scratching my head ? engine stumbling - The 1947 - Present Chevrolet & GMC Truck Message Board Network

roadking · 07-10-2005, 09:10 AM

my engine acts like its almost running on 7 cylinders kinda out of the blue, 2000 miles on a gm crate with new everything. eldeblock 600 carb., edel fuel pump and intake, summit hei. engine was running fine, last thing i did to the engine was adjust the idle mixture srews, ran fine after that until i started one morning about a week later then it had the miss. heres what i"ve done since then. had ignition module checked, changed plugs. wire , cap, rotor, checked voltage to the hei, fuel filter clean, adjusted ims about 3 turns out, choke opens up properly, timing has not changed (10degree) seems to be getting plenty of fuel, engine is not smoking. i have not done a compession check but doesn't seem cylinder related. so im kinda scratching my head now, is there anything else i've i need to check? thanks

Gordo · 07-10-2005, 09:22 AM

Sounds like you have eliminated the ignition system, better do the compression test. Is this a steady skip or a random misfire?

Gray Ghost · 07-10-2005, 10:14 AM

If it's random, check your ground and the wire to the distributor, before you do a compression test...mine was the ground and the power wire. It was dropping 500 rpm at will. Found the dissy wire almost apart (inside the harness no less) and wired to the alternator.

roadking · 07-10-2005, 12:27 PM

only thing i've noticed different is when i adjust my right side idle mix. screw in all the way it does not want to die out like before, the left side will die out if i adjust it in. what would be the procedure for checking and cleaning the IMS ?

jhow66 · 07-10-2005, 02:56 PM

Take mixture screw all the way out and and use air hose to blow out the passage. This wiil probably cure your problem as the idle passage is stopped up if it will not affect the idle speed.

1STtimePRo'71 · 07-10-2005, 06:23 PM

roadking · 07-10-2005, 10:29 PM

i got a chance to blow out the ims, no more stumble ran great. reset ims to edelbrock recommendation ran fine for awhile then started to stumble again on road test. i'll blow out again tommarow and see what happens.

Gray Ghost · 07-10-2005, 11:09 PM

Have you checked your fuel filters? Sounds like trash is getting in.

07-10-2005, 09:10 AM	#1
roadking Registered User Join Date: Nov 2003 Location: kc Posts: 229	scratching my head ? engine stumbling my engine acts like its almost running on 7 cylinders kinda out of the blue, 2000 miles on a gm crate with new everything. eldeblock 600 carb., edel fuel pump and intake, summit hei. engine was running fine, last thing i did to the engine was adjust the idle mixture srews, ran fine after that until i started one morning about a week later then it had the miss. heres what i"ve done since then. had ignition module checked, changed plugs. wire , cap, rotor, checked voltage to the hei, fuel filter clean, adjusted ims about 3 turns out, choke opens up properly, timing has not changed (10degree) seems to be getting plenty of fuel, engine is not smoking. i have not done a compession check but doesn't seem cylinder related. so im kinda scratching my head now, is there anything else i've i need to check? thanks __________________ 71 C10 SWB BLACK AND WHITE 350 CRATE TH350 ENJOY LIFE Last edited by roadking; 07-10-2005 at 09:13 AM.

07-10-2005, 09:22 AM	#2
Gordo Registered User Join Date: Jan 2001 Location: Killingworth, CT. USA Posts: 3,378	Sounds like you have eliminated the ignition system, better do the compression test. Is this a steady skip or a random misfire? __________________ 1971 C10 swb stepside 350/700R4/3.73posi (retired as of 4/22/03) 1998 S10 short bed 2002 S10 Blazer 1942 Oldsmobile 1958 Massey Harris Pony 1951 Wife Killingworth, Connecticut May those who love us, love us, any of those who do not love us, may God turn their hearts. And if God is unable to turn their hearts, may he turn their ankles so we may know them by their limping. A man who works with his hands is a laborer; a man who works with his hands and his brain is a craftsman; but a man who works with his hands and his brain and his heart is an artist.

07-10-2005, 10:14 AM	#3
Gray Ghost Senior Member Join Date: Sep 2004 Location: Terrell, TX Posts: 1,967	If it's random, check your ground and the wire to the distributor, before you do a compression test...mine was the ground and the power wire. It was dropping 500 rpm at will. Found the dissy wire almost apart (inside the harness no less) and wired to the alternator. __________________ Kelly '05 GMC Sierra SLE Z71 Bone stock except for new bed rail caps.

07-10-2005, 12:27 PM	#4
roadking Registered User Join Date: Nov 2003 Location: kc Posts: 229	only thing i've noticed different is when i adjust my right side idle mix. screw in all the way it does not want to die out like before, the left side will die out if i adjust it in. what would be the procedure for checking and cleaning the IMS ? __________________ 71 C10 SWB BLACK AND WHITE 350 CRATE TH350 ENJOY LIFE

07-10-2005, 02:56 PM	#5
jhow66 Registered User Join Date: Jun 2002 Location: Knoxville Tenn. Posts: 3,058	Take mixture screw all the way out and and use air hose to blow out the passage. This wiil probably cure your problem as the idle passage is stopped up if it will not affect the idle speed. __________________ 56 Chevy Bel-Air 2dr. HT (purchased new) 71 Chevy Cheyenne SWB PU (502HO) 65 GMC short bed step--work in progress and my gofer

07-10-2005, 06:23 PM	#6
1STtimePRo'71 Registered User Join Date: Feb 2005 Location: Lake Crystal, MN Posts: 656	__________________ -Cory 1967 2 Wheel Chevy

07-10-2005, 10:29 PM	#7
roadking Registered User Join Date: Nov 2003 Location: kc Posts: 229	i got a chance to blow out the ims, no more stumble ran great. reset ims to edelbrock recommendation ran fine for awhile then started to stumble again on road test. i'll blow out again tommarow and see what happens. __________________ 71 C10 SWB BLACK AND WHITE 350 CRATE TH350 ENJOY LIFE

07-10-2005, 11:09 PM	#8
Gray Ghost Senior Member Join Date: Sep 2004 Location: Terrell, TX Posts: 1,967	Have you checked your fuel filters? Sounds like trash is getting in. __________________ Kelly '05 GMC Sierra SLE Z71 Bone stock except for new bed rail caps.



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