Large IQ change after new filter.

nathanacura

Active member
Joined
Jul 11, 2017
Location
Cocoa, FL
TDI
2002 Jetta TDI
2003 Jetta manual.
IQ was 3.8, I adjusted it to 4.8 with adaptation. Nothing changed after intake and intake port cleaning ~10 days ago.
Car has a K&N filter -- which I realized while digging around in there was VERY far past due for a cleaning. OK, I haven't touched it since I got the car(with the filter already installed and dirty) say ... almost 9 years ago.
I cleaned the filter thoroughly including getting all of the old(and mostly solidified) filter oil out this weekend.
I re-oiled and everything still runs fine.
When I checked the IQ, it had shifted from steady 4.8 to 7.8ish. All measurements with the car fully up to temp.
Software adaptation limit is now like 6.5 minimum ... where it was below 3 before.

I assume this is obvious and just comes down to me not understanding how IQ really works and what it means.

Car feels fine and boost logs look OK. Any reason I need to lower that IQ? To do so would require the hammer mod, which I have done in the past.
Thanks!
 

IndigoBlueWagon

TDIClub Enthusiast, Principal IDParts, Vendor , w/
Joined
Aug 16, 2004
Location
South of Boston
TDI
'97 Passat, '99.5 Golf, '02 Jetta Wagon, '15 GSW
Obvious, but not necessarily correct, answer is that the engine is now getting a lot more air than when you initially set the IQ, changing the effective setting. Has the car ever had the hammer mod done on it? If not, it's possible that the pump has some wear that is causing the IQ to be on the high side.

I would also wonder if it will come back down after you drive a while.
 

nathanacura

Active member
Joined
Jul 11, 2017
Location
Cocoa, FL
TDI
2002 Jetta TDI
I did hammer mod it to get the value lower(I think) a few years ago. I could be remembering that backwards which would make more sense. Was terribly silly of me to not touch the filter ... or just try measuring without it ... before messing with the hammer mod.
I will ride around a few tanks before I mess with it. If it stays high, maybe I will adjust it back down to 4ish. Car does have 520 injectors ... but has been that way(along with the dirty filter) since I bought it.
 

IndigoBlueWagon

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Aug 16, 2004
Location
South of Boston
TDI
'97 Passat, '99.5 Golf, '02 Jetta Wagon, '15 GSW
I'd get rid of the K&N and put a MANN filter in it. Although they seem OK initially, I believe K&Ns tend to cause the MAF to fail after re-oiling.
 

nathanacura

Active member
Joined
Jul 11, 2017
Location
Cocoa, FL
TDI
2002 Jetta TDI
I would happily put the stock intake back on if I had it. Had a cold air intake with k&n filter which was mounted too low and sucked up water years back and hydrolocked the motor(I had told myself when I bought the car that I need to remove that stupid intake).
 

nathanacura

Active member
Joined
Jul 11, 2017
Location
Cocoa, FL
TDI
2002 Jetta TDI
Hmm, what do you know. Today my IQ was holding solid at 4.4. No other changes. It seems strange that the ecu would "get used" to a change and settle back in by that much.
 

gforce1108

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Joined
Aug 2, 2006
Location
Newburgh, NY
TDI
04 Jetta GLS BEW, 14 Audi A7 V6 TDI, 13 Porsche Cayenne V6 TDI
I'd get rid of the K&N and put a MANN filter in it. Although they seem OK initially, I believe K&Ns tend to cause the MAF to fail after re-oiling.
You know what's funny? - I work on 5 MKIV TDIs. 2 that have had K&Ns for 200k miles. Both of those are on original MAFs and have no issues. Every one running dry (usually Mann) filters has needed a MAF. Obviously the Mann isn't causing it, but K&Ns oiled correctly don't either. FYI - I still recommend dry filters to anyone else.
 

IndigoBlueWagon

TDIClub Enthusiast, Principal IDParts, Vendor , w/
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Aug 16, 2004
Location
South of Boston
TDI
'97 Passat, '99.5 Golf, '02 Jetta Wagon, '15 GSW
"Oiled correctly" is the key. I agree that in that case they can be fine. I just wonder how often that happens. In your case at least twice. :)
 

gforce1108

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Joined
Aug 2, 2006
Location
Newburgh, NY
TDI
04 Jetta GLS BEW, 14 Audi A7 V6 TDI, 13 Porsche Cayenne V6 TDI
"Oiled correctly" is the key. I agree that in that case they can be fine. I just wonder how often that happens. In your case at least twice. :)
You are correct there! I had a coworker kill the MAF in his certified used BMW 540 (covered under warranty) by over oiling. I was just so used to running them in every car I owned that I ordered one back in 06 when I bought my Jetta. Both TDIs I referred to have been cleaned and oiled at least 5-8 times each.

Sorry to sidetrack the original discussion!
 

nathanacura

Active member
Joined
Jul 11, 2017
Location
Cocoa, FL
TDI
2002 Jetta TDI
I don't get how the MAF fails. Can't the oil just be cleaned off?

I still have smoking at startup after the car sits for hours and a bit on heavy acceleration.
My group 13 is ~1.8, -1, .5, .2 - give or take. I assume that I have at least one injector that is leaking a bit of fuel into a cyclinder giving the short period of smoke and few seconds of light stumble. PO had 520 nozzles installed by Kerma, but that was years back.

However I am still super cheap so I am going to try and pull them and see if they are nasty. Will give them all some ultrasonic attention. If that doesn't help I see $500 in injector work in my future.
 

BobnOH

not-a-mechanic
Joined
May 29, 2004
Location
central Ohio
TDI
New Beetle 2003 manual
The MAF uses something called a hot film sensor. Does not like oil.
You should be fine if you don't over oil the thing. An excess of oil will get to the MAF and corrupt the film.
There are many many long flaming threads about just how bad a K+N is, but in your situation I would go with it, just monitor things.
 

gforce1108

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Joined
Aug 2, 2006
Location
Newburgh, NY
TDI
04 Jetta GLS BEW, 14 Audi A7 V6 TDI, 13 Porsche Cayenne V6 TDI
I don't get how the MAF fails. Can't the oil just be cleaned off?
As BobnOH mentioned, it's a hot wire. Basically, voltage is applied to the wire to keep it a constant temperature. The more air that passes through the MAF, the more voltage it takes to maintain that temperature. The ECU uses that voltage to calculate air flow. It can throw the reading off, or cause the unit to flat out fail.

If you catch it before damage is done, a MAF cleaner can be used. I have a good luck with Walmart brake cleaner - when I clean the air filter, I pull and clean the MAF as well.
 

wonneber

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Joined
Oct 12, 2011
Location
Monroe, NY, USA
TDI
2014 Jetta Sportwagon,2003 Jetta 261K Sold but not forgotten
The MAF uses something called a hot film sensor. Does not like oil.
You should be fine if you don't over oil the thing. An excess of oil will get to the MAF and corrupt the film.
There are many many long flaming threads about just how bad a K+N is, but in your situation I would go with it, just monitor things.
I read an article about the MAF getting contaminated and causing problems because the gunk holds the heat in.
The spray cleaners loosen the contamination but do not thoroughly remove the contamination.
It said you have to carefully use a lint free pad to lightly remove the residue.
Showed a picture of the pad with some gunk on it.
 
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