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Should I be concerned about these compression numbers?

1273 Views 21 Replies 7 Participants Last post by  Ubermensch
Dealer measured:


Dealer says spec is 130-140 and everything is good.

Manual says spec is 128-156.

Should I be concerned about the 125 cylinder, or is 3 psi no big deal. I'm guessing they did a dry test and if they added a little oil the numbers would have been better. What do you guys think?
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Actually, that is pretty low for a 2JZ-GTE motor. You've also got a variance of 20 psi from #1 to #6, which also isn't a great thing. I'm moving this post over to MKIV Tech, where it might get noticed and stay closer to the top. Good luck to you.

Steve T.
i had very similar readings right before I bought my supra 2 weeks ago except i had a 90 in the # 6 cylider. Are they doing the compression test wet or dry becuase mine was 90 dry 120 wet. Anyways since the car i bought was toyota certified from the dealer they agreed to install a whole new block and rebuild the entire top end. But they were at first trying to say the same shit about how the manual says 128-156. you will never be able to put out the high hp numbers with compression on the low end of the spectrum. My recomendation would be to take it apart. It might only be rings and valves but it could be scarring in the cylider in which case you need some serious work. Anyways i hope your under warrenty.

SuprasOwnU, your opinion would mean a little more if you weren't trying to buy it too :D

A little more info, the car only has 46k miles.
yeah i went and looked at it last night, its pretty nice....i wish i got a change to listen to it run, it just looked pretty nice. the center console what broken, but in every single supra ive ever seen they are broken....the hood paint was screwed up pretty bad though

let me know what you decide..
Eh, I don't think the hood is that bad for a seven year old car. I'm far more worried about the compression results than the hood. I'm trying to figure out what could have happened in a stock car with only 46k miles to cause it. The only thing I can think is it was run hard from day 1 and the rings didn't seat well. You guys have any idea on the price of new rings?

It was pretty cold this morning so I think that may have caused the low numbers, but the variation is a concern.
i remember hearing that running some pretty sh!tty octane gas screw up the compression as well, like some 87 octane but i dont know if im correct or not
I think I'm going to go for it. The tech that ran the test felt it was fine. He said that previous supras he had tested were similar and that usually if there's a problem the cylinder is under a 100 psi. Hopefully if I run some better oil and clean the carbon out it will help things.
dont do it the #s are to boarder line i would just wait and look some more ! unless you can get a warrenty with it!
I was just about to call when I saw your post. The dealer said that they'd sell me a warranty if I wanted it. The car is $21.5k for a 46k mile '94. What do you think?

Also, it doesn't make much sense to purchase the warranty since I'm sure if I go BPU they'll blame that on the problem and wouldn't cover it anyway...
get it toyota certified. that means you get a 100,000 mle warrenty from the time you purchase on drivetrain. I skipped the wrap around but got it toyota certified. Then they will have to fix the engine low compression problem.

Toyota Certified only applies to vehicles less than 5 years old. Also the warrenty is from the original date of purchase (unless you spring for the bumper to bumper).

I wouldn't buy it because it could have a burnt valve. I believe that 6 is the cylinder which gets the EGR.

I wouldn't consider it normal compression based on other numbers I've seen.

An dealer that is telling you they've done compression tests on lots of turbo supras is flat out lying. There aren't more than a handful of supras in any city anywhere.
That 125 is too low. You also want to stay within 14 psi of each other. Which 3 cyclinders are marginal and one isn't close. I wouldn't buy it without planning on a rebuild. Getting the dealer to to a rebuild after they know the compression before they sell you the car and the warranty is going to be a challenge. Sorry for the bad news ,but it beats spending 20K for a broken car.


For a point of reference I just did a compression test on my 94TT with 56K(bpu+++ for the last 30K) and got:

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My car is BPU, and has been run very hard for the past year and a half with many many many high speed pulls. My compression #s (cold, so they would be a little higher warm) were all 172-177. While the gauge was probably inaccurate and read a little high, they were within 5 psi of each other.

Those #s suck. Of course the dealer could be trying to con you into buying a new engine, I'd just do the test myself.

Remember to get an EGR blockoff plate, or your new engine could look like that after a while...
you can always buy the car and if it goes bad and its bpu just put everything back to stock !
Thanks for all the help guys. I told him I was going to pass on the car. To he honest I've been fighting with myself back and forth and you guys helped convince me. When I bought my current car there were no doubts in my mind and I think I'll wait for the same on the supra..
Uber...I had even lower comp. readings AFTER I bought my SUPRA. The guy before me put NOS in the car and noticed the cylinder heads were scorched. Luckily I had a TLC Warranty and they, Arlington Toyota, bought me a new short block. My comp. readings ranged from 105-140. Now the car runs great!!
Uber, use low readings to get the car for $3000-$4000 less, and then buy a new short block for $2000 and have it put in. Voila.
Monster, I was thinking the same thing, but realistically I'm sure he can sell the car at the given price to someone that doesn't bother getting the compression tested. Hell, he had some people from this board offer to buy it for 2k over what he was asking in cash, sight unseen.:rolleyes:
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