81 vanagon missing under load over ~2200rpm

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Firstclassdumbo
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Re: 81 vanagon missing under load over ~2200rpm

Post by Firstclassdumbo » Fri Sep 22, 2017 4:50 pm

Latest post of the previous page:

Satchmo, it does have the double relay. I checked all the pins and then followed the method for testing it in the bentley. When touching the test light to one of the connections, I touched it to another one accidentally and fried the double relay.

I did not find the double relay to be part of the cure, but now it is part of the problem. If anyone has a suggestion for purchasing a reliable one of these from someone other than busdepot because they want 85 bucks, I'm all ears.
Dumbo- 1981 vanagon/house/daily driver

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Re: 81 vanagon missing under load over ~2200rpm

Post by Amskeptic » Fri Sep 22, 2017 6:02 pm

Firstclassdumbo wrote:
Fri Sep 22, 2017 12:57 pm

A) I pinned the throttle wide open to get ~2500 rpms and tickled the wiper seductively in both directions. Tickling it to the left resulted in more stumbling. Tickling it to the right just over 1/4" made the engine rpms skyrocket, like it should do when snapping the throttle wide open. Oxs still disconnected.

B) Drive that Lexus into a lake and drink a glass of scotch while watching it gurgle it's last breaths.

a) THIS IS YOUR CLUE!
So, I shall ignore your report that the engine wouldn't even start when you leaned the cog thus throwing us all off the trail and sending you into the Blow Up The Double Relay Thicket.

If the rpms skyrocketed, that means it was HAPPY to have less fuel at the stumble rpm point. You need to read my AFM article .. .. .. :

viewtopic.php?f=50&t=7761

.. .. .. but ignore most of what it says. You must be bold, creative and sensible. Make initial setting marks on the wiper and the cog. Before starting engine, get the silicone blob off the wiper screw. That blob is just to let the Feds know that you committed a felony in tampering with your emissions related components.

What you need to do is gently, incrementially, get to the stumble point, note once again that the engine may rev up as you lean it out, then YOU reduce the engine speed with the throttle lever as you keep the wiper where it is happiest.

YOU must make the AFM provide a leaner mixture at high rpm, without affecting the mixture so much at idle. It is a matrix between the wiper adjustment and the spring adjustment. Personally, I think you may find that you need to move the wiper almost a tooth lean (it has its own teeth) and then maybe relax the spring to help recover your idle.
Where are you located?
Colin

b) I drove the Lexus into the lake, like you suggested, but now I am sad for some reason. Should I down another bottle of Scotch?

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Image
BobD - 1978 Bus . . . . . . . . . . .110,350 miles
Chloe - 1970 bus . . . . . . . . . . . 206,775 miles
Naranja - 1977 Westfalia . . . . 73,930 miles
Pluck - 1973 Squareback . . . . . 55,478 miles
Alexus - 1991 Lexus LS400 . . . 64,428 miles

Firstclassdumbo
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Re: 81 vanagon missing under load over ~2200rpm

Post by Firstclassdumbo » Fri Sep 22, 2017 6:54 pm

Colin! I think you may be on to something!

I'm going to attempt to salvage a double relay from a junkyard tomorrow. I has a feeling that they're on some other cars somewhere. If not, I will build one from the link at the bottom of the page. Either way, this weekend will likely result in no experimentation.

I'd like to reiterate your suggestion in my own words to see if I understand you correctly. So what I am to do, is when the engine gets to stumble point, I am going to step in as a manual wiper arm and see if I can change rpm and control the wiper across the board like it should do on its own. In the event it works, attempt shifting the wiper arm one tooth lean and compensating on the clock spring, which should be six-ish clicks rich.

I have been constantly hunting the internet for people with a similar issue. I finally stumbled upon this thread: viewtopic.php?f=3&t=13148

He is describing my issue to a "t." Too bad he never filled everyone in on his (assumed) discovery.

I'm currently located in Loomis, California.

