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Limited power from malfunctioning fuel shut-off

February 02, 2011, 03:11:11 pm

Sometimes our Cummins C-8.3 would start fine, but we could only drive at low speeds for a few minutes, then all would seem ok.

After finding it was not caused fuel or air filters or King-Control, I noticed that our fuel shut-off solenoid did not fully open.
With engine running, I could just push the solenoid further up by hand and the problem went away until we turned engine off.

So this week we replaced our probematic solenoid and we are good to go again.
A detailed write-up with photos on the replacement is on Barry Beam's BeamAlarm web site:
Fuel Shut Off Solenoid Replacement

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Re: Limited power from malfunctioning fuel shut-off

Reply #1 – February 02, 2011, 03:24:57 pm

Hi Barry, Just for info, the 8.3 Cummins is a popular engine for generators, and the weak link is also the fuel solenoid, while slightly different than what is shown in the above article, it is still very close.  The issue we have found it to take the solenoid apart, remove the plunger, clean and using silicone grease (lightly), reassemble and the sticking issue goes away for a very long time.
Make sure the adjustment is correct, meaning the plunger bottoms out with a slight amount of free play in linkage.  It needs to bottom out so the pull in coil is disconnected with just the hold in coil holding it in.
Not as complicated as it might sound.
Cheers and hope to see some pix soon of your Xtreme progress.
Dave M

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Re: Limited power from malfunctioning fuel shut-off

Reply #2 – February 02, 2011, 08:04:15 pm

I this a problem with both the mechanical and electronic 8.3's?

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Reply #3 – February 02, 2011, 08:40:21 pm

Mechanical only

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Re: Limited power from malfunctioning fuel shut-off

Reply #4 – February 02, 2011, 09:16:47 pm

On my 1997 the boot around the plundger was split and it let dirt and water get in, blocking the electrical  connection

Ben
1999 u320

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Re: Limited power from malfunctioning fuel shut-off

Reply #5 – February 03, 2011, 12:25:02 pm

Barry, as you might recall, I too have had an intermittent low power problem.  And still have after doing all the King Control fixes you and others offered.  So, if I read this latest detection and solution correctly:
    1.  Physically move the plunger arm to see if the problem goes away.
    2.  Clean and lubricate the solenoid as Dave M suggests, or replace as your article and photos explain.
If this is my problem, it seems that the fact of sudden and immediate recovery--when it wants to work right--would fit this binding fuel shutoff solenoid sticking partially open, and then "magically" sliding open fully and giving proper power.

Again thanks for a great explanation and photos.

Andy1

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Re: Limited power from malfunctioning fuel shut-off

Reply #6 – February 04, 2011, 10:27:34 pm

Our solenoid failed about 2002 and we had a mobile tech address the problem.  He indicated that one of the coils in it had burned out.  He replaced it with an updated style and I gave my failed parts to someone in the group.  Has not failed again.  I guess that I would check for an update to yours.
Regards,

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Re: Limited power from malfunctioning fuel shut-off

Reply #7 – February 04, 2011, 10:36:14 pm

Jon, just for info, yes there are two coils in the solenoid, one for pull in (heavy current draw) and second is to hold in (very low current draw).  the plunger needs to bottom out in order to hit the switch in the base to change from pull in to hold mode.  If not adjusted correctly, and the plunger never hits the swsitch, the pull in coil will burn out shortly there after.
This principal has been used on mechanical fuel solenoids for many years, however today the computer engines do not use that system.
 

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