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RaraBlacksheep Sun Aug 24, 2014 6:47 pm

Vehicle is an '82 Westy, but the Vanagon forum seems pretty WBX focused - as far as I know this has more in common with the late bay windows than the '83.5+ Vanagons so I thought this might make more sense.

Backstory: Bought a super straight but troubled Westy. Engine allegedly rebuilt but no documentation, etc. California van, but the ignition was replaced with a Pertronix Ignitor unit so it doesn't have the stock ignition box or idle stabilizer. Had a Federal exhaust setup with no O2 sensor. Ran smoothly, but pretty weak.

Vitals:

Compression - 115-120 across the board
Valves Adjusted - 1.5 turns in from zero lash
Vacuum - Steady 15-17"
Timing - 4 degrees at idle, ~22 at 2800 or so (lines on)
Coil - Blue Bosch, 3.6 ohms + to -, 9K ohms post to +
Temp II - In spec hot/cold
Coil - Blue Bosch, getting full voltage
Plugs show a darker tan coloring

New parts:

- Cap/Rotor/Wires/Plugs
- Fuel Pump (German Bosch), Filter and lines
- Added a converter, Bosch O2 sensor, new muffler/tailpipe
- Lots of wiring patches and repairs of crusty wires front and back; all grounds cleaned up and extra grounds added to the engine and ECU, I've probably hit every visible terminal and connector with a wire brush and dielectric grease.

Currently runs very strong; up until about 25-30% throttle or more, where it bogs and runs pig rich (black smoke out of the tailpipe, gas smell, etc) and almost sounds like it's bouncing off a rev limiter or something if you don't let off but doesn't die. Will rev to 4000+ just fine so long as you aren't giving it a lot of gas. Getting somewhere along the lines of 10 MPG and the tailpipe is pretty sooty. Adding the O2 sensor helped quite a bit in a general sense, and the idle no longer races when it's warm, but it didn't affect the bucking/bogging much if at all.

Through a ton of searching around I keep landing on the AFM causing this sort of Vanagon Syndrom-esque behavior. I popped it open and while the tracks don't look too bad (shows wear marks, but nothing looks to have worn through the coating), I shifted the potentiometer board a bit, hit it with some contact cleaner, slid some copier paper under the contacts, etc. Nothing is making a huge difference. I scrounged around and have Bus Boys sending out an AFM to be rebuilt since that's about the only place I could find that could help in this department.

What else could this possibly be though? I've got at least another week before I'll have the rebuilt AFM here (with the lead time and general unavailability of it I decided to just get it on the way, risking a misdiagnosis). I can't really get out of town in this condition (heck of a way to spend my vacation, eh?) so I might as well keep stabbing away at diagnostics.

I did notice the fuel pressure regulator doesn't seem to care if the vacuum is connected or not while doing no-load revving; is that normal? It is my understanding that the FPR failure mode is for it to run really rich at all times due to the pressure being maxed the whole time, which doesn't seem to fit my symptoms here.

The rev-limiter-like behavior makes me think ignition, but everything there seems ok, and since it will rev as high as I like so long as I don't exceed a certain throttle position it's not simply cutting out at high RPM. I have read some have had trouble with the Pertronix ignitions, however. From what I am seeing, the blue coil would be the right one to use with a non-OE electronic ignition.

This basically leaves me with nothing else to question beyond the injectors (unknown situation here but seems unlikely), ECU (would it run this well if it were failing/failed?), and deeper wiring issues.

Anyway, long post but I wanted to include everything I thought that might be useful to know. Thanks for any input!! Trying to keep the spirits up and not get fatigued, but the latter is starting to set in along with a "what on earth was I thinking" sentiment. I was hoping to throw a few weeks of work in and be on the road in early July...and let's not even talk about money. :oops:

timvw7476 Sun Aug 24, 2014 7:15 pm

The timing specs look waaay to late.
If this is a 2.0, 7.5-8 degrees BTDC @ idle & 28 degrees @2,800 rpm,
any vac line to distributor plugged, golf tee, pencil, anything!

