Ambac Injection pump

I have a white 2-150 tractor that i swapped a 465ldt multifuel engine into last year. It saw limited use, but this year i got all of the bugs worked out. The tractor idles great, runs
great at any rpm when under no load. This year i tried to use it for fieldwork and ran into a problem. It runs excellent with no load, but when going down the road with an
implement, or when using in the field, it will randomly seem to bog and then stop completely. Sometimes it will start up immediately and go for a little longer, other times it will
not. I have a small inline electric fuel pump that feeds the fuel from the tank to the filter that then feeds the injection pump. I have changed all of the rubber fuel lines and
stopped all leaks thinking perhaps i was sucking air. I then thought that the electric pump may have been messing up, but then realized it is always still working when the tractor
dies. I believe i have a problem in the injection pump. I changed the fuel filters last year and also dont believe there is any kind of restriction in the tank. I know it is a fuel
problem. The model of the injection pump is Ambac psb 6A-90EH-5337A3. Im a decent mechanic but have no experience tearing into a pump like this and honestly dont have a
clue what to look for. Hoping for some guidance or advice as i really dont want to spend another 1000 to have the pump rebuilt.

Would have been best to replace the timing cover and keep the Stanadyne DM pump than the PSB. Are you still using the gear pump the PSB came with or has it been removed? What fuel flow and pressure does the electric pump have, under load the injection pump may be pumping fuel out faster than the supply can keep up with. That's why at idle or light load it runs fine.

The motor that was swapped in was different than the engine that was originally in the tractor. The pump on it now was on the engine when we pulled it from a truck to put in the tractor. The electric pump has as 35 gallon per hour capacity. 4-7 PSI I believe. Would that be enough?

(quoted from post at 10:21:15 07/07/15) The motor that was swapped in was different than the engine that was originally in the tractor. The pump on it now was on the engine when we pulled it from a truck to put in the tractor. The electric pump has as 35 gallon per hour capacity. 4-7 PSI I believe. Would that be enough?

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ift pumps can still run but not pump fuel.
Put a 15 psi gauge on a filter plug or other convenient spot and see if it does build pressure.

Some engines require more fuel pressure but i like to see at least 10 psi on mine.
Also check the last ditch filter in the fuel supply fitting in the injection pump for being plugged (most IP have one)

GALLANAGE IS PLENTY---PRESSURE IS NOT ENOUGH-NEAR AS I CAN FIND Case needed 15-20psi

Some PSB pumps will work with 5 to 7 PSI, but yours should have 20 to 30. If you are using the fuel viscosity compensator I would disable it by rerouting the fuel line to it and go directly to the hydraulic head. I would also do a flow test through the final filter and see what the actual flow is with a 15 to 20 PSI restriction, your electric pump sounds too small to feed the head at full load. Take care of the PSB, few parts are available anymore, that's why I would have done the extra work needed to reuse the tractor timing cover with the Stanadyne injection pump. That can be repaired with less trouble finding parts.

What should the pressure be coming out of the fuel filter into the pump diesel tech? Also how would I test that? Tee a pressure gauge into that line with tractor running or would off be ok? I have another inline pump rated for 40 psi, would that be too much fuel? Also I am going to post a picture of the pump. Is the fuel density compensator you refer to the part of the pump to the right of the Hyd head near the electric oil pressure sending unit? Like I said this pump was ok this motor when pulled from a truck. The other motor I had was not a Hercules in the tractor and would not have been able to swap the pumps as far as I know as the other engine was a moline with a rosa master.

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It looks like in the photo the PSB gear pump is still in place, some have a relief valve built into the gear pump cover, it may be stamped with the pressure rating. 40 PSI would be a bit high but should be OK. The fuel density compensator is the box to the right of the PSB hydraulic head, you don't need it, and the line that feeds it can be run to the hydraulic head, unless you plan on using some gas or jet fuel along with your diesel fuel.. I'll still bet the flow is not keeping up with the injection pump when it's at full load.