Intermittently loses power - '90 Westy


RBEmerson

Member
During our extended trip this past winter (4400 miles), our Westy has developed an intermittent power loss. When it happens, the engine will idle normally - right speed, no surging. But... when applying throttle, the engine feels as though it's just about to quit altogether. Back off the throttle and the engine doesn't threaten to quit. The problem persisted for two days of local driving. The weather was dry and in the 70's.

The first time the problem happened was near Melbourne, FL; that is, flat road. Nothing happened again until we were almost home. Driving through Harper's Ferry, again we had the "fixin' to die" problem. While temperatures were in the 70's, it was pouring rain and the problem started while pulling a hill.

In each case, I ran a can of Seafoam through the engine. That stopped the problem. The second time, I though more about wet wiring. I'd think more about that except earlier, in Tampa, FL, we were caught in a "frog choker" which didn't bother the engine at all.

The problem has returned, although, so far, it's been milder (lasts for 1/4 - 1/2 mile). The problem, again, was on the flat, the weather is hot (90F), and there was no rain. I haven't put in some Seafoam but, of course, I will.

My first guess is one or more clogged injectors. The fuel filter was new at the start of the trip (let's say it had about 800 miles on it in Melbourne) and now has 4700 miles on it. I did new plugs, wires, rotor, cap, air filter at the same time.

My second guess is a vacuum leak, but I'm not very enthusiastic about that idea.

Anyway, I need a memory jump start on "intermittent no power, idles OK" causes.
 

RBEmerson

Member
At this point it seems as though the issue is tied to the a/c compressor running or not. The compressor is new and comes from the OEM source used by GW, etc. When the problem shows up, switching off the A/C may (or may not) clear the problem, but usually it does. This is not, repeat, not the slight power loss associated with the HP load from the compressor. This is a "just this side of the engine stalls" loss. Except the engine idles as it should when I pull over to the side of the road.

Today the problem returned and almost always came and went to the A/C. We stopped at a local farmers market - call it about 20-30 minutes - and afterward all was well.

I put a can of Sea Foam in the tank, but I'm less inclined to think the problem is something Sea Foam can address.

Thoughts?
 

Les

New member
Try disconnecting your O2 sensor. Follow the wires back from the catalytic converter and unplug the connector.
This same problem came up with 2 vans I've had and this solved the problem with no ill effects so far.
I changed the sensor a time or two but the problem came back. I've now been driving my 87 for two years with the sensor unplugged and it runs great. My son has been driving my old 86 for about the same time or longer with no problems.
 

RBEmerson

Member
At this point, the O2 sensor is way down on the list. We have fairly stringent emissions requirements in the Philadelphia, PA area. Our Westy falls into the category of needing a dyno test(!) to pass the emissions test. If the O2 sensor was tired, I'd know. :)

To date the throttle body and idle control valve have been replaced. They appear to be either very old or original parts. Either way, they were out of spec. The next item to be replaced is the Temp II sensor, which talks only to the ECU. The final strong contender for causing problems is the air flow meter signal filter. Reading VW info, this is a common source for the Vanagon Syndrome or Vanagon Highway Hiccup (pick your fave name). The description is close to the power loss problem we've seen. So I'll put in the GW "splice it in" replacement.
 

wanderer

New member
I'm an air cooled guy with no running problems but with the wasserboxs; the same symptoms your experiencing were referred to as Vanagon Syndrome. Google it to see if this sounds like something your dealing with. From what I recall its a fix to the air flow meter. VW issued a service bulletin recommending a type of harness that eliminates it.
Good luck and safe travels to you.
 

RBEmerson

Member
In fact, there seem to be two problems at work. "Loses power" sounds very much like "Vanagon Syndrome" or "Highway Hiccup". The other problem is the engine races after idling for some minutes. If the A/C is on, the problem happens within about 5 minutes. The idle creeps up from about 900 RPM to 1500-1750 RPM. It jumps to 2500-3000 RPM if I tap the throttle pedal. Driving for a couple of minutes clears the problem (with the engine pulling the Westy, the engine speed is held down, of course).

