[ozgleaner]

I have a 1994 R62 with the 8.3l Cummins engine. There seems to be an ongoing problem with engine power loss when the machine is loaded up. Revs drop away quite markedly. Most of the cereal crop I've harvested this season hasn't been any thing that should seriously challenge this combine and all the belts are in good condition , no signs of slippage (hot belts) except for the main drive belt which is newish but always seems to run a bit hot . I remember reading comments on this forum a few years ago about governor problems with this engine type, anyone got any ideas?

 

[tbran]

check the two nuts on the draw bolt that pulls up on the main drive idler. They should be at least 2 " above the bracket to allow the idler to lower and maintain tension on belt. They are there only to hold idler up when changing belts or to not allow threaded bolt to lower and come out of hole. The idler must be in line as well.
As to HP , yes there was an issue of too low an rpm drop before the govs kicked in, but it still had hp just at below the beeper range. There is also an issue of the waste gate carboning up and allowing the exhaust to bypass and not develope boost which will not allow the aneroid to allow pump to open up. That is assuming turbo is ok. Take the waste gate lever and open it via pair of pliers and see of it 'pops' back on its seat. If it sounds soft seated it could be carbon has built up and it is leaking exhaust around the turbine or it has burnt out. This can be see by removing turbo and visually checking. Check the pressue of intake boost at full hp is the next diagnostic check . I guess I am also assuming your fuel supply is good and the lift pump is supplying the correct supply pressure to the pump and the correct filters are installed. I have seen incorrect fuel filers installed where the sater separator filter goes on the lower lh side and this can restrict flow. Also a stopped up vent inthe bin can cause fuel starvavtion. Finally in this quick reply there is a prepressure valve on some of the pumps that maintains fuel pressure by cating as a relief valve. A piece of oring stuck in this can result in low supply pressure as well. And also worn helicals and or cylinder bars can cause tremendous hp requirements. Check out the hypermods section of www.harvesting.com/combine/gleaner - happy troublesooting/hunting and thanksgiving

 

[rolf]

I have a 30 PSI boost gauge in cab on our 8.3 94 R 62 which is plumbed in to the port of the inter cooler were the either inlet line goes (don't need it our part of the world!)
This one little gadget makes a world of difference to driving it and setting up! And also an aid to help if there is problems with power or filters both air and fuel.

Ive had guys with same header as ours drive our machine in years gone past, and they have install a boost gauge the next day in theirs! Just makes you not push to hard on the hydro as much and stop running to the beeper all the time! You can see the power building and know to start to back off before it runs behind the torque curve.

Rolf

 

[nddan]

I'm not 100% sure the '94 Cummins had a wastegate control on turbo for we were still selling with Deutz. Earliest Cummins did not have them. If it does have wastegate (diaphram can with link rod on turbo) you need to be sure diaphram is not ruptured. It will leak boost pressure from intake manifold which will not cause problem with turbo but will rob boost pressure from signal line to fuel pump aneroid. The same line feeds wastegate and fuel pump aneroid and comes threw orificed fitting in intake manifold. Any leak in diaphram will prevent signal for max fuel at the fuel pump. I will remove hose to wastegate control to rig pressure pump or vacuum pump to see it holds pressure or vacuum. I will usually just such some vacuum with my mouth and a hose I can get at for a quick test during normal check overs. Some units have a rubber hose which you can squish with vise clamp to block off a possible leak to wastegate for a quick test to see if power is back. Otherwise I have seen a fair amount of fuel charge pumps fail and even junk in fuel charge check valve at back side of main fuel pump as tbran suggests. I will usually just pump the hand pump fairly slowly during a check over and you should hear this charge check valve release the fuel with a little crackly noise. If you have to pump fast and or have trouble priming up after a fuel filter change you certainly have trouble with charge pump or charge check valve. I've seen junk in check valve at charge pump and the piston seal failed. Not enough fuel charge pressure will definitely drop off your power. We did have one turbo fail suddenly so far but otherwise have no problems with wore blades or wastegate flippers not sealing in our area. Good luck

 

[qmark]

I found the copper line from the top of the fuel pump to the intake manifold broken off. I put a hose over it to couple togather again and had way more power.

 

[farmerharv]

Sorry to drag up this old thread, but I was wondering what the "correct" boost pressure for maximum power would be?

I just put a 30psi gauge in my '98 R62, and at max speed going down the road I'm seeing 15psi. Just finished up harvest so I can't play with it in the field, but might as well be ready for next year.

I have a 30 PSI boost gauge in cab on our 8.3 94 R 62 which is plumbed in to the port of the inter cooler were the either inlet line goes (don't need it our part of the world!)
This one little gadget makes a world of difference to driving it and setting up! And also an aid to help if there is problems with power or filters both air and fuel.

Ive had guys with same header as ours drive our machine in years gone past, and they have install a boost gauge the next day in theirs! Just makes you not push to hard on the hydro as much and stop running to the beeper all the time! You can see the power building and know to start to back off before it runs behind the torque curve.

Rolf