1976 Bus - Test for AFM? ** It's still bucking!!**

[DurocShark]

On mine it was the signal wire from the coil to the computer. I replaced it and the bucking went away. Have you tried jumping that wire to see if that fixes it?

[TrollFromDownBelow]

^^ No, have tried that, but will! I think you're onto the right track - I suspect it is a bad ground/connection somewhere.

[Amskeptic]

really it is all conjecture until i do real real diagnosis

Yes.

Bucking is a catch-all symptom any time the ECU's parameters are exceeded. That means too rich, too lean, too much TS II, too little TS II.

Here is a fascinating new cause for bucking. I started the Squareback two days ago after a long winter (!*@&! still is winter up here!) and it was bucking and carrying on. Pulled the wires one at a time from the distributor cap, and found #2 was not participating at idle. Pulled the plug, and it was clean and wet with fuel. The phenolic connector had *pinholes* along the sides that had apparently gotten contaminated with nothing more than *humidity*. Replaced the connector with a BobD connector and the engine ran fine.
Colin

[TrollFromDownBelow]

The phenolic connector had *pinholes* along the sides that had apparently gotten contaminated with nothing more than *humidity*. Replaced the connector with a BobD connector and the engine ran fine.
Colin

what is a phenolic connector, and where do I find it?

[Randy in Maine]

It looks sort of like this....

http://www.busdepot.com/details.jsp?par ... 021035255B

[TrollFromDownBelow]

Thanks Randy

[Amskeptic]

Thanks Randy

Remember #1 and #3 are short, #2 and #4 are long.

[Lanval]

Ya know, it's raining here in So Cal. I ran the Desert Rat for the first time in a few days Monday, and it too was bucking, but only for about 2 minutes or so. Suspect that this is also a humidity issue. I wasn't in a situation where I could check it (time-wise) but I know my tranny ground is old and rusty, and I'll bet with all the other electrical crap that something is damp or has poor connection.

I'll check the plug wires Colin ~ I'm curious, how did you spot the 'dampness' and 'pinholes' so that I know what to look for?

L.

[Amskeptic]

Ya know, it's raining here in So Cal. I ran the Desert Rat for the first time in a few days Monday, and it too was bucking, but only for about 2 minutes or so. Suspect that this is also a humidity issue. I wasn't in a situation where I could check it (time-wise) but I know my tranny ground is old and rusty, and I'll bet with all the other electrical crap that something is damp or has poor connection.

I'll check the plug wires Colin ~ I'm curious, how did you spot the 'dampness' and 'pinholes' so that I know what to look for?

L.

Looked like a horror movie where the carbon eats the victim alive from the inside out. You really can't miss it. Since this post, the #4 failed too. I had all kinds of trouble with the Squareback yesterday, the above connector, then temp sensor wire failed inside the connector spade in the carwash, and a loose wire or SUMPIN is making the engine die dead if it moves in a position that it deigns not to enjoy. Bucking occurred when I left Vdubtech this afternoon, manifold sensor hose had slipped off when replacing yet another spark plug connector, rich buck. Running ...... splendidly, now.
Colin

[TrollFromDownBelow]

After reading Colin's post, I decided to go check the plug wires. Guess what I found... plug wire for #1 cylinder was not clicked into place; merely laying there. Woohoo! start doing the happy dance....until I took it for a test spin... it was actually worse. :(. Oh well.

[Amskeptic]

After reading Colin's post, I decided to go check the plug wires. Guess what I found... plug wire for #1 cylinder was not clicked into place; merely laying there. Woohoo! start doing the happy dance....until I took it for a test spin... it was actually worse. :(. Oh well.

Maybe it was worse because the wrong wires are on the wrong cylinders. That is the only way I can think to make an engine run worse when you hook up a necessary wire, ya know?
Colin

[TrollFromDownBelow]

Naa... I'm sure they are hooked up correctly. It may have been my frustration that made it seem worse. Guess it will give us something juicy to work on

[Amskeptic]

Naa... I'm sure they are hooked up correctly. It may have been my frustration that made it seem worse. Guess it will give us something juicy to work on

I live for just these sorts of moments . . .

[TrollFromDownBelow]

Hey Colin, we're gonna have to find other things to tinker with ... think I got it figured out.

It was the connector to the temp sensor II. It wasn't fitting tightly, and I didn't see any way to crimp/tighten the connector inside the plastic cover thingy, so I cut it out. First time I replaced it with a wire nut...was planning for this to be temp to determine if I had diagnosed it correctly... it became worse. Replaced this with a bullet connector, and all is well! :) :) . I drove it hard on the expressway (70-75 as indicated by the speedo) for 30 miles an nary a hiccup/cough/cazuntite.

[chitwnvw]

Nice, troll.