Almost stalling? Timing issue?

[Snowman]

I just got back from lunch. While out I noticed that as I took it out of gear coming to a stop at almost each stoplight, it sounded as though the engine wanted to stall. Almost sounded like that classic diesel sound skipped a few beats. It also sounds a bit louder than normal and more engine vibration coming through as well.

I did my timing belt last fall and there's now about 10,000km on it since then. Could this be a timing issue? I'm going to check with VAG-COM when I get home.

Ideas and comments are always welcome!

 

[weedeater]

don't think so. Perhaps IQ at idle. Remember that when you are slowing down (in gear) or take it out of gear and let the engine return to idle, there is no fuel going into the motor until idle is reached. Hence the engine can stumble if the IQ is low. I think.

 

[Snowman]

Well, this has just started recently. When I came home it stumbled once under acceleration (not hard but steady). It feels like there's something definitely different. Haven't had a chance to vag-com it. Will do it in the morning now.

 

[rahsut]

I am having the same trouble. Has anyone been able to figure out the cause?

 

[Snowman]

Forgot my Twin-com cable for vag-com at work

Shoot! I'll have to wait till Monday to check my timing! Anyone else have comments on this?

 

[rahsut]

Am thinking of just changing the fuel filter to see if that can make a difference...

Any thoughts?

 

[Birdman]

Mine did this once in a while and i set the IQ a bit higher which did take care of the problem.

 

[rahsut]

How is the IQ set higher? and from what value to what?

 

[turbo tractor]

could be fuel pump going, i had this problem, turn to warranty, could be expensive... when it goes u know, black smoke very bad and car dies... bad news

 

[Snowman]

No black smoke. And I can't find my Vag-Com cable yet!! (yikes!)

 

[rahsut]

Well, I checked my timing using Vag-com and it is within specs (in the upper half of the shaded area in the graph).

I am suspecting the fuel filter. Am going to drain water first, and if the problem still exists, replace the filter. Will post my findings here.

 

[Davin]

Folks, this sounds like the classic "slow-down shudder". Increase idle IQ as recommended above. See the FAQ.

 

[rahsut]

I followed the instructions in the FAQ and checked my idle IQ. It was at 3.6 mg/st which seems within specs.

I then decided to drain water from my fuel filter and some phlegm-like stuff came out. Wonder if its because of the Biodiesel I have been using.

The good news is that the car does not seem to be 'almost-stalling' any more...

any thoughts?

 

[weedeater]

replace the filter.

And find out what's been growing in your tank.

 

[rahsut]

Well, I changed my fuel filter. The car stopped stalling. Yesterday (after almost two months of the filter change), it stalled again... I was at a stoplight, and could not get the car to move when the light turned green (much to the annoyance of people behind me).

May need to get the fuel tank thoroughly cleaned...

 

[rahsut]

OK, I think the problem could be because of a gradually failing MAF. I disconnected the MAF and have driven the car for a while without seeing the problem.

Am goint to get the MAF replaced under warrenty, and see how it goes... /images/graemlins/grin.gif

 

[rahsut]

Well ... replacing the MAF made the car run better, but the occasional stalling did not go away. Noticed a crack on the intercooler, cleaned the crack area and put some epoxy to seal the crack... Will see how it goes...

 

[rahsut]

Problem seems to have gone away after fixing the crack...