Timing Issue

[Prestobismol]

Two days ago I was driving home and when I merged onto the freeway I floored it like anyone would, but I noticed that my car would not go past 4k rpm or 60mph.

I limped it home where I found out that at idle it had a really bad choking rhythm indicative of a misfire. As if one of the cylinders wasn't firing at all. I turned it off and went to bed.

I work in a diesel shop so two days later I brought it in to look at it. Scanning codes I got the usual misfire codes and P0016 and P0011 for timing faults (timing too advanced). Did the usual misfire diagnostics and even a compression test to be safe and everything came out good.

My first thoughts were that maybe I skipped timing just barely enough to where it could still run. I pulled idle logs and what I found was a misfire every stroke for cylinder 3, and if I gave it throttle and let it settle back down to idle the constant miss would move to cylinder 2. Probably the VVT just messing with the timing enough to change the miss. Logging timing also found a massive discrepancy between requested and actual. There were no consistent misses on any cylinders under any throttle.

However, things get weird when after turning on and off the car multiple times over the course of 3 hours logging, messing with controllers, and diagnosing. The last time I turned it on the problem fixed itself. The idle was smooth and after logging the idle the misses were all gone and actual timing went back to being similar or the exact same as requested. This only lasted for a little while though as I took it for a 5 mile drive and the timing issue came back around 3 miles in.

Now what could be causing this? My best guess right now is Cam position sensor number 1, Crank position sensor number 2, and VVT solenoid number 3. I don't think it skipped timing anywhere because obviously it went back to normal for a period of time. Also for reference, I had my cam chain and tensioner replaced around 10k miles ago at an Audi specialist shop. I will likely be purchasing a new CPS and throwing that on soon and I will share the results and see where this goes.

Any thoughts? Please anyone feel free to chime in. This isn't a usual problem I see a lot of people have so it would be nice to hear some more opinions.

[Theiceman]

floored it like.anyone would ? lol....

anyway, you have a VVT issue, unlikely to be sensors as that is like shooting the messenger.
1. timing control rings broken in timing cover.
2..VVT solenoid
3. cam phaser
4. oil pressure.

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[Prestobismol]

Of all those the only one I want it to be is the VVT solenoid so I'll start there. Thanks!

[Jayz691]

Of all those the only one I want it to be is the VVT solenoid so I'll start there. Thanks!

You can run output test, with vcds. Also, pull it out, and make sure its clean, and no oil leaking into the connector.
I would also check the timing with vcds, block 91/93.

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[Theiceman]

Of all those the only one I want it to be is the VVT solenoid so I'll start there. Thanks!

of course I am assuming the tensioner and chain are quality parts and the timing belt and tensioner are in good order

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[Prestobismol]

The chain and tensioner were replaced around 10k ago with a iwis chain and a febi bilstien tensioner. Belt and waterpump were replaced at 125k I'm currently at 162k. I drive pretty spirited but not redline every shift spirited. And even if I did I don't think it would let the belt slip that easily. And as I already said it randomly fixed itself at a point so I'm almost certain that the belt and chain+tensioners are fine

[Prestobismol]

Upon recent inspection the connector to the vvt solenoid is drenched in oil. Guessing a whole lot of connector cleaner and a new solenoid is a go.

[HudsonBarrett]

Upon recent inspection the connector to the vvt solenoid is drenched in oil. Guessing a whole lot of connector cleaner and a new solenoid is a go.

I would clean it and also test the solenoid itself. Use a 12v battery and connecting clips. Once connected you should hear/see the solenoid moving.


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[Jayz691]

Upon recent inspection the connector to the vvt solenoid is drenched in oil. Guessing a whole lot of connector cleaner and a new solenoid is a go.

Yup, new solenoid

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[Prestobismol]

I got two solenoids off of audis from a junkyard. Next day I cleaned all the connectors with electrical cleaner to get all the oil and gunk out. I took the old solenoid out and tested it's resistance which was reading all over the place, no good. Testing the junkyard solenoids got about 11 olms each. Then I sprayed down the solenoids with MAF sensor cleaner through all the holes and everything to get the old oil out. Put one of the junkyard solenoids in and we're golden. Car has been running great for around 3 days now.

Hope this helps the next poor soul, thanks everyone!

[Theiceman]

good to know . i have to think there is an inherent design failure of that solenoid that allows oil to pass through it back to the connector, it is not an uncommon issue. the 11 ohms is good info for our data bank.