hard starting 4.8(chokin and pukin)
07-17-2008, 12:50 PM
#1
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hard starting 4.8(chokin and pukin)
Hey fellas my truck is really actin up when I first start it up...after sitting all night and starting it for the 1st time in the morning it will crank fine and fire right up but the completly fall flat on its face...then crank over again but I have to play with the throttle to keep her to run and it will stay like that for about 1-3 min...
there is a very strong smell off raw fuel from the exhuast...I dont have any cats but it doesnt smell like reg. exhuast...if I try and drive it, it will go but as soon as I go to shift the rpms drop so quick it will usally stall before I get it back in gear and the clutch out...
somethings I tried was making sure that I turned the key on for alteast 10 sec. to let the fuel pump turn on and that kinda helped but it still happens...even after my truck sits all day at work (7-4) it starts fine!...Im wondering if its some sort of temp sensor maybe or and injector leaking down fuel over the night...if you guys have any ideas please throw them out there
by the way the truck has 160k and is maintained reg. with a tune up and filter changes about 5k ago...no tune or anything like that but next week Im swapping out the 00 PCM for an 02 with a custom tune so I really hope that helps me!...thanks for readin
there is a very strong smell off raw fuel from the exhuast...I dont have any cats but it doesnt smell like reg. exhuast...if I try and drive it, it will go but as soon as I go to shift the rpms drop so quick it will usally stall before I get it back in gear and the clutch out...
somethings I tried was making sure that I turned the key on for alteast 10 sec. to let the fuel pump turn on and that kinda helped but it still happens...even after my truck sits all day at work (7-4) it starts fine!...Im wondering if its some sort of temp sensor maybe or and injector leaking down fuel over the night...if you guys have any ideas please throw them out there
by the way the truck has 160k and is maintained reg. with a tune up and filter changes about 5k ago...no tune or anything like that but next week Im swapping out the 00 PCM for an 02 with a custom tune so I really hope that helps me!...thanks for readin
Is gas dripping from the vacuum line when you remove it or does it appear wet?
07-17-2008, 01:41 PM
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oops guess that was one thing I forgot to mention...it was replaced about two years ago but I have pulled the line off and it does not seem to be wet or smell like fuel at all...I did check fuel press. really quick a while ago and it was like 54 at idle or somewhere like that...hoepfully tonight I can check again...you guys think i should just replace it or not???...
07-17-2008, 03:18 PM
#4
Are you in an ethanol state? In MN here we go through fuel pressure regulators on cars like people go through toilet paper. Ethanol is corrosive and eats away at the rubber diaphragm. I would think a member on here would be kind enough to send you one from a regulated intake manifold for free. I would if I had one anyways. An LT1 I was working on 2 years ago started great when cold, hesitated starting occured when warm. You had to hold the gas down to start it and then pump it once it fired for about 10 seconds until the idle became stable. This car would not squirt gas out the regulator nor was the vacuum line wet. When i put my nose up to it, it only had a hint of a gas smell which I thought was normal. (it's an intake afterall). However I replaced the regulator anyways and that solved the problem. If you had a mityvac hand vacuum, I'd tell you to put like 15-18 inches of vacuum on it and see if the guage holds steady for at least 5 minutes. Any loss in vacuum and your regulator is shot.
07-17-2008, 03:29 PM
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How about a bad MAF?
I've heard of some strange problems related to the MAF failing. It's easy to eliminate as the problem by just disconnecting the harness before starting the truck in the morning. Maybe a long shot?
Mike
I've heard of some strange problems related to the MAF failing. It's easy to eliminate as the problem by just disconnecting the harness before starting the truck in the morning. Maybe a long shot?
Mike
07-18-2008, 07:07 AM
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Are you in an ethanol state? In MN here we go through fuel pressure regulators on cars like people go through toilet paper. Ethanol is corrosive and eats away at the rubber diaphragm. I would think a member on here would be kind enough to send you one from a regulated intake manifold for free. I would if I had one anyways. An LT1 I was working on 2 years ago started great when cold, hesitated starting occured when warm. You had to hold the gas down to start it and then pump it once it fired for about 10 seconds until the idle became stable. This car would not squirt gas out the regulator nor was the vacuum line wet. When i put my nose up to it, it only had a hint of a gas smell which I thought was normal. (it's an intake afterall). However I replaced the regulator anyways and that solved the problem. If you had a mityvac hand vacuum, I'd tell you to put like 15-18 inches of vacuum on it and see if the guage holds steady for at least 5 minutes. Any loss in vacuum and your regulator is shot.
by the way...the shifter works awesome hirdlej
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07-18-2008, 07:11 AM
#8
Glad you like it!, Now go find an ol' pistol grip or T-handle and screw it on! 
As far as the regulator goes, enough people on here have done engine swaps along with having oodles of extra crap laying around you think someone would give you a regulator. I would but all I have is '04+ stuff, sorry!
As far as the regulator goes, enough people on here have done engine swaps along with having oodles of extra crap laying around you think someone would give you a regulator. I would but all I have is '04+ stuff, sorry!
07-18-2008, 11:30 AM
#9
Sure sounds like the ever common fpr...I know I've had to replace mine once so far...dirty throttle body/bad IAC also comes to mind, not so sure how strong the raw fuel smell would be though. An injector leaking down would also give those same symptoms.
07-18-2008, 12:32 PM
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when I did the tune up I also sea foamed her as well as clean the IAC which was horrible!!!...def helped a lot but I might true the FPR but I wouldnt be suprised if it was a injector...what would be a good upgrade/replacement for the stockers if they are leaking?