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Discussion Starter · #1 · (Edited)
24v timing chain, idle issue diagnosis help?

Picked up a Eurovan that was diagnosed with needing a timing chain replaced. Wouldn't idle, cam position codes (that didn't move with the sensors). Runs smooth from 1,800ish rpm up.

Has 152k on it so figured it needs it no matter what.

I have searched and searched and have not found a good write up of the 24v timing chain. (For example, just exactly where and how to line up the timing marks?)



Anyone know of one that maybe I'm missing? Anyone have a good source of info stored on their computer they want to share?

...or anyone in the Denver area want to come show me:D:p

I've been all over the UK T4 forum (vr6 is rare there), TheSamba(Eurovan and VR6 rare there too), the EV Update yahoo group,and here....

Thanks.

 

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I'm not 100% familiar with the axk (your engine code iirc), but I assume that the guides and tensioners are identical to a bdf.

there really isn't a DIY specific to the 24v to my knowledge, but you can follow the 12v one, just look up torque specs elsewhere. if you've done chains on a 12v before you'll probably be able to figure it out pretty easily. it's pretty much the same process with a little bit different parts.


that said, even at 150ish thousand miles I'll bet the chains are still fine. unlike 12v's we usually don't have chain problems. I'm at 135 and have no chain noise. when I did my clutch a few months ago I popped the covers and took a look at them and there was barely any wear.

I'd look into the sensors first. did you try logging that sensor's measuring block while the car is running with vcds?
 

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You can use the 12v chain DIY as a guide. It will get you 95% of the way. There is probably just going to be a few nuts and bolts in different spots.

12v DIY
http://forums.vwvortex.com/showthread.php?1264409

You will have to pull the trans to get to the lower timing cover. If you haven't already started do that. Align the crank pulley, pic 5/6 on the DIY I linked, and see if arrows on the cams line up with the notches on the head.



http://forums.vwvortex.com/showthread.php?5641278-Puzzled-Timing-chain-replaced-fault-code-remains.
There are some really good shots of the alignment marks in this thread.
 

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We dont have the 24v v6 eurovan here in the uk/europe as far as im aware its just north america that got it hence why its rare/none existant here , theres loads of guides for the 12v vr6 i would just follow them and then make your own judgemant calls
 

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Discussion Starter · #7 · (Edited)
Thanks for all the links and input so far. I would LOVE some help from you guys to get th is thing running. :D

I bought this van with a diagnosis of needing a chain and tensioners replaced.

When I got it it had multiple misfire codes and a bad sensor code.

Forgive the photos, I'm using a ancient computer that I can't export my vagcom from.





I cleared these codes and logged data block 208-209. The only code that comes back is the cam position code.

When I log those data blocks there is a missing field for block 208. I tried swapping the sensors to see if the problem moved with the sensors but it stayed on block 208.




I ordered timing chain kit from ECS and began taking the vr6 apart. I have just the upper cover off at this point. The van would not idle 90% of the time but ran smooth with a touch of throttle. No chain noise, but again it would not idle to the chain was always under a bit of tension.

I lined up all the timing marks and locked them in place today. All the chain guides I can see from above look fine with very little wear. The chain was tight before I took off the tensioner with the upper cover. I can see the sprockets and they look good, teeth are not worn down. Lower chain as far as I can feel with a couple of fingers is snug.

Honestly, if this is not the problem I would prefer to not remove the transmission and change the chain if I don't have to.

What else could be causing the issue? Could it be just a bad upper tensioner bolt? (Letting one cam slack off and not idle right until pressure is applied?) (I'd feel silly if it were that simple, but not as silly as the previous owner and two shops)

The back cam is off just a half mm or so compared to the front one. How precise are these? Could a cam adjuster be bad?



 

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Discussion Starter · #9 ·

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It is possible to be off by 1/2 a tooth, but it would be on both sprockets. Not just one.

There should be 16 pins/links/rollers between the 2 arrows on the cams.

Maybe someone tried to replace them already and the intermediate is off by 180 or the crank is off by 1 tooth. It's not unheard of for this things to happen.
 

