dr_68832
Nebraska
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Yea my needle does bounce. Dang it, I was hoping it wasn't that! I also bought the new updated injector spider for this engine, I'll keep you informed on how it goes.
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Thunderbolt
North Branch, Mn USA
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Could be the pump or the regulator. Is your fuel gauge bouncing all over or just vibrating rapidly ??? If it seems accurate but vibrates it is usually the instument cluster and if it bounces all over and is inaccurate it is the sending unit in the tank.The symtom you describe is almost always the fuel pressure regulator in those trucks so you may need a regulator and the fuel pump module to correct both problems. If you replace the fuel pump use only an OEM pump, but don't buy from a dealer. They wat $550.00 for the part. Napa sells the Delphi unit for $374.00 and they are who make the GM pump.
Bryan
2003 2500HD Ext. cab short box
6.0 liter 4.10 gears, Nelson performance PCM
98 K1500 4x4 heavy duty 1/2 ton
6,600lb GVWR 5,280lbs on the scale empty
14 bolt rear diff. 3:73 , Tranny and oil coolers
318,000 miles still purrin' like a kitten
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dr_68832
Nebraska
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Thanks guys for all the help. I'm kinda leaning to the fuel pressure regulator also because of the flooding. I got the fuel spider today and will let you know the outcome. It's kinda funny because both items cause almost the same failure.
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Engineer9860
Eagle Scout dad
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Fuel pump is the most common "no-start" ailment for the Chevy C/K series. TBI or Vortec, doesn't matter.
That is the area that I would look to first. If that isn't the cause, check that other stuff later, but suspect the fuel pump first.
I got 200,000mi out of the fuel pump on my '97 Blazer, but I have known them to fail at only 75,000mi.
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dodge guy
Bartlett IL
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Next time try and turn the ignition on and off 3-4 times before starting the truck. what happens is the fuel drains back into the tank because the check valve in the pump isn`t seating. by turning the ignition on and off a few times you are priming the fuel sysytem. the regulator is a possibility, but my money is on the pump!
Good luck!
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Thunderbolt
North Branch, Mn USA
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Engineer9860 wrote:Fuel pump is the most common "no-start" ailment for the Chevy C/K series. TBI or Vortec, doesn't matter.
That is the area that I would look to first. If that isn't the cause, check that other stuff later, but suspect the fuel pump first.
I got 200,000mi out of the fuel pump on my '97 Blazer, but I have known them to fail at only 75,000mi.
His isn't a no start though. It is a hard start which is usually the regulator, however the pump can also cause the same symptom. If his gas gauge is bouncing all over he needs to replace the pump module to fix that either way. It could be either one and the first thing I would do is check the fuel pressure with engine on and off and see if it maintains pressure.The other reason I suspect the regulator in his case is because it appears that the regulator is leaking into the intake. He states that it starts hard like it is flooded and then finally idles out which would mean gas is leaking into the engine. The pumps just plain bleed the pressure back into the tank.Regulators can be bad without a leak as well, but in his case it sounds like it is leaking. Just guessing though.
* This post was
edited 04/21/10 10:40am by Thunderbolt *
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WHS
Waitsburg, Wa.
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One other thought... One my 97' 5.7L, I had a similiar problem. Did a tune, which you have already done, but I also cleaned my TBI... This was a simple process, just pulled the air box and sprayed it down with carb cleaner. No more delayed start and ran like a champ. Sold it to my neighboe with 115K in 2006, with the same fuel pump and regulator, and it is still running today.
With 25+ years experience in the automotive service business, I always recommend to try the cheap and easy first!
Good luck
Fred
05' Layton Lite 170LT Cascade edition
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bucky
Eastern Shore of MD
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A pressure regulator failure will cause a hot hard start, not a cold hard start. An example would be it fires right up when you leave for lunch, but thirty minutes later wants to crank and crank but will finally start to get you back to work. When was the last time the filter was changed? The regulator will usually light the SES lamp once it gets bad enough.
99 Chev 7.4 crew dually and a Coachmen TT.
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Thunderbolt
North Branch, Mn USA
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bucky wrote:A pressure regulator failure will cause a hot hard start, not a cold hard start. An example would be it fires right up when you leave for lunch, but thirty minutes later wants to crank and crank but will finally start to get you back to work. When was the last time the filter was changed? The regulator will usually light the SES lamp once it gets bad enough.
Never once have I seen a pressure regulator on a Vortec 5.7 light the SES light and they almost always cause a cold start issue unless they leak bad. Most of the time they act up after sitting overnight and after the intitial start-up work fine unless the vehicle is parked a long time.Even the ones that I have replaced on cars were do to a cold start problem as well as a smell of gas. They work fine when the pump is running, but slowly leak down when the pump is off. Some leak more than others so sometimes they start harder after only sitting a short while.Also on these trucks they can get an SES light when the fuel pump is weak or the fuel filter plugs and causes a lean condition a PO171 & PO174 bank 1 and 2 lean comes to mind, but not sure. Under normal driving the there are no symptoms except the SES light. I had a Tahoe that would set a lean code occasionally and after replacing the filter it was fine for awhile. I eventually checked the pressure and it was loww. A new fuel pump permanently solved the problem. His problem still sounds like a regulator to me, but I have been wrong before.
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dr_68832
Nebraska
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Well guys the verdict is in. It was the fuel pressure regulator. When I lifted the plenum off there was a puddle of fuel under the regulator. Replaced the unit and fired right up. Thanks for all the input fellas!
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