compression test how to? doing this right now..

silverevo05 · Joined: 17 Jul 2006 Posts: 234

I bought the compression test device from kragen auto, though I wanted to know if anyone knows the proper way to do a compression check on an xb

thanks in advance

oh and what are teh specs I am looking for?

cobb · Joined: 16 Apr 2007 Posts: 1346 Location: Richmond, VA

In general you disable the fuel pump and or ignition, set the parking brake, chulk the wheels and jam the throttle open. You unscrew the spark plug, screw in the tester and crank it 4 cranks or the needle bobs 4 times.

Thats what basically your cylinder psi is. Second test to see if there is ring damage is to squirt some oil in the cylinder and retest it. If it goes up, the engine has ring wear and needs to be rebuilt, if its the same and low, the valves need adjusting.

I think around 150psi is fine. Anything below 80psi, it needs to be rebuilt. If its low for one or two joint cylinder, you got a blown headgasket.

Ace83 · Joined: 26 Aug 2006 Posts: 5586 Location: TX

here a DIY, http://www.youtube.com/watch?v=ujVhVt_rhOk enjoy :P

silverevo05 · Joined: 17 Jul 2006 Posts: 234

man I have dial up

it'll take me about 2 hours to see that vid

are ther any how to's anywhere

thanks

cobb · Joined: 16 Apr 2007 Posts: 1346 Location: Richmond, VA

Its not rocket surgery, the guage should of come with a manual.

silverevo05 wrote: man I have dial up

it'll take me about 2 hours to see that vid

are ther any how to's anywhere

thanks

silverevo05 · Joined: 17 Jul 2006 Posts: 234

Do I disable the ignition or fuel pump

what fuse - theres one #8 the starter system and there are many mulyiport fuel injection #5 7 18 and 30

I know its not rocket science but I dont want to mess it up

I tried search

I'm doing this now so the quicker the better thanks

CarbonXe · Joined: 05 Mar 2007 Posts: 6369 Location: Parsippany, NJ

Remove the EFI fuse and the EFI relay.

silverevo05 · Joined: 17 Jul 2006 Posts: 234

it also says to disable the ignition system

and I only find the efi #5 fuse where is the relay

on the owners manual it says that # 5 7 18 and 30 are also multiport fuel injection system

so do I unplug all of them? doesnt sound right

Reactor · Posted: 11/5/08 3:54PM Post subject:

Standard compression: 213psi
Minimum compression: 156psi
Max difference between cylinders: 14psi

Disconnecting coils is another way to disable ignition.
Take all the plugs out, screw in the tester, floor the trottle and crank the engine. Watch the gauge, usually 5-7 revolutions is enough to obtain the max reading.

silverevo05 · Joined: 17 Jul 2006 Posts: 234

no need to stop fuel injection?

sorry I'm such a noob

how do you disconnect the coils?

Reactor · Posted: 11/5/08 4:18PM Post subject:

Each of 4 coils have an electical plug on them with wires, just unclip them.
Better to disable fuel like thay said, just to be safe.

cobb · Joined: 16 Apr 2007 Posts: 1346 Location: Richmond, VA

I no longer own an xa, however if its silver and from a dealer in richmond, I already messed up the engine.

Anyhoo, its in a box under the hood near the battery, inside the cover it says what the fuses are for, one should say efi. Unplug that, Dont bother with the coils other than plugging your plug back into the one for the cylinder you are testing and touch that to the engine block, valve cover, etc.

Either way, you need to cut off the ignition or fuel, not necessarly both. This way when you crank it wont start and lets you do the test properly.

Ok, cant find the fuse? Unplug all spark plugs and do it that way. May want to head to an advance auto or auto zone in your area for some help, its easy to do a compression test and in their parking lot.