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fuel starvation

I have a fuel starvation problem in the making...occasionally when i shut down the engine while hot for only a short time (fueling, grocery stop, short shopping center stop, ect..) when i get back on the road i only get enough fuel to run 25 or 30 mph. After a few blocks of crawling along, closing the throttle, going to wide open throttle, it will pick up and run normally for the rest of the day.

First time this happened i had just fueled up (i always shut down while fueling) and was convinced i had picked up some bad fuel, but before i could find a place to get off the road and change filters, it picked up and ran normal, so i have ruled out plugged filters.

I have since noticed that if i shut down and start up again before the engine cools completely down even without fueling, i may very well experience this problem. It has never did this starting up from a "cold" start. Doesn't do it every time, but is becoming more frequent.

Can't see if the injection pump linkage is working from the driver's seat or course, but i suspect either the throttle control or possibly lift pump. Anyone else experienced this problem??

Ralph Trotter
96 U270
Ralph
96 U270

Re: fuel starvation

Reply #1 –
Ralph, when you say closing the throttle and open the throttle, does the engine rev up when you step on the throttle.  If it doesn't you could be having problems with the King throttle control.  I think your unit has that system.  If you can not speed up the engine with the foot throttle while in netural go back under the bed and see if you can speed the throttle manually.  If this is the way it is acting call me.  580-223-3399
Jimmy Freytag,  Ardmore, Ok
1999 36ft U320. — -SOLD—-
1988 40ft GV        1990 36ft U280
1993 40ft U280      1996 36ft U280
  TRAVEL WHILE YOU CAN THE TIME WILL COME
            WHEN YOU NO LONGER CAN.

Re: fuel starvation

Reply #3 –
If you check the above posts about the King throttle control and the fuel solenoid and have no luck, take a look at the check valve and rubber O rings on the manual pump. They can let air in the system and may show symptoms like you are having. See crack in the check valve housing in photos. These were bad on my U300.
Pierce and Gaylie Stewart
'93 U300/36 WTBI
Detroit 6V-92TA Jake
1140 watts on the roof
SBFD (ret)

Re: fuel starvation

Reply #4 –
Ralph may get better reply,s if he tells us what engine he has.
The selected media item is not currently available.Bill&Doris 97 U270 36'
University of Parris Island Class of 66
Semper Fi  Build# 5174 MC#17094

Re: fuel starvation

Reply #5 –
Quote from: Ralph Trotter –
I have a fuel starvation problem in the making...occasionally when i shut down the engine while hot for only a short time (fueling, grocery stop, short shopping center stop, ect..) when i get back on the road i only get enough fuel to run 25 or 30 mph. After a few blocks of crawling along, closing the throttle, going to wide open throttle, it will pick up and run normally for the rest of the day.

First time this happened i had just fueled up (i always shut down while fueling) and was convinced i had picked up some bad fuel, but before i could find a place to get off the road and change filters, it picked up and ran normal, so i have ruled out plugged filters.

I have since noticed that if i shut down and start up again before the engine cools completely down even without fueling, i may very well experience this problem. It has never did this starting up from a "cold" start. Doesn't do it every time, but is becoming more frequent.

Can't see if the injection pump linkage is working from the driver's seat or course, but i suspect either the throttle control or possibly lift pump. Anyone else experienced this problem??

Ralph Trotter
96 U270
Ralph,
 If you have a mechanical 8.3,  an auto-stop fuel supply solenoid, that is only partially opening, could very well exhibit your symptoms.  I had to replace mine for the new style, which appears to be much more reliable.  On my original, the shaft would move full stroke, but the stem was actually severed and the valve seat (hidden from view) wasn't moving.  Therefore, no start and dead in the water.  Actually, Cummins replaced it without any parts or labor fee....Bless them!
 But, you may also want to read the following thread:
 Allison AW or King Throttle Control (or other) problem
 I had similar or identical symptoms to yours over 5K + miles.  Thanks to Barry Leavitt (Barry and Cindy), it was easily resolved.
 Mine turned out to be a poor ground path for the King Controls throttle control unit (through the air brake pressure switch terminations, located in the street-side forward compartment, high on the forward bulkhead, through the brake light filaments, to ground).  The symptoms seemed to come and go in no logical sequence.  The King Control unit requires this reliable ground path in order to ensure that energizing the brake light circuit will disengage the cruise control.  If it doesn't see the  ground path, it will limit throttle opening to 1500 to 1800 RPM.  A high resistance ground path seems to have other strange effects on the King throttle control unit, as well.
 Curing my poor King Controls ground path through the brake light filaments cleared all of my symptoms.
 As an aside, King Controls refurbished my original Throttle Control unit for $95 plus shipping.  I installed it and carry the removed unit as a proven, functional spare.
 FWIW,
 Neal
 
The selected media item is not currently available.
Neal (& Brenda) Pillsbury
'02 U320 SPEC, 4200, DGFE, Build #5984
'04 Gold Wing
'07 Featherlite 24'
'14 Jeep Grand Cherokee Summit
MC #14494
Exeter, NH & LaBelle FL
Quality makes the Heart Soar long after Price is Forgotten

Re: fuel starvation

Reply #6 –
Thanks guys for the tips...I suspect now the fuel solenoid may be the culprit, but will checkout the other possibilities also, never hurts to make sure the King control has a good ground path.

And yes, it is the mechanical 8.3.

Ralph Trotter
96 U270
Ralph
96 U270

Re: fuel starvation

Reply #7 –
(copied from another topic)
Fuel shutoff is easy to diagnose and temporarily repair on C-8.3 engines. Find it on curb side of engine near fuel injector pump. Linkage should move easily by hand when engine is off. And the solenoid should FULLY snap up to allow fuel to flow when engine is started.

Solenoid is pulled up (fuel can flow) with strong coils that are only energized when starter is engaged. Smaller coils keep solenoid up when ignition is on, but cannot pull solenoid up.

If solenoid does not move when engine is started, fuel will not flow and engine will not start.
Partial upward movement will allow engine to start just fine, but with limited fuel flow, RPMs will be limited. Solenoid can hang up from lack of lubrication or misaligned connection at fuel injector pump. And limited RPMs are often diagnosed as fuel or air filter restrictions or bad fuel. Important to check fuel shut off solenoid before changing filters.

For a temporary fix, with engine off, manually push linkage fully up and hold it up with a plastic cable tie. Engine will start, but not shut off until cable tie is removed. You can drive with this arrangement for weeks until you find repair facility.
Cummins has a new upgraded, larger, stronger solenoid (for a lot of $). Unplug wire, remove a few bolts, replace bracket & solenoid, plug cable back in and you are good to go. Changing to this new solenoid may be a worthwhile upgrade before problems occur.