Compression Test

[RanjS8]

Hi guys

I m planning on getting a compression testing gauge to check the health of my engine....Now I've been reading and it seem I need to the following


1. Get engine up to operating temperature
2. Disconnect Fuel Pump Relay
3. Disconnect all coil packs
4. Remove one spark plug at a time and screw in the compression tester
5. Turn engine over using key in the ignition


Can some one advise me whether the above is the correct procedure or do i do something else....

Thanks in advance for your help

Ranj

[ainarssems]

1. Oil temperature at least 30C. But you do not want it too hot so that it is easier to work around it and do not burn yourself
2. Getting the fuel pump fuse out is probably easier but relay will also work.
3. Not strictly necessary if you leave them on spark plugs but best to remove and disconnect all.
4. You can remove all plugs at once that way it will be easier for engine to turn and less load to battery/starter. Use compressed air to blow any dust and dirt out from around spark plugs before removing them.
5. Full throttle when turning engine.

[Nollywood]

To disable fuel and spark for compression test, you only need to disconnect one plug - the CKP (Crankshaft Position Sensor). Plug is on the passenger's side bellhousing. It triggers the fuel pump and ignition.

[RanjS8]

Thanks guys....

Now I know what to do should go smoothly...and hopefully all is well....

Is the crank position sensor towards the rear of the engine or towards the front???? or do you happen to have a picture of it.....

Thanks

[Nollywood]

Originally Posted by RanjA8

Thanks guys....

Now I know what to do should go smoothly...and hopefully all is well....

Is the crank position sensor towards the rear of the engine or towards the front???? or do you happen to have a picture of it.....

Thanks

It's towards the read, on the passenger's side. It's actually on the trans, just behind where the motor mates to it, approx. 2 o'clock.

I'll see if I can find a picture.

[RanjS8]

Cool I should be able to find that pretty easy

Thanks

Ranj

[ainarssems]

There is no need to do anything to disable ignition. If you remove coil packs that is good enough. If you really wanted to you could pull camshaft position sensor plug instead which is easier accessible and will do the same but like I said there is no need. Pulling any of them will also trigger fault in ECU. This fault will not give any issues afterwards but still.

Here are the instructions from Elsa:

[daviesbike]

what about the 40v engine ? i have the AQF engine and i have a comp test so i will also do this just to check as it dose tend to use half a pint of oil a month

[adjuster]

Yep, on the 40v engines, I'm interested in this myself. (Was tempted to do a compression check when I did the plugs, but they were coming out dry, so did not figure it was leaking at the rings, or that I have a valve seal leak.)

Besides, the engine runs great. Plenty of power, so I doubt that it's down much on compression, but in any case, when I'm bored, I might pull the COP's and plugs, and do a check.

I'm guessing on the E-throttle, there is no need to floor it. (Not that it will do anything anyway unless the ECU wants to let you open the throttle, but it should open the throttle enough anyway to get enough air in the intake for a compression check at the very low RPM the starter spins the motor.

Dang, now that I think about it more, I'd like to see if it's even across the engine.

[ainarssems]

Here you go - D2 40V compression checking