Author Topic: Trucks bogging down  (Read 4046 times)

Offline three8six

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Trucks bogging down
« on: January 06, 2011, 04:28:03 pm »
My truck is a 1986 c10 4.3 v6 quadrajet carb TH400 transmission shorty headers single 2 1/2 inch exhaust turbo muffler. Problem is my truck bogs out either too lean or too rich or something whenever you press the gas for any sort of mild acceleration. It just dies out,  Ive replaced distributor, plugs twice, wires twice. Set timing to 0. It runs fine idling very smooth, even can rev it up and it doesnt really bog down its more when its under load. If anybody knows where I can find a wiring diagram for this engine also would be helpful? I did find a vacuum leak today fixed it, problem still wasnt corrected. I was curious if anybody has any more suggestions before I take this to a shop or burn it down in my yard?

Offline Slooby

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Re: Trucks bogging down
« Reply #1 on: January 06, 2011, 04:55:57 pm »
Have you replaced the fuel filter yet?  If not try that, it can cause it to bog down.

Offline Layne

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Re: Trucks bogging down
« Reply #2 on: January 06, 2011, 05:15:40 pm »
What about your vacuum advance? Maybe that?
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88 sierra - reman 350 700r4 "Eleanor"
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Offline three8six

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Re: Trucks bogging down
« Reply #3 on: January 06, 2011, 06:07:22 pm »
New carb, is there a fuel filter somewhere else other than that?  Half full tank....and my vacuum is right about 20-21 at idle. Please dont be too rough on me...

Offline three8six

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Re: Trucks bogging down
« Reply #4 on: January 06, 2011, 06:08:20 pm »
Also wanted to note is it "new" gas.

Offline Lt.Del

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Re: Trucks bogging down
« Reply #5 on: January 06, 2011, 09:34:06 pm »
does it overheat at all?  How old is the exhaust/muffler, any cat converter?  exhaust could be clogged w/ carbon and soote/rust.  Mine had that problem.  Too much back pressure.

Check for more vacuum leaks w/ some WD40, sounds like that too.
Choke working right?  Opens up all the way after 2 or 3 minutes idling?

Offline three8six

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Re: Trucks bogging down
« Reply #6 on: January 07, 2011, 12:38:08 pm »
Exhaust is all new. Headers are prolly a year old. The rest about a month old. No Cat converter, just a thrush welded muffler only about a month old. Id like to also say that none of this stuff has any miles on it maybe 2-3 miles tops?

Offline three8six

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Re: Trucks bogging down
« Reply #7 on: January 07, 2011, 12:38:43 pm »
And no, no overheating. I did see my knock sensor isn't hooked up could this be an issue?

Offline Grim 82

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Re: Trucks bogging down
« Reply #8 on: January 07, 2011, 12:49:40 pm »
Yes. If you have ESC it can do crazy things to your ignition timing without the knock sensor hooked up.
Give a man a gun, and he might rob a bank. Give a man a bank, and he might rob the world.

Offline three8six

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Re: Trucks bogging down
« Reply #9 on: January 07, 2011, 02:49:33 pm »
ESC? you mean the electronically controlled carb?

Offline Grim 82

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Re: Trucks bogging down
« Reply #10 on: January 07, 2011, 03:19:31 pm »
Electronic Spark Control. When the knock sensor detects pinging the ESC controller retards the timing. Hook up the sensor and see it that helps. Down the road though I would consider relocating the ESC system to the nearest garbage can.
Give a man a gun, and he might rob a bank. Give a man a bank, and he might rob the world.