My sons 96 gmc 1500 died last night as he was driving it. It has ignition, fuel and air. I put a fuel pressure tester on it and it gives me 60 psi with the key on , with the key off pressure drops off rapidly. So its either fuel pump or fuel pump regulator am i on the right track or am I missing something?
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Opps its a 5.7 and TBI . -
Any codes thrown? Crank position sensor, cam position sensor. Timing belt/chain comes to mind. Do a compression test too.Comment
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If it looses pressure rapidly when the key is turned off it's more than likely a non-return valve in the pump not closing.
All the valve is supposed to do is keep some residual pressure between injectors and pump so that it doesn't take 45 seconds of cranking in order to develop enough pressure to start.
What does the fuel pressure do when cranking ?
And how many miles are on it ?
If you have fuel, air and heat it should run unless it's got a timing issue.Comment
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this^^^^ If you have all the above, timing is your answerOriginally posted by HTDUCK View PostComment
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My 99 did that. It had spark but the distributor had broke internally. I could literally turn the rotor by hand with the engine not spinning. Turned out this is a common issue on the 5.7.Comment
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geezer points you rightComment
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Remember when we worked on engines based on the way they ran and sounded? I want to go back to those times!Comment
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My '89 5.7 has no pressure till it pumps back up with the ignition on. Then it runs. I have to wait till the pressure comes back up before it will fire and run. I can sit there with just the ignition on and hear the pump till it reaches pressure. Then it will fire right off. Or I can turn the ignition/starter, and wait till the pressure comes back up for it to fire,
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Last three times mine would not start were due to corrosion inside the distributor cap, and plug wires there. Mine is notorious for collecting moisture there when it rains. That back firewall seems to suck rain up that direction for some reason, even with splash panels in there.Last edited by Texas Grown; 12-14-2018, 10:58 PM.Comment
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Having the distributor on the back of the engine was always giving us fits on the old points systems.Originally posted by Texas Grown View PostMy '89 5.7 has no pressure till it pumps back up with the ignition on. Then it runs. I have to wait till the pressure comes back up before it will fire and run. I can sit there with just the ignition on and hear the pump till it reaches pressure. Then it will fire right off. Or I can turn the ignition/starter, and wait till the pressure comes back up for it to fire,.
Last three times mine would not start were due to corrosion inside the distributor cap, and plug wires there. Mine is notorious for collecting moisture there when it rains. That back firewall seems to suck rain up that direction for some reason, even with splash panels in there.Comment
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Happens with the electronic I have too. Just a bad location for a distributor cap with those aerodynamics. And that body style.
The fish are biting. And there's hogs to be kilt. Gotta go!Comment
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I had a '74 that I was changing points on pretty regular. it was because of all the water and crap coming up the firewall. Plus the stupid trap door on the old caps.Originally posted by Texas Grown View PostComment
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I wonder if it still drafts up on the new models.
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My 96 7.4 would do this randomly....it was the fuel pump AND sending(so) unit in the rank. Started shutting down at more frequently as time went onComment
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Fuel pump/sending unit.
That body style GM PU fuel pumps were junk. I had a 99 Yukon and always kept it half full of fuel. Still had to replace the sending unit/ fuel pump 2 times in 5 years.Comment
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