Vanagon syndrome

[Tomoc]

Working on finding a solution to a brief stumble while driving at hiway speeds . The symptom shows up after the engine is thoroughly warmed up. 15 to 20 miles on the freeway. Engine stumbles for a short moment then runs fine 3-5 min later same thing. Starts easy always, runs in town well. Similar problem several years ago was the afm. It was fixed and still tests fine.In the last year for maintenance reasons I have replaced the coil, the spark wires , the cap and rotor, the fuel tank, fuel filter, tested the fuel pump in diesel for cleaning, flushed and run the pump for flow , disconnected the fuel return line, checked for flow,replaced the vacuum fuel controller, replaced all the vacuum lines etc. I have followed the Bentley book for test procedures, wondering why the coil tests at above resistance at primary, 1.200, and the secondary at 4100. New coil at ORiellys tests the same. The Bentley says the primary resistance should be 0.52-0.76 and the seconary should be 2400- 3400. Who's right? Also the voltage with the ignition on is 11.85 at positive terminal 15 with a good ground.. The book claims the voltage should be approximate battery voltage. That is 12.40. Is that close enough? The power to the coil comes from the ignition directly I think???
_________________
'85 Vanagon. " Evelyn"
'66 split windshield bus, Green and White two tone, 1st car, deceased

[Ahwahnee]

Since the subject mentions 'Vanagon Syndrome' and you say "...Similar problem several years ago was the afm. It was fixed... -- was a capacitor fitted to the AFM at that time?

Classic smoking gun clue for the Syndrome is that switching the ignition off then right back on again clears it for at least a while.

[thatbaldwinlife]

Do you have a spare ECU to toss in there to check? You can get an Vanagon Syndrome patch at GoWesty pretty cheap to try as well.
nate
_________________
1987 Westy
Insta: @Thatbaldwinlife
Vanagon Adventure and DIY videos:
That Baldwin Life YouTube Channel

[Tomoc]

The original afm was adjusted to run on a different track . Worked well for 4000 miles. Started acting up again and was replaced with a much younger afm. Tested out well. Tonite after “looking over the ignition switch” as something to do it really acted up. All I had done was unplugged the ignition switch, RE plugged it and then driven it. Car was spitting and when I wiggled the key it died. Started right up again. Will change the ig switch tomorrow to see if it makes a difference.
_________________
'85 Vanagon. " Evelyn"
'66 split windshield bus, Green and White two tone, 1st car, deceased

[Tomoc]

The afm was not fitted with a capacitor. When you say a smoking gun are you referring to the capacitor or the ignition switch?
_________________
'85 Vanagon. " Evelyn"
'66 split windshield bus, Green and White two tone, 1st car, deceased

[jlrftype7]

[thatbaldwinlife]

Yeah ignition switches are cheap. I always keep a spare in the glove box. I would also recommend adding in a starter relay to take the full starting load off of the new switch.
nate
_________________
1987 Westy
Insta: @Thatbaldwinlife
Vanagon Adventure and DIY videos:
That Baldwin Life YouTube Channel

[Tomoc]

Well, no go. The new ignition switch did nothing. It seems to be getting worse, the max rpm is about 1500, maybe 1800 before the engine cuts out.
backing off on the accelerator seems to calm it down. Drove a few blocks (5) and didn't dare to go any further. Did manage to kill it once wiggleing the ignition key???? This is a brand new out of the box ignition switch. Could there be some kind of short in the key part of the switch?
Did manage to clean out 35 yrs of gunk from the blinker/high beam controls.

It feels like its losing power but it will idle, start and rev in the driveway. Drops out as I excelerate with load. This got worse after I pulled the plug off the ignition switch to look over things. Put it back on and the next morning it was stuttering badly. It should be noted that we drove through a heavy rain storm the day before on the freeway with no problems.
tom
_________________
'85 Vanagon. " Evelyn"
'66 split windshield bus, Green and White two tone, 1st car, deceased

[thatbaldwinlife]

Maybe something to do with the Hall sender in the distributor? Weird it died by wiggling the switch after you replaced it. Do you have the Digifant checklist/troubleshooting guide? Might start there?
_________________
1987 Westy
Insta: @Thatbaldwinlife
Vanagon Adventure and DIY videos:
That Baldwin Life YouTube Channel

[Tomoc]

This is the digijet system. I was following along on the diagnostic when I found a problem with the Hall controller. Replaced it and the sytem ran well for two days. I did have a question about the resistance of the coil which doesn't match the Bentley book stats. Went to the Oreillys, ordered a new coil , the stats on the new coil were the same as mine. I will go back to the book and check the hall sender on the dist.
thanks for the input
_________________
'85 Vanagon. " Evelyn"
'66 split windshield bus, Green and White two tone, 1st car, deceased

[thatbaldwinlife]

Maybe I should learn to read! I don't know much about the Digijet system, sorry
nate
_________________
1987 Westy
Insta: @Thatbaldwinlife
Vanagon Adventure and DIY videos:
That Baldwin Life YouTube Channel

[jlrftype7]

Hmm, just to be on the safe side, gently remove the plastic cap on your AFM and look very carefully at the carbon tracks, your 'younger' AFM may have enough of a worn spot to cause your problems.

The heat related symptom kind of points to Ignition Coil or Primary Circuit, or Fuel Pressure issue, you said you cleaned the pump, and checked for flow, does that mean a pressure test , or a Volume test for the spec listed in Bentley.

Not sure why the coil readings don't match Bentley either, unless you keep getting the wrong coil from the parts people[ it happens, and IS frustrating... ]

Does unplugging the Idle Stabilzer ECU over by the Coil, and connecting its 2 connectors together, help in any way while driving[ long shot, but though I'd ask]
_________________
'68 Westy- my first VW and vehicle/Bus- long gone.- sold it to a traveling Swiss couple....
'67 Type 3 Fastback, my 2nd car- gone
'69 Semi-Auto Stick Shift Beetle-gone
2017 MINI Coopers, our current DDs
‘84 Tin Top - Hilga....Auto

[Tomoc]

Right now the next step is to plug the old ignition switch in with it removed from column. A mechanic said there might be an issue with the switch when it’s installed. The new switch made no difference from old. A screwdriver will rotate the switch. I will also try unplugging and joining the two ignition controller. That is part of the test procedure for several tests. I didn’t know you could drive it that way. And the other test would be to retest the afm just to make sure. I still can’t get an answer about the resistance on the coil. Is the Bentley correct for 1st and secondary resistance.
I have made an appointment with the mechanic but I’d rather tell him what was wrong.
_________________
'85 Vanagon. " Evelyn"
'66 split windshield bus, Green and White two tone, 1st car, deceased

[Tomoc]

One more thing, the fuel test was a volume test, and what is included in a primary circuit.
_________________
'85 Vanagon. " Evelyn"
'66 split windshield bus, Green and White two tone, 1st car, deceased

[DuncanS]

[Ahwahnee]

[Vanagon Nut]