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Stalling in 1978 VW bus

my 78 vw bus stalls all the time. it’s very random, except when first started. without fail, it will stall about 4 min after initial start. a sucessful restart depends largely on heat (engine, outside) or whim. that is, if the engine is hot or it is very hot outside, most times i need to wait 5 mins. or so before it will restart (turns over, no start). Sometimes the engine smells very gassy upon a restart attempt, other times, nothing. sometimes, hot or not, she fires right up again. sometimes if she stalls while rolling (even at highway speeds!) i can “pop” start. other times, i cannot and have to pull over for 5 min and try again. sometimes (often) she’ll drop out while rolling down the street, and suddenly restart. again, i cannot find any method to this madness. there is absolutely no consistancy. been this way for 18 mos., at least. it’s like driving a mule. Help!

The details of your post are very familar, as in you have made this post before,is this true?

I don’t remember this post, but it could likely boil down to one of 2 things, although I’m leaning towards the latter.

  1. Carburetor acting up.
  2. Memory is fuzzy on this but it seems like this model of bus uses a vacuum valve as part of an EGR control. These valves have a tendency to screw up with age. What happens is that vacuum is applied to the EGR under certain conditions and that vacuum is held to the EGR rather than being released. This in turn keeps the EGR in the open position (can remain this way even when the engine is turned off) which then will stall the engine at lower RPMs.

This valve should be located on the chassis around the top left side of the engine compartment. A test method could be to tightly insert a BB into one of the vacuum lines and see what happens then.

never posted before. is that all you can offer? as far as the problem w the bus, yes, it’s all too true, and very annoying.

Thanks! I’ll give the ERG a look-see. Just what’s supposed to happen with the BB in the line? How do I know if the valve is failing? Oh, and the engine is fuel injected (w new injectors).

Yep that all I can offer,a real shame isn’t it? I kinda thought (no I knew) your engine was fuel injected. Coincidentaly we have several posts about 78 VW Buses acting very similar to yours. You may want to use the search feature and check the responses.

ok! and yah, I noticed that this problem is nothing new. I was kinda hoping that it’s frequency would produce some sort of answer. I could just get another car, but that wouldn’t be as fun!

new gas cap made a world of difference.

My bus does the same exact thing. Its almost like our buses are twins seperated at birth!
I recently put some fuel injection cleaner into the bus and that has seemed to help a bit. Cleans out the fuel lines and all.
let me know how this works out and email me so we can compare ideas!

someone suggested getting a new rotor cap and rotor. Keeping the gas tank half full seems to help, although its sort of a pain to remember. What year is your bus? More importantly, what color is it? Mine’s that burnt orange with cream top. Maybe that’s why it’s acting up. It needs a new (cool) paint job.

The problem is your heat sensor on the engine, it is intermittent. when that gos the engine will quit almost exactly 4 to 5 minutes., if you let it sit for a few minutes it will start up again and drive for another 5 minutes give or take. (the engine cooled down). Replace the head temperature sensor. if you look through the upper panel it is on the left next to the air intake tubes.