can't figure it out - The 1947 - Present Chevrolet & GMC Truck Message Board Network

wyatt earp · 05-03-2010, 08:12 PM

i have a 1986 Gmc truck. Bought it a little rough and have been changing minor problems. Just recently after i changed the thermostat housing it started to act up.

I have poor acceleration when going up hill. tonight it stalled itself out. It smells really rich. I can't figure out why it is doing this and why.

any help would be great.

bitchin85 · 05-03-2010, 09:01 PM

thermostat housing shouldnt affect the way it runs unless u put the wront thermostat back in it and even that wouldnt be that dramatic of a differance.. get the carb rebuilt and go from there.. also just go aroung and look at your plugs and check your timing and go from there but my guess would for sure be carb problems.. whats on it now? stock quadrajet?

lester622 · 05-03-2010, 09:52 PM

if its a tbi im having the same problem and have no idea wat the hell is the problem

Hoods69BadBowTie · 05-03-2010, 09:57 PM

Yea there should be nothing that the t-stat or housing would have caused even with the wrong one. Sounds like a misfire with the plug wires or plugs maybe or the carb needs a good cleaning or rebuild. Might also check for any vacuum leaks you can find.

bitchin85 · 05-03-2010, 10:00 PM

Quote:

Originally Posted by lester622

if its a tbi im having the same problem and have no idea wat the hell is the problem

they didnt start tbi in these till 87. if its stock, its carbed

lester622 · 05-03-2010, 10:49 PM

Quote:

Originally Posted by *****in85

they didnt start tbi in these till 87. if its stock, its carbed

oops, thought they started tbi in 86

asphaltburner · 05-03-2010, 11:11 PM

Yo!
Given no other variables, and that only the t-stat housing was changed out,...what's the possibility that the t-stat has been reinstalled backwards?
You don't mention coolant temps during operation.
Todd.

wyatt earp · 05-04-2010, 12:01 PM

i had problems with leaking before this . i have changed all coolant hoses, new thermostat, new water pump, plugs and wires are not but about 3 months old. so its not running hot. i still have been leaking fluid, but not much(figured out what was causing that).

The dumb thing will run ok and then just die on me. yesterday it died when i was going up a hill. its like it will not power down to a lower gear and when it finally does, it dies or almost dies.
If i stomp on the gas, it sputters, if i gradually ask for gas it does ok.
Wish i could figure this truck out.

1974ChevyC10 · 05-04-2010, 02:22 PM

i hd this problem on a 74 i used to own basically if i stomped the pedal it would fall on its face like it had no power but if i gradually gave it gas it ran fine and going uphill it was lose power.turned out to be the fuel filter was dirty and needed replaced.changed it out and cleaned all the gunk out of the carb after that it ran like a champ.i would check the fuel filter as well as all lines and give the carb a good cleaning and rebuild if necessary.

**Captkaos** · 05-04-2010, 02:54 PM

lester622,
do you have a way to scan the ECM for the temp reading? If not you can try and replace the coolant sensor in your manifold. If it is faulty it will make the truck run rich.

05-03-2010, 08:12 PM	#1
wyatt earp Registered User Join Date: Apr 2007 Location: ohio Posts: 77	can't figure it out i have a 1986 Gmc truck. Bought it a little rough and have been changing minor problems. Just recently after i changed the thermostat housing it started to act up. I have poor acceleration when going up hill. tonight it stalled itself out. It smells really rich. I can't figure out why it is doing this and why. any help would be great.

