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86-95 Trucks & 4Runners 2nd/3rd gen pickups, and 1st/2nd gen 4Runners with IFS

Low Compression

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Old Mar 3, 2008 | 01:37 PM
  #1  
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Low Compression

i did a compression test o3vz-e and on one cylinder it came back 45PSI where it was supposed to be 171 so any suggestions to what it might be causing this
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Old Mar 3, 2008 | 02:41 PM
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From: Salem, OR
head? Maybe sludge in the rings? Or shot rings...???
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Old Mar 3, 2008 | 03:18 PM
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From: Camino, Ca
burnt exhaust valve. They burn valves regularly
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Old Mar 3, 2008 | 03:36 PM
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From: Salem, OR
You should always keep a spare valve on hand so when your driving and burn one you can simply replace it!
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Old Mar 3, 2008 | 06:54 PM
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From: Camino, Ca
Originally Posted by 91Toyota
You should always keep a spare valve on hand so when your driving and burn one you can simply replace it!
I hope to hell you're joking....
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Old Mar 3, 2008 | 07:20 PM
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Did you squirt some oil down the weak cylinder and retest it?
If compression increases significantly then its rings.
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Old Mar 3, 2008 | 07:43 PM
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From: Salem, OR
Originally Posted by toytech76
I hope to hell you're joking....
Yeah...I am a jokester...lol
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Old Mar 3, 2008 | 08:44 PM
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From: NW Ark on wooded ten acres...Ozarks at large!
Originally Posted by 91Toyota
You should always keep a spare valve on hand so when your driving and burn one you can simply replace it!
Yeah, get ya some of them quick disco valves. Greatest thing since butter patties!

One cylinder being low like that it's more likely to be an exhaust valve. Bad rings don't tend to run low readings like that unless you have some major damage....which you would really notice. Major bad noise. Plus, ring wear isn't typically isolated to one cylinder. But, run the oil test for sure. Easy enough.
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Old Mar 3, 2008 | 08:58 PM
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From: Camino, Ca
rarely do you ever see rings go bad like that in a 3.0. We do so many valve jobs its not even funny. I can do those things blindfolded. lol If you do a valve job..make sure and do it right. Nothing half ass
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Old Mar 3, 2008 | 09:01 PM
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From: NW Ark on wooded ten acres...Ozarks at large!
Originally Posted by toytech76
rarely do you ever see rings go bad like that in a 3.0. We do so many valve jobs its not even funny. I can do those things blindfolded. lol If you do a valve job..make sure and do it right. Nothing half ass
Probably lack of regular valve adjustments? Finicky little buggers, the 3.0.
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Old Mar 3, 2008 | 09:08 PM
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From: Camino, Ca
yah, i think thats a big part of the problem. We charge about $400 to adj them and im sure the dealer charges even more. I can see why alot of people are turned off on wanting to do it. Better $400 then $2800
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Old Mar 3, 2008 | 09:13 PM
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From: NW Ark on wooded ten acres...Ozarks at large!
I totally agree.
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