1981 Westfalia - Stuttering

lora_britt · Post by **lora_britt** » Mon May 07, 2007 6:05 pm

My bus has been worked on by several mechanics recently and no one seems to know how to fix my issue. It runs great overall, just returned from a 2000 mile road trip, thru a 50 mph wind storm that tore off the grille! But sometimes it stutters as if it's about to die, and the whole bus jerks. When I downshift or just keep the RPMs high it does better, and it seems most frequent in second and third gears (manual). Also, it happens more often when going uphill, but not always. I was told by one mechanic it was the flapper box which controls air intake, but haven't confirmed the diagnosis. Any ideas about what to look at would be appreciated.

Thanks,
Lora

Westy78 · Post by **Westy78** » Mon May 07, 2007 9:41 pm

Firstly, welcome to the forum. Second, the easiest solution to this symptom is a new fuel filter. What you're experiencing sounds like a fuel starvation issue. That said, I chased a stumble/shutter in my bus for a year before I checked the resistance on the AFM (that's the flapper that the mechanic was talking about, Air Flow Meter) pins. Problem solved. This procedure is explained in the Bentley manual if you have one. In the back under fuel injection trouble shooting. You can also do a visual inspection to the inside of the AFM by gently prying off the cover and looking at the potentiometer track to check for wear through. This will make much more sense when looking at it but here is a photo of the track. You can see the wear marks on the black track. If there is wear through to the circuit board that can cause the same symptom. Who is doing the work on your Van?

Post by **Amskeptic** » Tue May 08, 2007 7:35 am

lora_britt wrote: sometimes it stutters as if it's about to die, and the whole bus jerks.

If this symptom just pops up. . . . and as mysteriously, just goes away, it may be the famous gremlin that afflicted some of the early Vanagons whereupon the ECU and the AFM bicker with each other. See if you can find a technical service bulletin. There was a bunch of number-matching required between the ECU and AFM.

However, if it is intermittent, or tied into temperatures, bumps, and other environmental variables, a good system-wide check of all wires, connectors, and ground paths, is called-for. Be so thorough. . . . . . . .
Colin

lora_britt · Post by **lora_britt** » Tue May 08, 2007 9:43 am

Thanks for the information, I will have to go check on some of these things. I only have the Haynes manual, not the Bentley, but should I buy one, are they better? I am thinking Colin may be right because it is intermittent and seems affected by weather/environmental factors. I like to do the work myself when I can but since it seems rather vague I'm wondering if anyone knows a GOOD VW mechanic in Portland. Again, thanks for the info, any more would be great too. I'll start looking for someone I can trust to work on my bus!

Thanks,
Lora

Post by **Amskeptic** » Fri May 11, 2007 6:46 am

lora_britt wrote: I only have the Haynes manual, not the Bentley, but should I buy one, are they better?
I like to do the work myself when I can but since it seems rather vague

Bentley is good, but the Vanagon Bentley's are written in shorthand compared to the more conversational bay window manuals.

Vague is the best time to do your own bushwhacking through the mysteries. Who wants repair shop rates ticking away against your bank account as they wander through the briars and thickets of intermittent symptoms?
Colin

ruckman101 · Post by **ruckman101** » Fri May 11, 2007 7:17 pm

I seem to have the same Gremlin on an '82. I thought it was an '83 as that's what my Mother told me, but the title claims 82. I haven't taken a look into the little box yet. The cost of a new one is scary enough, and I'm trying to sell this for my Mother. I guess I better look at miscommunication between devices.

Faster acceleration, and higher rpms seem to bring my gremlin out. It was also suggested that I take a jumper wire to the air temperature sensor near cylinder 3 after the engine is warmed up. If it runs dandy, the sensor may need to be snugged down. No doubt a cheaper resolution, if that is the the problem and not the AFM.

Now to dig up the technical service bulletin.

neal

lora_britt · Post by **lora_britt** » Mon May 21, 2007 5:22 pm

So I've taken my van to a mechanic who comes well recommended for Vanagons and after several hours of 2 guys checking everything they can think of, they're stumped! I'm luckily not being charged some insane amount of money since they were unable to help, however I'm left with this issue, reinforcing my ideas that it is the Gremlin. The shop did say that it may have to do with the fuel injection. After reading that last post about how it seems worse at high RPMs I am pretty sure this is what is going on. It began a while ago and seemed worse if I didn't keep the RPMs high. but it was intermittent then and seemed very weather/condition related and almost always in 3rd gear. This is now happening constantly almost always in second if the RPMs are high. I'm going to have A&P use their computer to see what they come up with.
(recommended by the shop who looked at it)
The good news is that this began on the last 100 miles of a 2800 mile road trip, up till then she ran great!

I'll let you all know when we get to the bottom of it.
Peace,
Lora

Post by **Amskeptic** » Mon May 21, 2007 6:14 pm

lora_britt wrote:they're stumped!
I'll let you all know when we get to the bottom of it.

My favorite sort of inspiration. . . to get out there to Portland in September and have a go at it. Money-back guarantee by the way.
I will anxiously await your update.
Colin

dingo · Post by **dingo** » Mon May 21, 2007 8:00 pm

as they wander through the briars and thickets of intermittant symptoms?

that made me laugh

after several hours of 2 guys checking everything they can think of, they're stumped!

briars and thickets indeed.

lora_britt · Post by **lora_britt** » Tue May 22, 2007 10:16 am

The mechanic called this morning and told me they've fixed the problem! They found a kink in a fuel line and also replaced a couple of ground wires and she's good to go! I'm glad it turned out to be a simple fix.
Thanks for all your input and suggestions, I appreciate it!

Lora

Post by **Amskeptic** » Tue May 22, 2007 6:05 pm

lora_britt wrote:
ground wires!

Let us bow our heads:

Lawdy we shore thank you much and we promise to always always always check our grounds before beseeching thee for thine intervention.
Amen.

Westy78 · Post by **Westy78** » Tue May 22, 2007 8:49 pm

Blast those damn ground wires. The first rule of bus FI trouble shooting, Always Check The Grounds First!@$ At least they didn't just start throwing new parts at the problem.

ruckman101 · Post by **ruckman101** » Sat May 26, 2007 12:07 pm

Hmmm, well, I don't know where the grounds are for the fuel injection system. Guess I better look. A friend suggested bending the contacts in the air flow meter so they would track on a fresh spot. But once I got the lid up, I realized that wasn't going to work, so i cleaned the contacts with a q-tip doused in brake cleaner and it seemed to help, but I still detected a miss today.

neal

scruffy · Post by **scruffy** » Sat Jun 23, 2007 6:28 pm

Here's my 2 cents worth....
I have to say that the Bentley manual is worth every cent I paid for it. I own an 82 Westy and would've been lost without it. I've used the troubleshooting section for the FI many times!
Here's some other things I would check related to your problem. Be SURE you have the CORRECT distributor for your engine! and that's it's functioning PROPERLY! You can check most functions with a timing light, make sure you're getting the correct amount of advance for a given RPM and...be sure the timing isn't "bouncing," This could indicate wear in the dist. shaft or bushings. If you've got an all-centrifugal 009 on there...GET RID OF IT! The 009 does NOT have enough advance for our engine. I'd also check the points/dwell.
Pretty much everything on the FI can be diagnosed with a multimeter, test light and the Bentley manual.

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