With all of that said, I've replaced the throttle body (it showed the classic wear patterns), the idle control valve (it buzzes much louder than the old one), and Temp II sensor (think mostly about the racing engine issue).

VW came up with a signal filter that smooths out the signal from the air flow meter. The filter is a simple op-amp. GW makes a replacement, selling for about $50. It has to be soldered onto the existing cable that plugs into the air flow meter. Long story short, the engine wouldn't start with the GW air flow meter signal filter (which uses an improved op-amp design with lower voltage loss). Returning to the original wiring, the engine starts and runs as expected. Again cutting to the chase, it seems likely the VW part is OK. NTL, I'm waiting for how GW will resolve the issue with cable.

The filter was VW's response to Vanagon Syndrome. Unfortunately, there's no quick way to see if I have the problem under control (the "hiccup" can't be produced on demand). OTOH, the racing engine problem is (too!!) easy to reproduce. At the moment, I'm thinking hard about (yet again) cutting to the chase and replacing the idle stabilizer control unit, mounted behind the right tail lamp. Replacing it might also cure the hiccup.

Decisions, decisions, decisions...
 

RBEmerson

Member
Yep, I'm finding out about "highway hiccup" or "Vanagon Syndrome". The cable you're referring to is the Air Flow Meter Signal Filter Cable, which contains a small op-amp circuit that smooths data coming from the air flow meter sensor (or potentiometer, to get pedantinc). Over time the signal (effectively the amount of air flowing, as determined by how far the door or flap in the air flow meter moves) becomes noisy as the sensor wears and accumulates dirt. The easy thing would be to open the housing, clean the "pot", and call it good. But the housing is very tightly sealed. So the alternative is a block of electronic bits. GW makes a replacement that's a little cleaner, and also gives a slightly stronger signal to the ECU ("engine computer"). I've replaced the VW part with the GW part. That may or may not fix the problem, but it'll probably be weeks, if not months, before I can relax and think the matter's cured.

I also have a problem with the engine racing if it idles too long. To that end, I've replaced the Temp II sensor (didn't fix the problem - I now have a spare, if older, part) and will replace the Idle Stabilization Control Unit (the Idle Control Valve, Temp II sensor, and the ISCU are the common villains in this problem - the ISCU lives behind the right taillight assembly, BTW). After that... [/shrug] I hope I don't have to worry about that.
 

okbyenow

New member
This is exactly the experience I had while on a 4000 mile trip to the American south west. My 1990 Westy finally quit and wouldn't start. I was referred to a VW dealer in St. George, Utah who said it was dead. I opted for a subaru conversion and when the wasserboxer was pulled it was compression tested and was just fine. I was pissed at the VW Service but went ahead with the Subaru. I found out after the fact that this is common with Wasserboxers 86-91. I found a description of the Vanagon Syndrome on gowesty.com. - Digifant fuel injection system found on 86-91 Vanagons. The culprit is the antiquated air flow meter (AFM)no-longer-available, and unreliable parts of the Bosch Digifant Electronic Fuel Injection (EFI) that came in all 1986-91 Vanagons. A New replacement kit available 12-2014 NEW GW Fuel Injection Component Replacement Kit Price: $2495
It's an expensive fix. Good Luck
 

RBEmerson

Member
Yep, I'm finding out about "highway hiccup" or "Vanagon Syndrome". The cable you're referring to is the Air Flow Meter Signal Filter Cable, which contains a small op-amp circuit that smooths data coming from the air flow meter sensor (or potentiometer, to get pedantinc). Over time the signal (effectively the amount of air flowing, as determined by how far the door or flap in the air flow meter moves) becomes noisy as the sensor wears and accumulates dirt. The easy thing would be to open the housing, clean the "pot", and call it good. But the housing is very tightly sealed. So the alternative is a block of electronic bits. GW makes a replacement that's a little cleaner, and also gives a slightly stronger signal to the ECU ("engine computer"). I've replaced the VW part with the GW part. That may or may not fix the problem, but it'll probably be weeks, if not months, before I can relax and think the matter's cured.

