Bus went "soft" at high speed

[vwlover77]

I was on the interstate last night and the Bus was "feeling it's oats" by daring me to try to keep up with the light high-speed traffic.

As I was cruising along with the speedometer hovering between 75 and 80 (it's optimistic, I'm sure), the Bus did something that I can only describe as "going soft". It felt like there was no longer a connection between the accelerator pedal and the engine. It wasn't a lurch or a dramatic loss of power, but something definitely happened.

I immediately backed off to a more reasonable speed and everything was fine the rest of the short trip home.

When I got home, I pulled off the distributor cap and found some carbon on top of the rotor and scattered around the inside of the cap, apparently from the center connection in the cap, which I cleaned up. Could this have been the cause?

I should also state that I have a Pertronix installed.

Thanks!

[midatlanticys]

It wasn't a lurch or a dramatic loss of power

. . . maybe just a slight loss of power because the fuel pump &/or filter wasn't keeping up with the demand at 4000+ revs? no softness the last time your speedo read 75/80? The carbon inside the cap, does it look like it was caused by arcing? any stray moisture or an oil film in there that would aggravate any errant arcs or create current paths? If you visualize the rotor spinning at highway speeds the cap plus all contact points really should be squeaky clean to keep current flowing only to the plug wires.

Are you sure it was the bus that was feeling the oats?

[vwlover77]

I'm tellin' ya, that Bus was like a puppy pulling hard on its leash. I had nothing to do with it!

The last time I was at that speed was a long time ago, but this is the first time I've ever experienced this.

The carbon in the cap did not show any signs of arcing. It appeared to be specks that had worn off the center post and were flung around inside the cap. I rinsed down the inside of the cap with brake cleaner and it came right off. Other than the carbon, everything looked perfectly clean inside the cap.

The fuel filter has only a few thousand miles on it and was brand new after a thorough tank cleanout a couple of years back.

[Amskeptic]

I suspect fuel delivery if it was a smooth loss of power.
Colin

[vwlover77]

Well, I had the Bus on the interstate again tonight and ran a couple of short stretches at an indicated 75-80. It ran perfectly and seemed to have good power. Maybe I just got hit by a headwind the last time, or maybe there was some spark scatter going on in the cap.

[sped372]

I like how you described it. Probably not your cause but that's what ours felt like just as the battery gave up the ghost. We had been driving for 6 or 7 days and multiple starts on no charging system...(just bought the bus and were heading home) finally the battery had enough and the throttle pedal didn't feel connected to the engine any more. Hope your troubles stay away.

[Amskeptic]

maybe there was some spark scatter going on in the cap.

Backfiry, baby, stumbly too.
Colin

[Manfred]

Clutch slipping, maybe?

[vwlover77]

Clutch slipping, maybe?

No, the revs did not increase. The clutch disk is also brand new - less than a tankful of gas on it so far!