Help! Just did a compression test...

[silver-s]

Well, i just went and bought a compression test meter. i did the compression test after following all the steps listed in the manual. well, it's kind of strange, but here are my results:

Looking from front of car, reading left to right:

1. average- 1400 kPa

2. average- 1600 kPa

3. average- 1600 kPa

4. average- 1600 kPa

Average didn't vary but a couple of kPa per test.


Now here is my biggest question. What the h*ll is going on. Toyota specs are 1400 kPa for new condition. why am i getting 1600 on cylinders 2, 3, and 4? i did do cylinder 1 last. maybe that might be the difference, but still. 200 kPa over isn't good. is there too much carbon buildup in there? What is the best thing i can do to get rid of the carbon buildup? additive? I have run it hard enough to blow the carbon out i'd say, but i'm stumped. Should i be worried?!?

Also, as i was pulling out the plugs, i noticed that the engine was hotter on the right side. i just now put 2 and 2 togather. SOMEONE PLEASE GIVE ME SOME INPUT!!! i am really, really stumped at the moment.

H E L P ! ! !

[t2000gts]

more pressure probably isn't hurting anything. it's LESS pressure you should be worried about :)

[Griffin]

If you have excessive carbon buildup the best thing I have found to get rid of it is GM top engine clean. The stuff is absolutely amazing - pour a little into each cylinder and let it sit for 30 minutes or so - then run the rest through the intake bu using a vacuum hose as a "straw" to suck it out of teh bottle a little at a time. Stuff works great and is totally safe for your cat and O2.

Griffin

[silver-s]

i may try that. where can i get the GM engine cleaner?

thanx for the replies guys. i hope a few more people tell me something more,........... i don't know,............. "solid?" i want someone to tell me if they know if this is bad. but thanx, i do appreciate it!

[BlackGTS2002]

cyl 1 usually has a lower compression then all the rest.. i dont know how those # convert to PSI though...thats what I am familiar with... where can we get the Gm top stuff Griffin?

[silver-s]

roughly, 1400 kPa equals 204 psi, and 1600 equals 230 psi. factory rating in psi is 204. also, when you say cylinder 1, how are you looking at it. i stood in front of my car facing it, and called the far left cylinder, #1. Reading left to right. i don't know if that is the way everyone does it, but that's what i did.

does that help blackgts2002? maybe you can tell me something a little more concrete. thanx

[BlackGTS2002]

i wasnt talking about the celi in specific..my dad was a mechanic...and we were tuning up our boat the other day..and ran the test on the 4 cyls.....he just happened to tell me that the 1st one is usually a few psi lower cause it gets the hottest and does the most work....or somthing to that extent.... i think 204 and 230 are way too far off though for that theory...

[Griffin]

GM top engine clean is sold at GM dealerships. Chevy, GMC, Pontiac, Buic, Cadillac, Saturn - they should all have it I think.

Griffin

[BlackGTS2002]

will it work for carburated engines?

[Griffin]

Originally posted by BlackGTS2002
will it work for carburated engines?

It should - I don't know that you could use it very well to clean the carb itself but for general carbon removal purposes it would work just fine.

Griffin

[BlackGTS2002]

thanks....do you think i could just pour it in really slow into the top of the carb with the arrestor removed?... (this is for my boat...but its a 75 chevy I4...)

[Griffin]

Probably - or just buy a cheap squirt bottle and use that. The carb itself you are still better off using carb clean for.

[BlackGTS2002]

no..i want to clean the carbon build up..we just rebuilt te carb because it was eating plugs like crazy (running too lean...and a lot of carbon...) so i think this will help...the carb is nice and shiny though..thanks

[Griffin]

No prob. Small amounts of water also will do the job, but you have to be very careful with both.

BTW - back to the original topic, I dont think the 1600 Kpa cylinders are really anything to worry about. I did the conversion and its about 232 PSI which is not too bad. I would worry about the cylinder thats at 1400 (203 PSI) - I would do a leakdown test and check valve clearance for an overly tight or bent valve.

Griffin

[rearendman0]

Originally posted by BlackGTS2002
thanks....do you think i could just pour it in really slow into the top of the carb with the arrestor removed?... (this is for my boat...but its a 75 chevy I4...)

does the cleaner just burn out when you start the motor, or do you suck it out with something after its sat for a while? I used this stuff called sea foam green or blue and it worked pretty good on cleaning the carb on a older jeep i have but i dont know about the carbon buildup.

[Griffin]

Originally posted by rearendman0


does the cleaner just burn out when you start the motor, or do you suck it out with something after its sat for a while? I used this stuff called sea foam green or blue and it worked pretty good on cleaning the carb on a older jeep i have but i dont know about the carbon buildup.

It is a combustible liquid so it burns off. But it is VERY important that you not put too much because of that. Remeber - liquid is NOT compressible - if you put a ton you risk hyrolocking your motor.

The deal through a vacuum hose is done when running and its is burned with teh combustion fo rthe most part.

Griffin

[rearendman0]

ok I searched , looked at all the posts and searched on google but nothing that realy helps. So .... I know hydrolock is when water gets into the motor threw the intake and its not good at all but what are the affects of it ? Does it bend thigs up of just shut your motot off? cus i know if you get water in your pistons you can take the spark plugs out and crank it over and push the water out threw the plug holes. I was just wondering what other types of things it causes? everyone acts as if it is not repairable.
thanks alot for youe help : )

[Griffin]

Originally posted by rearendman0
ok I searched , looked at all the posts and searched on google but nothing that realy helps. So .... I know hydrolock is when water gets into the motor threw the intake and its not good at all but what are the affects of it ? Does it bend thigs up of just shut your motot off? cus i know if you get water in your pistons you can take the spark plugs out and crank it over and push the water out threw the plug holes. I was just wondering what other types of things it causes? everyone acts as if it is not repairable.
thanks alot for youe help : )

Oh its not that its not repairable, its just that its very expensive. What happens is when the piston comes up on the compression stroke and the cylinder is full of water something has to give. Well they waters not gonna give - its not compressible. The heads normally not going anywhere and the piston itself isn't going to pop a hole in itself to relieve the pressure. That leaves the rod and teh crank and the crank always wins. In otherwords what happens is you will bend a rod and in so doing lock the motor. Can it be repaired? Sure - but its expensive and time consuming.

Griffin

[rearendman0]

thats what i thought, its just people in other theads acted like it would cause re-occuring problems from then on( which it very well might, i assume).

[Griffin]

Originally posted by rearendman0
thats what i thought, its just people in other theads acted like it would cause re-occuring problems from then on( which it very well might, i assume).

If not repaired it would. but parts is parts - once replaced they are fixed. The problem is normally that people dont catch all the damage the first time around.

Griffin