2002 H6 - no compression!

[1 Lucky Texan]

maybe try holding a strip of paper at the tailpipe. If it is 'sucked in' diruing portions of the rotation while someone cranks the engine, it's because valves are open when they shouldn't be.

[tdelker]

Ouch... Not looking good.

My bad, right with spark the crank sensor must be getting triggered...

[FFR5445]

Well I got the timing cover off. I was expecting to see carnage but it all looks good. Timing marks all align where they should be. So now I'm really confused.

Got to thinking I need to do a cylinder leak down test (should have done that yesterday). So I dug out my tester put the timing marks all up and plugged it into the the forward-most drivers side cylinder. Can somebody confirm for me that this is indeed the #1 cylinder? I know the cylinder is at the top of its travel. I get 80% leak and it is coming out of the tailpipe.

Anybody have a diagram of firing order and cylinder identification?

[grossgary]

Drivers seat
5 6
3 4
1 2
Front of car

1 is front passengers side, 2 is front drivers side.
1, 3, 5 on passengers side front to back. 2, 4, 6 drivers side front to back.

[grossgary]

This is very bizarre, will be following along hopefully.

Any repair history at all?

Originally Posted by FFR5445

Anybody know of an easy way to check if the cams are turning without taking the timing cover off? Maybe my scanner can read the cam sensor, but I doubt it, I only have a basic one.

bump the starter just for a second. it'll get oily but some proper cardboard will take care of that. i've bumped, and even ran for a second, an engine with exposed valve train, it's just a little messy. It's just like a timing belt except some of the oil won't get captured so to speak...

although you should just be able to turn the crank by hand and see all the cams moving.

[Novablue]

Zero compression usually means one of a few things namely:

Valve issue

Piston issue

If when performing a leak down test the compression rises significantly it is a piston issue. If it stays the same it is a valve issue. I don't know your engine specs but 5-10% difference can be normal, more than that is bad.

If you have oil coming out the tailpipe, you likely did the leak down test incorrectly or your engine is toast. Rotten eggs is a tell tale smell of a blown engine btw. You only need a small amount of oil to perform the test. If you are confident you did the test correctly you may have a broken crankshaft. It is really rare to have zero compression in more than one cylinder on both sides of the engine and have it be a piston issue. What you are describing sounds like the valves are not sealing correctly.

Of Course if you have a broken crank, nothing would line up right and the valves would be open when you do the tests. Lets hope it's something simple. It sounds bad at the moment. If a pulley went bad or the chain/belt was loose or broken you might experience what you are describing.

If it were me:
Perform a compression test on all cylinders. If all cylinders are zero it is likely a valve or crank issue.
A) Compression is zero on all cylinders, most likely a valve issue: a) double verify timing belt is correct b) Verify that the crank is in the proper alignment which is more difficult.
B) Compression is good on other cylinders but not the two: Suspect bent valves on bad cylinders

From here we could check more but I'd need to know the results of that to proceed.

My first guess without seeing it is the chain/belt/pulley broke.

Edit: Also make sure you are using the correct threads for your compression tester. Line them up with the spark plugs to be sure.

[1 Lucky Texan]

if you have any doubt about the compressions tests, check for the cracked cap/blown o-ring on the fuel pump.

(I'd like to see a picture of how you do a compression test on this engine, especially cyl #6 !)

[Novablue]

Originally Posted by 1 Lucky Texan

if you have any doubt about the compressions tests, check for the cracked cap/blown o-ring on the fuel pump.

(I'd like to see a picture of how you do a compression test on this engine, especially cyl #6 !)

What does the fuel pump have to do with cylinder compression?

[1 Lucky Texan]

Originally Posted by Novablue

What does the fuel pump have to do with cylinder compression?

nothing, just suggesting the possibility the low/no compression is an incorrect reading. (with apologies to the OP)

I'm with gg, this is becoming bizarre.

[FFR5445]

Thanks for the replies. This is really rackin my brain.

I need more data. Now that I have the correct cylinder ID (thanks grossgary) and firing order, I'm going to do a cylinder leak test on at least the accessible cylinders tonight. Hopefully I will get somewhere. To get at all 6 cylinders I would need to loosen some engine mounts and jack up the engine. After all the parts I have out of this thing, that wouldn't be a huge deal, but the results from a few cylinders should tell me something.

I notice the spark plug threads are really long (~1.5") on this H6 but my compression tester only has threads that are much shorter (~.25") long so maybe all that extra air would affect my compression tester???