05-03-2010, 09:01 PM	#2
bitchin85 Registered User Join Date: Aug 2009 Location: Lambertville MI Posts: 962	Re: can't figure it out thermostat housing shouldnt affect the way it runs unless u put the wront thermostat back in it and even that wouldnt be that dramatic of a differance.. get the carb rebuilt and go from there.. also just go aroung and look at your plugs and check your timing and go from there but my guess would for sure be carb problems.. whats on it now? stock quadrajet? __________________ "I'll keep my guns, money, and freedom. You can keep the "change"

05-03-2010, 09:52 PM	#3
lester622 Registered User Join Date: Jan 2008 Location: New Orleans, La. Posts: 229	Re: can't figure it out if its a tbi im having the same problem and have no idea wat the hell is the problem

05-03-2010, 09:57 PM	#4
Hoods69BadBowTie Chevys Kick A$$ Join Date: Jan 2005 Location: Zootown, MT Posts: 12,699	Re: can't figure it out Yea there should be nothing that the t-stat or housing would have caused even with the wrong one. Sounds like a misfire with the plug wires or plugs maybe or the carb needs a good cleaning or rebuild. Might also check for any vacuum leaks you can find. __________________ HOODS is what I answer too -'79, '77, '88 Pickup Sold, '85 Camaro, '83 T/A, '81,'83,'90 K5 Blazer All Sold -'79 3/4 ton "Big Yellow Bananna" Lifted 4spd. 39.5 TSL Swampers, The money Pit -'86 K5 Blazer Silverado 6.2 4" lift 35"s -'95 Ext. Cab Shorty 4" Tuff Country rolling 35" M/T's -'83 Monte Carlo T-Tops. 126,500 Original Miles -LATER I would rather push a Chevy then drive a ford!!

05-03-2010, 11:11 PM	#7
asphaltburner Registered User Join Date: Jul 2008 Location: Ault, Colorado Posts: 862	Re: can't figure it out Yo! Given no other variables, and that only the t-stat housing was changed out,...what's the possibility that the t-stat has been reinstalled backwards? You don't mention coolant temps during operation. Todd. __________________ '78 3/4 ton 4x4 custom "Todd-built" FRANKENTRUCK! Last edited by asphaltburner; 05-03-2010 at 11:12 PM.

05-04-2010, 12:01 PM	#8
wyatt earp Registered User Join Date: Apr 2007 Location: ohio Posts: 77	Re: can't figure it out i had problems with leaking before this . i have changed all coolant hoses, new thermostat, new water pump, plugs and wires are not but about 3 months old. so its not running hot. i still have been leaking fluid, but not much(figured out what was causing that). The dumb thing will run ok and then just die on me. yesterday it died when i was going up a hill. its like it will not power down to a lower gear and when it finally does, it dies or almost dies. If i stomp on the gas, it sputters, if i gradually ask for gas it does ok. Wish i could figure this truck out.

05-04-2010, 02:22 PM	#9
1974ChevyC10 Overworked and Underlaid Join Date: May 2002 Location: Flagstaff,Arizona Posts: 1,279	Re: can't figure it out i hd this problem on a 74 i used to own basically if i stomped the pedal it would fall on its face like it had no power but if i gradually gave it gas it ran fine and going uphill it was lose power.turned out to be the fuel filter was dirty and needed replaced.changed it out and cleaned all the gunk out of the carb after that it ran like a champ.i would check the fuel filter as well as all lines and give the carb a good cleaning and rebuild if necessary. __________________ I'd rather push a Chevy than drive a Ford The Beast-1978 C10 LWB Red-1978 C10 LWB (Uncle Mike)Michael Henry Millett 11/5/1957 to 03/08/2012 Gone but will never be forgotten-RIP (Uncle Chuck)Charles Manning Gulbronsen Sr 1956-2012 Taken from us to soon but you will live on in our hearts-RIP

05-04-2010, 02:54 PM	#10
Captkaos www.73-87chevytrucks.com Join Date: Dec 1999 Location: Birmingham, AL Posts: 6,935	Re: can't figure it out lester622, do you have a way to scan the ECM for the temp reading? If not you can try and replace the coolant sensor in your manifold. If it is faulty it will make the truck run rich. __________________ Chris Lucas 1973 Chevy C-10 1978 GMC Jimmy (2WD) - SOLD 1987 R10 twin turbo LS 1991 R3500 SRW CrewCab 1985 K5 diesel swapped project 1989 K5 2WD conversion w/ Vette susp Project Captkaos Customs 73-87chevytrucks.com



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