P.S.- where did you find a lake filled with Armor-All?
Dumbo- 1981 vanagon/house/daily driver

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Re: 81 vanagon missing under load over ~2200rpm

Post by Amskeptic » Sat Sep 23, 2017 12:47 pm

Firstclassdumbo wrote:
Fri Sep 22, 2017 6:54 pm
So what I am to do, is when the engine gets to stumble point, I am going to step in as a manual wiper arm and see if I can.....

P.S.- where did you find a lake filled with Armor-All?

You will step in and make the mixture correct. The rpm changes only tell you "happy" or "not happy". You are the engine speed boss at the throttle plate. The AFM is just trying to provide an optimal mixture at various rpms/loads based on air flow. The AFM does not control air flow, it only reads it.

You set the rpms with the throttle lever, you attempt to maximize them with the wiper because that will be the optimal mixture point. Then, it is your job to make the AFM provide the optimal mixture by actually adjusting the position of the wiper on the flap shaft and adjusting the spring resistance to give correct slope. Remember that the wiper adjustment is very powerful and a little adjustment goes a long way.
Colin
BobD - 1978 Bus . . . . . . . . . . .110,350 miles
Chloe - 1970 bus . . . . . . . . . . . 206,775 miles
Naranja - 1977 Westfalia . . . . 73,930 miles
Pluck - 1973 Squareback . . . . . 55,478 miles
Alexus - 1991 Lexus LS400 . . . 64,428 miles

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Re: 81 vanagon missing under load over ~2200rpm

Post by Firstclassdumbo » Wed Sep 27, 2017 3:46 pm

Update: received new double relay. Plugged in double relay. Turned key to ignition. Engine turned over and fired one cylinders, then gave up. Left key in on position. Went back to afm box and closed fuel pump circuit. Pump does not run. Jumpered 30 and 87 on right relay for test, pump runs. Turn key to ignition with pump running. Engine fires one or twice, then turns over with no combustion.

Just filling everyone in so you don't think I fixed it and abandoned the thread.
Dumbo- 1981 vanagon/house/daily driver

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Re: 81 vanagon missing under load over ~2200rpm

Post by Amskeptic » Wed Sep 27, 2017 7:02 pm

Firstclassdumbo wrote:
Wed Sep 27, 2017 3:46 pm
Update: received new double relay. Plugged in double relay. Turned key to ignition. Engine turned over and fired one cylinders, then gave up. Left key in on position. Went back to afm box and closed fuel pump circuit. Pump does not run. Jumpered 30 and 87 on right relay for test, pump runs. Turn key to ignition with pump running. Engine fires one or twice, then turns over with no combustion.

Just filling everyone in so you don't think I fixed it and abandoned the thread.
What "30" and what "87" on what "right relay"?

Hang in there! Let's avoid the stupid tests that blow shit up unnecessarily. I like a more organic trip through our investigations.

Now then, I THINK you said the pump is good, the power and destination wires are good, and the pump only doesn't run when you move the wiper with the ignition on.

Make sure control circuit is energized, that is the black wire from coil #15 that goes to the double relay via a junction at the reverse fuse. It is a black wire. Control circuit needs good grounds through the brown wires that are supposed to be grounded at the double relay mounting screws. Make sure finger terminals are good and precisely in line with each other in the plug under the black boot at the AFM connector. Sometimes, one of the little finger terminals will dislodge loose from the molex plug and you will not see it recessed.

Hang in there. I will drive across the #&!@! country and MAKE that thing run.
Colin
BobD - 1978 Bus . . . . . . . . . . .110,350 miles
Chloe - 1970 bus . . . . . . . . . . . 206,775 miles
Naranja - 1977 Westfalia . . . . 73,930 miles
Pluck - 1973 Squareback . . . . . 55,478 miles
Alexus - 1991 Lexus LS400 . . . 64,428 miles

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Re: 81 vanagon missing under load over ~2200rpm

Post by satchmo » Wed Sep 27, 2017 7:39 pm

"Sometimes, one of the little finger terminals will dislodge loose from the molex plug and you will not see it recessed."

