Stumbles after starting

jjcsnlynn

Veteran Member
Joined
Nov 18, 2007
Location
Felton, DE
TDI
02 & 03 Jetta TDI,99 Beetle TDI, 04 Chevy Duramax 2500HD 4x4
This summer I replaced the gaskets on my injection pump and last year I changed the timing belt. After chaning the timing belt, I posted my timing numbers and the only comments from the forum were 'maybe raise it a little to help with cold starting".

Shortly after changing the gaskets on the drivers side and top of the pump housing, I noticed the enging stumbling a second or two after starting. It recovers itself and everything is fine, but it started getting colder this week and it seems to be a bit worse. It's not cold enough for glow plugs, but I'm thinking it will be worse as it gets colder.

I put the IC (I think it's called) on 10 after I changed the gaskets.

Any suggestions?
 

Abacus

That helpful B4 guy
Joined
Nov 10, 2007
Location
Relocated from Maine to Dewey, AZ
TDI
Only the B4V left
If by IC you actually mean IQ (Injection Quantity), then 10 is your problem, you're underfueling. It should be more like 3-9, with lower number running and starting better but giving slightly more smoke. I run 2.8 in the wife's B4, 3.8 in the wagon, and 5 in the sedan due to a worn turbo not providing enough air resulting in more smoke on acceleration. More than 5 on the '97 and it starts harder with reduced perfromance.

Adjust the IQ adaptation setting to 32768 then hammer mod it to an IQ of about 5, then adjust with the Vag-Com from there to get your desired results, which will vary by individual car, driving style, and preference.
 
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jjcsnlynn

Veteran Member
Joined
Nov 18, 2007
Location
Felton, DE
TDI
02 & 03 Jetta TDI,99 Beetle TDI, 04 Chevy Duramax 2500HD 4x4
OK, I use the link on this forum and I'm pretty sure it stated 10, but I will give it a try. Do I need the special key to do the hammer mod? I borrowed the tool and have given it back to the owner.
 

TonyJetta

Top Post Dawg
Joined
Sep 15, 2005
Location
Tucson, Az
TDI
'15 Jetta TDI SE / '06 Jetta TDI DSG Pkg0 / '96 Passat TDI
Do I need the special key to do the hammer mod? I borrowed the tool and have given it back to the owner.
You will need the tool to slightly loosen the QA housing. And, by hammer, we mean lightly tap the QA housing. I have successfully used a small block of wood. It really doesn't take much.

Tony
 

jjcsnlynn

Veteran Member
Joined
Nov 18, 2007
Location
Felton, DE
TDI
02 & 03 Jetta TDI,99 Beetle TDI, 04 Chevy Duramax 2500HD 4x4
Abacus,
I just checked my IQ (sorry, it's been a while. I have some issues at the house right now). When I started it the IQ was about 8, but as is smoothed out it's now down to 3.0-3.4.

I don't know how to do the adaptation. Can you send me directions?

Also, now that it's cold and the GPs are coming on, I smoke a whole lot when I start it up. It lasts for about 2 minutes then goes away. It's only done this since getting cold and it looks like fuel smoke. I think I've always had one FI that is leaking down. Could this be the cause or is it the extra fuel being injected since its cold. If so, Can I disable the extra fuel?
 
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