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The intermediate sprocket is the one where both chains meet, not the cams or crank. But if no one has been in there it probably isn't off.

With how baked on that oil is the engine was probably ran pretty hot. I'm guessing chain stretch, and maybe a jumped tooth.

It sucks getting to the chains, but it would be a lot easier to troubleshoot if you can verify all the alignment marks.
 

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Discussion Starter · #13 ·
I can see the notch in the intermediate sprocket pointing up at me like it should.

My guess at this point is that the chains are stretched, but not really the root of the problem. The baked on oil has probably gummed up the cam adjusters and tensioners to the point that they don't smoothly do their job. Even a moment of sticking could cause an over correction in timing issues and cause the poor idle. (Surging).

I have the new chains here today so I guess I will go ahead and pull the transmission and replace them and clean everything up the best I can with brake cleaner. At least then I will have that maintenance item out of the way and know they are good.....and hope it solves the issue:D



......anyone in Colorado bored out of their mind today and want to help remove a Eurovan transmission:what:
 

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for the rough idle issue, if it still feels off once it's all back together, I've found that bumping up the idle speed by about 100-150 rpm helps idle smoothness a hell of a lot. did sai/evap delete on a car and it helps cold start a lot. as well as getting rid of flywheel chatter if you go to a lw fw.

using lemmiwinks :thumbup:
 

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Discussion Starter · #15 ·
Thanks, I may have to try that. Fortunately I already have Lemmiwinks on my old VAGCOM laptop.

This project had moved VERY VERY slow. What a pain in the butt vehicle to work on (and I've worked on some of the most classic "hard to work on" cars out there).

I'm still battling with getting the transmission to drop free so I have access to the lower timing chain. :banghead:

I have every bolt out of the headers and downpipe and can't get them to break free so that I can swing the motor down and forward to get the trans out:banghead::banghead:
 

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Discussion Starter · #17 ·
honestly after 4 clutch jobs on an 02m I find it 10x easier to just drop the motor. That whole tilting, lowering, lifting on an angle bs is too much.

If I don't have an engine hoist I drop the subframe. Then you have acres of room to do what you need to do.

Honestly, after dropping my MR2 Turbo and Audi S4 motor that way a total of 10 times I would normally agree with you:laugh:

This just did not look like it would work out as easily since its torsion bars instead of coils. They run through some frame spots and over the exhaust, rear heater lines and gas tank. So it looks like all of that would have to come out too in order to drop the subframe with the engine and trans. The A/C also has a weird hardline that loops out infront of the motor and has no way to just set out of the way, even with removing the compressor. You can probably see that in the picture above. So it looks like the easiest way on this van is to drop/tilt the motor.......we will see....:facepalm:
 

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Discussion Starter · #18 ·
Just a little update. Took some time to work on the Eurovan today. (Only about an hour, I work slow)


Dropped the transmission out of the way. This thing will at least need totally cleaned up before going back in, and with a new external cooler.



I don't see any obvious visible signs of anything wrong with the timing chain, tensioners or sprockets. But it's all getting replaced so hopefully this cures the problem and it really needed to be done anyway. Will also try to get all the carbon build up cleaned off all the sprockets etc before it gets assembled.....cause its a nasty mess in there!





 

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anyone happen to know the chance on piston damage when a chain breaks, im looking at a 24v with a wrecked head, comes with a new head but the kid says he hasnt taken the other one off...i know sketchy but so cheap! just wanna know the possibiblty of other internal damage
 

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Hey Thanks for this post. It really can't come at a better time. I picked up a Eurovan MV in the spring and have some misfires like you've described. I was assuming the chain was stretched and needs to be replaced.
Any chance you could do a little write up with pictures for the work you're doing. As you know and I'm realizing this would be a huge blessing to many of us with the Eurovan VR6.
A few questions:
Did you drop the subframe to pull the transmission?
Any hints I'm planning on doing this same project.
Can I fly you to Charlotte, NC when I dig into mine?!! LOL
Thanks again

Just a little update. Took some time to work on the Eurovan today.
 
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