Injector pump Diagram

TDIJetta99 · Feb 4, 2009

Your fuel economy is determined by your right foot... I usually set the IQ on a stock TDI as low as I can get it without having any slowdown shudder.. Usually around 2.0-2.5 does the trick.. Some will shudder at 2.0 and others won't..

kwalsh24 · Feb 6, 2009

My car smokes like a SOB @ 2.5, smokes a little @ 3.6 so i put it up to 4.6 and i think its not smoking, The higher the number the leaner isnt it? or do I have it reveresed?

TDIJetta99 · Feb 6, 2009

you got it right.. higher number = less fuel

kwalsh24 · Feb 9, 2009

Okay, so my car is @ 4.6IQ (may have toadjust the startup IQ as the car turns over and over and over before firing) I took it out for a test drive and it drives rather nice in comparison to my old 95 IDI Jetta, but will this setting harm the engine down the road? The diesel engine gets some lube from the diesel fuel will this leaner mode cause harm?

TDIJetta99 · Feb 9, 2009

Your timing is probably off if it cranks for a bit before starting, it should fire almost instantly unless it's bitter cold and been sitting overnight..

No harm at all running the IQ at 4.6..

kwalsh24 · Feb 9, 2009

Timing as in fuel pump timing? My sisters car is worse than mine and it can be sitting in the garage... I know with my car it only does that after sitting for a while, my sisters car however we brought it in the garage one night and it took a few attempts to get it to fire...

TDIJetta99 · Feb 9, 2009

An ALH engine with the Injection timing set right and a properly functioning glow plug system will fire up right away.. usually a "rur, rur, rur, bam!" running.. Usually quicker than that though..

sullyTDI · May 6, 2009

My car takes a while to start to. Have new TB and all, check valve in tank is ok, getting plenty of fuel and IQ is 3.6. I reset the IQ when I installed my nozels.

Where is the startup IQ Setting? I would like to try changing it, would it be up or down?

I don't know what the heck is wrong with it, runs freaking great, just starting, crazy thing is, it will start ok some times........

Toby_B · May 6, 2009

i have the same issue, i hadnt heard of startup iq before how is it adjusted? i have a vag com.

Toby_B · May 7, 2009

nobody?

tditom · May 8, 2009

search for hammer mod

TDIJetta99 · May 8, 2009

if you have an issue with cold starting, something is wrong... period. messing with the startup IQ won't help or hurt, i've never noticed a difference either way with the adaptation on any ALH I've tried it on. if it's warm starting, most likely is the software programing (early ALH hot start issue)... There's a BIG HUGE thread on it..

TDI'ed · May 11, 2009

Hey guys, is there any how-to's on cleaning the quantity adjuster? I have the odd code here and there. I also don't get much smoke even with VEG 216 nozzles and an IQ of 2.0!? I know for a fact that my turbo vanes are not moving their full range but its not bad enough to negatively affect my performance and it seems to be getting better with every italian tuneup

HwyChild · May 12, 2009

I just did the hammer mod tonight.
After a couple taps with the hammer I tried to start the engine. It started, but, not easily. I hooked up the VAG COM. My IQ was at .11. Took me some reverse hammer mod tapping to get it back. Car runs great and starts easily again.

TDIJetta99 · May 13, 2009

you can do it with the engine running while watching the IQ on Vag-com.. If you loosen the bolts only about a half of a turn you won't have much if any fuel leaking.

TDI'ed · May 13, 2009

I have done it countless times (hammer mod) I wouldn't recommend doing it without the engine running and using vagcom. It takes very little movement to make a significant change.

Beetlebat · May 16, 2009

I'm gettng ready to set mine after replacing the seals. I've seen several recommended settings, should it be set to 3.5,4.0 or 4.6 ( all of which I've seen mentioned here). I replaced the adjuster seals , tops and bottom and it fixed my leak. I started right up, but I noticed a bump in the idle every few seconds. Is this the mentioned shudder?
Thanks,

TDIJetta99 · May 18, 2009

kinda depends on which injectors you have.. stock injectors on a 5-speed I'll usually set it down around 2.5, slightly higher if there's any hint of slowdown shudder.. With bigger nozzles you'll want the IQ a little higher to avoid excessive smoke/shudder.. My PP502's smoke like a train with the IQ any lower than about 6..

RCPaul · Jun 17, 2009

Can anyone tell me what it means when its says to adjust or tap the injector pump until it reads 3.4-3.6 or 4.0 in block 2?? When I go into the basic settings in my vag com and select "group" 000 its says 47 in the second "block". Is this the correct reading or am I looking in the wrong place??

Thanks!

TDIJetta99 · Jun 18, 2009

RCPaul said:
Can anyone tell me what it means when its says to adjust or tap the injector pump until it reads 3.4-3.6 or 4.0 in block 2?? When I go into the basic settings in my vag com and select "group" 000 its says 47 in the second "block". Is this the correct reading or am I looking in the wrong place??

Thanks!

Look at group 001 instead of group 000 and don't put it in basic settings.. the second block is your injection quantity..

freeantelope024 · Jul 27, 2009

Did I miss something

I read through the entire thread and may have missed something. So why does one consider a Hammer Mod...I have a shudder issue with my wife's 2002 Jetta, definitely injector pump...my mechanic says replace the pump...which hes is currently doing...says the VWO has caused the issue...Should I have tried this first?

Thanks

tditom · Jul 27, 2009

hopefully there was a good reason to replace the pump. If all it needed was an IQ adjustment, then its time to replace your mechanic...

TDIJetta99 · Jul 27, 2009

tditom said:
hopefully there was a good reason to replace the pump. If all it needed was an IQ adjustment, then its time to replace your mechanic...

Agreed... if the IQ was too low, it'll shudder.. If it shudders with the IQ in the 3.5-4.5 range and the nozzles are in decent shape, something's wrong with the pump..

edgardotcom · Apr 3, 2011

I just did the "hammer mod" to my car a few minutes ago and it was a success!!! my car had 14 IQ (thats why it was so slow over all) I lowered to 4.2 what a difference in performance!!, I have one question.. can i add the evry mod after the "hammer mod"?

m1ketdi · Apr 4, 2011

Yes you can add the evry.

Bebuxa · Apr 15, 2012

my vag com sho me 2,2 mg/str, but if i lowered more my motor shakes in a idle, why?i change the noozles of tdi 90 for tdi 110 . mY car has a lot of smoke, and with nozzoles of tdi 90 i dont remember that smoke black...

TDIJetta99 · Apr 15, 2012

You want to raise the IQ.. lowering the IQ delivers more fuel..

Bebuxa · Apr 16, 2012

but if i raise de i.q the car lost performance of ecu chips....my noozles is of tdi 110 now...

TDIJetta99 · Apr 17, 2012

Don't raise it too far.. Just enough to lessen the smoke and stop the shaking.. I usually set the IQ to about 3.5..

Injector pump Diagram

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