Itinerant Air-Cooled

I have a 1976 2.0L FI bus, and last year it started bucking whilst coasting about 60mph. Last year whilst trying to fix the problem I replaced the points with electronic ignition, fitted a new coil, new plugs, new HT leads, new fuel pump, new fuel filter, drained the tank (the fuel and filter looked okay) fitted a NOS AFM and the bucking eventually stopped! I had six months of no problems.....

Today I drove her on a 30min journey on the freeway with no problems. Stopped at a friends house for 15mins and when on the return journey home she started bucking badly! Damn! It was pretty frequent and at one point I though I wasn't going to make it..... The bucking was happening at various speeds / driving scenarios and when I got home I noticed that the engine missed two or three times whilst idling....

Any ideas on what I should try first? I am gutted that the bucking has returned The bucking is like a complete cut out for a fraction of a second...

Any help would be much appreciated...

Tell us about your Temp Sensor II.

Replacing parts on a whim is a quick way to add cost to a repair bill with little or no results. Did you replace all those things at one time, or did you do them incrementally and have the problem stop after one component replacement?

Dubstar77 wrote: Any ideas on what I should try first?

Yep.
Try this:

Sit down.

Ponder.

Do not throw parts at it.

Stick your stroboscopic timing light on it the next time it misbehaves. Do the timing light flashes disappear as the engine bucks? Ignition issue. Do they stay flashy? Start with a simple check/clean/snug of every ground in the engine room and do starter post and transaxle ground strap while you are at it.

Intermittent usually means "loose" or "electrically overheated". That includes your fuel pump and wiring.

Give us good feedback and descriptiveness and we can lick this thing.
Colin

Check every pin on your double relay connector block to make sure a wire isn't backing out when you plug it in. This was the cause of the bucking on my 78. The intermittent electrical connection there also cause some pitting and carbon build up on the points in my bus, so it may lead to secondary problems with your electronic ignition. I don't know for sure if there is a problem with your EI unit, but I would probably put regular points ignition back in until you can confirm the problem is not ignition related.

Good luck, Tim

Thanks for your help guys!

I pulled up a stool at the back of my bus. I pondered... I had a smoke and pondered some more... Then it jumped out at me. The electrical block connector for the injector resistor bank was not seated correctly. I squeezed the connector together and it clicked shut! I cleaned all the earth connections also and some were not great..... I took her out today on a two hour drive and she didn't miss a beat!

Thanks for your help, it is really appreciated. The parts catalog is no longer required!

Well done, young Jedi. The force is strong in you.

Tim

Dubstar77 wrote: I pondered... I had a smoke and pondered some more...
Then it jumped out at me. The parts catalog is no longer required!

HA! Congratulations.