Changing Injection Quantity issue

TDITim83

Veteran Member
Joined
Oct 17, 2010
Location
Ocala, FL
TDI
96 Passat Wagon TDI B4V Storm Gray 258k, 98 Jetta TDI 260k (retired for spare parts)
I have been on VAG Com and I can't seem to be able to drop my Injection Quantity low enough. Instead of being around, 3.2 I am above 6. And am only able to adjust it down to 5.8 at best. What am I missing?
 

jdulle

Veteran Member
Joined
Feb 4, 2017
Location
Ithaca, NY
TDI
96 B4, 97 B4
I think what you need to do is loosen the bolts on the top of the injection pump and tap in the direction that lowers injection quantity. You should search for the procedure and follow those instructions, the top of the injection pump needs to move only a fraction of an inch. You should have the vag com connected so you can watch what is happening to IQ in real time.
 

Tdijarhead

Top Post Dawg
Joined
Nov 10, 2013
Location
Lawrenceville PA
TDI
2003 TDI Jetta Daughters Car, 2001 TDI Beetle, Wife’s car, 2005 Golf TDI Mine, all 5 spds
Here is a video of the hammer mod. As you watch it keep in mind that you do not need to hit the pump very hard. Maybe it just the video and a light hammer but it seems like these guys are really beating on that pump.

You will need the triangle bit to get the one bolt loose. Or hammer a 12 point socket down over it. The other three are torx.

They are raising the IQ and you need to lower yours so you’ll be going in the opposite direction. If you have one I would use a rubber or plastic headed hammer.

https://m.youtube.com/watch?v=TL_7KN4Nbvo
 

KLXD

Top Post Dawg
Joined
Aug 22, 2009
Location
Lompoc, CA
TDI
'98, '2 Jettas
After a minimum of 15 years the QA on a VE pump that has never been apart may not want to move.

Even heavy tapping may not overcome the adhered seal and when it does let go there's no telling how far it might move. Then the hardened gasket may not seal again.

I'd be prepared with a new gasket set before attempting the hammer mod.
 

greenskeeper

Top Post Dawg
Joined
Mar 10, 2003
Location
USA
TDI
1998 Jetta TDI
It'll move, doesn't take much to make a big impact.

On my old 98 the "sweet spot" with RC3 tuning was to adapt to the lowest IQ and then hammer to 1.5
 

Mongler98

Top Post Dawg
Joined
Mar 23, 2011
Location
COLORADO (SE of Denver)
TDI
98 Jetta TDI AHU 1.9L (944 TDI swap in progress) I moved so now i got nothing but an AHU in a garage on a pallet.
those seals are $4.00~ and easy as heck to replace. i would replace them if you so much as move it, well at least order the seals, if it leaks, then you can fix it easy, otherwise you have a $4.00 set of seals for when they eventually do leak
 

Giberish33

Veteran Member
Joined
May 30, 2017
Location
Montreal, Qc
TDI
1997 Jetta TDi 1z
It'll move, doesn't take much to make a big impact.

On my old 98 the "sweet spot" with RC3 tuning was to adapt to the lowest IQ and then hammer to 1.5
Just out of curiosity greenskeeper, what was the reasoning for dropping the adaptation all the way before hammer modding? I understand that each car might want a slightly different IQ to run best, but from what I understand the general thinking around here is that you should keep adaptation stock before hammer modding for best ECM control over IQ. No criticism just genuinely interested as its the first time I've hear someone doing it in that order.
 

TDITim83

Veteran Member
Joined
Oct 17, 2010
Location
Ocala, FL
TDI
96 Passat Wagon TDI B4V Storm Gray 258k, 98 Jetta TDI 260k (retired for spare parts)
Hammer Mod accomplished....not much change

I have completed the Hammer mod.....I'm now at 3.2 IQ. I do seem to have a little more power, though still low powered for sure. Im gonna switch injectors from my 98 TDI Jetta.....see what happens
 

greenskeeper

Top Post Dawg
Joined
Mar 10, 2003
Location
USA
TDI
1998 Jetta TDI
Just out of curiosity greenskeeper, what was the reasoning for dropping the adaptation all the way before hammer modding? I understand that each car might want a slightly different IQ to run best, but from what I understand the general thinking around here is that you should keep adaptation stock before hammer modding for best ECM control over IQ. No criticism just genuinely interested as its the first time I've hear someone doing it in that order.
exactly what you said...each car is different. I also ran full timing advance (5 degrees) and no EGR.

Adapting the IQ first then hammering to 1.0 gave me the best fuel economy/power balance (provided I kept my foot out of it, as it did smoke pretty good when WOT with that setting)
 
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