From: Art (MTA) (aws@mtaofnj.us)
Date: Thu Jun 29 2006 - 15:59:32 PDT
Vinny,
Put your hand on the top of the in tank pump cap and have someone turn
on the master switch on. If it's working, you should feel the pump
humming.
As always if it's not working, check the fuse under the cap.
Art
-----Original Message-----
From: V SCHWARTZ [mailto:vsaws@optonline.net]
Sent: Thursday, June 29, 2006 17:54
To: Military Vehicles Mailing List
Subject: Re: [MV] M342 (M35A2)fuel delivery problem
I've been thinking about that with my duce. It won't idle. I changed
the
filters and ran it but it's back doing the same thing . I'm going to
look
for thata thngy ansee if it might be dirty . Would the lack of a in tank
pum
also cause that problem. I know that I'm hard of hearing but I nowonger
hear the pump running whin I turn the master switch on. Something to
look at
I think. Thanks Vinny
----- Original Message -----
From: "Bill & Bonnie" <bprestin@chartermi.net>
To: "Military Vehicles Mailing List" <mil-veh@mil-veh.org>
Sent: Thursday, June 29, 2006 1:25 AM
Subject: Re: [MV] M342 (M35A2)fuel delivery problem
> After last falls trail ride my truck sat all winter and spring
awaiting
> further attention. I was finally spurred to figure it out so as not
to
> miss this years forth of July parade here in Birch Run, MI.
>
> You can read the previous message below this one to see what my engine
> problems were.
>
> The fuel system looks very complicated but is not too bad once it is
> understood.
>
> Here is how the system works:
> There is an in tank electric fuel boost pump that sends 5-7 lbs of
> fuel pressure through the frame mounted primary fuel filter housing to
the
> fuel supply pump mounted on the side of the fuel injector pump. This
fuel
> supply pump is gear driven from the injector pump and supplies fuel
under
> pressure(30lbs at idle-75lbs at speed) depending on engine RPM to the
> engine mounted fuel filter housing.
> In the top of the engine mounted fuel filter housing is a pressure
> regulator valve that starts to open at approximately 60 lbs and
regulates
> the engine fuel pressure between 65 and 75 lbs psi. at 2000 RPM and
above.
> Any excess fuel allowed to escape by the opening of the fuel pressure
> regulating valve is sent back to the fuel tank. This 65-75 lbs.
> pressurized fuel is sent through the engine mounted secondary fuel
filter
> housings and to the fuel density compensator mounted on top of the
fuel
> injector pump. After passing through the fuel density compensator the
fuel
> enters the fuel injector pumps hydraulic head and is pressurized to a
high
> level and sent to the fuel injectors. Excess fuel returning from the
fuel
> injectors and flame heater assy returns to the injector pump fuel
overflow
> valve assy on top of the front of the fuel injector pump and is sent
back
> to the fuel tank via the same fuel line coming from the fuel pressure
> regulator valve.
>
> I measured the pressure at the primary fuel filter and found I had the
> necessary 7lbs of pressure. I measured it at the top bleeder valve on
the
> secondary fuel filter housings mounted on the engine and found 50lbs
of
> pressure at 1200 RPM. This was within the specified 48-57lbs for that
> engine speed. I measured it after the secondary fuel filter housing
but
> before it re-entered the injector pump and found the same 50lbs of
> pressure.
> Then a funny thing started to happen. As the engine warmed up(about
10
> min.of running) the 50 lbs of pressure dropped off to 28lbs. After
really
> reading into the manuals I figured out the above system and thought it
> might be the fuel pressure regulating valve. If it was the fuel
supply
> pump the engine would have to be jacked up to remove it from the side
of
> the injector pump as there is less than one inch between the boost
pump
> and the steering gear box. I am not sure the engine could be raised
enough
> as there is only a couple of inches between the top of the flywheel
bell
> housing and the cabs firewall.
> On top of the engine mounted secondary fuel filter housing there is
> what looks like an extra bolt, its really a plug with an O-ring. When
I
> unscrewed it a spring flew out and almost got lost under the truck. I
used
> a pair of needle nose pliers and pulled out the valve plunger and
under it
> was a piece of crud holding it up off its seat. I cleaned the plunger
and
> its seat and reinstalled the parts.
> After this I ran the engine for almost a half an hour at 1200 RPM.
The
> pressure stayed above 50 lbs. at all times.
>
> I'll take it for a test drive tomorrow but I am sure it is fixed.
>
> Here are the pressures necessary at the top of the secondary fuel
filter
> housing.
>
> RPM Min press lbs Max press lbs
> 700 30 35
> 1200 48 57
> 1600 57 64
> 2000 63 69
> 2400 65 73
> 2600& above65 75
>
>
> Bill
> Michigan
>
> ----- Original Message -----
> From: "Bill & Bonnie Prestin" <bprestin@chartermi.net>
> To: "Military Vehicles Mailing List" <mil-veh@mil-veh.org>
> Sent: Sunday, October 09, 2005 4:03 AM
> Subject: [MV] M342 (M35A2)fuel delivery problem
>
>
>> Hi,
>> I have an M342 dump truck with an LDS465-1C engine, I am
struggling
>> with fuel delivery problems. It will drive down the road great for a
>> couple of miles (accelerates fine) then just runs out of fuel. After
>> sitting for a few minutes with the fuel pump turned on, it will start
>> back up and drive a couple of miles more. It will also idle fine
forever,
>> so a little fuel is getting through. I changed all the fuel filters,
>> still no luck. I also tried bleeding the valve above the fuel filters
on
>> the engine while the truck is idling. Plenty of fuel squirts out, so
the
>> problem must be beyond there. The problem developed while I was up in
>> northern Michigan on our clubs fall trail ride. The 120 mile trip
home
>> was pretty rough.
>> Anyone have any ideas where the system might be clogged? My engine
has
>> the sticker on the side that says
>> "use diesel fuel only. Fuel compensator has been bypassed to prevent
>> engine oil dilution"
>> But there is still a maze of fuel lines around the injector pump.
>>
>>
>>
>> Bill
>> Michigan
>>
>>
>>
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>
>
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