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#1 |
Registered User
Join Date: Aug 2010
Location: Ventura
Posts: 151
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89 S10 4.3 misfire
What do think of these readings??
Cyl 1 - 130 - Wet 140 Cyl 2 - 135 - Wet 155 Cyl 3 - 120 - Wet 130 Cyl 4 - 150 - Wet 160 Cyl 5 - 140 - Wet 150 Cyl 6 - 125 - Wet 130
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1990 Chevy Suburban v2500 1990 Chevy/Geo Tracker LSi 4x4 2Dr 1996 Chevy/Geo Tracker LSI 4x4 4Dr 2011 Chevy Silverado Crew Cab LT 1991 Nissan 300zx SlickTop |
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#2 | |
Moderator
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Location: Cherryville, NC
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Re: 89 S10 4.3 misfire
Quote:
These readings are indicative of a well used engine... The variance between dry and wet are about standard, with the exception of cyl 2 which has some ring sealing issues. Cyl 4 is the only one with a reasonable result.... ![]() ![]() ![]()
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#3 |
Senior Member
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Location: Orem, Utah
Posts: 7,923
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Re: 89 S10 4.3 misfire
They're probably not directly related to your misfire. While some of them are low, early gasoline engines ran with 5:1 compression ratios.
However, as Aussie said, #2 readings indicate you may have some blow-by, causing spark plug fouling. How does that plug look?
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#4 |
Registered User
Join Date: Aug 2010
Location: Ventura
Posts: 151
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Re: 89 S10 4.3 misfire
We have pulled the plugs and none of them stuck out from another. All looked fairly normal. No smoke from the tail pipe. We have changed the plugs and wires a few days ago. We did notice, after starting the truck a few minutes after running, the exhaust smells like raw fuel. The hard misfire is only present at idle, and moving from a stop. The truck can cruse on freeway going 70mph no problem. We have found a good used (Compression tested) engine a county over with 98k miles for $450. Might be way to go
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1990 Chevy Suburban v2500 1990 Chevy/Geo Tracker LSi 4x4 2Dr 1996 Chevy/Geo Tracker LSI 4x4 4Dr 2011 Chevy Silverado Crew Cab LT 1991 Nissan 300zx SlickTop |
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#5 |
Registered User
Join Date: Jan 2013
Location: Calgary Alberta
Posts: 1,166
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Re: 89 S10 4.3 misfire
I put quite a few hundred thousand kms on those. I think I changed at least three coils on the 90. One quit in the intersection and I had it changed before AMA arrived. They don't always quit outright. Keep a spare.
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#6 |
Registered User
Join Date: Aug 2010
Location: Ventura
Posts: 151
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Re: 89 S10 4.3 misfire
We tried the MSD coil out of my 90 Suburban and the mis is still present
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1990 Chevy Suburban v2500 1990 Chevy/Geo Tracker LSi 4x4 2Dr 1996 Chevy/Geo Tracker LSI 4x4 4Dr 2011 Chevy Silverado Crew Cab LT 1991 Nissan 300zx SlickTop |
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#7 |
Moderator
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Location: Cherryville, NC
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Re: 89 S10 4.3 misfire
This sounds like a leaky fuel injector...dribbling fuel into throttle body causing over rich mix flooding a plug or 2....
Grab a couple of second hand injectors from a wrecking yard and try it,,,they are not that expensive to buy new. ![]() ![]() ![]()
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Family and country before all others... 2006 Chevy Silverado (Daily Driver) 2012 Chevy Equinox ![]() ![]() ![]() |
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#8 |
Registered User
Join Date: Aug 2010
Location: Ventura
Posts: 151
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Re: 89 S10 4.3 misfire
Tried another set of injectors, problem remains. Time to get another engine.
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1990 Chevy Suburban v2500 1990 Chevy/Geo Tracker LSi 4x4 2Dr 1996 Chevy/Geo Tracker LSI 4x4 4Dr 2011 Chevy Silverado Crew Cab LT 1991 Nissan 300zx SlickTop |
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#9 |
Registered User
Join Date: Oct 2005
Location: Overland Park, Ks.
Posts: 5,221
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Re: 89 S10 4.3 misfire
If it has a vacuum outlet on the back part of the intake manifold, a vacuum leak can cause a misfire like that. Check power brake booster & trans modulator & a/c vacuum resavoir.
George |
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#10 |
Registered User
Join Date: Jan 2013
Location: Calgary Alberta
Posts: 1,166
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Re: 89 S10 4.3 misfire
Two of the three 4.3's I had leaked coolant into the rear left combustion chamber but you would have noticed that sooner it its life.
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4.3, compression test, misfire |
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