Author Topic: Engine being cranky...  (Read 2217 times)

Offline Tomr80

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Engine being cranky...
« on: October 30, 2014, 07:10:04 AM »
I have a 1986 gmc 4x4 3/4 ton high sierra. Just got finished restoring it. However the engine is out of an 81. I don't know much about the engine other then it looks clean and runs really good and strong, well it did. The other day when I was driving it, it acted kinda funny. I want Opinions besides mine. While in first gear shift to second and if you accelerate normally runs just fine but when you lug the Engine it seems to me it's missing or something while accelerating pretty hard, it starts to go away soon as you let off the accelerator. If you mash it to the floor while it is doing this it almost acts like it wants to kill it. But just driving around normally it seems fine. But when you mash the gas while in gear or hot rod it a little bit it acts up. It's a manual btw. I think I know what it is causing it, I want some opinions to reassure me. Thanks
1986 gmc 3/4 ton white.

Offline 87burb4x4

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Re: Engine being cranky...
« Reply #1 on: October 30, 2014, 11:58:55 AM »
Mine is doing the same thing. Even tho I have a 700-r4 tranny and it's a tbi engine, the symptoms are the same. I've cleaned the tbi, changed the EGR and EGR solenoid and vacuum lines, replaced spark plugs wires cap rotor etc. My timing was off initially and it helped it out tremendously. Have you checked time?
« Last Edit: October 30, 2014, 09:22:35 PM by 87burb4x4 »
87 4x4 v10 Suburban
350 tbi
3" lift w/ 33x12.50xr15 tires

Offline Tomr80

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Re: Engine being cranky...
« Reply #2 on: October 30, 2014, 12:08:14 PM »
I Ordered acap, rotor, wires, and spark plugs. I'm going to go with that for now see what that does. What is the correct timing for these trucks I've heard it's like 15 to 16°? Hopefully that will whip it into shape!
1986 gmc 3/4 ton white.

Offline 87burb4x4

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Re: Engine being cranky...
« Reply #3 on: October 30, 2014, 12:19:11 PM »
I'm not sure about the timing on an 81. My 87 requires a 2-4o setup. Surely someone on here will chime in on that. There are lots of folks on here way more qualified than I for that question. Good luck!
87 4x4 v10 Suburban
350 tbi
3" lift w/ 33x12.50xr15 tires

Offline rich weyand

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Rich

"Working Girl": 1978 K-10 RCSB 350/TH350/NP203 +2/+3 Tuff Country lift

Offline Tomr80

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Re: Engine being cranky...
« Reply #5 on: November 03, 2014, 10:19:48 AM »
Timing was good. Cap, rotor, plugs, plug wires, air filter and oil filter were horrible! It runs like a striped ape!!! One of the post terminals on the cap was actually broke. It was a much needed tune for sure. Now my next focus is that junk quadrajet!! Ha ha
1986 gmc 3/4 ton white.

Offline Tomr80

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Re: Engine being cranky...
« Reply #6 on: November 03, 2014, 10:26:00 AM »
1986 gmc 3/4 ton white.