Weirdness in the MAF Department 01268 and 00553

Joined
Apr 27, 2003
Location
Stafford Virginia 22556
TDI
96 glx variant tdi
My RC tuned (I think) 96 tdi b4v glx sat for 4 years although occasionally started. Now I get 01268 35-00 and 00553 27-10
1. The 01268 I'm thinking is a gummed up pump even though diesel purge sat in it for a year.
2. The MAF specified reads 1000 (I think that's correct for the tune) and after key off, start, the MAF actual reads 29.9. Raise the rpm some and the actual decreases to maybe 10. Raise the rpm to about 1500 and the MAF actual goes to 547 and stays there.
3. The 547 specified occurs with two different MAF's.
4. The 547 specified occurs with the MAF unplugged or connected.
5. The 547 specified occurs with or without EGR.
6. Group 19 key on/engine off reads .700 and 4.540
7. All conditions remain identical with a different ECU.
8. No signs of critters chewing on anything.
9. Harness wiggle test didn't reveal anything.
Any suggestions ? Thanks.
 

oilhammer

Certified Volkswagen Nut & Vendor
Joined
Dec 11, 2001
Location
outside St Louis, MO
TDI
There are just too many to list....
I'd say you do have a stuck QA in the pump for the one DTC.

The other, I'd check the EGR... be nice to know if it was deleted or not.
 

GTiTDi

TDIClub Enthusiast, Macht Schnell! Vendor , w/Busi
Joined
Oct 18, 2010
Location
3 Spruce st Wareham, gateway to Cape Cod Massachus
TDI
'91 GTI CJAA swap,'02 Jetta wagon ALH swap, '03 GTI 1.8T rally car, '03 Sprinter 3500
Most harness failures I see on 1Z/AHU pumps are due to the wires chafing inside the spiral wire loom sheath, the wires vibrate against the ribs of the sheathing wearing through the insulation and eventually through the wire itself. Corrosion can set in before the wire is fully broken causing all sorts of resistance as well as a voltage drop. I know you said a harness wiggle test didn't give you any love, but if the wire is actually broken like I said it may be, a wiggle test won't do anything unless you miraculously bridge the connection momentarily. The wire that gave me grief last time I encountered this was a black with a white tracer IIRC. YMMV
 
Joined
Apr 27, 2003
Location
Stafford Virginia 22556
TDI
96 glx variant tdi
I didn't mention that the IQ does bounce around more than normal so I did brake clean the IQ module but didn't help. The pump did have straight diesel purge in for the last year. No rust was evident when the top cover was removed. Group 19 looks normal. Fuel temp cold matches air and coolant.

To answer OH's question, I'm sure the EGR was not physically deleted, and don't think it was deleted in the tune if that is possible.

I can understand the pump gumming up after 4 years even though it had diesel purge in it. The MAF is what has me baffled.
 
Last edited:

burpod

teh stallionz!!1
Joined
Nov 27, 2004
Location
cape cod, ma
TDI
82 rabbit vnt ahu, 98 jetta vnt ahu, 05 parts car, 88 scirocco.. :/
is the tune for maf delete? if not, that can be easily remedied and not waste any time/$$ chasing maf issues :)
 

burpod

teh stallionz!!1
Joined
Nov 27, 2004
Location
cape cod, ma
TDI
82 rabbit vnt ahu, 98 jetta vnt ahu, 05 parts car, 88 scirocco.. :/
also, if the tune is for a maf delete, the actual maf values could be completely meaningless, as the tune can fill in default maf values. and iirc it's a 2d map so it can change across rpm range... so i wouldn't worry much about what those numbers are
 
Joined
Apr 27, 2003
Location
Stafford Virginia 22556
TDI
96 glx variant tdi
The 00553 turned out to be two bad MAF's, the one that sat on the car for 20 years and died somewhere in these last 4 years of dormancy, and the "known good" spare that sat on the shelf probably that long as well.

My new question is how does the maf work ? Where do the Specified and Actual figures come from ? I know if you unplug the MAF the Actual goes to 550, which is close enough to 547. Should I have recognized 547 from two MAF's is an almost 550 and understood it was a bad MAF to begin with ? Thanks for the suggestions.
 
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