Series 60 check valve?

Jim Blackwood · July 31, 2020, 09:36:06 AM

My bus has developed an idle problem. It will start normally, idle a few seconds, maybe just about enough to get up and walk around to the rear of the bus and then it dies. Cranking won't restart it but after powering down and then back up with the main switch on the dash it will start normally again and go through the same cycle all over, maybe half a dozen times before it settles down and stays running.

Brother Andy, a Pete owner/operator says it's a check valve in the fuel return line that needs replaced.

Do you guys agree? If so, where is it located on a '96 DL3 and what does it look like?

Jim

luvrbus · July 31, 2020, 10:45:09 AM

You can check the fuel for losing prime just turn on the priming if it keeps pumping there is a problem some where and the check valve is on the suction side on the DL3 I owned, return lines are open,If you have a Davco Fuel Pro there is a ball check that sticks and needs to cleaned

Jim Blackwood · July 31, 2020, 02:06:44 PM

Does that check ball give these symptoms if it needs cleaned? If so then I will need a little guidance to find it. Just assume I'm completely clueless here, as I don't even know where the pump is or what the Davco is.

It does run just fine after a few starts.

Jim

DoubleEagle · July 31, 2020, 02:32:43 PM

The Davco looks like a miniature R2D2, about a foot high. Hard to miss if you have it, but you probably have two spin-on filters on the passenger side in the lower half of the engine. To find a check valve you will have to follow the fuel lines.

luvrbus · July 31, 2020, 03:00:53 PM

The priming pump switch is in the rear panel all DL3 having a electric priming pump

Jim Blackwood · August 01, 2020, 10:20:08 AM

I took some pictures since I didn't find what I was looking for. On the right side (passenger) there are two filters but they look like oil filters based on the hose routing. On the left there are two filters and I haven't a clue what they are. At the right front corner of the head is an upright silver cylindrical can with lines attached, no clue what that is either. Didn't see a reasonable facsimile of a fuel pump anywhere.

On the panel the fuel pump switch is in the up position, spring return. With the big power disconnect on, when I engage it I can't hear a sound.

Switching on main power (dash) I still can't hear a sound from any fuel pump. After it dies and while power is still on I can't hear any sounds from the fuel pump either, whether the pump switch is depressed or not. And the fuel pump switch has no effect on the engine dying, if I depress it at the first sign of shutdown it still shuts down. It also has no effect on cranking for restart.

But, if I switch the engine run switch off and back on it will start normally.

Jim

DoubleEagle · August 01, 2020, 12:54:35 PM

As I thought, two fuel filters on the passenger side (primary to the rear, secondary towards the front with fuel shutoff near it), oil on the other. Fuel pump is above the primary. Check valves, I don't specifically know, but they are probably in a bad spot.

luvrbus · August 01, 2020, 01:36:57 PM

The way he is describing sounds like the coolant level is low turn the pump on fill the surge tank

Jim Blackwood · August 01, 2020, 04:05:43 PM

Just tried that, How do I know if the surge tank is full, is there a sight glass? (I will look for one tomorrow) I held the switch down for a good while, topped off the lower reservoir and ran the pump some more but it made no difference. When I started it using the rear controls it ran just about long enough to walk to the front of the bus and then quit. Started easy though.

Jim

thomasinnv · August 02, 2020, 06:12:26 AM

When you turn the ignition on do the check engine and stop engine lights come on for about 5 seconds then go off? I ask because sometimes these indicators stop working due to a wiring issue or burned out bulb. Verify that they are working, then start the engine. If the stop engine light comes on and then the engine dies, you will know that the ecm shut it down due to a safety concern. Low coolant, low oil pressure, and high coolant temp are the only things that will trigger a shutdown. (Test the corresponding sensors) If the engine dies without any lights coming on to indicate an ecm shutdown then you can move on to a fuel issue. If the ecm shuts it down then it will store a code which you can retrieve via the indicator light.

Also FYI, there should be a site glass in the surge tank above the radiator. Pop the upper cap open while pumping coolant in.

Jim Blackwood · August 02, 2020, 11:02:42 AM

BINGO! Dead on the numbers.
I had to take the top line loose from the transfer pump to prime it but then I got the coolant up to the middle of the sight glass and it started and idled perfectly.

Red coolant huh? I'll have to find out what that is.

I haven't looked at the annunciator panel for fault lights yet. I can do that later. So anyway thanks a bunch, that really helps.

Jim

luvrbus · August 02, 2020, 11:27:14 AM

Quote from: Jim Blackwood on August 02, 2020, 11:02:42 AM
BINGO! Dead on the numbers.
I had to take the top line loose from the transfer pump to prime it but then I got the coolant up to the middle of the sight glass and it started and idled perfectly.

Red coolant huh? I'll have to find out what that is.

I haven't looked at the annunciator panel for fault lights yet. I can do that later. So anyway thanks a bunch, that really helps.

Jim

Most owners of the 60 use the Power Cool coolant sounds like that is what is there

Jim Blackwood · August 02, 2020, 11:41:29 AM

Thanks. I'll get some of that.

Jim