Deuce multifuel fuel pressure spec?

[tm america]

I have been searching my manuals for about an hour.i have done a search and no luck.. I'm needing a fuel pressure spec for a multifuel .. or reference to a chart ... Any help would be much appreciated..

 

[doghead]

Fuel pressure where?

 

[doghead]

The Troubleshooting the LDS manual is useful for fuel issues, and so is IP repair manual, TM 9-2910-226-34

 

[tm america]

I put my guage where the bleed screw goes on the secondary-final filter housing... Just want to get a idea where it should be and see if i am on the low side or loosing pressure alltogether when it acts up.

 

[doghead]

Rotation (viewed from drive end) . . . . . . . . . . . . . . . . . . . . . . . . .Clockwise
Fuel injection sequence. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1, 5, 3, 6, 2, 4
Delivery valve opening pressure . . . . . . . . . . . . . . . . . . . .250-400 psi
O v e r f l o w p r e s s u r e . . . . . . . . . . . . . . . . . . . . 5 psi max.
Fuel pressures, minimum (after final filter):
700 RPM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 psi min.
2600 RPM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60 psi min.
Fuel density compensate (all except 2910-860-2333 and 2910-968-6317 pumps):​

Pressure regulator valve setting (all fuels) . . . . . . . . . . . . . . . . . . . . . . . . .20-21 psi

 

[tm america]

That's what i was looking for ..I'm getting 60-70 psi after the secondary filter so i can't imagine there is much more a 1 or 2 psi drop across the final.. I have changed the filters twice.. same issue..I'm gonna drive it tomorrow with the guage on there and see what happens

 

[gimpyrobb]

What symptoms led you to look into the fuel pressure "pre HH"?

 

[tm america]

It starts fine,idles fine.Has great power but after driving for a half hour or so it will pretty much shut off but it still idles.. If you let off the go pedal and get back on it a couple of time it will be fine.. It will do it three or four times if you keep getting right back into it.Once you are past that point is it fine for another half hour or so... When it does it it acts like you just reached over and pulled the cut off Except it doesn't completely shut off...I know the intank pump is dead.. I ordered a inline pump .. I'm thinking it is getting air in the lines or loosing fuel pressure....If i drive it easier i can make it not do it or it will go along time before doing it..So if i keep it less than 1000 on the egt it is ussually fine.It is really kicking my but I can't see anything in the injection pump that would do that,, and the fuel pump is a gear type so i doupt it could be that unless it just can't keep up with the volume and in cavatating and airrating the fuel?That's why i'm am monitoring the fuel pressure .So far i have changed the filters,bypssed the fdc,replaced and polished the fuel bypases at the hydraulic head and sec-final filter housing...I have no fuel leaks and i have pulled the intank pump out and checked the tank for contaminates...It was clean so i disconnected the hose where it hooks onto the pump to eliminate any chance the pump is restricting the flow .. All of this and still no change

 

[doghead]

Running hard and stalling is typical of a worn out HH.

 

[phil2968]

Any chance the fuel tank is not venting properly? Just thinking out loud. Down here dirt dobbers will plug up everything!

 

[tm america]

Any chance the fuel tank is not venting properly? Just thinking out loud. Down here dirt dobbers will plug up everything!

I haven't blown thru the vent yet.but it isn't making any sucking noises when I open the tank to fill up.but good idea one more thing to check.

 

[tm america]

Running hard and stalling is typical of a worn out HH.

It. Always starts right up.like less than a half revaluation. It never dies or misses.it runs great till it just falls on its face a couple times then its fine.it acts like a gas motor in cold weather with no choke

 

[samsimpson]

It starts fine,idles fine.Has great power but after driving for a half hour or so it will pretty much shut off but it still idles.. If you let off the go pedal and get back on it a couple of time it will be fine.. It will do it three or four times if you keep getting right back into it.Once you are past that point is it fine for another half hour or so... When it does it it acts like you just reached over and pulled the cut off Except it doesn't completely shut off...I know the intank pump is dead.. I ordered a inline pump .. I'm thinking it is getting air in the lines or loosing fuel pressure....If i drive it easier i can make it not do it or it will go along time before doing it..So if i keep it less than 1000 on the egt it is ussually fine.It is really kicking my but I can't see anything in the injection pump that would do that,, and the fuel pump is a gear type so i doupt it could be that unless it just can't keep up with the volume and in cavatating and airrating the fuel?That's why i'm am monitoring the fuel pressure .So far i have changed the filters,bypssed the fdc,replaced and polished the fuel bypases at the hydraulic head and sec-final filter housing...I have no fuel leaks and i have pulled the intank pump out and checked the tank for contaminates...It was clean so i disconnected the hose where it hooks onto the pump to eliminate any chance the pump is restricting the flow .. All of this and still no change

I kind of had a similar problem, but I did 2 things and it has been fine ever since. I had a leak at the HH so I replaced the 2 o-rings, and I had a dead in tank pump so I swapped it with another pump that worked. I am not sure which fixed the issue, since they were both done about the same time.

 

[706james815]

Hope this isn't a dead thread. Hopefully someone can help. M35a2 has been running great untill I changed filters . It is now very sluggish takes for ever reach 52mph beforehand would top out at 58mph. I have checked fuel lines ,filters ,intank pump,changed pick up hose in tank and pressure. Intank pressure is 6 to 7 psi reading at bleeder at secondary and final filter is 60 psi at idle. Don't know what else to do truck has never been turned up but would that be an option?

 

[Floridianson]

Should be 30 minimum at Idle and 60 minimum at high idle. If your is correct reading then you have a restriction after the secondary. Is you FDC bypassed? The part that could get restricted is the overflow valve on the head and easy to check.

 

[706james815]

The in tank pump is reading about 7 to 10 psi and. At bleeder on second and final filter it's reading 55 to 60 psi at idle and 80 to 90 psi full throttle. I haven't found anything in lines ,have pulled in tank pump no trash in screen . I've removed the line coming from tank to booster pump blew air back to tank . Then rechecked the in tank pump screen and haven't found any trash. Cracked open all lines on injector all push fuel . When I do idle to Max throttle it acts like it holds at around 20 rpm for a brief second then goes on to 29 to 30 rpm

 

[706james815]

My fdc is still hooked up. Overflow valve? Is it on the head unit also I have food return back to tank

 

[Floridianson]

The pressure relief valve on the secondary fuel filter will open if I remember around 70 psi so that might be why you are getting fuel back to the tank. Almost sounds like you are not flowing any fuel through the head. The engine will run with the pressure relief valve wide open but no performance.

 

[706james815]

I see what you are saying. The only thing is that it's been running awesome. I went from two 10 micron filters to one 10 and one 2 micron. made it harder to start that's when I noticed the power issue so I went back to two 10 micron spin on filters and problem still there . I pulled that bypass out cleaned and inspected it put back in. Removed the lines blew through them I'm at a loss now I did notice a gear noise coming from around the injection pump couldn't pinpoint the noise to one area. The tie wire was still on the fuel adjustment I opened it up today moved it out about a round and a half then went up a click on the inside of the fdc

 

[706james815]

Wondering now if the nozzels on the injectors are stopping up? I don't have a bench tester