Well, that's what I was suggesting might have happened at the double relay plug. Same thing can happen at the AFM plug as well.

Satchmo
By three methods we may learn wisdom:
First, by reflection, which is noblest;
second, by immitation, which is easiest;
and third, by experience, which is bitterest. -Confucius

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Re: 81 vanagon missing under load over ~2200rpm

Post by Firstclassdumbo » Wed Sep 27, 2017 10:09 pm

Haha okay. Ignore that 30 and 87 thing. I was writing off the top of my head and in a hurry. How about I give a bit cleaner information!

I jumpered 88d and 88y on the double relay and turned my fuel pump on. Fuel pump runs when those wires are jumped. It does not run if those wires are not jumped and I turn key to on and close wiper contacts.

On to terminal #15 on the coil. According to the wiring schematic in the Bentley, the other end of that wire is at 86c on the double relay. I get continuity from coil #15 to 86c. With the key in the on position, I have battery voltage at 86c.
"Control circuit needs good grounds through the brown wires that are supposed to be grounded at the double relay mounting screws."
I see no brown wire that connects to the double relay mounting screws. There are no brown wires leaving the double relay in the wiring schematic. There is a blue/brown wire that runs to the starter solenoid, according to the wiring diagram. I get continuity when I touch that and ground to the body. If 85 is the ground, as you listed in another thread on double relays, then that wire would terminate at pin 28 of the ECU plug. I have continuity between 85 on the double relay and pin 28. The other control circuit ground is 88c. It goes from 88c, to AAR, to pin 34 on ECU. I get continuity in both sections.

If the key is on and I ground out 85, the relay, presumably the ECU side, closes. And surprise, surprise, if I try starting the engine, it runs. Thoughts? There has never been a ground wire running out of 85 before.

I don't know where the reverse fuse is located. Is that something worth checking?

I checked all of the spade connectors on the double relay and molex plug. Every one of them is in their proper place.

Thanks again, team! During week one, I was stressing about this thing. I've been procrastinating on learning the fuel system since I bought it two years ago. But now... Now I'm really excited to understand it better!

So now we are back to the engine stumbling. I think.
Dumbo- 1981 vanagon/house/daily driver

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Re: 81 vanagon missing under load over ~2200rpm

Post by Amskeptic » Fri Sep 29, 2017 7:34 pm

Firstclassdumbo wrote:
Wed Sep 27, 2017 10:09 pm

I see no brown wire that connects to the double relay mounting screws.
There are no brown wires leaving the double relay in the wiring schematic.
There is a blue/brown wire that runs to the starter solenoid, according to the wiring diagram.
I get continuity when I touch that and ground to the body.
There is not a blue brown wire that leads to the starter solenoid. There IS a blue/red wire that leads to the fuel pump. The only wire to the solenoid is a red/white wire.

How can we possibly work towards a solution if we are missing so severely on colors and numbers?
Firstclassdumbo wrote:
Wed Sep 27, 2017 10:09 pm
If 85 is the ground, as you listed in another thread on double relays, then that wire would terminate at pin 28 of the ECU plug.
Who made that rule? The double relay has to ground the relay coils to make the control circuits work. It just uses brown wires with split end to slip under the mounting screw.

BobD has them under the lower screw for the series resistors:

Image


Image


On NaranjaWesty, the double relay ground wires are up under the upper screw:

Image

Firstclassdumbo wrote:
Wed Sep 27, 2017 10:09 pm
I have continuity between 85 on the double relay and pin 28.
Perhaps that is because both use the metal of the car as the common (ground).

Firstclassdumbo wrote:
Wed Sep 27, 2017 10:09 pm
If the key is on and I ground out 85, the relay, presumably the ECU side, closes. And surprise, surprise, if I try starting the engine, it runs. Thoughts? There has never been a ground wire running out of 85 before.

