TheSamba.com :: View topic - Do Rebuilt AFM 's still need a capacitor or pigtail?

Wed Jul 12, 2017 5:58 pm

Hi folks. I searched but didn't find.

When an AFM is rebuilt or remanufactured, are they improved to help avoid Vanagon Syndrome or, is it still wise to install a capacitor or pigtail on a rebuilt AFM to help avoid Vanagon Syndrome from happening?

Thanks

Neil.

Wed Jul 12, 2017 6:48 pm

I heard it was fixed when rebuilt, but you can open the cover and check to see if there is a capacitor. Adding the pigtail won't hurt I believe...

Wed Jul 12, 2017 6:48 pm

It depends on where you get it from, I think: GoWesty and Van Cafe have their rebuilders take care of the capacitor fix. I don't know about Bus Depot. Probably not for the rebuilds from the various all vehicle part vendors. This is for the Digifant rebuilds. I have no idea what they do to Digijets. They probably don't include any capacitor fix on the Digijet rebuilds, because there is considerable debate on whether or not Digijet can even get Vanagon syndrome, but I am not sure.

Wed Jul 12, 2017 7:16 pm

Alika: Yes. Thanks. Certainly one could open the AFM to inspect but I have to wonder how that would affect warranty of the part? Can't see how often a warranty would normally get used though.....

Gauche: good question for the vendor I guess. Thanks for GW VC suggestion. FWIW, the TSB on Vanagon Syndrome was amended to cover 'all water cooled Vanagons'. (no mention of diesel Vanagons though. LOL). But I see what you mean.

Neil.

Mon Jul 24, 2017 2:24 pm

. YES I know for a Fact that Bus Depots are rebuilt to include this Fix..

No need for the PigTail Fix, actually if trying to use the older pigtail along with the upgraded AFM may complex your problem as you can't double fix it..

Mon Jul 24, 2017 7:48 pm

^^

Good point.

I could've been more specific (see below) but I was curious of the 1.9 AFM more than anything.

On Bus Depots web pages for the 2.1 and 1.9 rebuilt AFM, the 2.1 AFM page mentions 'upgrades' done to the 2.1 to help combat VS but nothing about that is mentioned for the 1.9 AFM.

2.1

https://www.busdepot.com/025906301c

1.9

http://www.busdepot.com/410038

I recently replaced the AFM on a buddies 1985. It had obvious wear on the resistive strip and a definite resistance dip when wiper was turned across that worn portion. We'll see if the rebuilt AFM cures the random engine on/off thing which is most likely Vanagon Syndrome. It had been doing this since it was near new.

Tue Jul 25, 2017 11:55 am

Vanagon Nut wrote: ^^

Good point.

I could've been more specific (see below) but I was curious of the 1.9 AFM more than anything.

On Bus Depots web pages for the 2.1 and 1.9 rebuilt AFM, the 2.1 AFM page mentions 'upgrades' done to the 2.1 to help combat VS but nothing about that is mentioned for the 1.9 AFM.

2.1

https://www.busdepot.com/025906301c

1.9

http://www.busdepot.com/410038

I recently replaced the AFM on a buddies 1985. It had obvious wear on the resistive strip and a definite resistance dip when wiper was turned across that worn portion. We'll see if the rebuilt AFM cures the random engine on/off thing which is most likely Vanagon Syndrome. It had been doing this since it was near new.

The 1.9's never suffered from the VS or not that we know of..

.

Tue Jul 25, 2017 12:07 pm

DubNuts wrote: Vanagon Nut wrote: .....
I recently replaced the AFM on a buddies 1985. .... We'll see if the rebuilt AFM cures the random engine on/off thing which is most likely Vanagon Syndrome. It had been doing this since it was near new.

The 1.9's never suffered from the VS or not that we know of..

.

Yes. This is what I'd thought too. But as mentioned prior, the TSB initially issued for the 2.1 was amended to include 'all water cooled Vanagons'. And, this buddies '85 had been suffering from this issue even when it had much lower miles; he bought it from the original owner in the early 2000's. I'd always assumed Digijet and Digifant were vastly different but they share the same or similar components for inputs and use a separate idle control system so the engine management software (called "firmware" ?) is probably somewhat similar? Anyhow......

Tue Jul 25, 2017 1:24 pm

From the Van-Cafe website,

"Description

This unit includes the widely recommended upgraded filter cable circuitry (capacitor soldered inside unit during rebuild to address the dreaded "Vanagon Syndrome")."

Tue Jul 25, 2017 2:17 pm

I was reading this on the bus enroute home and recalled seeing a ground strap on my 1990 connecting the afm housing to the passenger side head. The afm "pigtail" came with the van as well.

The air intake housing is off the van because we are renewing fuel lines so here is a picture of it in the workshop that I just took when I got in the door. Not a direct answer to the OP's question, but it got me thinking about what the pigtail harness was for and maybe VW thought adding this strap was helpful in maintaining a clean signal.

Tue Jul 25, 2017 2:45 pm

Snort wrote: From the Van-Cafe website,

"Description

This unit includes the widely recommended upgraded filter cable circuitry (capacitor soldered inside unit during rebuild to address the dreaded "Vanagon Syndrome")."

Thanks. Yes. But:

http://www.van-cafe.com/air-flow-meter-1.9l

As I linked to, Bus Depots' comments are similar. I obviously can't speak for the vendors but if buying a rebuilt 1.9 AFM asking if it too has the "upgrade" might be worthwhile because......

From TSB 92-02 (I put text in bold):

Technical Bulletin
Group: 24
Number: 92-02
Date: April 30, 1992
Subject: Vanagon Driveability Complaints
Model(s): All Water Cooled Engine Vanagons
SUPERCEDES TECHNICAL BULLETIN 24-92-01 (February 29, 1992)

CONDITION
After driving for an extended period of time at a constant speed, the
vehicle may, on occasion, experience a deterioration of performance
which may be accompanied by a hestiation or surging.

In many cases, after turning off the engine and subsequent re-start or
without having taken any action, the symptoms disappear. These symptoms
may not recur for several weeks or months.

SERVICE
To resolve this condition, wire harness Part No. 025 906 302, should be
installed. This harness provides improved signal voltage stablization.
* remove electrical connector from air flow sensor
* install wire harness, Part No. 025 906 302, between main harness
connetion and air flow sensor connection.
*****************************************************************
* CAUTION *
* Part numbers are for reference only. Always check with your *
* Parts Department for latest information. *
****************************************************************

NOTE
When troubleshooting this system and performing continuity checks, the
following should be noted. Due to active components in the wire
harness, Part No. 025 906 302, there is not continuity between pin two
of the connectors. The following chart on page 2 lists the resistence
of each circuit.
---------------------------------------------
Terminal Approximate
Number Resistance
---------------------------------------------
1 Zero Ohms
2 Greater than 1 Meg. Ohms
3 Zero Ohms
4 Zero Ohms
5 Zero Ohms

NOTE
If customer complaints persist after performing the above repair,
contact your Zone Product Support Specialist for assistance.

Tue Jul 25, 2017 2:56 pm

Good detective work but I would chalk that up to a poorly written service bulletin. After all, diesels are watercooled as well, and some of the non-US models had single carbs.

Tue Jul 25, 2017 4:24 pm

I've also seen reference to this issue for Mk2 Digifant VW's. And yes, I noted the hastiness of 'all water cooled' ;) Time till tell. This has been a long standing issue with this 1.9 Regardless, his AFM was very worn over one area so it was time.

Neil.