Hesitation, bucking and stalling

[Egan Custom Guitars]

So I finally got my 77 Bay Window on the road this summer. Ended up bringing to a mechanic to do the work. After a month of success(ish) in the van, I'm back wrestling problems again. Cruising along, it just dies and shuts off. I can pull over and fire it up and keep going right away. Also 4th gear seems to lose power, I can feel the van slowing down and sputtering so I fly back to 3rd and am usually able to limp back to 4th gear and resume before it shuts off again.

Any ideas on where to start?

Recent work done in last few months.....New fuel pump and filter, replaced 2 fuel injectors, timing, new points and condensor, compression issues and push rods problem dealt with.

I pulled the filter out and short of busting it open to look at the guts, it looks clean.

[TomWesty]

Replace the filter again, just do it it’s cheap. This sounds like fuel starvation to me. It will at least eliminate the cheapest easiest possibility and will most likely fix it.
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[Egan Custom Guitars]

Ya, I've got a few coming in the mail.

[Randy in Maine]

Have you tested the Temp Sensor II?

[Egan Custom Guitars]

I did read about somebody else arriving at the Temp Sensor II....I ordered in another one just incase.

[Randy in Maine]

Clean up the connection (notably the electrical connection) and make sure it is snug on the head but don't reef on it.

That costs nothing to do and you can do it in about 10 minutes.

[Clara]

[KentABQ]

[Egan Custom Guitars]

I'm measuring about 1900 on the sensor,on a cold van. Which I was told to be somewhere closer to 3000. Being about 2/3 of what it should be, should this be cause for concern, or can this number vary?

[airschooled]

[Egan Custom Guitars]

[quote="asiab3"]

[curtp07]

I’m gonna take a shot here on the fuel/electrical side.

1. Check and clean all the FI grounds perfectly?
2. Possible fuel starvation (filter mentioned), up stream of filter..creating fuel tank vacuum of some sort?

Following.
Curt
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Subaru

[Randy in Maine]

~1900 ohms is about right on a cold engine, but as it gets warmed up is what is important.

If the sensor is faulty or has a poor connection, the ECU always thinks (through too much resistance) that the engine is still cold and sends too rich of a mixture to the engine. The engine will get all jerky and it will feel like it is running out of gas.

It is tests OK when warm, move on.

[Egan Custom Guitars]

I just went for a few laps around the farm in the bus, about 10 minutes not getting past 2nd gear, it's also 33 celsius outside. When I got back I was measuring 104 on the sensor.

[Randy in Maine]

The outside air temp doesn't matter, it is the engine temp that counts.

Have you done a fuel pressure test?

https://www.thesamba.com/vw/forum/viewtopic.php?t=175058&highlight=l-tronic+fuel+pressure+test

[Egan Custom Guitars]

I myself haven't done a fuel pressure test.....but I had my bus with one of the better VW mechanics here on the coast, and he went through the whole fuel system and checked fuel pressure. He replaced the filter, pump and 2 of the injectors.

[Randy in Maine]

Can you take it back to him?

[SGKent]

sounds like a filter unless it started right after you were working on it. If it just gradually got worse it might just be the filter. So many of these buses sat for years and never had the tanks professionally cleaned before bringing them back to life.

check the dwell just on the possibility that it is a broken rubbing block on the points.
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[Egan Custom Guitars]

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Well, it seems as though I will be replacing my fuel tank. I actually did end up swapping in a new temp sensor and it ran great right away and was able to put about 100k on it. And then the next morning it would not fire up. I ended up ordering in a few spare filters as well. The flow from the outlet on the tank to the fuel filter was a slow dribble, so I suspect a pile of crud is sitting at the bottom of the tank.


And ideas or tips?
Re-furb the old tank or just swap in a new one? The plan would be to do the fuel lines at the same time

[Randy in Maine]

New tanks are available I see.....

http://www.busdepot.com/211201075l

Easiest to do with the engine out. That way you can also easily change out all of the fuel lines, clean up the engine compartment, and even paint up the tinwork. Change out the injector seals and intake runner hoses while you are at it.