No compression on one side of 3.5l

[Borjawil]

09 3.5l blown head gasket. Fixed head gaskets. No compression on left or firewall side cylinders. Needle doesn't even move. 

 

Even with a bad valve, rings, etc. I'd have something if I'm not mistaken. Only thing I can think of is a cam, timing, or rocker issue. 

 

First time around no compression so I checked timing. Timing was about a tooth or 2. Reset timing, tightened timing belt tensioner, turned engine over at the crank and it was still spot on. Tightened rocker bolts and put everything back together. 

 

Same issue. Figured the head gaskets weren't on the correct side or timing jumped. Checked timing again to be sure. Aligned. So I checked head gaskets. Incorrect sides per alldata site.  Corrected. Set timing again. Double checked it. Everything back together. No compression. 

 

Either the rear cam pulley is slipping due to a slightly sheared key that catches with slow hand turned revolution but not starter torque...or idk. So I'm here for any help I can get. 

[John/Horace]

Key stock is not that hard to come by, if the pulley key slot is ok I would replace key.
 

Or use paint marker on pulley and shaft and confirm it’s not slipping.

 

How about a table spoon of oil down the three cyclinders and try for compression. Wet test in other words.

 

[Borjawil]

I'll give the wet test a try. Hard to believe all three ring sets are broken to the point of not compression though. I'll double check the pulley as well. See if I can have someone crank it while i watch/use a paint marker. Recovering from the surgery well so hoping I can get it done today. 

[Borjawil]

Looks like the key on the pulley sheared off Just enough to not rotate the cam well enough but by hand would turn and stay in place when setting the timing. Looks like its part of the pulley? im guessing filling the gap and using a removable key would out of the question?

[John/Horace]

A new key way can be cut with a broaching tool in a shop with arbour press. But if small piece comes out cleanly and slot is good then a new piece of key worth $2 can be used.  Some filing for sliding fit.
Key stock is mild steel, acts like a sheer pin if shock loaded.

 

Or go full McGyver  since you have another engine. Line it up and tac weld in place. 

 

My lawn old Craftsmen tractor has a lot of welded in place stuff, new tractor parts are gold where I live, same as shipping.

Edited May 31, 2020 by John/Horace

[John/Horace]

I don’t see  three broken rings or bad pistons since it was just running. Rings can get gummed up from carbon if car is burning significant ,oil.  Fixing cam pulley looks to be the right thing. 

[Borjawil]

John, the pulleys are cast as far as I can tell. The key is a part of it. I just took the pulley off the other engine I have. Same F****ing issue. No compression in the rear 3 cylinders. I feel like im going insane. Im REALLY good at replacing the timing belt though so theres that.

 

A few questions because im starting to doubt my own sanity. 

1) Some engines  say to remove all or just the plug for the cylinder youre testing compression on. I dont seem to get different readings so far, but wanted to confirm the correct procedure

1a) when testing the rear cylinder compression, and this may seem like a silly question, but removing the top intake manifold is the correct way yes?

 

2) when setting the timing,

1) loosen tensioner (i loosen the two 13mm bolts to the assembly) 

 2) loosen rocker bolts - i find if my rocker bolts are tight I can not set the timing as the cam will rotate CW or CCW when setting it on the timing mark. As if the cam lobes or sitting on the point of the lobe (but that was also before I knew the pulley key was sheared)

3) turn crank clockwise till mark lines up (little point on back of gear to point "TDC" mark on block

4) put belt on crankshaft gear, then around the front cam pulley ( I set it 1 tooth behind as when the tensioner is tightened itll jump forward), then around the rear cam pulley (also one tooth behind), 3) tighten tensioner and check timing

5) rotate crank two revolutions to same TDC mark and block and check cam alignment.

6) tighten rocker bolts

7) I like to remove the fuel pump fuse and turn the engine over and recheck timing to be sure. 

 

Is it something Im doing incorrectly here?

 

and 3 question - The only way I can see there being absolutely no compression in a cylinder let alone 3, would be severely damaged block/cylinder, piston, head, incorrect installment or broken compression gauge, or cam not timed correctly thus opening closing valves incorrectly. I know its not the gauge or use of it. I fixed the pulley but will again tear into it and check. I cant see the back side of the block, but am ruling this and piston damage out as it ran before. Id say the head is fine too as it ran before but may be warped (though Id expect some compression still). So that leaves cam/timing issues thus the above procedure Ive used. 

3a) another thought, and again seems silly, but would the front cam pulley key (I didnt check cause im an idiot) slipping as the rear did cause the rear cam timing to be off?

When I check compression in rear (intake off fuel disabled or not, spark still going) I get literal fire out of the lower intake manifold. So im getting explosions. Im assuming from front 3 cylinders but Hard to tell. 