Nice chart!

canadianveedub Sun Aug 24, 2014 7:26 pm

I recently had a lot of issues with my AFM and with your issues being RPM and load dependant, I would put my guess there, especially if everything else is checking out.

RaraBlacksheep Sun Aug 24, 2014 7:28 pm

timvw7476 wrote: The timing specs look waaay to late.
If this is a 2.0, 7.5-8 degrees BTDC @ idle & 28 degrees @2,800 rpm,
any vac line to distributor plugged, golf tee, pencil, anything!

Nice chart!

Yep - 2.0!

The idle races when the spark retard line is disconnected in its current state, more so than I can compensate for with the idle speed adjustment screw; is this a symptom?

timvw7476 Sun Aug 24, 2014 7:39 pm

I didn't even want to ask if you had a dual-can distributor, mine on a '74
was going bad on the retard side so it causes problems setting up
timing by a manual when half of your distributor can is blown/non-op,
I resorted to plugging the feed to the vacuum retard side and going
vacuum advance only-the original "idle" timing for '74 dual can was
10 degrees ATDC, you have to forsake that absurd set-up if you don't
have a NOS vacuum advance/retard can lying around!

timvw7476 Sun Aug 24, 2014 7:53 pm

To answer the question about fast idling, that is the extra air coming in through the spark retard hose, it is a port on the intake plenum
if I recall, so it can be capped at the plenum or plug the hose with
anything that seals well, that should give you idle speed control at the
adjustment screw. If your vac. retard function is non-op the distributor
can no longer handle the spread from idle timing near 0 to 5 degrees ATDC
and also advance to where it belongs for best power/acceleration beyond
idle, blown vac. retard makes timing set-up by any manual impossible,
the default setting is 7.5 degrees BTDC, moving to 28 deg. BTDC max.

RaraBlacksheep Sun Aug 24, 2014 7:54 pm

What's the best way of ditching that dual can setup entirely? Get a Federal distributor?

2nd reply edit: the idle races even with the hose plugged up..it actually doesn't make a huge difference if it's plugged or not, whatever is going on in the distributor is far more significant than the vacuum leak!

timvw7476 Sun Aug 24, 2014 8:04 pm

Both cans are capable of failing, and the advance plate can get partially
stuck as well, so you lose the full sweep of the cans and have tune up
issues! You can run vacuum advance only, IF that portion still holds
vacuum, the retard side was for emissions purposes only, the engine
does not get hurt with idle set to 7.5 BTDC, you may have other vacuum
leaks as well as the late timing.

SGKent Sun Aug 24, 2014 9:40 pm

have you tried another distributor with points to see if the ignition is breaking down under load? What about the plug wires, how old are they?

Have you done the FI tests here? http://www.thesamba.com/vw/archives/manuals/fuelinjection.php

tootype2crazy Mon Aug 25, 2014 4:58 am

RaraBlacksheep wrote: What's the best way of ditching that dual can setup entirely? Get a Federal distributor?

An SVDA works quite well with L-Jet. I have one and it is a treat. http://vwparts.aircooled.net/Pertronix-Brand-SVDA-Distributor-12-Volt-Version-p/d186504.htm

As far as a racing idle, I have seen one case where a bad decel valve caused issues with a very high surging idle and bad performance whilst driving.

Wildthings Mon Aug 25, 2014 6:00 am

RaraBlacksheep wrote: What's the best way of ditching that dual can setup entirely? Get a Federal distributor?

2nd reply edit: the idle races even with the hose plugged up..it actually doesn't make a huge difference if it's plugged or not, whatever is going on in the distributor is far more significant than the vacuum leak!

Your timing is way retard and when you remove the retard hose it is getting it into the normal range. Set your timing at 28-30* BTDC at 3500+ rpms with both hoses off and plugged.

You may have other problems as well, but you need the timing right before you try to address them

RaraBlacksheep Mon Aug 25, 2014 2:06 pm

OK, got an almost decent night's rest and I'm back at it..

