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http://www.myturbodiesel.com/1000q_how_to/multi/IQadjusthammermod.htm

If you've never checked the fuel injection quantity on your 1996-2003 TDI it's possible it's off. Included are VCDS menu screenshots and how to do the hammer mod.

Fuel injection quantity (IQ) adjusts power, smoke, and economy. It can be misadjusted from the factory or it can change after a mod to your car. The middle section of the injection pump adjusts IQ using an electronic arm. However, the electronic arm has mechanical limits. The hammer mod changes the mechanical range of motion on the arm.
 

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It depends on where the mechanical limits of the quantity adjuster are. If it's already at one end the software can't adjust it further in that direction.
 

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More notes added. And just to clarify, you can check IQ on pump duse engines but you cannot change IQ on them (at least for US engines, euro may be different due to different engine management system).
 

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... As a "Newbie" this is my first POST on MyTurboDiesel.Com FORUM...

... As a "Newbie" this is my first POST on MyTurboDiesel.Com FORUM...
and the title of this [edit] THREAD [<-edit->]makes me inclined to think this is about:
either adjusting the IQ using VCDS OR doing it by the "Hammer Mod" method...
but then when I read and study this more closely,
I wonder after reading the photo captions near the end...
I wonder if the title could also read:
"Set your IQ with the Hammer Mod [<-edit->] first for the lower limit of the range AND then use VCDS to set upper range!" [<-edit]
Q1 - Am I missing something as a Newbie...
or is my suggested title more clear as to this POST's intended message
?


Here is why I ask:
After a 3-week "No-Start" project, we recently faced the decision to send in or replace our 2002 Jetta TDI's IP and we ended up taking the top of the IP and found the QA shaft frozen.
While connected by telephone with DFISpdx.com in Portland we then removed the next section ["QA assembly" (my name?)], freed up the shaft, cleaned things up and put it back together. Yes we marked the IP's adjacent case sections and replaced things very precisely... but it had a very bad/rough idle and so we ended up at a local INDY VW shop with a Ross-Tech system & "some" experience and he was able to cure the idle problem.
So:
Q2 - Should we redo the QA after first performing the IQ by first the "Hammer Mod" method and then use VCDS to set the upper limit?
Thanks in advance...
I really like your collection under your pages"
"1000q" and "1001q/multi" !!
Regards,
Sam Ross / Novato, CA
 

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I would use the default software value and then do the hammer mod so that it's in the middle. This way you have more room to move with the software. If it's running well now, I wouldn't touch it.
 

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Discussion Starter #10
1: it should ideally be set to optimal but sometimes it just isn't. Set to middle of range.
2: To the best of my knowledge, VCDS adaptation can not set the upper or limit. It merely sets the adaptation. The ECU map and physical limit of the QA controls the upper and lower limits
 

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... Clarifications PLEASE...

First let me clearly state that in this my 2nd POST on this FORUM is to LEARN...
and right now specifically to LEARN about the VE-e series of IPs and their actions/reactions with the car's "ECU"/"ECM"...
so let me ask for clarifications in both of your kind & prompt responses:
[note that it helps my aging brain to break down such written dialogue with each sentence and/or phrase starting on separate lines... probably dementia setting in upon my 67 year-old gray cells]

I would use the default software value and then do the hammer mod so that it's in the middle.
<-OK... so my thinking was "bass-akwards"!
This way you have more room to move with the software.
If it's running well now, I wouldn't touch it. <- OK, makes sense now... I think!?
1: it should ideally be set to optimal but sometimes it just isn't.
Set to middle of range. <- OK... or as I think is correct thinking...
or you can set it a little higher IF you want to try to squeeze out a few more MPGs...
but NOT too much for you could shorten the engine and/or IP's life expectancy?!

2: To the best of my knowledge, VCDS adaptation can not set the upper or limit.
<-So you are saying that the "upper" limit is merely a programmed line on the VCDS's software generated graph...
OR that the IP does not have the necessary "actuators" for the Ross-Tech and ECU/ECM programs to manipulate?

