Trouble staying running - The 1947 - Present Chevrolet & GMC Truck Message Board Network

76CustomDeluxe · 03-20-2008, 04:15 AM

I have a 87 GMC with a 305 tbi that won't stay running for me. What it is doing lately is it will start up and run for a while, start faltering and die. I try to restart it and it will try and start every once in a while but it will never stay running. If it does happen to start again it will run for a while and then falter and die. I've changed out the fuel pump, fuel filter and one of the fuel injectors and none of that has done any good. Anyone have any suggestions on what it could be?

zombiescustoms · 03-20-2008, 04:25 AM

Have you checked the fuel pressure? I'm not real familier with TBI (just bought one myself) but I'm sure there is a pressure regulator up near the injectors, usually there is a vacume line that changes the pressure depending on the load on the motor, if you are not getting enough pressure to the injectors they wont work right and the motor will run like crap or stall.

*** I just looked up the specs on the TBI aparentlly there is not a fuel pressure regulator but the pressure should be between 9-13 psi***

**old Rusty C10** · 03-20-2008, 05:13 AM

youve checked to make sure that this is a fuel problem and not a spark problem.. do you have good spark after the truck dies?

James McClure · 03-20-2008, 02:23 PM

Fuel pressure regulator is built into the TBI upper half. 9 to 13 PSI is correct pressure. A quick test to see if regulator has failed is pinch off return line (smaller of the two lines) Best thing is a pressure guage though because you can use the pinch off at the same time to check the fuel pumps ability to excede 13 psi. Be careful doing that though, pump can deliver 50+ psi. jim

**old Rusty C10** · 03-20-2008, 06:51 PM

if the fuel seems ok im betting the distributor or the pickup coil in it although some times ive seen a coil pack do this

sjarrett71 · 03-20-2008, 07:14 PM

If it runs long enough for the truck to get warm it might be the ignition module under the distributor cap.

69BBsuburban · 03-20-2008, 09:04 PM

Believe it or not.....try replacing the PCV. It has an affect on TBI engine runability....to the point of not running at all. I've done a few.

03-20-2008, 04:15 AM	#1
76CustomDeluxe Registered User Join Date: Oct 2004 Location: Wichita, KS Posts: 10	Trouble staying running I have a 87 GMC with a 305 tbi that won't stay running for me. What it is doing lately is it will start up and run for a while, start faltering and die. I try to restart it and it will try and start every once in a while but it will never stay running. If it does happen to start again it will run for a while and then falter and die. I've changed out the fuel pump, fuel filter and one of the fuel injectors and none of that has done any good. Anyone have any suggestions on what it could be?

03-20-2008, 04:25 AM	#2
zombiescustoms Registered User Join Date: Mar 2008 Location: Abingdon, MD Posts: 74	Re: Trouble staying running Have you checked the fuel pressure? I'm not real familier with TBI (just bought one myself) but I'm sure there is a pressure regulator up near the injectors, usually there is a vacume line that changes the pressure depending on the load on the motor, if you are not getting enough pressure to the injectors they wont work right and the motor will run like crap or stall. * I just looked up the specs on the TBI aparentlly there is not a fuel pressure regulator but the pressure should be between 9-13 psi* Last edited by zombiescustoms; 03-20-2008 at 04:36 AM.

03-20-2008, 05:13 AM	#3
old Rusty C10 Robert Olson Transport Join Date: Oct 2002 Location: recent transplant to NC USA Posts: 20,316	Re: Trouble staying running youve checked to make sure that this is a fuel problem and not a spark problem.. do you have good spark after the truck dies? __________________ Bob 1951 International running on a squarebody chassis "If a man's worth is judged by the people he associates himself with, then i am the richest man in the world knowing some of the fine people of this board" http://67-72chevytrucks.com/vboard/a...t.php?f=25&a=9 (you can review the site rules here!) PM Me for your vehicle/parts hauling needs in the North East US or see my Facebook page Robert Olson Transport Live each day to the fullest.. you never know when fate is going to pull the rug out from under you... I hate cancer!!

03-20-2008, 02:23 PM	#4
James McClure One shot, one kill. Join Date: Dec 2007 Location: Saratoga Springs NY Posts: 859	Re: Trouble staying running Fuel pressure regulator is built into the TBI upper half. 9 to 13 PSI is correct pressure. A quick test to see if regulator has failed is pinch off return line (smaller of the two lines) Best thing is a pressure guage though because you can use the pinch off at the same time to check the fuel pumps ability to excede 13 psi. Be careful doing that though, pump can deliver 50+ psi. jim __________________ 1984 K20 350M engine with 465,000 miles. Well, it's finally done!! Almost 2 years of work, but it was really worth the effort. Little stuff left to do is mount winch, wet sand & buff out and build belly pan\running boards. Body work takes lots and LOTS of beer!!!! God, Guts and Guns made America and God, Guts and Guns will preserve it! The worst thing you could do is get into my sights, but that don't matter, you'll never know it, cause you'll never hear the shotJim or Paladin whichever you choose.

03-20-2008, 06:51 PM	#5
old Rusty C10 Robert Olson Transport Join Date: Oct 2002 Location: recent transplant to NC USA Posts: 20,316	Re: Trouble staying running if the fuel seems ok im betting the distributor or the pickup coil in it although some times ive seen a coil pack do this __________________ Bob 1951 International running on a squarebody chassis "If a man's worth is judged by the people he associates himself with, then i am the richest man in the world knowing some of the fine people of this board" http://67-72chevytrucks.com/vboard/a...t.php?f=25&a=9 (you can review the site rules here!) PM Me for your vehicle/parts hauling needs in the North East US or see my Facebook page Robert Olson Transport Live each day to the fullest.. you never know when fate is going to pull the rug out from under you... I hate cancer!!

03-20-2008, 07:14 PM	#6
sjarrett71 Registered User Join Date: Dec 2006 Location: Rolla, MO Posts: 2,463	Re: Trouble staying running If it runs long enough for the truck to get warm it might be the ignition module under the distributor cap. __________________ -Scott-

03-20-2008, 09:04 PM	#7
69BBsuburban Right in front of you. Join Date: Jan 2006 Location: Roy, Wa Posts: 584	Re: Trouble staying running Believe it or not.....try replacing the PCV. It has an affect on TBI engine runability....to the point of not running at all. I've done a few. __________________ Pinstriping by Josh '78 Chevy Silverado SWB (lowered, 454) '90 Chevy Sport Truck '68 Dodge Charger R/T 1930 Ford Model A

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