H3 Engine Tick

[Jeepwalker]

Yeah, that's the solenoid in the pic. Did you ohm out the pins? Are you saying you got nothing (OL)? That would indicate a bad solenoid.

Did you say you had the exhaust VVT unit previously replaced? Or did I read incorrectly? Did it work ok afterwards? How long? Who did the work? It has to be installed properly. Go to the manual (link below) and read about it. But if the solenoid is ohming out 'open' then you gotta start there.
http://file:///C:/Users/Mark/AppData/Local/Temp/Hummer-H3-Engine-Mechanical-3.5L-1-4-1.pdf

 

[Jeepwalker]

Scrub my question about the VVT being replaced. Looking at your head pic, it looks orig. (RockAuto -$107).

How many miles on that engine? Can you see what the timing chain guides and tensioner look like in terms of wear?

BTW, some people have (in the past) reported on Colorado's and H3's a plugged up oil pick-up causing low oil pressure. Not saying you have that, ..I just remember reading it in old posts.

 

[edmundocano26]

The teeth on the sprocket look in good condition I rotated the harmonic balancer and looked at the teeth all the way around and they both look good, chain looks like it fits snug. The H3 has 243k miles. From just looking the top part looks fairly good, as far as the rest of the timing chain I haven’t taken the front plate off yet, I have to get the tool to remove the balancer. While I’m doing all this I am going to go ahead and pull the oil pan just to look and make sure. It’ll be cheaper doing that if that is the problem versus diving into tearing apart the top of the engine.


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[Jeepwalker]

At this point it might be wise to do a compression check (youtube it) before you dig into it a whole lot further. Just borrow one from OReilly's or wherever. Ideally you do it with the engine warm (all plugs out, 4 or 5 puffs each cyl.) But since you can't do it warm ..and it won't be quite as accurate, ...it'll be accurate enough and you will get a good sense what each cyl comes out as. Let's say the results come back with one cylinder at 75# and the rest at 140 or so.. then you might consider pulling the engine and do all the work on an engine stand where you can take your time and do it 'right', rather than on your back and hunched over. Or even if you do it in the engine bay you'll know how far to take things. Could have a burnt valve (not unheard of). If you did the work on an engine stand you could future-proof things by sticking in new chain guides (front/rear), oil pump components, etc (check bearings, etc).

But if the compression check's decent and even, then you know it's good and can feel good about just dropping the oil pan. Just a thought.

I have a low compression cyl on my H3. Been like that since I bought it. Runs fine. But that along with the low oil pressure and the miles, I'm thinking I might yank it this summer and re-do a number of critical things (not a whole rebuild if I can avoid it).

It's not unheard of these engines going 300k ..you just have to get past this 'tick' issue....

 

[edmundocano26]

At this point it might be wise to do a compression check (youtube it) before you dig into it a whole lot further. Just borrow one from OReilly's or wherever. Ideally you do it with the engine warm (all plugs out, 4 or 5 puffs each cyl.) But since you can't do it warm ..and it won't be quite as accurate, ...it'll be accurate enough and you will get a good sense what each cyl comes out as. Let's say the results come back with one cylinder at 75# and the rest at 140 or so.. then you might consider pulling the engine and do all the work on an engine stand where you can take your time and do it 'right', rather than on your back and hunched over. Or even if you do it in the engine bay you'll know how far to take things. Could have a burnt valve (not unheard of). If you did the work on an engine stand you could future-proof things by sticking in new chain guides (front/rear), oil pump components, etc (check bearings, etc).

But if the compression check's decent and even, then you know it's good and can feel good about just dropping the oil pan. Just a thought.

I have a low compression cyl on my H3. Been like that since I bought it. Runs fine. But that along with the low oil pressure and the miles, I'm thinking I might yank it this summer and re-do a number of critical things (not a whole rebuild if I can avoid it).

It's not unheard of these engines going 300k ..you just have to get past this 'tick' issue....

So for the compression test, I know I’ll have to reinstall the valve cover and alternator, do I also have to reinstall the intake manifold? I wanted to do both a vacuum check and compression, but I don’t know where I would begin with a vacuum check..


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[H3Hummer]

At this point it might be wise to do a compression check (youtube it) before you dig into it a whole lot further. Just borrow one from OReilly's or wherever. Ideally you do it with the engine warm (all plugs out, 4 or 5 puffs each cyl.) But since you can't do it warm ..and it won't be quite as accurate, ...it'll be accurate enough and you will get a good sense what each cyl comes out as. Let's say the results come back with one cylinder at 75# and the rest at 140 or so.. then you might consider pulling the engine and do all the work on an engine stand where you can take your time and do it 'right', rather than on your back and hunched over. Or even if you do it in the engine bay you'll know how far to take things. Could have a burnt valve (not unheard of). If you did the work on an engine stand you could future-proof things by sticking in new chain guides (front/rear), oil pump components, etc (check bearings, etc).

