I have a 94 classic wrx import and it has started ticking and sounds maybe like its firing only on 3 so want to do a compression test. I want to remove the ignition fuse and the fuel pump relay but everything on the car is written in japanese so havent a clue whats what, I think fuse 11 is the ignition?

Anyone know which ones i need to remove please?

Also what compression should i be reading on each port? I seem to think it should be around the 125?

 

spoke to a mechanic friend just now and he checked his autodata and he said the ignition fuse is a 15amp and is in position 16 which is bottom row second in from left but cant see any details where fuel pump relay is

 

Why don't you disconnect the crank sensor that should stop the spark and fuel.
I can't be certain for a Subaru, but every other petrol engine iv done I have been looking for about 200 psi.

 

Ok thanks will try it that way

200 sounds a bit high but will do a bit more investigating unless someone here can confirm what it should be.

 

Just had a quick search on here, Paul at zen performance posted 160-170 Is the result you would be looking for on a good engine.

 

ok ta - how acurate it is but autodata states between 8.3 and 11.8bar (120-171psi)

 

Around the 150 mark should be fine

 

Ok thanks

If its not compression thats at fault anything else i should be looking at? i've taken plugs out and looked at condition incase it was a coilpack at fault and they look fine, also checked the timing marks and they look ok aswell

I'm not getting emgine management light on but will connect black connectors together later just incase it has picked up a fault

 

so i removed crank sensor, wound in the compression tester on left hand side back port and took plug out the other on the left so if gasket gone across the two ports then i wouldnt have any compression and it read 120psi which is the minimum autodata says which i would expect it to be low as its 18 years old and done 117k, left it a few minutes to see if compression dropped but it stayed there fine, I then tried all the others and they all read exactly the same so all 4 pots are even compression. To me that isnt a cause for concern so decided to put plugs back in and start thinking of what else it might be, fired the car up and all fine, no loud ticking, no sounding like running on three, hmmm left it to warm up and still fine, took for a drive and goes how it should do. Wierd, oh well carry on driving and see if it does it again. Will keep an eye on one plug as it was slightly blacker than the other three, will run for a few days then take it out and have another look at it.

 

You could have not had a lead on properly. As they arc they make a ticking sound and also would run on 3 ofcourse.
Cant remember on your year car
whether you have coil on plugs. A cracked/split coil boot would do the same thing

 

well that did cross my mind but it was running for 3 weeks fine prior to this.

Fingers crossed your right and it doesnt happen again or maybe a coilpack is breaking down.

Cheers