1998 gmc truck

kandyman · 07-21-2008, 09:50 AM

ive got a 98 gmc with a 383 vortec in it. I have a problem where it wants to cut out when you get on it. It is fuel injected with 1.6 rockers, lt4 hot cam, cai and some other parts. If I easy into it I can get it to go clear past 5 grand but when you punch it it cuts out at 4 grand. It acts like its starving for fuel but the fuel pressure says its alright. I dont know if the fuel regulator is adjustable or not is it.

bradrhale · 07-21-2008, 11:56 AM

how hot of cam?? what pistons are you using and what grade gas are you using?? have you changed your ignition system or still using stock??

kandyman · 07-21-2008, 12:24 PM

still stock ignition but I have read up on this and there are plenty of people that have 383 with stock ignition. with 1.6 ration rockers the cam is .525/.525 which there again plenty of people run this cam. I use only premium 91 octane. I am running keith black pistons.

bradrhale · 07-21-2008, 03:09 PM

when did you start with this problem?? how long after the buildup i mean?? does she spit and sputter at 4 grand?? hard to diagnose with the little info that i have but it might have an air problem. if she cant get enough air when gassin her, she will try to pass out and stall. have you replaced the stock breather with something that is going to breathe better?? might be why you can ease off into her and not be able to push the envelope.

kandyman · 07-22-2008, 03:22 AM

I havent got it to run good enough to put it on the road yet, so the build isnt over yet. I have a huge cold air intake that moves plenty of air. When it hits 4 grand it cuts out and tries to die on me.

bradrhale · 07-22-2008, 06:46 AM

have you pulled the plugs to see if they are fouling out?? also, have you reprogrammed your ecm to allow for the increased displacement and fuel air ratio??

kandyman · 07-22-2008, 10:22 AM

sry, yes it was tuned by wheatlet tuning outta texas, the plugs look fine they show just a little brown or tan on the ceramic parts of the plug. I dont know what to do.

bradrhale · 07-22-2008, 02:56 PM

wish i could tell you something good to look for. i have been thinkin about this half the day and cant come up with anything besides that you might have 2 new parts that are conflicting with each other. sorry that i cant be anymore help. hopefully, someone here will chime in with an idea. sneakysportsman is pretty good with engine performance but havent seen him in a while.

stumpuller454 · 07-22-2008, 05:19 PM

if you can road test with a buddy and a fuel pressure tester that is visable, check the pressure at the 1-2 and 2-3 shifts at W.O.T must make 52 psi minimum, i`ve heard of alot of guys removing the regulator (on 383s) or by-passing it to get full pressure, not sure how "okay" that is...

kandyman · 07-22-2008, 07:04 PM

is there a way to adjust the regulator.

07-21-2008, 09:50 AM	#1
kandyman Junior Member Join Date: Jul 2008 Posts: 8	1998 gmc truck ive got a 98 gmc with a 383 vortec in it. I have a problem where it wants to cut out when you get on it. It is fuel injected with 1.6 rockers, lt4 hot cam, cai and some other parts. If I easy into it I can get it to go clear past 5 grand but when you punch it it cuts out at 4 grand. It acts like its starving for fuel but the fuel pressure says its alright. I dont know if the fuel regulator is adjustable or not is it.

07-22-2008, 05:19 PM	#9
stumpuller454 Senior Member Join Date: Dec 2007 Location: Grande Prairie, AB Posts: 2,043	if you can road test with a buddy and a fuel pressure tester that is visable, check the pressure at the 1-2 and 2-3 shifts at W.O.T must make 52 psi minimum, i`ve heard of alot of guys removing the regulator (on 383s) or by-passing it to get full pressure, not sure how "okay" that is... __________________ SUPERCHARGED 454 K2500 GMC! 450hp and 600ft/lbs http://www.youtube.com/watch?v=WJ27RJHfJKE "sailing with Captain Morgan often!"

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07-21-2008, 11:56 AM	#2
bradrhale Senior Moderator Join Date: Apr 2006 Location: Texas Posts: 8,030	how hot of cam?? what pistons are you using and what grade gas are you using?? have you changed your ignition system or still using stock??

07-21-2008, 12:24 PM	#3
kandyman Junior Member Join Date: Jul 2008 Posts: 8	still stock ignition but I have read up on this and there are plenty of people that have 383 with stock ignition. with 1.6 ration rockers the cam is .525/.525 which there again plenty of people run this cam. I use only premium 91 octane. I am running keith black pistons.

07-21-2008, 03:09 PM	#4
bradrhale Senior Moderator Join Date: Apr 2006 Location: Texas Posts: 8,030	when did you start with this problem?? how long after the buildup i mean?? does she spit and sputter at 4 grand?? hard to diagnose with the little info that i have but it might have an air problem. if she cant get enough air when gassin her, she will try to pass out and stall. have you replaced the stock breather with something that is going to breathe better?? might be why you can ease off into her and not be able to push the envelope.

07-22-2008, 03:22 AM	#5
kandyman Junior Member Join Date: Jul 2008 Posts: 8	I havent got it to run good enough to put it on the road yet, so the build isnt over yet. I have a huge cold air intake that moves plenty of air. When it hits 4 grand it cuts out and tries to die on me.

07-22-2008, 06:46 AM	#6
bradrhale Senior Moderator Join Date: Apr 2006 Location: Texas Posts: 8,030	have you pulled the plugs to see if they are fouling out?? also, have you reprogrammed your ecm to allow for the increased displacement and fuel air ratio??

07-22-2008, 10:22 AM	#7
kandyman Junior Member Join Date: Jul 2008 Posts: 8	sry, yes it was tuned by wheatlet tuning outta texas, the plugs look fine they show just a little brown or tan on the ceramic parts of the plug. I dont know what to do.

07-22-2008, 02:56 PM	#8
bradrhale Senior Moderator Join Date: Apr 2006 Location: Texas Posts: 8,030	wish i could tell you something good to look for. i have been thinkin about this half the day and cant come up with anything besides that you might have 2 new parts that are conflicting with each other. sorry that i cant be anymore help. hopefully, someone here will chime in with an idea. sneakysportsman is pretty good with engine performance but havent seen him in a while.

07-22-2008, 07:04 PM	#10
kandyman Junior Member Join Date: Jul 2008 Posts: 8	is there a way to adjust the regulator.