I thought I would post this to help others out with frustrating loss of prime on Cummins engines. It's a known issue with M11's and N14's and maybe other models. It was giving me fits on my M11. I tried a Baldwin BF1259 filter that was originally marketed specifically for this issue but it didn't help. I thought I had it solved by just increasing the throttle to about 1200 RPM but it got worse again. I checked the check valve on the cooling plate and it was working properly. I changed the fuel hose from the check valve to the filter because it was showing signs of weeping. No change. I was thinking I'd just have to live with having to crank it for 20 seconds to get it going when it quit after 30 seconds on the initial start. Then I came across an old post by Truck Shop on here for a similar problem. Some Cummins don't like long filters. He solved a Cummins loss of prime problem using a Baldwin BF957 or Napa 3109 short filter. He also suggested it to me. For $15 it was worth a shot. I was skeptical but I can now report using a BF957 fuel filter has solved the problem. After sitting almost a week the truck started right up as usual but didn't quit 30 seconds later. At 30-40 seconds the engine slows slightly making a rattily noise but recovers 2 seconds later. After sitting about 20 hours the the stumble at 30 seconds was barely noticeable. Big thanks to Truck Shop!
I’ll keep that in mind…we’ve always used a Fleetgaurd FS1000 on ours, which is also a long filter. No problems as yet, might take 4 or 5 seconds to fire up, hot or cold.
Your welcome Dave.-----don't toss too many accolades, that will ruin his cranky patina!
Changing all the fuel hoses under the cab would be nightmare and no guarantee it would fix the problem. The short filter worked. Even the Donaldson (eq. to FS1000, BF1212) that was a couple inches longer didn't solve the problem. I wonder if the BF957 just being listed as a fuel filter rather than a fuel/water separator makes a difference. Something different in the filter media maybe that reduces the suction from the pump?
Ain't nothin ever good or fun about changing fuel or air hoses under cab.
Great info, thanks TS & Dave! Going to try this (Baldwin BF 957)on our L10 (Pt pump). I am currently using a Baldwin 1259 and am still having some issues with loss of prime… All the fuel lines are old and need replacing but haven’t got to that yet…
Our symptoms are virtually identical to what you describe…. Cummins L10. Pt pump. Before the Baldwin BF 1259 I had to use shop air to pressurize the fuel tank (through vent hose, non vented cap..) Will report back once I try that short filter (BF 957)
For s&g's here my solution for loss of prime, using a primer pump and some valves. It's around 3 min in
I was amazed. The only fuel hose that looked suspect was replaced and made no difference. BF1259 with a stand pipe didn't make any difference. Wasn't expecting any difference with the BF957 but was shocked the truck kept running. After sitting almost a week, it did bobble at about 30 seconds but it only lasted about 2 seconds. The engine kind of rattled like when it's running out of fuel but picked up fuel right away. I'd guess the RPM's dropped maybe 100 RPM. If the truck sat for a month or longer and needed a second start I could live with. It's sure nice to not have to start it twice, especially if it needs a boost after sitting for awhile. In the past I'd have to let it sit and charge to have enough power to crank over fast enough for 20 seconds to fill the filter.
I've also got a bunch hyd. hoses from the crankshaft pump running underneath the cab. I think if I had to do any work under the cab I'd dig a trench with the backhoe.
Or a big hole to bury it.
The short filter seems to have magical powers. Not only does the truck keep running on initial start but after 20 hours the truck still had 60 PSI air pressure. It usually bleeds off a lot faster than that. Very strange.
Yes--the 957 is a crystal ball--too. It works well for {What are your hourly rates?}.
You might have sold me on the short filter now
You never know?? I'm doing some big improvements to the MX track for the 20th anniversary next year and another fairly popular track has just shut down. I need to promote the track for next year and wondering if giving some free day passes to dealers is a good idea? Trying to get sponsorship was like pulling teeth when I first started the track. Maybe the fact I'm still going after 20 years will be an incentive for sponsorship? Maybe a 2 for 1 pass would be better? I don't really like the idea of free passes without something in return but on the other hand getting more riders out might bring people back again.
I just put the short filter on my n14, I close the fuel supply valve when I shut the engine off but sooner or later I'll forget it and see how it does, it took a couple days to bleed down
I had the truck sit for 2 weeks and it kept running after starting. Very slight bobble after 12 seconds or so but not close to stalling. I was quite shocked the short filter was such an easy fix.