Diesel idle problem and more - perkins

I've got a turbo perkins in my Massey with 4300 hrs, it works fine, and works fine under load with the following exceptions:

-It has a hunting idle, it will just wander up and down, especially if you disturb it a bit by starting to move a bit them pushing the clutch in, then steadies out over several minutes. While doing this it almost stutters like its missing.

-When the engine comes into a load, it will sort of stumble for a sec then catch itself and sometimes overshoot the rpm it should be at. An example is running the haybine in a hilly field, it will be fine cutting accross the slope, then when turning up hill it will lose 200 rpm in the first couple of secs, then surge ahead and overshoot by 200 rpm the next few secs, then fall back to the set rpm while making the stuttering/missing sound like it does at idle. Basically it doesn't like transitions in power output.

I've not done much work with diesel motor or turbos, but my brains is saying there shouldn't be anything that causes missing under load like this. It would seem to be related to the governer or some type of boost regulator, but I still don't see how to make it stutter under load.

If it was a change in fuel flow causing air to get sucked in, it should be on the supply side of the pump and should be a delay instead of so instant, and should cause a problem at full fuelling. But the thing will pull fine at full power once it gets stabilized.

Does the governor change the timing in the injection pump?

So far I've found they commonly get a hole in the boost diaphram that can cause the wastegate not to actuate, leading to high boost levels without extra fuel. Also there is an electric solenoid for temp based advance / retard on the bottom of the pump that gives trouble once in a while as it will come unplugged causing hard cold starts.

I can't see how either gives my exact problems.

What pump does it have? When you get in that power class, the term 'Perkins' got used pretty loosely. There are some things wandering around with yellar paint on them that get called Perkins in some cases, Cat in others... and in reality are ISM (Shibura) engines. Think NewHolland...
Those will have Kiki works inserted directly into a block arpeture and are a rack controlled port and helix. So you could have a sticky rack or some slop in the govenor...
If it's a real Brit Perkins with a Lucas pump... I guess it could have a govenor problem but I'd really expect it to be more related to drawing air somewhere. They do strange things when they get a bit of air or some other obstruction. An airleak would also be possible on the Kiki pump...
That's really where I'd look first or a possible obstruction in the tank... crud floating around and sometimes obstructing the outlet.

Rod

Its a Perkins 1104T (I think a "c" non-electronic) with Lucas CAV rotary pump that has never been messed with.

Weak lift pumps are common on this model but she runs at full load without problem.

I suppose she could be getting air into the hp injector line making it miss on that injector until the air clears the injector?

Never starts hard though even if its been acting up as I shut it off.

Sounds like what my 6.9 Ford diesel pickup was doing when the governor ring went bad. Don't know if that one has the same setup or not?

Does yours have the flame heater in the intake manifold with the small fuel line running into the middle of it? I had one exhibit similar problems when the valve in the heater went bad. Probably wouldn't happen on a nonturbo model but with the turbo building boost pressure it was forcing just enough air into the fuel system to cause problems. May or may not be your problem but I know I was just about to pull my hair out trying to figure out what was wrong with the thing when I pulled the line loose to use as an axcess point to hook up a guage to check supply pressure. Blew my mind when all of a sudden it ran fine just because I unhooked the line. I installed a new heater and never had the problem again. Since I've talked to one other mechanic, at the OEM for the drill the engine was setting on, that has seen the problem happen on one of the machines he has worked on. Good luck, problems like this can be a royal PITA.

Perkins manual says its got glowplugs. They don't work and I've never taken the injector cover off to find out more, we just plug it in like the old international. I've seen other references to it having a thermostart unit.

Its a pain to get into the side of her, its got a loader on it and its a cabbed tractor with a/c lines etc.

The actually exact pump is a DP210 which has a timing retard at high power and a timing advance at light load. From the pump sale lit:
" light load advance travel capability to 28° engine maintains misfire margin at part load. The light load injection timing is set on each pump and the speed advance is controlled by a fixed stop at rated speed to provide advance consistency. The advance response rate is optimized to help prevent transient misfire."

I'm guessing the advance/retard mechanism is sticky or bunged up.

Hi Ken, ork on those engines in Manitou telescopic handlers, just rebuilt one last week. The Manitou machines have plastic fuel tanks and when the turbo boost diaphram splits it pressures the fuel return system and expands the fuel tank. If you take the tank cap of after the engine as been running you get a pressure release for a few seconds. MJ