So a while back I was complaining about a P0017 code and rough idle. Someone suggested I change the oil and then possibly try an AC Delco VVT actuator solenoid (I had previously replaced it with a cheap no-name, which had no effect). After that, the comments were timing chain.

Well, it started not sounding too good on the way to the story, kind of like something rattling, although it wasn't clear that it was from the engine or underneath the car, and then when I went to start it to go home, it started but ran terribly. I tried revving the engine and it would barely do it, coughing and sputtering. I shut it off, and then tried starting it again...no dice. What's worse, it sounds way different than it ever has before. Almost like the starter is encountering very little resistance. The crankshaft is turning, so it's not the starter that's doing something wrong...my suspicion is that I broke a timing chain, so the starter is just spinning the crank but it's not spinning the camshaft, moving the pistons, etc. This, of course, means I'm *&(*^ed.

Here's the weird thing...I tried to read the codes, and it's saying "No codes." Why would this clear my P0017 code?

Also, what's a good way to tell, in the absence of any codes, if this is in fact what has happened? I'm pretty sure I'm not paying to put a new engine in this thing, but I'm not sure how to sell a truck with a blown motor, who would buy it, etc.

Very upsetting actually. I had a year and a half remaining on the transmission rebuild warranty, and had just fixed a bunch of stuff so that it seemed to be running really well (other than the P0017/idle thing of course).

 

This is weird...I'm looking at the repair manual and it lists "broken timing chain" as a possible cause for "engine wont' start - no crankshaft rotation" symptom. I would think the starter would rotate the crankshaft in that scenario, regardless of the timing chain status (which is what I'm seeing).

 

maybe you can find an engine cheaper if you look for one for an Isuzu i-350 many cars came with the I-5 like Chevy Colorado, GMC Canyon Hummer H3 and the Isuzu.

 

I'll look, thanks for that suggestion. I'm just not sure it's worth a few thousand to put into this thing at this point.

If it's a broken timing chain, what are the chances that replacing the chain, etc would fix it? I read that these are interference engines, but it doesn't sound like anything is hitting when I try to start it. I've never had a car with this condition so I'm not quite sure what I'm looking for.

 

So what's the easiest way to confirm the broken timing chain hypothesis? Second question: If I DO have a broken timing chain, is it at all possible that the motor isn't junk?

I don't want to throw good money after bad. If I can prove it's the timing chain myself I won't have to tow it someplace, pay them to give me the bad news, and then (likely) tow it back if that means a junk motor. And I certainly don't want to go through the expense, or effort, of putting on a new timing chain, etc if I almost certainly have bent valves at a minimum.

I just have no idea what to do here, to be honest.

 

Review and print off the relevant sections of one of the GM H3 Hummer Engine service manuals on line.....

Pull of the front cover and look inside. Going to need the special tools listed in the service manual regarding changing a timing chain.

 

If it's broken, what are my chances that just replacing the chain and tensioner will get me back on the road? Isn't it likely that I have bent valves, damaged pistons, etc? Or am I overbowing that risk?

 

IMHO, it would be unlikely to "break", and much more likely to skip/jump some teeth and be out of timing so far it cannot start. As for the rest, we'll never know unless you look what's up with the timing chain from the top.

The other possibility includes a messed up VVT cam shaft phaser assembly.

Have you checked the oil? Good way to see if there is internal damage is to look at oil level and quality on the dipstick. If suspect, drain the oil and inspect for metal or anything that is not supposed to be in there.

 

Oh, that's a good idea. I just changed it a few days before The Event, so anything in there that looks amiss is likely something new.

 

The phase is different than the solenoid, but since you just made that change before things went south, definitely investigate that.

Good luck.