Alpine951

Do I just follow what the haynes 944 manual says? Anything different for a turbo?

Mike B

Nope...it's all the same procedure. It's usually best to do it on a warm engine. Here is a link (ignore the talon reference) with straight forward instructions.

http://www.dsmgrrrl.com/FAQs/compression.htm

Alpine951

Thanks Mike.

Alpine951

What about the injectors spraying gas. Will this happen or is there a way to defeat this?

Mike B

When I did it I pulled the DME relay. Had no problems.

Your car and mine have alot in common

hosrom_951

Don't forget to have the throttle fully open.

Alpine951

Yeah i figured pulling the dme was a good idea plus i pulled the fuel pump fuse.

Alpine951

Is 2 hours after shut down too long to wait to do the test?

hosrom_951

I did mine just a few seconds (literally) after shutting down the engine when the oil was at operating temp, got 145-150psi across all cylinders.

Campeck

i got 220 on the NA. woot for high compression....sorta.

something weird happened during my test. the #2 cylinder would over pressurize the seal on the comp tester. and start blasting air at over 220psi out of the sparkplug hole....freaky.

mtnman82

Don't want to steal the thread ... but along these lines, how does one do a leakdown test? Do you need special equipment to do this, or just a compression gauge?

Campeck

you need an air compressor and a leakdown tester.

NZ951

Well most of the pressure will be released from the rail by then, but there will still be a decent amount of fuel, even with the DME relay out. If you really want the fuel out, then just pull the DME relay and crank it 3-4 times, that will get most all the fuel out. The car will be close to cold 2 hours later also, kinda defeating the point of having it hot.

Alpine951

mntnman82,

you asked my next question so don't feel like you stole the thread. I did the test again this morning after taking it out for a drive. I am losing a good amount of oil which is why i did the test.
#1 130, #2 116, #3 133, #4 135. That #2 worries me.

I put some oil in each cylinder after these readings and all pressures went up to either 155 or 157. The number 2 spark plug was all black. It had some slight oil on it but the tip, electrode and insulator had hard black carbon all over it. I was hoping it was a valve issue instead of rings but after the pressure in #2 went up after adding the oil now I don't feel so good. Any one have any advice? I guess I need a leak down test.

I put in a used k27/6 earlier this year that there was not any info as to how many miles were on it. The play seem OK and it spun easily. I am going to try and pull the ic pipes off to see how much oil is there.

Campeck

ok. do you have an air compressor at your house? capable of 100psi?
leakdown testers i think you can rent or buy and they arent to expensive. and will cut the troubleshooting time down to nothing...cause you will know whats wrong.

plug it in. turn the **** and put it at 100 psi. open the throttle..listen to the intake. no noise, then your intake valves are fine. listen tot he exhaust, no noise, exhaust valves are fine. take the oil cap off, you should hear a *slight wooshing, but if its anymore than that then it could be your rings.