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73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: 87swb on December 06, 2005, 02:36:00 pm

Title: thermostat question
Post by: 87swb on December 06, 2005, 02:36:00 pm
when i first start my truck when the engine is cold i accelerate and the engine boggles down but when the engine warms up it wont boggle down anymore or not as bad and i have a 160 degree thermostat now and the truck runs about 110 degrees now and about 130 or 140 in the summer. could it be boggling down because of the thermostat or something else. the motor is timed at 15 degrees if that matters.

Title: Re: thermostat question
Post by: roundedline on December 06, 2005, 02:02:00 pm
How cold does it get where you are?  Is the truck "warmed up" by the time you start driving it?

Chris Lucas
www.73-87chevytrucks.com
www.captkaoscustoms.com
Project Su
Jimmy 2WD Project

Title: thermostat question
Post by: 87swb on December 06, 2005, 02:52:00 pm
i live in tipton county, TN which is in west TN and yesterday it was in the low 30s high 20's. but the truck isn't warmed up to operating temperture when i start driving it but after i crank it i usually let it sit for about 3 to 5 minutes.

Title: carb
Post by: Leadfoot on December 06, 2005, 05:57:00 pm
Is it a stock elec. choke quadrajet?? If so thats normal ,keeps ya from screamin a cold motor..

Tim

Edited by: Leadfoot at: 12/6/05 6:40 pm
Title: carb
Post by: Lt.Del on December 06, 2005, 05:38:00 pm
How about the choke?  Is it manual or electric. You didn't give any info on the type of truck...year, model, engine?  

SgtDel

www.delbridge.net

Title: carb
Post by: 87swb on December 06, 2005, 06:57:00 pm
ah yeah you're right, sorry about that. it is a 1987 Chevrolet Silverado R-10 2WD SWB. it has a TBI(fuel-injected) 305 that is bored 0.060 over with headers. it has a Turbo 400 tranny with a 10 bolt rear-end to top it off.

Title: operating temp
Post by: ChevyGuy on December 06, 2005, 10:24:00 pm
I would find out what operating temp your year model motor runs the best and buy the right thermostat. Every motor runs at a certain temp the best and if its not at that temp it wont run like it should. Example is my 76 the motor in it is 180 operating temp compared to my 2003 chevy truck I drive at work runs about 210.

Title: Re: operating temp
Post by: roundedline on December 07, 2005, 09:29:00 am
For an 87, I think you have one that is too cold.  I would suggest a 180.

Chris Lucas
www.73-87chevytrucks.com
www.captkaoscustoms.com
Project Su
Jimmy 2WD Project

Title: operating temp
Post by: 87swb on December 07, 2005, 09:38:00 am
the one i had in it said 195 but only ran about 160 or 170 in the summer. i guess i'll get another one and try it. thanks everybody i'll keep ya updated.

Title: Re: operating temp
Post by: roundedline on December 07, 2005, 03:16:00 pm
The temp number isn't what the temperature will be, it is the temp that it opens.  ECM vehicles run hotter because it lowers emmissions.

I am in no way saying the thermostat is what is causing all of the problems.

Chris Lucas
www.73-87chevytrucks.com
www.captkaoscustoms.com
Project Su
Jimmy 2WD Project

Title: operating temp
Post by: 87swb on December 07, 2005, 03:51:00 pm
well it may not help nothing but it won't hurt nothing either and there only about $3.99 at Auto-Zone so i'll try it. you don't think it could be be the timing because it is timed at 15 degrees and it is suppost to be at 10 degrees. a mechanic timed it at 10 but it wouldn't stay because he said the timing chain had slack in it, so....i don't know.

Title: operating temp
Post by: 87swb on December 07, 2005, 07:41:00 pm
well i sort of have an update. i tested the computer with one of those keys you get at auto zone and a code 32 flashed which is a problem with the EGR valve. anybody think this could be part of the problem?

Title: driveability
Post by: VileZambonie on December 07, 2005, 07:50:00 pm
1st your t-stat should be a 195° Running a colder tstat will not do anything accept lower your thermal efficiency and waste fuel economy.

2nd your ignition timing should be set at 0° with EST in bypass mode.

As far as your DTC 32 that really doesn't sound like your driveability problem.

Start with the basics and check all of your ignition components and finally check your fuel pressure. Bogging is usually lack of fuel pressure or an exhaust restriction.

Good luck

Title: driveability
Post by: 87swb on December 07, 2005, 09:49:00 pm
so you don't think the EGR has anything to do with it??? what is EST in bypass mode?
and how does a lower thermostat hurt gas mileage?

Title: driveability
Post by: 87swb on December 08, 2005, 08:42:00 pm
i took my EGR valve off and cleaned it today and i changed my thermostat to a 195. unfortunately neither have helped. can anyone else suggest anything?

Title: Re: driveability
Post by: roundedline on December 09, 2005, 11:42:00 am
Are you still getting the code?

Chris Lucas
www.73-87chevytrucks.com
www.captkaoscustoms.com
Project Su
Jimmy 2WD Project

Title: driveability
Post by: 87swb on December 09, 2005, 08:31:00 pm
i don't think so or it hasn't at least while i've been driving. i turned the distributor a little like maybe a millimeter counterclockwise and it seemed to help since it is timed at 15 degrees so it is probably at about 12 or 13. it is running a little better since i've changed that stuff.

Title: Re: driveability
Post by: H A REDNECK on December 13, 2005, 07:53:00 pm
Chevy's are [cold natured] bad about acting like yours when not at proper operating temp during cold wether. I would put a 195 thermastat in set timing at o , the computer will control advance or retard. Hey I'm from TIPTON CO. myself. ATOKA

Title: driveability
Post by: 87swb on December 26, 2005, 02:04:00 pm
i have finally figured out what is wrong. my truck has dual tanks. the left gas tank's fuel pump is going out because when i switch over to the the right tank, when i first start my truck, or when it is cold, it won't do it. what does everybody think about this???

Title: Re: driveability
Post by: roundedline on December 29, 2005, 09:47:00 am
Does it do this consistently with the "good" tank, if so, you can crank it with the bad one and then swap to the good one and see if the syptoms disappear.

I am not disagreeing, as one of my pumps went out and right before it did, the truck started running like crap and then lost power and died.  It was doubly bad since the selector switch was going out at the same time.  I was about 800 miles from home..

Chris Lucas
www.73-87chevytrucks.com
www.captkaoscustoms.com
Project Su
Jimmy 2WD Project

Title: Re: driveability
Post by: DnStClr on December 30, 2005, 07:26:00 pm
87swb, Hope you found the problem- it seems like the truck ought to be bogging down when cold AND warm when the fuel pump goes out. I was thinkin that the throttle plate wasn't closed completely when cold.(worn plate shaft bearing).