Skipped Time?

[tempest0mouthy]

Hey guys - just a recap and then a couple of new questions...

So I had a p0340, independent shop changed the sensor, ran normal for a week, then acted the same way (check engine light, bucking) and got p0344. Independent guy has literally only worked on one other Cruiser and all he did for it was an oil change. He put the old sensor back on and refunded my money.

Took it to the dealership, they wanted about $30 more to replace it with Mopar, so I said okay. That didn't fix it. They wanted $400 to crack it open and look at the actual cam. Oh, and since I was at 78k, a grand on top to do timing/water pump, etc. They said they thought it skipped time and the timing/water would fix it, but couldn't be sure without looking.

My regular mechanic (I went to the other well recommended guy because he was in towing range and my regular wasn't) said they could do timing/water for $4-450. No brainer. They also agreed it sounded like the car had jumped time, but they would let me know. So, waiting on that today.

I've googled and looked around in here, but I can't understand what would cause an 05 with normal mileage to skip in the first place? Especially since it's automatic? Is this a common problem? Anything else related you want to throw in?

Also, when I talk to my guy(s), should I tell them there's a newer style tensioner arm that should be used? My friend had a very similar symptoms on her husband's Ford and it was the tensioner, so I am hopeful this will end this two-going-on-three-week problem.

Oh, it drove fine under 2500-3000 rpms to the dealer, but can you give me any insight as to if I might have damaged the head or anything? My husband keeps saying if it threw a rod, it would have stopped, but I'm a nervous nelly. :/ I had it towed from the dealership to my mechanic, but since it seemed fine for a week, I'm worried I was just banging away at something even more costly during that time.

THANKS GUYS!

[CREWZIN]

Before they do anything I'd have whichever mechanic take a look at the wiring for both the CAM and CRANKshaft sensors. Lots of problems with wires harnesses rubbing and cutting into the wires.

A signs of a timing belt about to go is that it will stretch and cause the timing to go off. You didn't say what you mileage is but you said "normal mileage for an 05" so I'm guessing 60,000. You shouldn't need a timing belt at that mileage be it stick shift or automatic.

The belt hasn't broken (you wouldn't go anywhere) and unless you've been to the drag strip lately, the chances are there's no internal damage.

The tensioner was changed in 2003 so you already have the newer one. As long as the mechanic gets one for your engine, it will be alright.

[quicksilverdon]

Dealer sounds scary...
78,000 is early for a timing belt - but I guess not impossible.
$400 - $450 for a timing belt is a real bargain, and yes, be sure you get new tensioner, but I'm not sure you need it done yet.
The P0344 is camshaft sensor intermittent - could VERY well be wiring - have that looked at before you pay for timing belt that may not cure it.

[tempest0mouthy]

Cruz - it's at 78,000. A little high for an 05, but not astronomical, IMO. When I got her in March she already had 70,980 (and the lady at Chrysler corp asked why I didn't renew the warranty - uh, cause you sent it to me way late AND it had already expired, so ask the 1st owner).

To address both of you guys, I guess I should have mentioned I did ask the first mechanic if he checked the wires and he said yes. I'll have my guy check again just to be sure.

Thanks for the reassurance about not warping her. I logically know that, but with the luck I've been having and the laundry list Chrysler presented (they wanted to also give me a new oil pan - mine's not leaking, so I have no idea why other than more $$$). Haha, when he told me $4-450, I told him if we hadn't been on the phone, I would have kissed him! :*

[tempest0mouthy]

Hmm, just talked to my guy - said the belt seems to have enough tension and timing looks okay on top. Wires look okay, too. Cracking her open to look... The only other thing I can think of is the dealer said maybe it was the actual cam? Can anyone give me ideas about that? Is it expensive? If it is, should I just go ahead and have the timing/water done while it's open?

Ugh, I hate this guessing game!

[quicksilverdon]

Talk to your mechanic - he's got to take belt off to get head off, so a lot of labor would be duplicated to do belt later.
Depends on how many miles you put on car & how long you intend to keep it - belt is typically good to 100,000 miles.
I would guess a valve problem, not cam.

[tempest0mouthy]

Originally Posted by quicksilverdon

Talk to your mechanic - he's got to take belt off to get head off, so a lot of labor would be duplicated to do belt later.
Depends on how many miles you put on car & how long you intend to keep it - belt is typically good to 100,000 miles.
I would guess a valve problem, not cam.

Valve, huh? I don't know much about those other than their function, so I have no idea what all that could mean... Guess I'll find out!

[quicksilverdon]

Originally Posted by tempest0mouthy

Valve, huh? I don't know much about those other than their function, so I have no idea what all that could mean... Guess I'll find out!

Only a couple causes of low compression - piston rings are shot, or a valve or valves not seating or burnt.

[cdynaco]

hmmm... these engines aren't variable valve timing are they?

I find it odd that it runs fine up to 3k but acts up at higher rpm's. If these engines are VVT then it could be related to cam timing above 3k - which would explain the error codes.

Or could it be vacuum related? (not sure why the cam sensor error code would log though if it were vaccum related which brings us back to potential sensor/sensor wiring failure, but why does it run fine up to 3k?)

Or is the PCM not advancing spark at higher rpm's? Spark not hot enough?

If it was a valve, a compression check/leak down test should confirm before tearing into the head. If it was bad enough there might even be a slight 'tick' from the leakage in the compression chamber. Might try a stethoscope or the old screwdriver trick touching the area of the cam covers near each valve with the other end of the screwdriver against your noggin'. LOL

While a cam lobe could have been damaged that seems unlikely unless the engine has been pushed hard.

What about a failing cam follower that can't keep up at higher rpm's?

If I remember correctly, a backfire could cause a cam sprocket skip. Like from detonation when starting the engine. Wonder how the teeth on the belt look.

Ignoring the cam sensor code, could it be fuel related whereby the engine is starved for fuel above 3k? Any change in the quality of fuel being used?

(way out in left field... my chain saw just started the same problem kind of LOL... would start fine but give it throttle and it bogs and dies. It was a vacuum leak in the fuel line...)

Thinking out loud from the days before data logging.

[quicksilverdon]

Originally Posted by cdynaco

hmmm... these engines aren't variable valve timing are they?
.

Nope.