2010 JSW Random hard start/stumble

jimmyfine · Oct 21, 2019

Hello all, to start, my JSW has 164k miles on it currently and recently got a new fuel filter 4k miles ago and is due for an oil change.

This weekend we were starting a 2 hour trip and stopped about 30 minutes in to get fuel as I was getting close to the 1/8th line. After fueling the engine did not start for 4 key turns, it would fire one or 2 times then get a weak fire and die, kind of like low fuel pressure or an injector not firing. I also noticed that the engine temp was running on the low side up to this point, it got to operating temp about 20 minutes after fueling. The car started on the 5th try and had no problems the rest of the day. No codes or lights are on.

If anyone has thoughts it would be appreciated. It has occasionaly had some long cranks to start or maybe 1 stumble like I described but this was a first.

kjclow · Oct 21, 2019

The long cranks and single stumble could be a weak battery. Enough juice to turn the starter but not enough to get the engine up to full compression.

jimmyfine · Oct 21, 2019

It has enough amperage, it doen't turn slow at all when it happens and compression sounds normal to the ear. By long crank I mean about 2-3 seconds before I stop the crank and cycle the glow plugs again, normally starts really quick on the second crank though.

jimmyfine · Oct 21, 2019

Without doing any diagnostics yet, will have it checked this week with VCDS, it sounds like I am having either an ASV issue or low fuel rail pressure. Glad I am under warranty if either of these end being the case.

DivineChaos · Oct 21, 2019

a problem that i have found was the vvt thing on the motor going bad. It was redesigned because the ram would get sticky and way retard the timing. Watch valve timing as you crank when it doesnt start. you can see the valve timing change as it starts. it is a warranty part. But will only be replaced if it throws a cel. Witch it rarely ever does. if you have a good dealer and you ask them to look into it they might change it.

DivineChaos · Oct 21, 2019

And in these mk6 cr 2.0 tdi's, the ASV is built into the intake manifold. Not into the egr valve like the older ones. you could have also gotten bad fuel that had water.

jimmyfine · Oct 22, 2019

I did not know about the vvt, I will try to check the ASV today but fuel should have been good, not saying it was 100% but the station I use is small and has semis filling very often.

I work with goodmonkey on here and we should be checking it out this afternoon with VCDS.

Update: This morning it did 1, 3 second crank, then fired on the first compression stroke on the 2nd crank.

MikeH31324 · Oct 22, 2019

The 2.0 TDI engine does not have variable valve timing. It does has a variable vane turbo which has nothing to do with hard engine start.

jimmyfine · Oct 22, 2019

After searching google again it seems that it was ignoring my TDI tag, I know about the turbo and most of the engine but haven't had to troubleshoot anything yet, about to hook VCDS up so I will update if it has anything pointing to an issue after lunch.

jimmyfine · Oct 22, 2019

No codes were present for the engine, will try to check the ASV tonight.

DivineChaos · Oct 22, 2019

MikeH31324 said:
The 2.0 TDI engine does not have variable valve timing. It does has a variable vane turbo which has nothing to do with hard engine start.

are you sure? i talked to a tech and he confirmed the 2.0 tdi has an oil driven vvt. He also soid it would cause hard starting after it has sat. cranking up to 10 seconds when above 50f. but will start within 2 sec when engine is warm. Could also be your hpfp bleeding pressure off, an injector not sealing. https://www.youtube.com/watch?v=DXvHdmq0reA

DivineChaos · Oct 22, 2019

jimmyfine said:
Hello all, to start, my JSW has 164k miles on it currently and recently got a new fuel filter 4k miles ago and is due for an oil change.

This weekend we were starting a 2 hour trip and stopped about 30 minutes in to get fuel as I was getting close to the 1/8th line. After fueling the engine did not start for 4 key turns, it would fire one or 2 times then get a weak fire and die, kind of like low fuel pressure or an injector not firing. I also noticed that the engine temp was running on the low side up to this point, it got to operating temp about 20 minutes after fueling. The car started on the 5th try and had no problems the rest of the day. No codes or lights are on.

If anyone has thoughts it would be appreciated. It has occasionaly had some long cranks to start or maybe 1 stumble like I described but this was a first.

wait is this a tdi or tsi?

MikeH31324 · Oct 22, 2019

DivineChaos said:
are you sure? i talked to a tech and he confirmed the 2.0 tdi has an oil driven vvt. He also soid it would cause hard starting after it has sat. cranking up to 10 seconds when above 50f. but will start within 2 sec when engine is warm. Could also be your hpfp bleeding pressure off, an injector not sealing. https://www.youtube.com/watch?v=DXvHdmq0reA

Positive. See VW self study program for an overview of the engine systems.
http://www.vaglinks.com/vaglinks_com/Docs/SSP/VWUSA.COM_SSP_826803_2.0L_TDI.pdf

DivineChaos · Oct 22, 2019

MikeH31324 said:
Positive. See VW self study program for an overview of the engine systems.
http://www.vaglinks.com/vaglinks_com/Docs/SSP/VWUSA.COM_SSP_826803_2.0L_TDI.pdf

interesting. we both were proven wrong. if you watched the video anyway. Different engine models.

jimmyfine · Oct 28, 2019

DivineChaos said:
wait is this a tdi or tsi?

It is a TDI.

jimmyfine · Oct 28, 2019

Ok, more info. Fuelled up again Saturday and had 2 failed starts, fires 1-2 times then a half-power ignition and stops, did it twice and started the 3rd try after leaving it sit with the key on for 30 seconds to connect my bluetooth OBD scanner to monitor fuel injection timing and fuel rail pressure for the 3rd try. Edit: So it seems I have a no start after fueling/filling up for a couple start attempts.

tjg · Oct 28, 2019

I had similar issues with my 2014 JSW and it turned out to be an ECU issue... the dealership ran tests on the ECU and it failed several of them. After having it replaced, I haven't had any issues. (issues were a flat spot/stumble when in second gear after a cold start and eventually a condition where it would start for a second and then die).

jimmyfine · Oct 28, 2019

tjg said:
I had similar issues with my 2014 JSW and it turned out to be an ECU issue... the dealership ran tests on the ECU and it failed several of them. After having it replaced, I haven't had any issues. (issues were a flat spot/stumble when in second gear after a cold start and eventually a condition where it would start for a second and then die).

Do you mean that it would start then die or fire and fail to start? I also experiance the flat spot/stumble while it is cold but in random gears at low speed and light/no throttle.

tjg · Oct 28, 2019

so it would start and then die after about 1-3 seconds of running... it would happen a few times in a row and then eventually catch and run normally.

jimmyfine · Oct 28, 2019

Ok, mine is right after fueling, and I mean just tightened the fuel cap and wiped diesel off my hands, will fire a couple times and stop. It did it 4 times the previous fill up and 2 times this fill up.

It goes something like, cranking for 1-2 seconds, fire 1-2-3 times and dead, like hit hit stop. My only other explination is like when my '02 TDI is below 40f with no fuel treatment, it may fire once or twice but won't run. After a few attempts it starts well for the rest of the tank, not considering random first crank no start, or random times when it won't catch and needs cranked again.
EDIT: Spelling and grammer.

2010 JSW Random hard start/stumble

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