stumble

My tdi has an annoying stumble when I first apply throttle after starting. It only happens after starting, it does it every time, and only stumbles once. With that first acceleration at 2k rpm or so power is cut (it does not die) and then if I push the throttle again it drives normally until I turn it off again. No CELs. Any ideas?

in first gear? This is the vanagon right?

any codes that didn't trigger the CEL?

what year engine/controller? 99?

Yes, whatever gear i start out in (granny or first). In vanagon. I have only two error codes. Missing ABS controller and missing tcu databus controller (transmission). I used to have an egr code but it went away with Up II (?!) Controller is 99.5 Beetle. thanks.

does it smoke when it stumbles? Could it be overfueled right there at the rpm - too much fuel not enough boost, then boost kicks in...

no, no smoke. Feels electronic, like throttle abrubltly cut, same stock as Up II, same every day every place.

Poss. an auto tranny coding issue? Is the ECU still set up for an auto, but you're using a manual tranny?

Strangely enough, my Grand Vitara diesel (Peugeot HDI powered, Aisin electronically-controlled tranny)does a similar thing- give it a bit of juice to get going, and if you ease up and reapply the pedal (say the traffic is slower moving than anticipated), it's like someone just tapped the brakes.

Does it do it if you floor the pedal or only if you feather it?

I'm trying now to eliminate my missing controller codes (TCU and ABS) I succeeded in finding a code (00002) that seems to eliminate the abs code. But I havn't found a way to disable the tranny code, which may cause the stumble. The engine came out of a 99.5 beetle and my bently only has info for golf/jetta. Could someone with the beetle bentley check what code variations there are please? Any other way to turn the tranny off in software? Thanks in advance...

Hi:

Haven't got the answer to your prob, but some info that might help.

I have an ETKA and I looked up the auto transmission controller part numbers as follows:
99 beetle.
01M 927 733 FM Control unit
F 1C-Y-499-000 for engine 1 ALH
also

01M 927 733 HR Control Unit
F 1C-Y-400-001 for engine 1 ALH

Now for the 99 Golf

01M 927 733 FM control unit
F 1j-X-800-000 for engine ALH

So there's a 50/50 chance that the beetle uses the same part number as the golf. In which case whatever the bently says for the golf should also apply to the beetle.

Now how did you apply the abs code to turn off the abs error. I've got an abs controller that has died, and I'd love to turn that blinkin and beepin off until I get it fixed.

I have a bentley and a vag-com, just point me in the right direction.

thanks

Frank

Thanks for looking it up. The golf codes don't work for the beetle ecu (as far as my limited programming skills tell me). What I did was simply login, then recode button and there is and ecu number, mine was 00001 I think. I changed the 1 to 2, and the abs cel went away. Problem is so did my upII software, and my program reverted to stock. I think 00002 means auto w/out abs. I don't think I'll ever get rid of my tcu (tranny) code because both manual and auto versions have a controller which I don't in my vanagon.

Hi Again:

Thanks for the clue.
I went looking and found the following:

http://www.ross-tech.com/vag-com/cars/vwmkIV.html
it applies to golf, jetta and new beetle.

I think it might solve both your prob and mine.
See section 19

Frank

Beta,
Did you get your stumble to go away?
My Jetta is doing the same thing. Almost after every restart. After shifting into 2nd and mdoerate throttle it will stumble. Then it's fine.
It's about to drive me crazy. Before everyone jumps on the MAF bandwagon, I have looked at and greased the connections.

Troy