Compression Readings - Toyota Nation Forum : Toyota Car and Truck Forums

patcal · 08-12-2009, 06:48 AM

I did a compression test last Sunday. Here are my specs.

1. 200
2. 200
3. 190
4. 180

200-180=20PSI. The 20 PSI is over the factory limit. It is supposed to be 191 PSI with a minimum of 142 with a max difference of 14 PSI. Is this a big deal? Thanks.

eage8 · 08-12-2009, 09:29 AM

I wouldn't really worry about it...

patcal · 08-12-2009, 10:44 AM

Thanks.

toyotaspeed90 · 08-12-2009, 10:44 AM

that's just a 10% variant..... 10% of 142 is 14psi, which is probably where that # derives from....

Ghostyman · 08-12-2009, 03:02 PM

Those are pretty healthy numbers, I wouldn't worry about them either.

One thing you might want to try is retesting and doing the lower compression cylinders first. Sometimes you will get lower readings later in the test because the battery is weak from so much cranking.

patcal · 08-12-2009, 03:29 PM

Thanks. I will give that a try. I also will not worry about. One less thing.

Donald · 08-12-2009, 08:19 PM

Quote:

Originally Posted by patcal

I did a compression test last Sunday. Here are my specs.

1. 200
2. 200
3. 190
4. 180

200-180=20PSI. The 20 PSI is over the factory limit. It is supposed to be 191 PSI with a minimum of 142 with a max difference of 14 PSI. Is this a big deal? Thanks.

Yes. A 10% difference is a lot.
I bet your idle is not smoothe. If it is, it won't be for very long.
If they were all at 180, I would say don't worry about it, but 10% difference is at the limit.
I suggest you start planning for some engine work in the not too distant future.

patcal · 08-13-2009, 10:49 AM

My idle is rough. That is the main problem. I have another thread but it has just about run it's course. I did the compression check as a last resort. If this is a real problem that I am unable to fix without major engine work, than it's time to get rid of it. I do not have a garage anymore so I have nowhere to do that kind of major work.

Donald · 08-13-2009, 11:45 AM

Oh yeah! That's you.
I had suggested the compression test.
The most likely cause is stuck or broken rings, but it could also be a leaking valve seat, or head gasket.

If you get rid of this car, will you replace it with another? At what cost?
Why don't you look into the cost of replacing the engine with one from a salvage yard (with a gurantee)
A rebuild might be worth it, depending on what they quote you.

I have heard people say that Seafoam (any auto parts store) can un-stick rings and clear out carbon buildup, but have never tried it myself.

For a few dollars I think it is worth a try. It might save you a few hundred if it isn't something serious like broken rings or blown head gasket.

You might want to try that, and start using gas from stations on the Top Tier List.

http://www.toptiergas.com/

http://www.toptiergas.com/retailers.html

http://www.toptiergas.com/why.html

canadianae92 · 08-13-2009, 01:23 PM

your compression looks pretty good

mine was
210
130
170
210

yea... lol, and my car still runs fairly good, so I bet yours runs perfectly fine.

toyotaspeed90 · 08-13-2009, 01:46 PM

could be from a chip in the valve....

my 4afe had a bad idle (back in the day, I know.. me with a 4afe) which was misdiagnosed by Toyota as a bad coil.... fast forward a few months and I blew the HG somehow (was babying it because I knew it wouldn't last much longer.... car only had like 130k at the time) and that was the 4afe's end....

Donald · 08-13-2009, 03:45 PM

Quote:

Originally Posted by canadianae92

your compression looks pretty good

mine was
210
130
170
210

yea... lol, and my car still runs fairly good, so I bet yours runs perfectly fine.

210 to 130 !!??

And it runs fine? WOW! I'm impressed!!!

canadianae92 · 08-13-2009, 09:58 PM

It idles rough at 1000 like it has a mild cam. Since I did the compression test I've been to a number of auto-x events, it makes it to redline with no problem. I've taken it to redline countless times too... I beat a 2003 3.8 v6 automatic mustang in a drag was ahead the whole time then he started gaining at the end of third and they are supposed to have about 200hp stock.

Maybe I buggered up on cyl #2 but I thought it was pretty straight forward. Dropped a tad bit of oil into the cyl and it bumped compression up to 240 If I remember correctly so I'm guessing bad rings or bad test....

patcal · 08-14-2009, 06:35 AM

Thanks for all the suggestions. I really do appreciate all of them. I am going to re-do the test tomorrow. I may try the Seafoam. I have never used it. I use the cheapest gas out there. I will also try Donald's suggestion of using TOP Tier gas for awhile.

Donald · 08-14-2009, 04:59 PM

Quote:

Originally Posted by canadianae92

It idles rough at 1000 like it has a mild cam. Since I did the compression test I've been to a number of auto-x events, it makes it to redline with no problem. I've taken it to redline countless times too... I beat a 2003 3.8 v6 automatic mustang in a drag was ahead the whole time then he started gaining at the end of third and they are supposed to have about 200hp stock.

Maybe I buggered up on cyl #2 but I thought it was pretty straight forward. Dropped a tad bit of oil into the cyl and it bumped compression up to 240 If I remember correctly so I'm guessing bad rings or bad test....

If oil in the cylinger brings the pressure up, rings are your problem.
If you also have cylinders with pressure above the specks, you have carbon build up.
That probably means the discrepant cylinders have stuck rings caused by carbon deposits.

Try the seafoam, or just squirt some transmission fluid or Marvel Mistery Oil into the cylinder, and let it sit over night. If you have stuck rings, that could possibly help.
Do it a few times just to be sure.