CAv injection pump update!!!

Well I finally figured out what is wrong with the JD 239 motor with the CAV injection pump. I cleaned the complete inlet fuel system. I pressured tested for leaks. Everything checked out fine. I still had the trouble of the system sucking air when the engine RPMs where above 1500. So I installed a fuel pressure/vacuum gauge between the transfer pump and the filter. At low idle (500-600 RPM) I have 5-6 PSI which is within spec. At 1250 RPM I have 1 PSI and at 1400 RPM I have zero. At 1500RPM it pulls a vacuum on the fuel system. So I concluded that the injection pump might be the issue. So I took the return line off and put it into a measuring glass. At full throttle I have 1600 CC per minute of return. It should be under 750 CC. So there is an internal leak in the injection pump. So it is pulling more fuel than the transfer pump and inlet lines can provide.

So I get to take the injection pump off tomorrow. It will be fun!!! NOT!!! LOL This thing is rusted up from fertilizer. I am willing to bet that some of the injector lines will not come free. I am not sure that this pump can be rebuilt because of the corrosion. I am looking at a reman pump. The numbers on the pump are: Type: RE21504, DPA R3448F* ( Last digit not readable), Serial# 31817 KEG.

I know there are a few diesel pump rebuild guys on here. I would be interested in what they would have rebuilt/remaned. Shot me an email. I have been quoted $650 for a rebuild IF the housing/casing can be taken apart. It maybe too corroded.

CAV spec card book shows RE21504 is Rotodiesel 3448F310. Card also shows if the hydraulic head is replaced a new metering valve is also needed. Not sure if your pump has one, but some Rotodiesel pumps had a recirculating ball valve in the head assembly. It may be stuck shut if it has one.

Thanks for the update-it had sounded as if it was going to be the pump from your previous posts.Also it's good to hear what exactly you found that gave you your conclusion.Mark

Just curious. Did this tractor run but have a real bad sputter above 1500? Having the same issue. What did they find wrong on the pump?
Thanks, Ben from NY