Stranded campingbus dies at under load at moderate throttle

[energyturtle]

I'm camping in NC. On the way here all was good for the first hour. Symptoms presented themselves suddenly without warning. The bus would cut out then cut back on as if someone turned the key off. Limped into camp and let it set overnight. Checked all the ground connections, vacuum lines, plugs, wires, fuel pump, filter, etc. All is good. I took off the AFM cover and went counterclockwise just a bit 1/8 in or so and the idle smoothed out and sounded good. I do not know how to set the adjustment (what screw does what) I have read the AFM adjustment thread, but for me it is a little hard to understand. I have basic tools and no multimeter. The bus starts, idles, and will go through the rpm range sitting, but not under load. Runs well even while sitting. It is a combination of slight bucking, cutting off and on, and falling flat under load. 3500 rpm in 1st is the sweet spot. Shift into second it falls on its face then kicks back in. Help please. I forgot my Bentley too:( 2.0 fi 78 westy

[Boxcar]

Is the double relay happy?How are those electrical connections way in at the starter?

As a curious aside, is this engine what was being written about with cam saddle issue?
Or existing Type4 power acting up?

Please have good luck!//E

[Boxcar]

oh and fuel filter?
that big dia fuel line headed from the filter still stout?

still thinking..hope NC is nice in the meantime.

[energyturtle]

I have no means to test the double relay. This is my personal bus, not the cam saddle case. The fuel pump kicks on in the acc position and continues to run without engaging the starter. Once again the problem is only under load. Starts, idles, it will try to backfire,(hiccup) while sitting still under a full pedal rev. I tried to adjust the mixture screw at the AFM and it does nothing?

[energyturtle]

All new fuel lines, filter, pump, relined tank. The fuel pump makes a very loud buzzing sound and yes it has the rubber dampeners. Thanks y'all for the feedback. Still hopeful, but a ride on the flatbed seems probable at this point:(

[Westy78]

Man, I feel your pain. Nothing worse than being stranded while camping. BTDT.

Sure sounds like fuel starvation. Particularly with that buzzing pump. What kind of procedure did you use to seal the tank? There have been others with the lining delaminating and clogging the fuel outlet. If the pump is buzzing it could be cavitation from starvation.

[energyturtle]

Por 15 r reline kit. I followed directions to z tee. I don't have a fi pressure gauge on hand. I'm with ya though, fuel starvation. I just don't know? @colinwhereareu...help:)

[Jivermo]

If you have REALLY checked all the vacuum lines, symptoms are very similar to a dying fuel pump. But, you say you just put a new one in?

[Westy78]

The POR kit is the one that people have had issues with. I think RandyinMain was one of them. Might be a good idea to pull that outlet fuel house from the tank and see what kind of flow you have.

[Randy in Maine]

Suggestion:

Hook up a 4' piece of fuel line to the fuel rail test port and see if it will really pump out 1L of fuel in about 30 seconds. I would run about 5 gallons of gas through that and see if it does clog up. A clutch cable sized wire inside the "out" line at the tank will confirm a blockage, but once the "suck" is off, the clog may float.

In a real pinch you can use a itre pressure gauge as a fuel pressure gauge but use real caution doing that.

My problem was that my POR-15 tank lining was coming off in postcard sized sheets inside the fuel tank and was blocking the fuel "out" line. The fix was for my tank to come out and went to "Tank Renu" or someplace like that where it was sandblasted inside and out and expoxy sealed.

Hard to believe that was 10 years ago.

[energyturtle]

Thanks everyone. I'm going to leave it at a friends house nearby and come back next weekend with more tools and an extra pump and get it going.

[Amskeptic]

Thanks everyone. I'm going to leave it at a friends house nearby and come back next weekend with more tools and an extra pump and get it going.

P.S. Look at the wiper track inside the AFM for any evidence of wear-through. You will see a little white plastic sticking through the black graphite track. It mimics running out of gas in that location only.
Colin

[energyturtle]

Wiper track is clean. Fuel pump is new, as is EVERYTHING on the bus. Tank lining coming off? Hmmmm. That certainly sounds like a major possibility. Why will the bus run fine while sitting, and even rev sky high without even a hiccup? Then while driving fall flat?

[Randy in Maine]

When you come back to get it, bring a spare Temp Sensor II and your volt ohm meter.

[energyturtle]

I checked my points and its opening very wide. What would be close to .016 as I don't have a feeler gauge.