[John/Horace]

Cast meaning cast aluminum ? I’ve never seen aluminum used on a key way, put a magnet on and check.

 

Most  compression test procedures say to remove all plugs (manifold on back of v6) for compression test. Disable fuel pump hold, fully charged battery,  all coils would be unhooked so no spark source would be present. Approx same number of cranks for each cyclinder.

 

If valves not functioning properly then valves can’t allow either air in or air to be held in place for pressure build up; at least that what it seems. Got a picture of this pulley key way part issue.

 

Ive done several timing belts on overhead cam engines, very awkward to do, some people use a set of wedges designed to hold pulleys from moving. As long as you get it on with out wrecking belt and everything gets retorqued that was loosened, I don’t a problem.

[Borjawil]

if you google 09 journey cam pulley youll see. The knub or key is part of the entire pulley as far as I an tell or very seamless. 

 

As for the compression test Im assuming you mean the rear exhaust manifold? I have not detached this when checking. I feel as if manifold on would help bump compression and not keep it from showing. Correct me if im wrong and feel free to explain.

 

My TDI jetta has locking wedges (SOHC) however it doesnt show them to be used in the manual for the procedure on this engine. But Since everything lines up I dont see it being needed. 

 

. Just got the timing cover off and everything is lined up correctly. Going to remove the pulleys again to confirm keys. Going to replace the rear head if theyre good. Only thing at this point I can see being the issue. If I were to do a wet compression test and I show compression, Im assuming it would lead to rings/pistons being the issue correct? Cant see a wet test affecting valves. I could do a leak down test to confirm valves as well. 

 

Oh one more thing, passenger side rear cylinder is #1? Want to make sure Im not checking  the incorrect cylinder for TDC. 

Edited June 1, 2020 by Borjawil
added question for info

[Borjawil]

Leak down test showed 20% leakage at all cylinder except the pass side front cylinder at about 10%. Front middle cylinder definitely air come from lower intake manifold. all others I can hear a leak but cant find the leak. Not coming from exhaust, coolant reservoir (no bubbles), dip stick tube or oil cap opening. Test was done with pass side rear cylinder at TDC. Not sure if each cylinder should be at TDC when doing that particular cylinder. Please confirm. If I up the PSI through leak tester, I can hear air coming from other two rear plug holes (all plugs removed. Tells me head or gasket to blame. 

 

Rechecked compression. front 3 pass to driver side at 115, 125, 115. Rear head still at 0 on all 3. Exhaust manifold still connected. 

[Borjawil]

Ok so, both pulleys replaced, set timing, it fired and died. Then will only start if I give it gas at wide open the feather it around half throttle to maintain 2-3k. However it sounds like a rattle, like its only running on 3 cylinders. 

 

looking further into things. I cannot be 180 degrees off as long as pulleys are on the right cam, and cams are in the right head, and all marks line up correctly. Its full proof. 

 

heres what I did notice when I was checking I was at TDC of the compression stroke (EX and IN valves should be closed), the exhaust rocker for #1 wont move. Theres just a slight amount of pressure on it. If I put a wrench on the cam bolt and pull towards be or CW, just to put some pressure on it, then I can move the EX rocker. So after doing this, I rotated the CCW and noticed my timing was off, until I rotated CW again. Which got me thinking, could there be an extra tooth or two between my pulleys causing my issue?

 

Also have a P2172 code for sudden high air flow detected. Not sure if thats from me flooring the gas pedal. 

Edited June 1, 2020 by Borjawil

[John/Horace]

I’m far from an expert on compression testing , there are various ways to get same result. Exhaust manifold always stays on shouldn’t have impact on compression test.

 

TDC doesn’t matter for compression, it’s only useful for setting up timing.

If all cam timing marks, all four and crank pulley Mark is on you should be fine. Cyclinder 1 will also have piston full extended at TDC.
I usually do 720 degrees or two revolutions CW and make sure marks are still lined up, then I put covers back on.
 I like to paint Mark belt and pulleys before removing and then transfer marks to the new belt before install. Lots of licensed mechanics do this as well. Some engines the marks are harder to see, paint marks eliminates that problem.
 

A car will kinda run on three cyclinders so that doesn’t prove anything.

Cyclinder one is on the rear bank, closest to front of engine where pulleys are.

Problems seems linked  to the pulley key issue.
 

 

[Borjawil]

Got the pulleys replaced, but either the rear head is warped or their is valve damage I'm guessing. 

 

Only recorded the above dtc and 0300 for random misfires. Not very helpful. But at this point I'm going to swap in the other engine. Spent too much time on this one and I'd rather not waste more time swapping the head to find another issue. I'll investigate further once I have it out of the vehicle and can more easily test things.