2005 Passat TDI crank issue (again)

[stefan]

Re: 2005 Passat TDI crank issue (again)

Thanks for checking that out. I do think the ALH had different parameters for start conditions. I did come across some info in that while searching for problems.

[BaggedGLI]

Re: 2005 Passat TDI crank issue (again)

They don't appear to list it on the site anymore and some further searching shows it was listed for 98-99 ALH's, not the new engines. I wonder if it is something that they just automatically do on new files or if it is even a known issue to them on the later cars.

[stefan]

Re: 2005 Passat TDI crank issue (again)

Hmm - was not aware there was a firmware side fix there?? Mine is old. I mean, I had it refreshed for the Manual transmission recently but not sure they would have redone the whole tune or just updated what needed to change there.

[BaggedGLI]

Re: 2005 Passat TDI crank issue (again)

How old is your Malone file? I thought the cranking issue/hot start fix was automatically included in their files?

[stefan]

Re: 2005 Passat TDI crank issue (again)

Got the started replaced and RPM on crank is looking better. So far, so good. Hopefully that was it.

Going to be time to find a new ride soon, I think!

[Geobmx4life]

Re: 2005 Passat TDI crank issue (again)

EGR is deleted in mine, few more things to check as well.

[stefan]

Re: 2005 Passat TDI crank issue (again)

Timing I have actually checked. And then I grabbed a cam sensor at Pick n pull, and re-checked after that. I think I'm ok in that department.

I have an EGR sitting here, if your that ends up having anything to do with your issue! I think its the same one.

[Geobmx4life]

Re: 2005 Passat TDI crank issue (again)

The only thing I can add is checking the timing….having a few hard starts myself and was doing some reading.

[stefan]

Re: 2005 Passat TDI crank issue (again)

more info:

I had a look at the hot start maps in a manual trans file for a BPW and an AWX and they do cut fuel until 250rpm above 70ºC. I'd look up the BHW specifically but the hard disk on my usual "tuning" computer crapped the bed a couple weeks ago so I have no files to view at present. They do inject fuel at 200rpm when coolant temp is 20ºC or below. The map is pretty coarse, but suffice to say you need at least 200rpm to fire when engine temp is above 20ºC and 250rpm above 70ºC.

The cold start maps inject fuel at pretty much zero speed, so cold starting will never be an issue.

[stefan]

Re: 2005 Passat TDI crank issue (again)

Thanks for help today, Colin.

I'm going to try to find out more about this crank RPM requirement. I have another comment from the TDI club guys:

"The PD does have a fueling cutoff on hot start, but I think it is at a lower RPM then the ALH, around 200rpm as I recall."

200rpm would be interesting as my VCDS logs are showing 189 to 210 (i just unhooked injector harness and let it crank).

[stefan]

Re: 2005 Passat TDI crank issue (again)

ECU was opened up when I did the transmission swap a few years back. Not since. I was thinking I would check it though and make sure it is all clean and well seated.

Its been an intermittent issue for so long, I really can't put my finger on when it started, or what the last thing I touched before it started was. I'll pop out the ECU and have a look though. Good idea.

[BaggedGLI]

Re: 2005 Passat TDI crank issue (again)

Definitely a strange one going on. Sounds like the pump is working correctly. We have replaced injector harnesses, but again, it was occasional issues, not outright dead.

Gasket should be available separately. 038 103 483D - go with a Genuine one, the aftermarket ones don't stay in the cover when you are trying to put them on. Sounds like you are on the right path though. Have you opened the ECU box and checked for any sort of moisture/corrosion?

[stefan]

Re: 2005 Passat TDI crank issue (again)

Fuel filter is new. Replaced pretty recently. The thermostatic T on the filter is also new since this issue (may actually have been your suggestion some time last year, Colin. I seem to remember the Passat one was like twice the price of the MK4 one. lol).

Lift pump, yup, that was a concern for me too. I tested the original OEM one for volume (like timed while pumping in to a bucket) and it passed, but as this is not an every-start issue, there was room for it to be an occasional issue. I sort of don't think it was ever the lift pump, but I wanted to swap something in just to see if I got a different result. I also put a gauge on the line from the original lift pump. It was not really the right gauge as it was meant for higher pressure, but it was enough I could see the needle tick up when turned the key. I left that sticking out of the hood for a week or so. So lift pump I think is actually unlikely, I just was running out of options. The one I got was from a shop in the UK. Seems slightly better reviewed than the EBAY ones from china, but could also be crap for sure. The relay running it is new OEM.

I'm a little stumped now why messing with the injector harness that connects at the back of the block triggered consistent check engine lights for glow plugs. I cleaned with electrical cleaner and put it back and now, no more CEL. But regardless, its an injector harness. Glow plugs are separate. So maybe I pulled on the wiring loom and moved something, or maybe there is a more general grounding issue somewhere. I'm hoping I don't have to go pin by pin on the main wire harness from ECU with a multimeter :(


I started googling for possible injector issues and the wire harness in the engine that connects the injectors seems to be a bit of a trouble maker, but common symptom is more likely misfiring. Not totally dead injectors. Still, it is something I'm considering. I know if I pull the cover and check, I'll probably be in for a new valve cover. My experience is they leak after removing, and the gasket/cover is sold as a single part on this thing. Maybe I can see some different resistances right at the pins on the connector if I check at the right temp.

[BaggedGLI]

Re: 2005 Passat TDI crank issue (again)

Interesting, when was the last time you replaced your fuel filter? Recently I saw an issue with a faulty fuel filter return valve as well that was not flowing causing a no start issue.

I would have questions about the aftermarket lift pump, I have seen issues with defective ones (like 3 in a row) on cheap ones.

[stefan]

Re: 2005 Passat TDI crank issue (again)

Coolant temp sensor?

Not out of the question. It looks good on vag-com, but as the problem is intermittent, I could just not be hooked up when it screws up.

But also, this only happens when the engine is still warm/hot. I'm not sure a bad coolant sensor would make a difference in that case? I doesnt need glow plugs or anything to come on at that point. I could be out to lunch there though. Is there something else that coolant sensor could trigger that I'm not thinking of?

I did disconnected the injector harness for fun. I wanted to see what the car did with dead injector solenoids. Cranks forever, in the same way. It SOUNDs the same as my intermittent issue. No sputtering, no ingition, no smoke, just no fuel. In this case though, I do get a code with the harness disconnected. Suspiciously similar though.

Now what was maybe a good thing though is when I reconnected that harness, I started getting several errors for glow plugs that I have never had. That harness has nothing to do with glowplugs, but my hands being back there changed something. I'm suspicious now I have a wiring issue. I may start by cleaning and re-seating some connections.