fuel pressure bleeding off
Thread Starter
On The Tree
Joined: May 2011
Posts: 133
Likes: 8
fuel pressure bleeding off 2001 5.3 bone stock Tahoe motor. still in the Tahoe.
first crank of the key it just turns over and it could just be for a blip.second crank fires every time.
little history.
chasing an oil leak changed valve cover gaskets, intake gaskets, knock sensors and valley cover gasket. change cam sensor and finally the rear main..... all had seepage but the rear main ended up being the problem. oil leak solved.
on to the next issue, not starting on the first crank.changed the regulator, changed the pump. so now im at a loss.... changed the regulator again thinking it was bad because it sounded like a kazoo. did the same thing with the new one. (no fuel in the vacuum line off the regulator.)
I checked the pressure at the rail and it is good on the first turn of the key it jumps up to 55 or so....but wont fire. after about 5 min I can try it and i would say 50-50 it will start on first crank. the pressure does bleed off over night. so thinking I have a bad pump I change it again......
so 2 pumps 3 regulators and a new filter...... am I missing something? Injectors? or something else? did i overlook something on the gasket changes? cam sensor?
Thanks all!
D
first crank of the key it just turns over and it could just be for a blip.second crank fires every time.
little history.
chasing an oil leak changed valve cover gaskets, intake gaskets, knock sensors and valley cover gasket. change cam sensor and finally the rear main..... all had seepage but the rear main ended up being the problem. oil leak solved.
on to the next issue, not starting on the first crank.changed the regulator, changed the pump. so now im at a loss.... changed the regulator again thinking it was bad because it sounded like a kazoo. did the same thing with the new one. (no fuel in the vacuum line off the regulator.)
I checked the pressure at the rail and it is good on the first turn of the key it jumps up to 55 or so....but wont fire. after about 5 min I can try it and i would say 50-50 it will start on first crank. the pressure does bleed off over night. so thinking I have a bad pump I change it again......
so 2 pumps 3 regulators and a new filter...... am I missing something? Injectors? or something else? did i overlook something on the gasket changes? cam sensor?
Thanks all!
D
Its a computer controlled engine and the damn thing needs all of kinds of electronics to make it run properly so it could be anything. You've got to have a healthy battery, good connections and proper fuel pressure for starters. If you figure it out please share your experience so others on here who may have a similar situation can find answers. Could it be the VATS? Could it be a poor ground? Could it be a melted wire? Could it be a bad ECM? Could it be a bad relay? There's just so many things that could cause a starting problem. I had a problem with one of my work trucks not wanting to start and I had replaced the cap, the rotor and was starting to think distributor but I figured I'd go ahead and install some new spark plugs and after that it fired right up. Go figure!
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What does it do if you key it on 2x before you crank it? I've seen several that just do not get enough prime pressure without 2 key on before crank if you want it to fire right away.
Thread Starter
On The Tree
Joined: May 2011
Posts: 133
Likes: 8
little update. I pulled the injector rails and keyed on. NO leaky injectors. I am stumped.
SPTURBO. it will fire every time on the second twist of the key.
STEVIETURBO haven't seen any codes. i suppose it it time to take it to a scanner.
SPTURBO. it will fire every time on the second twist of the key.
STEVIETURBO haven't seen any codes. i suppose it it time to take it to a scanner.
9 Second Club
Joined: Nov 2003
Posts: 13,616
Likes: 185
From: Norn Iron
The chances of a failed computer are almost zero.
Chances of a damaged computer through improper wiring or testing....much higher.
And you deleted your last post, so clearly something has changed since then ? And you still havent done the most basic first step...are there any faults reported by the ecu ?
Chances of a damaged computer through improper wiring or testing....much higher.
And you deleted your last post, so clearly something has changed since then ? And you still havent done the most basic first step...are there any faults reported by the ecu ?
Thread Starter
On The Tree
Joined: May 2011
Posts: 133
Likes: 8
I edited the post.
stock wiring nothing has changed from the factory.
trying to get it in to a reader. with my generic reader there is no faults no pending codes.
Once I get it read ill post findings.
stock wiring nothing has changed from the factory.
trying to get it in to a reader. with my generic reader there is no faults no pending codes.
Once I get it read ill post findings.
Thread Starter
On The Tree
Joined: May 2011
Posts: 133
Likes: 8
So I have an update on this. Had a mech look at this and said that the sensor/ magnet in the column for the key for antitheft is the problem. said have to replace the switch in the column.
odd. never heard of that.... but ok. been doing it for several years now. more annoying that anything.
odd. never heard of that.... but ok. been doing it for several years now. more annoying that anything.