Misfire codes, rough idle, blue smoke, shutter

I am having a problem with my 2002 Jetta automatic TDI that hopefully someone can help me with. I recently chipped the ECM with Upsolute Stage 2 and upgraded the nozzels to 184 um (was 157um). When running down the highway at about 60mph, I floored the accelerator. The trany downshifted, the rpm's went to 3500, after a few seconds I had severe shudder. I chopped the throttle, the shutter stopped, but the engine was running lumpy with reduced power and quite a bit of smoke. I hooked up Vag-com, got a misfire on cylinder #3. This coincidently occurred with my first tank of 15 ppm. I now have a rough idle, blue smoke (unburned diesel) and shutter at 1500-2000 RPM under light/medium load (OK under heavy acceleration), intermittant misfires on three cylinders.

I have replaced EGR valve, checked MAF, checked MAP, cleaned snow screen, pop tested and balanced injectors, checked compression. Last night I ran a tdi-timing graph (attached). I noticed that the timing is on the retarded side of optimal (below the blue line). Could I have slipped a tooth on the timing belt? This may have had something to do with the catastrophic event that occured. The timing belt, tensioner and water pump was changed 3K miles ago by a VW dealer. If I advance the injection timing with VAG-COM to 7 degrees BTDC (out of spec.), the idle smoothes out and the smoke is reduced. If this is the case, is there an easy way to check the timing belt alignment without major disassembly?

Do you have the tools? If so, you can remove the valve cover, vacuum pump and timing belt cover. Rotate the engine to lock the camshaft. Check the alignment of the flywheel through the window. Confirm that the IP pin hole will accept the pin. Will take about an hour the first time.

DBWs A4 pdf file will be a great reference to you.
http://pics.tdiclub.com/pdf/a4timingbelt.pdf

I have tools, but not the "special timing belt" tools. From the writeup, it sounds like I only need to remove the upper timing belt cover. This would allow access to both the cam pulley marking (horizontal line to be set parallel to the cam cover) and the IP pully hole. Am I correct? Also worth noting in the writeup, the IP bolts have been changed from a "stretch" type (partial threads) to a full thread. Do you know what this is all about?

peterdiesel said:

I have tools, but not the "special timing belt" tools. From the writeup, it sounds like I only need to remove the upper timing belt cover.
Correct, along with the valve cover and vacuum pump.
This would allow access to both the cam pulley marking (horizontal line to be set parallel to the cam cover) and the IP pully hole. Am I correct?
Almost. The slot on the end of the cam is aligned with the angle of the head and locked into place with a tool.
Also worth noting in the writeup, the IP bolts have been changed from a "stretch" type (partial threads) to a full thread. Do you know what this is all about?
Yup, the bolts on earlier pumps were indeed a "stretch" bolt. Designed to be tightened once. Most good TB kits include replacement bolts for these.

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See bold above

Timing looks good. I finally broke down an called the VW dealer. He informed me that it was the ULSD that was the problem. Apparently the cetane rating is lower than LSD. The ignition delay is related to the cetane rating. The higher the cetane rating, the less ignition delay. Long ignition delays can cause misfire and overboost codes, blue smoke (unburned diesel), rough idle and shutter. I am experimenting with additives to get the cetane rating up to about 49, where TDI's like to run at. I am now using Redline and all problems are gone except some smoke on a cold start. Keep you posted!

I call BS. It's not fuel related. Both fuels are 40 cetane. You're just masking the problem - there's a timing problem. Look at that graph.

fuel has no effect on TIMING. My car would start and idle rough, smoke a fair bit when my timing was approximately in the same range as yours is now. It was time for a new belt anyway, so I did it and the timing was just about dead center in the graph. Magically the car started easier, ran smoother at idle after first starting and smoked a whole lot less.

Adjust your timing (or replace your belt if it's due and then adjust timing). Your car will run a lot better. Not only smoother but with easier starts, more power and better fuel economy. Your car will thank you.

peterdiesel said:

I finally broke down an called the VW dealer. He informed me that it was the ULSD that was the problem. Apparently the cetane rating is lower than LSD. The ignition delay is related to the cetane rating. The higher the cetane rating, the less ignition delay. Long ignition delays can cause misfire and overboost codes, blue smoke (unburned diesel), rough idle and shutter.

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What a line of hooey! If that were the case none of our cars would run correctly!

Yep, total bunk. The timing is too low on the graph and your IQ is to low of a number. (too much fuel)

fuel may not affect timing, but time sure affects fueling!