Combines Cummins low on power

[NDDan]

Other than the obvious that you already checked I have found two things on them engines. Number one would be the fuel charge pump. I would fairly slowly pump hand plunger with engine off and feel for some restriction pushing plunger and listen for slight chatter of relief valve at main fuel pump. If no restriction or chatter the pump is likely bad. Second is wastegate control on turbo. If diaphram has developed leak in that control you will lose so much pressure in feed line that fuel pump aneroid won't get enough pressure to allow pump to flow full fuel. I would adapt a hose to pipe that goes to control and then blow or such with mouth to see if it holds pressure or vacuum. This is best way I can figure to test without special tools. I doubt very much you have a problem with turbo itself. Take S_N from engine plate to order parts and carefully get number off of turbo if you need wastegate control. If you determine you need wastegate control you may want Cummins out to replace wastegate control or someone that knows how to set it. Good luck

 

[strawwalker]

Dan, Thanks for the suggestions, I will take a look at these tomorrow. Could you clarify where the fuel charge pump is.. is it the electric fuel pump on the side of the combine that pumps the fuel up to the engine or is it part of the injection pumpIJ thanks

 

[tbran]

it is the pump Dan described that has the hand pump on it with the rubber bellows. Usually it is the culprit as we have replaced most of the old units on all combines. Cummins has changed the n several times.

 

[Kelly]

On your combine, it is the electric pump down on the side. I don't think yours has the mechanical lift pump that Dan is talking about. Number one cause for poor performance on the c series Cummins motor is the wastegate. They can be checked fairly easily with an air regulator. Kelly

 

[vstk]

It may be an engine problem but it sounds more like a main drive belt problem. There are two sets of nuts on the main drive idler snubber. The first set should compress the snubber......the other set needs to be several inches from the bracket. Way too many mechanics and farmers dont understand there function and move these nuts up to the bracket......and shazam.....no power. I often takes a while to show up, not always when the change is made.It is a possible cause of your problem........vstk

 

[strawwalker]

I checked out the charge pump first and it seems to be fine..next checked the wastegate controller and sure enough there is a major leak in the diaphram. I understand what you are saying that pressure loss here could also affect the fuel to the injector pump but now I'm worried that with this leak in the diaphram that the wastegate wasn't opening properly. Is it possible that the boost pressure got too high and may have damaged the engine IJIJ The engine runs fine except when you put it under heavy load. I will be going to Cummins dealer in the morning to get the part.

 

[NDDan]

I don't know about a C62 having electric pump for the R's don't. The reason it affects fuel pump is the same line that feeds wastegate control feeds the fuel pump also. That line has orfice in it so if a leak develops you will lose pressure to both circuits. Thus fuel pump will not pump the fuel to develop full power so boost won't skyrocket either. I would say there is no chance of further engine damage from wastegate failing. Good luck

 

[NDDan]

Correction to above statement. The QSC engine used in the 2000 and newer R62's and 65's does have an electric fuel pump. I believe it takes the place of the mechanical charge pump of the plane C series engine have.

 

[Kelly]

The C62s had a red Holley on the side of the combine. Probably because the engine sits quite a bit higher than the fuel tank. Kelly

 

[strawwalker]

Dan, You were right on the money....I went to Cummins for new wastegate control this morning but they didn't have it in stock they ordered it and it will be in tomorrow. I talked to a technician and he said that in the meantime it would be safe to set the wastegate to about the 3_4 open positon. I did this and blocked the air hose that goes to the controller. Engine ran great all day doing corn and back to it's old self with lots of power. Pushing an 8 row cornhead at 4-4.5 mph in very muddy conditions and rpm never went below 2240. I will put the new controller on tomorrow when it comes in. Thanks very much for the help.