Compression Test Results on 90 Pickup (1 Viewer)

Joined
Mar 18, 2005
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141
Location
Fayetteville, NY
I purchased the truck two weeks ago pretty much sight-unseen for $1200. It's a 1990 SR5 V6 with 163,000 miles. I checked the compression thsi weekend before investing any more $$ into the truck. Here are the partial results...it was raining like a bitch and 40 degrees so the fun wore off really quick.

Cylinder #2 = 130 psi
Cylinder #4 = 150 psi (first cylinder checked...)
Cylinder #6 = 30 psi
Cylinder #3 = 0 psi

I also noticed oil (more than just a sheen) on the end of the cylinder adapter for the compression test set-up following removal from the spark plug port.

So now I thinking maybe it's time to just junk this truck after going after the looser PO which outright lied about all the loving care and maintenance the vehicle had received. I did check the toyota repair history and the HG was done at 99k.

Any ideas ?
 
Joined
Mar 27, 2003
Messages
808
Location
Frederick, MD
Bummer.
Is an engine swap or rebuild out of the question?
Depending on the overall condition of the truck I wouldn't junk it. Part it out perhaps, but not junk it.
I'm in a similar boat. I bought a used 90 4x4 xtracab off of a wholesale lot with no history record. I knew there were maintenance issues that needed to be addressed, but the price was right and the rest of the truck was in excelent condition. The timing chain broke on me before I could get it to the state inspection :censor: But I knew that was the risk I was taking. Now I'm spending my evenings learning how to rebuild/replace the head.
If you do part it out, I'm interested in the seats!

:beer:
 
Joined
Mar 18, 2005
Messages
141
Location
Fayetteville, NY
So here's an update..I decided to recheck the compression since the last readings were taken with a cold engine...

Cylinder #2 155 lbs
Cylinder #4 160 lbs
Cylinder #6 30 lbs (added Tbs of oil and retest 70 lbs)
Cylinder #1 170 lbs
Cylinder #3 less than 5 lbs (40 lbs with Tbs of oil in cylinder)
Cylinder #5 165 lbs

So I need some advice....what is the probable diagnosis ? Should I tear into the engine or dump the truck. Are there any other checks I should do on the engine ?

Thanks for any and all advice !

Joe
 
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Joined
Jan 8, 2006
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9,797
Location
Ashland, OR
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www.jeffersonstatecruisers.com
The oil bringing up the compression usually means bad rings, but you can do a leak down test to confirm (leak down test is: set cylinder to top dead center on compression stroke, and use a leak down tester to pressurize the cylinder and measure the pecent of pressure loss). Read more here.

http://www.type2.com/library/engineg/leaktst.htm

Or do a poor mans leak down test (just use a compressor with a rubber air nozzle that seals the spark plug hole and listen to where the air is leaking) I had a 3.0 with an exhaust valve stuck open, from your super low readings this could be the problem. If it is, I heard a neat trick about threading rope into the cylinder and then turning the engine over by hand to force the rope up and close the valve... Didn't hear about it till I sold the 4Runner but! it sounds like it could work. Hope it's just valves and you can get them freed up...
 
Joined
Mar 18, 2005
Messages
141
Location
Fayetteville, NY
Thanks Jerod...I appreciate the tip..I'll try the air test this am on the two low cylinders.

I'm also looking at a new long block for $1400 assuming the worst case scenario....scored cylinder wall.

Does anyone know if the core returns for used engines require an assembled engine or would they take it in pieces ?

Joe
 
Joined
Jan 8, 2006
Messages
9,797
Location
Ashland, OR
Website
www.jeffersonstatecruisers.com
they usually want the block/heads all together. But all they are selling is the block and heads, no oil pan, or valve covers.... just the long block. But if you go that way and want to take a look in the cylinders, it's not too much work to put the heads back on before shipping it back.
 

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