CM2250/CM2350 Fuel Pump

[Shotgun74]

(05-26-2019 )zyNoT Wrote:  

(05-26-2019 )DVT873 Wrote:  Scares me and I'm fearless. There were NO symptoms or codes. Because of this sight I was curious about the failure,so on a slow day I pulled the head off the pump. When I saw the steel plungers I thought OK I'm good. Fortunately one of my guys was a bit more curious and pulled the tappers out of the housing. That's when we saw it. I have not been able to get a straight answer or a ESN break out of Cummins as to when steel tappets started being used. What I did find out is there is some kind of coating on the new cam and tappets. The best I can find out this engine was built with steel plungers. No fuel system related warranty repairs until this. Not an engineer but it looks like there must be one hell of a load between the tappet roller and the cam to put fuel pressure where it it needs to be. Was the move from the three piston to the two piston the result of "cost reduction engineering" ? Also makes me wonder the ceramic plungers were really the original problem. Or did they fail when the tappets/cam came apart. I AM guessing that would put some uneven load on the plungers. Ceramic, being what it is probably wouldn't handle that stress.

You are probably onto something. I've seen engines have stalling problems after fuel pump replacement (from three to two piston). I'm having problems with mine right now. It stalls randomly at idle. Still haven't been able to figure out what is causing it. No visible leaks, pump appears to build rail pressure without problems under load, but randomly at idle the fuel rail pressure will drop and just shut off. It all started with changing to new style pump, everything was fine previously. I'm curious if anyone else has had this happen...

If you have a fuel water separator filter. Bypass the filter & see if it still shuts down. I was having this problem. A new fuel water separator filter housing fixed the problem.