Archived fuel problem

[oldbusguy]

96 keeps running out of fuel have changed lift pump repaired tank unit truck will run for a few miles then when you stop it will run out of fuel after cranking over for a few minuets it will start and run for a few more miles

 

[Roostre]

Check that your tank can vent.

Easy test is to run with no cap and see if it still happens.

 

[oldbusguy]

did that no change

 

[Missouri Mule]

Have tried you tried changing your fuel filter. After replacing lift pump and overflow valve mine would stumble and/die occasionally first start in morning but would restart and blow white smoke.

Finally found time to change fuel filter all is well now (Engine died one morning would restart after I primed it but would die after prime ran out. Mechanic put new lift pump on and pulled tank to clean pick up tube screen, ran good for three weeks then died again one morning mechanic said metal ball was getting stuck inside overflow valve put a new one on. But had stalling out problems in morning when truck was pointer up hill. Took me 15 minutes to get fuel out of filter something had to get in there to plug it up. )

 

[oldbusguy]

changed lift pump and filter however what is the overflow valve??? and where is it

 

[hcole]

This sounds like it's running out of fuel due to a restriction in the line. Check solenoid on injector pump. Make sure it's staying all the way up. Maybe even hold it up mechanically. Then check rubber fuel lines for signs of sucking together or collapse. I assume you've already changed the filter.

 

[oldbusguy]

have replaced fuel lines shutdown solenoid was replaced with a cable last year so this is not the problem

 

[hcole]

Try this. Take a 5 gallon fuel can and hook up fuel pump inlet to it and see if it runs. That will tell you if it's the fuel tank, fuel lines or in the engine area.

 

[Missouri Mule]

Overflow valve is on p7100 injector pump. It is located on the front side of P7100 on the engine side. Has banjo bolt and metal fule line (return fuel line) comming off of it.

Try doing fuel pressure test. Pressure should be at 20 psi or higher at idle, at 2000 rpm should be 30 psi or little higher. If your not getting those readings squeeze rubber return line with pliers, if pressure goes up the overflow valve is bad if fuel does not go up or goes up slowly lift pump.



Also how is your idle? A low idle will cause the engine to stall when you come to a stop.



Is it blowing any smoke when you restart? and what color ?

 

[oldbusguy]

ok where are you connecting the fuel press guage ? in the return? idle is fine no smoke engine just runs out of fuel and will restart after its cranked for a few minuets

 

[HHhuntitall]

You say you have replaced the fuel lines..... Where and which ones? The main suction/supply line sounds like it may be the culprit here. Also, have you cleaned out the fuel screen in the fuel heater bowl?

 

[oldbusguy]

all the lines including the suction line in the tank fuel heater was removed a long time ago in fl dont need heat

 

[oldbusguy]

question if overflow opens and dumps back presure in pump this would make the engine seem to run out of fuel but the pump just could not get enough pressure to crack the injectors ????????????

 

[Missouri Mule]

Take fuel pressure reading at inectiom pump supply line.

If Overflow valve sticks open not enough pressure. If ball gets stuck in line going into overflow valve to much pressue in injection pump it won't supply fuel.

 

[Bob4x4]

You will need a fitting with schraeder valve to connect a standard fuel pressure gauge

 

[Missouri Mule]

oldbusguy, just thought of this solution. It's rare but the engine speed sensor (crank speed sensor, crank position sensor) connector can be dirty inside or have loose or bent pins.



This will and has made the Cummins stall/die but owner's were able to restart the engine. So get a can of contact cleaner(maybe two one lubricating and one drying) and clean out the the engine speed sensor connector and check the pins. Symptoms were reported back in 96 or 97 TDR issues, Owners said engine restarted but did not mention if it fired right up or took a while.