compresion issue in a 1.8, low on no. 4 Options

[broomhandle]

I have a 1.8, and it runs like a bus motor, its a EC 1.8. i can be driving and it will be a 914 for a few seconds and then back to a bus...

so, i did a compression test

4= 80-60
3= 100
2= 120
1 = 100


and my plug on no. 4 is black.

new plugs.

what could be going on?

the valves are not adjusted. and also, i feel like its timed right. but, then you drive it.... and it just not timed right...

what could be going on with No. 4? and why would No.2 be higher? because its the opposite side? compensate?

im a lone 914'er... and Vdubber... you guys are the only people to ask! (IMG:style_emoticons/default/smile.gif)

[aircooledtechguy]

It sounds like you have 2 un-related issues going on.

You NEED to do a proper valve adjust on the motor BEFORE doing a compression test. The motor also needs to be warm in order to get accurate readings. Pull all plugs and hold the throttle wide open while you crank it. Low readings can be from leakage at the valve or past the rings. If you have oily goo on the plug and a valve adjust doesn't make things better, I would suspect the rings.

The black plug could be from a few other things too:
1. bad injector; sticking open?? Easy to check. Pull the injectors and run the fuel pump to see if it leaks.
2. intake/exhaust valve seat coming loose. This will cause it to run poorly (intermittently) and explain the low comp. # on #4. Dangerous situation since when it fails, it junks the whole motor. You will discover this while doing that valve adjustment you need.
3. Vacuum leaks. Use a can of carb cleaner and spray around ALL joints/seals in the intake system. If the RPMs raise, you have found a leak. Do not stop looking if you find a leak, as there may be more than one.