I don't know where the reverse fuse is located. Is that something worth checking?
Well then, your problem seems to relate to the control circuit for the double relay not being grounded. 85 is the ground path. The brown wires as you can hardly see, come out of that black harness on the left side. The reverse inline fuse is also on the left side of the engine compartment, you should see the black wire from the coil going to the fuse and having a branch leading to the double relay as written earlier, but I don't know your engine compartment from a Hyundai, yours might be some horribly home-engineered hideosity, I just don't know, so you have to take up some slack here and go explore.
BobD - 1978 Bus . . . . . . . . . . .110,350 miles
Chloe - 1970 bus . . . . . . . . . . . 206,775 miles
Naranja - 1977 Westfalia . . . . 73,930 miles
Pluck - 1973 Squareback . . . . . 55,478 miles
Alexus - 1991 Lexus LS400 . . . 64,428 miles

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Re: 81 vanagon missing under load over ~2200rpm

Post by Firstclassdumbo » Sat Sep 30, 2017 3:35 pm

Colin, you're absolutely right. We are struggling with a communication problem. You are communicating information to me in regards to late bay window vans. I am communicating information in regards to air-cooled vanagons. There is a significant difference in wiring between the two, among other things. I'm not sure how to insert images into this post, but here is a link of the wiring schematic straight from the Bentley manual for my specific vehicle: https://photos.app.goo.gl/bfAifujeOLi167j12
If you have any questions on reading the schematic (I know the print is super tiny) please ask.

Besides the point, I messed with the wiper arm screw. Results look promising. It is better. Not anywhere close to peak performance, but maybe in a day of fiddling I'll have it dialed.
Dumbo- 1981 vanagon/house/daily driver

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Re: 81 vanagon missing under load over ~2200rpm

Post by Amskeptic » Mon Oct 02, 2017 7:12 am

Firstclassdumbo wrote:
Sat Sep 30, 2017 3:35 pm
Colin, you're absolutely right. We are struggling with a communication problem. You are communicating information to me in regards to late bay window vans. I am communicating information in regards to air-cooled vanagons. There is a significant difference in wiring between the two, among other things. I'm not sure how to insert images into this post, but here is a link of the wiring schematic straight from the Bentley manual for my specific vehicle: https://photos.app.goo.gl/bfAifujeOLi167j12
If you have any questions on reading the schematic (I know the print is super tiny) please ask.
Oh Lawdy lawdy, of course. I think I will go drive myself into a lake.
Colin :blackeye:
BobD - 1978 Bus . . . . . . . . . . .110,350 miles
Chloe - 1970 bus . . . . . . . . . . . 206,775 miles
Naranja - 1977 Westfalia . . . . 73,930 miles
Pluck - 1973 Squareback . . . . . 55,478 miles
Alexus - 1991 Lexus LS400 . . . 64,428 miles

Firstclassdumbo
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Re: 81 vanagon missing under load over ~2200rpm

Post by Firstclassdumbo » Tue Oct 03, 2017 8:44 am

Hold off on the lake. You still helped me tremendously by sharing info on late bay buses. Without your suggestion on terminal 85, I wouldn't have a running van. I ended up using that wiring setup and grounding 85 behind the relay. I'm guessing it fried at the CPU when I shorted the relay. So that's one new solution for future relay problems in vanagons!

You also gave me beaucoup information on the afm. So I ended up moving the wiper one and a half teeth lean, then richened up the top end with the cog. It doesn't stumble at all anymore, but I don't know if my mixture is too lean at this point. I know a lean condition burns valves, so I'm taking it to a shop tomorrow morning so they can use an exhaust sniffer on it. What tips me off on the lean condition is my mixture screw is all the way closed. Initially it was set two and a half turns out, when I removed the plug.

One way or the other, I don't understand how all of this was not an issue prior to me going to the shop in bishop for a new pilot bearing, but materialized out of nowhere upon leaving. I put thirty thousand miles on Dumbo last year. I'm very in tune with that engine. I'm not pointing fingers, but it's super fishy, and the fishing season was junk in the Eastern Sierra's this year.
Dumbo- 1981 vanagon/house/daily driver

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