But if the compression check's decent and even, then you know it's good and can feel good about just dropping the oil pan. Just a thought.

I have a low compression cyl on my H3. Been like that since I bought it. Runs fine. But that along with the low oil pressure and the miles, I'm thinking I might yank it this summer and re-do a number of critical things (not a whole rebuild if I can avoid it).

It's not unheard of these engines going 300k ..you just have to get past this 'tick' issue....

At all those points you're right, and yes :emb: i real can't compare my 30 years old 4cylinder Samurai's engine with the Alpha , i forget this some times cause they are so simple to work on .....
Can some valves have too much play causing the ticking and why if so?

 

[edmundocano26]

At this point it might be wise to do a compression check (youtube it) before you dig into it a whole lot further. Just borrow one from OReilly's or wherever. Ideally you do it with the engine warm (all plugs out, 4 or 5 puffs each cyl.) But since you can't do it warm ..and it won't be quite as accurate, ...it'll be accurate enough and you will get a good sense what each cyl comes out as. Let's say the results come back with one cylinder at 75# and the rest at 140 or so.. then you might consider pulling the engine and do all the work on an engine stand where you can take your time and do it 'right', rather than on your back and hunched over. Or even if you do it in the engine bay you'll know how far to take things. Could have a burnt valve (not unheard of). If you did the work on an engine stand you could future-proof things by sticking in new chain guides (front/rear), oil pump components, etc (check bearings, etc).

But if the compression check's decent and even, then you know it's good and can feel good about just dropping the oil pan. Just a thought.

I have a low compression cyl on my H3. Been like that since I bought it. Runs fine. But that along with the low oil pressure and the miles, I'm thinking I might yank it this summer and re-do a number of critical things (not a whole rebuild if I can avoid it).

It's not unheard of these engines going 300k ..you just have to get past this 'tick' issue....

So I was poking around before putting the valve cover back on and I noticed this, the black link and the timing indention on the sprocket isn’t lined up together.


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[edmundocano26]

So I was poking around before putting the valve cover back on and I noticed this, the black link and the timing indention on the sprocket isn’t lined up together.


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And it appears to be the same way on the other sprocket as well, so would it always be lined up the black link and the timing sprocket, or does that not necessarily mean it has jumped teeth?


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[Jeepwalker]

IDK, I haven't had to really dig into my engine to that depth (yet).


I would google it. Check the Colorado tk forums since they are more active. You should be able to find a lot more about this doing a normal search ..and also use the search strings GM Atlas engine... They made the same engine in 4cyl and 6cyl formats. Hopefully others will chime in.

 

[edmundocano26]

So I finally did a compression test.
Cylinder 1 hit 152
Cylinder 2 hit 121
Cylinder 3 hit 125
Cylinder 4 hit 156
Cylinder 5 hit 153

I saw the manual says it should have a compression of 215 psi, the 2 low cylinders didn’t build much they all started off around 100 on the first test then built up to the final.


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[Jeepwalker]

You did the test when the engine was cold though, right? Or were you able to run it for a few minutes before hand? Cold will usually give lower results. Obviously 2-3 are low. I have a low one too. So now you know. Something to factor in to your 'next steps' strategy. I guess it comes down to the tools you have, skills, shop availability, and all that and what you want with your hummer. I plan to keep mine a long time as long as possible.

 

[edmundocano26]

You did the test when the engine was cold though, right? Or were you able to run it for a few minutes before hand? Cold will usually give lower results. Obviously 2-3 are low. I have a low one too. So now you know. Something to factor in to your 'next steps' strategy. I guess it comes down to the tools you have, skills, shop availability, and all that and what you want with your hummer. I plan to keep mine a long time as long as possible.

Just wanted to do an update! Replacing timing chain, chain glides, oil pump, intake camshaft sprocket, o ring pick up tube. The pick up tube was super clogged up and dirty. Got everything back together started it up and there was another tick, as you press on the gas the tick becomes more audible it also has low oil pressure still. Ran compression tests:

Cylinder 1- 130
Cylinder 2- 130
Cylinder 3- 160
Cylinder 4- 160
Cylinder 5- 160

Then I did a leak down test input air was 100 psi to each cylinder the outputs were:

Cylinder 1- 100/98
Cylinder 2- 100/98
Cylinder 3- 100/98
Cylinder 4- 100/98
Cylinder 5- 100/82

I’m going to look in the direction of maybe the oil bypass valance being clogged and not allowing oil to the engine at the proper psi..unless it’s valves


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