It merely sets the adaptation. <-"Adaptation"... my understanding of this word is that it refers to how/&/how much the IP and ECU/ECM together to "adjust" the ECM's program that then varies the IP's output trying to optimize the engine's performance!?
The ECU map and [the] physical limit of the QA[mechanism] controls the upper and lower limits. <- ? IF you take the "s" off of "controls", I think I understand
OK, I'm a 67 year-old who many decades ago was a U.S. Naval communications officer and combat air controller [Vietnam] and this experience ingrained in me the fact that oral communications (dialogue) can far more readily cause misunderstandings than written communications...
but here too in such "written" FORUMs this engineer has learned that there are pitfalls... mostly born out of brevity!
So don't take me for "nit-picking" anyone here...
just trying to learn how these TDI systems work...
and then to work on my Son's car so that it works better!
Best regards,
Sam

P.S. - Please let me know IF you think I use too much color... or need a little more "brevity"!
P.S.S. - Yes, I came to this FORUM by way of the www.TDIclub.com FORUM.
 

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Discussion Starter #12
I don't think adjusting IP will shorten life expectancy of anything. More advanced timing, within a range, can raise stress and temps but I don't think it makes a difference in engine lifespan or will kill the injection pump.

To the best of my knowledge, the ECU map sets the upper and lower software limits. The physical range of the QA arm sets the physical limit. When properly assembled from the factory, the physical limits should not be limiting the software. However, this is often not the case.

You can do some adaptation to change this within the overall software mapping but the ecu map is the "superior" determining factor, the adaptation is the "inferior" factor. This is just how I understand it, I could be wrong. Feel free to start another thread in the Ross tech section under the general forum here asking about how adaptation of the IP works, they would know more and they respond quickly.
 

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... Where is this FORUM's glossary?

By all means... where is this FORUM's glossary?
I need to study TDI terms much more than I have!
Thanks: "chittychittybangbang" & "Fluid"
for the IP lessons!
Sam
 

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Hi all... I wonder if someone can provide me with a little insight. So my car (golf 4 tdi ahf) stock except for down pipe. Runs perfectly well starts up good but when I check the timing with vcds it shows as retarded, below the acceptable range. I tried using vcds to get it in spec but it hardly changes it. I then tried to do the hammer mod and when I knock it slightly to the right (passenger side) the idle becomes very rough, too much to the right and it revs up. Too much to the left (drivers side) and it stutters, but the graph itself shows no change. My question is if I leave it retarded as it has been running all along are there any issues?
 

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Hi all... I wonder if someone can provide me with a little insight. So my car (golf 4 tdi ahf) stock except for down pipe. Runs perfectly well starts up good but when I check the timing with vcds it shows as retarded, below the acceptable range. I tried using vcds to get it in spec but it hardly changes it. I then tried to do the hammer mod and when I knock it slightly to the right (passenger side) the idle becomes very rough, too much to the right and it revs up. Too much to the left (drivers side) and it stutters, but the graph itself shows no change. My question is if I leave it retarded as it has been running all along are there any issues?
Okay so I'm an idiot, I now realize that the hammer mod only adjusts IQ and doesn't affect timing at all, saw a video on youtube on how to adjust timing, doesn't appear complicated by any means, so I'll get on that. :)
 

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Okay so I'm an idiot, I now realize that the hammer mod only adjusts IQ and doesn't affect timing at all, saw a video on youtube on how to adjust timing, doesn't appear complicated by any means, so I'll get on that. :)
Okay if anyone is interested, I set my timing to slightly advanced (mechanically) and then reset my IQ to 2.5, previously I had it as low as possible just over 1.2 ish, It was running better with the lower IQ (felt perceivably faster/quicker response). So I will set it down again I think. Anyone have any possible negatives of a lower IQ besides shutdown shudder which I don't notice at all with a low IQ?
 
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