I also have a problem with the engine racing if it idles too long. To that end, I've replaced the Temp II sensor (didn't fix the problem - I now have a spare, if older, part) and will replace the Idle Stabilization Control Unit (the Idle Control Valve, Temp II sensor, and the ISCU are the common villains in this problem - the ISCU lives behind the right taillight assembly, BTW). After that... [/shrug] I hope I don't have to worry about that.
I thought I'd updated this thread... anyway...

The GW Air Flow Meter Signal Filter Cable turned out to be worse than an utter waste of time. Both units failed. The first lead to an engine that cranked, tried to fire, and didn't. That cable was diagnosed, working with the guy who designed the cable, as DOA. The second cable ran for a while and then failed about 90 miles from home - dead engine that cranked but didn't even try to fire. Lessons learned: 1) getting to GW to even address the problem took some serious pushing to get past the front desk, 2) the GW part is, IMHO, utterly not trustworthy, 3) the engine is happy with the original cable (that is, it wasn't broke, silly me for fixing it) and runs with no cable. 3a) Get inside the AFM (get the top off the square lid - not easy but doable with care and patience), dose the wiper arm, moved by the "barn door", with contact cleaner, move the barn door over its full range, dose with cleaner again, move the barn door again, and close up the top with the sealant of your choice. The signal filter seems to be VW's way of getting around cleaning the barn door sensor.

Since cleaning up from the AFM filter debacle, the problem with "Vanagon Syndrome" has gone away. (See below)

The racing problem was finally sorted out. The solution was embarrassingly easy. I added an after-market (AudioVox CSS-100) cruise control. The system is a case with some "smarts" in it and a throttle cable sticking out of one end. The cable is routed to the throttle body and a small bit of chain (think of the sort of chain used in key rings) is attached to the point where the stock throttle cable goes. The chain is used to provide some slack between the throttle arm (on the throttle body) when stepping on the gas with the cruise control engaged. Now for the point where the wheels fell off: the chain ends in a simple ring terminal crimped to the chain. The throttle cable from the gas pedal ends in a simple barrel with a set screw to hold the end of the VW throttle cable in place (step on the gas, the cable tugs on the throttle arm, the engine speeds up). I removed the cable end and lifted the barrel, slid it back down through the hole in the ring terminal, replaced the VW throttle cable end, and called it good. And, for much of the time it was. But... the VW cable tension was set too high (no slack in the VW cable). When the engine really heated up and the engine bay temperature climbed, too, the expansion of various bits in the throttle body conspired to keep the throttle plate from closing fully and... racing engine. Fix? Leave a bit of slick in the VW throttle cable. End of story.

One problem remains. The engine basically tries to die if we drive through heavy rain for an extended period. Bottom line: somewhere in the wiring there's a point that doesn't react well to being soaked. "All" I have to do is find that point.

Summing up: at a guess, a number of relatively minor problems, mainly wear brought on by being original parts, added up to less than optimal operation. The setting for the TPS probably added to some of the perceived problems. The racing engine problem was nothing more than a poorly adjusted throttle cable. On any day but a really wet day, the engine runs just fine.

I almost certainly replaced more parts than I needed to, but, with the exception of the GW AFM signal filter, at the worst, it didn't break anything. At best, things are better than when I started. Or so I'd like to think.
 

RBEmerson

Member
This is exactly the experience I had while on a 4000 mile trip to the American south west. My 1990 Westy finally quit and wouldn't start. I was referred to a VW dealer in St. George, Utah who said it was dead. I opted for a subaru conversion and when the wasserboxer was pulled it was compression tested and was just fine. I was pissed at the VW Service but went ahead with the Subaru. I found out after the fact that this is common with Wasserboxers 86-91. I found a description of the Vanagon Syndrome on gowesty.com. - Digifant fuel injection system found on 86-91 Vanagons. The culprit is the antiquated air flow meter (AFM)no-longer-available, and unreliable parts of the Bosch Digifant Electronic Fuel Injection (EFI) that came in all 1986-91 Vanagons. A New replacement kit available 12-2014 NEW GW Fuel Injection Component Replacement Kit Price: $2495
It's an expensive fix. Good Luck
IMHO, after the episode with the signal filter, and with a GW-remanufactured throttle body with a TPS that should never have gone out the door (no adjuster, only the locking screw, and a generally filthy [we're talking an ugly layer of old grease] switch body), I wouldn't touch the EFI with a 10' pole. I have no doubt that a re-mapped ECU probably does wonderful things, and it sure would be nice to have a knock sensor if I drove in places where the gas is more gasoline in name than in fact. But, after all of the digging around I did, I've come to the realization that, with a little care and maintenance, the OEM EFI actually does work. Further, given the problems with just making GW aware of the signal filter failures (I didn't waste my time griping about the TPS - I'll put a Van Cafe TPS on the throttle body when it's time to take the Westy out of winter storage)... I have little need to return to GW for much of anything. YMMV

