring but that was it. I put in a new crank position sensor, and I thought that got it until the cold weather started setting in, then the hard starting began again. Once the truck has been started, it is fine for the rest of the day no matter how long it sits. The engine has new plugs, wires, cap, rotor, and fuel filters, air filter, pvc valve, all GM OEM parts. Also has the new Felpro intake manifold gasket set installed. Runs great once started, but it does hesitate slightly from a dead idle when stepping on the gas. Any ideas? It has the 5.0 (305) V-8 with automatic transmission, no modifications. __________________ 1971 Shortbed 350/350 w/ Posi-traction 3:73's 1996 Chevy Silverado TJ in Springfield, Virginia Likes old Chevy trucks Drinks Miller MGD Last edited by 1971LT1SWBPOSI373; 12-05-2007 at 10:13 AM.

12-05-2007, 11:37 AM	#2
hgs_notes GEARHEAD Join Date: Aug 2003 Location: MN Posts: 6,134	Re: 96 1500 cold starting problem Might be the fuel pressure regulator. When they go bad it leaks and loses fuel pressure. Which explains the starting issue. The regulator may still function though to maintain enough pressure for normal operation. This is a very common issue on these trucks. Did mine right after I went through the trouble of replacing the intake gaskets, guess what, the rgulator was under the intake! Hope this helps. __________________ If no one knows what you're doing, they can't tell you you're doing it wrong HG's Dream Car Build - Shelby Cobra Kit Build your own adjustable track bar 71 Long Fleet C/10 72 Jimmy 4x4 (Junkyard Jimmy) HG's Plow Truck '78 K35 Dually Bigass Farm Truck HG's thread of miscellaneous stuff

12-05-2007, 12:06 PM	#3
1971LT1SWBPOSI373 Registered User Join Date: Mar 2002 Location: Springfield, VA Posts: 460	Re: 96 1500 cold starting problem the fuel pump will run about 10 seconds or so when i first turn on the key. Is the regulator part of the spider assy? As I believe that is all that is under my intake from memory. __________________ 1971 Shortbed 350/350 w/ Posi-traction 3:73's 1996 Chevy Silverado TJ in Springfield, Virginia Likes old Chevy trucks Drinks Miller MGD

12-05-2007, 09:37 PM	#4
hgs_notes GEARHEAD Join Date: Aug 2003 Location: MN Posts: 6,134	Re: 96 1500 cold starting problem Yeah, its a small part on the spider. __________________ If no one knows what you're doing, they can't tell you you're doing it wrong HG's Dream Car Build - Shelby Cobra Kit Build your own adjustable track bar 71 Long Fleet C/10 72 Jimmy 4x4 (Junkyard Jimmy) HG's Plow Truck '78 K35 Dually Bigass Farm Truck HG's thread of miscellaneous stuff

12-06-2007, 11:54 AM	#5
1971LT1SWBPOSI373 Registered User Join Date: Mar 2002 Location: Springfield, VA Posts: 460	Re: 96 1500 cold starting problem I'm not liking this.... OK, so if I gain access through the airhorn and go into the plenum area with a fiber optic borescope I should be able to see fuel dripping from the regulator at the end of the intial fuel pump 10 second run up cycle when first turning on the key correct???? I need to confirm this somehow before tearing it back down again, and this would seem like an easy way to do it. If this is the case, maybe I should just change the entire spider assy... __________________ 1971 Shortbed 350/350 w/ Posi-traction 3:73's 1996 Chevy Silverado TJ in Springfield, Virginia Likes old Chevy trucks Drinks Miller MGD

12-07-2007, 09:33 AM	#6
1971LT1SWBPOSI373 Registered User Join Date: Mar 2002 Location: Springfield, VA Posts: 460	Re: 96 1500 cold starting problem The borescope may not work as I forgot about the plastic cover that goes over the spider assy. What about sensors???? Is there a sensor that could be causing this??? __________________ 1971 Shortbed 350/350 w/ Posi-traction 3:73's 1996 Chevy Silverado TJ in Springfield, Virginia Likes old Chevy trucks Drinks Miller MGD



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