Compression test
 

2007 s type 3.0, does anyone have the procedure for the compression test?

Was able to figure it out, I have seen different answers on what the compression should be. Here is what I have: 1)130 2) 145 3) 160 4) 135 5)170 6)140 psi

Generally you are allowed a 10% variance between cylinders. The absolute numbers are not as important because the conditions of the test and the engine vary so much.

Yours are more than that but do you have any problems?
If worried you can redo the test and you should follow some guidelines when doing that.
Make sure the engine is warm before you do the test.
If still too much variance put a bit of oil in each cylinder and run the test again. Very often a bit of oil will help with the sealing and you will have a much better test.
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I’m trying to track down a multi cylinder mis fire

Which cylinders does your diagnostic scan tool report as misfiring? Bear in mind that "misfire" in OBD-speak means a cylinder that is firing with less force than the others.

All cylinders and misfire on start up

It's probably not a problem of compression.

Exactly which code numbers?

Which (if any) OBD monitors are not set?

What are the fuel trims? (See existing threads for what to do)

P0300,P0301,P0302,P0303,P0304,P0305,P0306, P0316. And a P0730.



thank you.

Misfires across the board, misfires on start-up usually indicate a failing crank position sensor (CKP sensor). This should be your first avenue of attack on your problem. Leave the P0730 for later.

I appreciate your input, I will try that.

In addition to checking the CKP, check the fuel pressure. It should be around 3 bar (300 kPa) with the ignition on prior to engaging the starter motor.

Or simply replace your battery! Oh, wait a minute. Is it too soon? ;)

https://www.jaguarforums.com/forum/s...7/#post2599165

I have 150 on all cilinders, warm engine

Any input on replacing the CKP? Looks like a real bitch to get at!

on the 3.0 i changed my water pump and when i took it off, the sensor was visible.

but i suppose it may be easier to go below and remove the alternator to expose it

https://cimg7.ibsrv.net/gimg/www.jag...ce9f7293f.jpeg

Yeah, I think under is going to be my best bet. I’m able to unplug from up top but I can’t see the bolt that holds it in place.. wish me luck! Lol!

Blatzhtr: Any progress on the crank position sensor replacement? If done, did it solve the problem?

Inquiring minds want to know....

I just got it, will do this weekend. I have the intake off. Will be replacing a few other things, lower intake, nut setter was stripped. Replaced spark plugs, coil packs and injectors, fingers crossed!

I would be cautious doing multiple repairs all at once. If something goes wrong, it can be challenging to determine the cause of the problem. If the intake comes off to provide easier access to the CKP, I certainly understand freshening the plugs and coil-packs, but you might want to do the injectors as a separate operation.

Also, in terms of coil packs, please use original or OEM grade units (Denso, NGK, Delphi, etc.). The forums are littered with threads of people having bad experiences with economy, no-name coils from eBay, etc...

Update!
 

So I did do multiple things, since I had the intake off and I knew the nut setter in lower intake was stripped. I’m looking to get this vehicle on the road I’m not a mechanic in a garage where I need to tell the customer what was wrong, I just want a nice running vehicle, don’t care how I get there.

anyway- replaced the crank position sensor, plugs, coil packs, left lower intake ( new gaskets both sides) new valve cover gaskets, plugs. And injectors.

car runs a lot better but I may still have a miss in cylinder 1 and on start up. Tranny code still here and it’s noticeable.

goes to the dealer Tuesday as 2 shops couldn’t help me.

that’s where I am now. Will keep you posted.

thanks for the help!!