And the AFM? See the comments on cleaning up the wiper arm. It's a shame that VW didn't see fit to make the cover for the sensor removable, but that's life. Replacing the AFM because of dirt between the wiper arm and resistance element is... the word "silly" comes to mind.
 

HGC101

New member
I replaced the fuel filter and solved the intermittent stalling problem. When I cut the old filter open it was almost full of fine dirt that was caked onto the screen. My van had about 325000 Km (about 200,000 mi.)
 

Jomo

New member
I thought I'd updated this thread... anyway...

The GW Air Flow Meter Signal Filter Cable turned out to be worse than an utter waste of time. Both units failed. The first lead to an engine that cranked, tried to fire, and didn't. That cable was diagnosed, working with the guy who designed the cable, as DOA. The second cable ran for a while and then failed about 90 miles from home - dead engine that cranked but didn't even try to fire. Lessons learned: 1) getting to GW to even address the problem took some serious pushing to get past the front desk, 2) the GW part is, IMHO, utterly not trustworthy, 3) the engine is happy with the original cable (that is, it wasn't broke, silly me for fixing it) and runs with no cable. 3a) Get inside the AFM (get the top off the square lid - not easy but doable with care and patience), dose the wiper arm, moved by the "barn door", with contact cleaner, move the barn door over its full range, dose with cleaner again, move the barn door again, and close up the top with the sealant of your choice. The signal filter seems to be VW's way of getting around cleaning the barn door sensor.

Since cleaning up from the AFM filter debacle, the problem with "Vanagon Syndrome" has gone away. (See below)

The racing problem was finally sorted out. The solution was embarrassingly easy. I added an after-market (AudioVox CSS-100) cruise control. The system is a case with some "smarts" in it and a throttle cable sticking out of one end. The cable is routed to the throttle body and a small bit of chain (think of the sort of chain used in key rings) is attached to the point where the stock throttle cable goes. The chain is used to provide some slack between the throttle arm (on the throttle body) when stepping on the gas with the cruise control engaged. Now for the point where the wheels fell off: the chain ends in a simple ring terminal crimped to the chain. The throttle cable from the gas pedal ends in a simple barrel with a set screw to hold the end of the VW throttle cable in place (step on the gas, the cable tugs on the throttle arm, the engine speeds up). I removed the cable end and lifted the barrel, slid it back down through the hole in the ring terminal, replaced the VW throttle cable end, and called it good. And, for much of the time it was. But... the VW cable tension was set too high (no slack in the VW cable). When the engine really heated up and the engine bay temperature climbed, too, the expansion of various bits in the throttle body conspired to keep the throttle plate from closing fully and... racing engine. Fix? Leave a bit of slick in the VW throttle cable. End of story.

One problem remains. The engine basically tries to die if we drive through heavy rain for an extended period. Bottom line: somewhere in the wiring there's a point that doesn't react well to being soaked. "All" I have to do is find that point.

Summing up: at a guess, a number of relatively minor problems, mainly wear brought on by being original parts, added up to less than optimal operation. The setting for the TPS probably added to some of the perceived problems. The racing engine problem was nothing more than a poorly adjusted throttle cable. On any day but a really wet day, the engine runs just fine.

I almost certainly replaced more parts than I needed to, but, with the exception of the GW AFM signal filter, at the worst, it didn't break anything. At best, things are better than when I started. Or so I'd like to think.
Thanks for the detailed write up. This will help many others as they strive to keep their Westy running dependably.
 

Top