Another prime issue.

demodriver · September 18, 2011, 05:49:07 AM

Ok I got fuel again yesterday in my bus. I shut it off while filling and it tried to die again after I took back off. I let it idle for about 10 minutes before pulling back on the road. As soon as I got the rpms up it fell on it's face. I let it return to a idle and pulled back off the road. It idled for another and then I held it on the floor for about three minutes. It then ran fine. It seams to only do this on fill up.

Any ideas?

luvrbus · September 18, 2011, 05:57:44 AM

The pump is getting weak 1st sign of one going bad install you a inline pump and run it for another 10 years or change the pump do you have any seepage around the pump ? you may can clean the relief valve on the pump and it help it a little it is doing on idle I don't believe filling has much to do with it

good luck

demodriver · September 18, 2011, 08:08:22 AM

Are the pumps rebuildable? I didnt notice any seepage anywhere. I looked for seepage this morning when we started to head back home and couldnt find anything.

How much psi does my engine require? its a 6v92.

Thanks

robertglines1 · September 18, 2011, 08:12:26 AM

Eric I think I paid just a little over a $100 for the last one I replaced (rebuilt). Bob

demodriver · September 18, 2011, 08:14:49 AM

That sounds alot more appealing then wireing in a electric one and messing with plumbing it in. My bus has all steel braided lines for the fuel lines still and I would like to keep it that way.

luvrbus · September 18, 2011, 08:28:54 AM

Eric 50 to 70 lbs for the standard pump you make sound like a major deal to install a inline lol

good luck

demodriver · September 18, 2011, 09:24:35 AM

No not a big deal but I spend almost all of my free time working on my autocross car (type of race car). The last thing I want to do is work on my stuff. A direct bolt in fit would be easier then wiring a electric one in and less time comsuming.

thanks again.

luvrbus · September 18, 2011, 09:37:05 AM

Wait till you change that pump LOL

Van · September 18, 2011, 09:55:27 AM

Quote from: luvrbus on September 18, 2011, 09:37:05 AM
Wait till you change that pump LOL

That's my story and I am stickin to it!

Live and learn
I guess for some

demodriver · September 18, 2011, 10:58:19 AM

Of what I can see it would appear to be a pertty strait forward change out. What am I missing that would make it difficult?

I found a rebuilt one for around $90. Witch rotaion is my engine. Left or right?

Once again thanks for the knowledge.

luvrbus · September 18, 2011, 11:11:18 AM

All fuel pumps on a 2 stokers turn left even the right turning engines

good luck

gus · September 18, 2011, 01:20:59 PM

It is very strange that this only happens on fill-up?

Do you mean this never happens after the bus sits overnight or longer?

If it only happens after fill up I don't see what that has to do with fuel pumps?

It sounds more like you're stirring up junk in the tank. Have you checked the filters?

If this is the problem it is still a mystery to me how it finally goes away though?

demodriver · September 18, 2011, 01:35:59 PM

It had happened the last two times that I have gotten fuel. I parked the bus last sunday and fired it back up this saturday with no problems. I drove it about 8 miles to the truck stop and got fuel and it did the previously mentioned.

Last weekend I had to pull the filters and reprime them to get it to restart. The filters were half empty when pulled.

Today when I headed home I stopped and got another $60 in fuel due to it making me nerveous now. It did NOT have any problems this time.

The bus is going to be sitting awhile now so I have time to figure it out for sure this time.

gus · September 18, 2011, 01:41:12 PM

Which brings up another point, was the tank near empty the times you had the problem?

That would increase the possibility that tank junk is causing the problem.

If this is really the problem a couple of filter changes will usually stop it. Same thing happened to me when I first got my 4104, it would clog the primary filter in less than a thousand miles.

Just Dallas · September 18, 2011, 02:37:57 PM

Just for FYI....

You asked about left and right hand pumps. Clifford is correct, all the pumps turn in the same direction.

When you go to order a new pump they'll ask you if it's left or right, that refers to the large and small fitting holes for the fuel lines. Some have the intake on the left, some on the right.

As for the fuel problem overall, I would look at the pickup tube. It's possible it either has a crack in it, and sucks air... allowing the filters to drain as they fill with air, or, someone 'fixed' the pickup tube and placed it too low so that it picks up crud and passes it through the filter, but stops at the secondary, (Probably not the problem). The secondary is really the only one that needs priming, as once you have the engine running you can pull the throttle on the governor up to about half way and the engine will prime.
Next I would look at the check valve between the pump and the tank. On many buses they are mounted on the bulkhead where the lines transition from a hose to a solid line. Others are placed at the fuel filter and still others are placed at the fuel pump. You just gotta find it.
The next, next to the last thing I would look at is collapsing hoses or leaking lines, although those have cost many a driver a lot of hours trying to find a problem. They usually are not the problem.
The next to the last would be connectors and fittings that may have been cracked at some point and due to vibration are now sucking air.
The last thing I would look at, (or maybe the very first thing), is the fuel filter itself. The last time it was changed was the old O-ring/flat gasket removed and replaced or was a second one installed over it? Is the fuel filter possibly warped? ( I had a whole bunch of Fram filters that wouldn't seal).

One thing I know almost for certain, this problem isn't going to get any better without some work. Hopefully not a lot of work, but some work nevertheless.

good luck there DD... We're pullin' for ya, keep your stick on the ice!