I am at ~7.5 BTDC now with the lines off/plugged, questionable aux/decel valves blocked. Thanks to my freshly blown front main redecorating my almost as freshly cleaned engine compartment it's a bit hard to see my now oil-soaked timing strip while monkeying with the throttle, fighting the license plate, sun glare and handling the timing light all at once but it looks to be about 22-24 degrees advance over 2800 RPM or so (didn't seem to change much beyond that up to 3500+). According to my interpretation of Bentley's Federal section, this is within spec; I'm getting the idea the CA specs only apply with the original CA ignition setup?

This however does fall fairly short of the 28-30 degree target given above; is that for aftermarket distributors though? I'm not opposed to a new distributor, and the idea of putting a new one without NLA parts attached has its own appeal even if not necessarily needed at the moment.

SGKent Mon Aug 25, 2014 2:16 pm

RaraBlacksheep wrote: OK, got an almost decent night's rest and I'm back at it..

I am at ~7.5 BTDC now with the lines off/plugged, questionable aux/decel valves blocked. Thanks to my freshly blown front main redecorating my almost as freshly cleaned engine compartment it's a bit hard to see my now oil-soaked timing strip while monkeying with the throttle, fighting the license plate, sun glare and handling the timing light all at once but it looks to be about 22-24 degrees advance over 2800 RPM or so (didn't seem to change much beyond that up to 3500+). According to my interpretation of Bentley's Federal section, this is within spec; I'm getting the idea the CA specs only apply with the original CA ignition setup?

This however does fall fairly short of the 28-30 degree target given above; is that for aftermarket distributors though? I'm not opposed to a new distributor, and the idea of putting a new one without NLA parts attached has its own appeal even if not necessarily needed at the moment.

put a few drops oil on the center wick of the distributor and one drop on each of the weight pivots. You can see them below the plate if you look carefully as you spin the engine slowly by hand. See if maybe the weights are sticking.

RaraBlacksheep Mon Aug 25, 2014 2:59 pm

Lubed it all up (was fairly oily looking to begin with), didn't seem to change anything. It does however seem slightly happier at idle with the retard line blocked. The bogging/bucking is still there but seems to have mellowed out just a bit, but could be my imagination.

Randy in Maine Mon Aug 25, 2014 3:18 pm

Suggestion....

(assuming you are running the correct factory distributor for a CA version VW# 039-905-205C)

Try timing this thing to 28º BFDC with the vacuum lines removed from the vacuum canister at what ever RPM that happens. It should be around 3500 or so. Let it loaf back to idle and hook up both vac lines.

If the retard side of the vacuum can is not working, just run it as a SVDA by removing the retard vac line and plug it at the throttle body.

Report back your findings.

Wildthings Mon Aug 25, 2014 4:55 pm

Randy in Maine wrote: Suggestion....

(assuming you are running the correct factory distributor for a CA version VW# 039-905-205C)

Try timing this thing to 28º BFDC with the vacuum lines removed from the vacuum canister at what ever RPM that happens. It should be around 3500 or so. Let it loaf back to idle and hook up both vac lines.

If the retard side of the vacuum can is not working, just run it as a SVDA by removing the retard vac line and plug it at the throttle body.

Report back your findings.

2x, the hose off high rpm test mimics full throttle high speed conditions, right where you expect the most from your engine.

RaraBlacksheep Mon Aug 25, 2014 5:07 pm

Well, maybe the oil just needed to soak a bit. Lines off/plugged, I got 28-29 degrees at about 3900 RPM. Still bucking and bogging though.

SGKent Mon Aug 25, 2014 5:45 pm

when you turn it off does the catalytic hiss for a minute like back pressure?

When were the plug wires last replaced?

RaraBlacksheep Mon Aug 25, 2014 5:48 pm

No hissing that I can tell. All ignition parts are fresh save for the distributor itself and coil; coil passes resistance tests (3.6 ohms + to -, 9K post to +).

KlassicBus79 Wed Aug 27, 2014 1:23 pm

If you continue to hold the pedal down does it backfire after it bogs?



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