M1070 Low Power Issue, resolved

[monstermog]

Morning everyone. I have a Oshkosh M1070 with the 2-stroke Detroit 8v92ta. I was hoping to find some answers here for my low power/low idle issue. Max rpm at this time is 1000-1100rpms. No CEL's.

I was driving said vehicle down the road and everything was running beautifully. Just hit 40mph then it was like...nothing....lost power....I pulled over and it was just enough to keep the engine running at idle. Again NO CEL's or anything out of the ordinary on the dash. So I limped Optimus Prime home...5-8mph....

Since then I've changed the fuel filter on the engine #86120-Napa...Also the filter next to the tank with the heating element...New. I also checked the coolant level. 1/2" down from neck.-Good. I also checked the Air filter and removed it to see if it would make any difference...none. I also replaced the Priming pump just below the storage box with a new MTU primer fuel pump...$76.00 at a local Interstate Power systems shop.

I am able to start the diesel...usually takes some effort...but once it starts it only idles at 500-600rpms...A small amount of smoky/black out of the exhaust. When I press on the accelerator pedal...sometimes I will get nothing and when I let up it stalls. Sometimes I'll get it to rpm up to 1000-1100rpms...but that's it. I will also get the sound of your air actuated throttle valve releasing even if there is no rpm gain.

Since changing the filters...I wonder if I am causing more issues since I tried to use the primer pump to fill the main engine filter since I didn't pre-fill the filter...but I did check the filter this last time and it was plumb full...but maybe there is some aeriation going on in the system now....despite this...

I just a had a tune-up done on the truck a while back where we tackled some minor issues. One issue that we did see but not sure if it would cause an issue is the
oil sensor on the oil pan...the wires were almost severed. Would this cause an issue as described above?

If not...I've been trying to read as much as I can so I can resolve the issue.

Charles
425-737-7039 cell

 

[goodguyzy]

Good luck with your issue. I don't have any suggestions other that talking to the Detroit dealer.

 

[cwc]

Charles, do you have DDEC III/IV? Have you tried to read fault codes? Do you have TM-9-2320-360-20-3? You can get it on the internet, e.g. at liberatedmanuals.com. FWIW, in the section for "Can't get full power", the second thing listed after "Plugged Fuel Filters" is "Hose not connected to turbo boost sensor (TBS)".

 

[monstermog]

I have ddec 3. I'll be checking too see if the the tube is connected. Thanks for the tip.

 

[Hummermark]

Any update on your fault?

 

[monstermog]

extra info

Well. Problem resolved. It turned out to be the fuel pump. The old one had seized and destroyed the pump. Easy fix. New pump installed. Runs great now. From the looks of the new drive fork...they are reinforced. Total cost of new part....pump...gasket...fittings...$170.00.

 

[Hummermark]

Hi thanks for update good to hear not to pricey and not to big a fault to fix,always good to know other people's experiences ie symptoms fault repairs if you have a m1070 could be of help in the future.

 

[wilmart01]

extra info

Well. Problem resolved. It turned out to be the fuel pump. The old one had seized and destroyed the pump. Easy fix. New pump installed. Runs great now. From the looks of the new drive fork...they are reinforced. Total cost of new part....pump...gasket...fittings...$170.00.

 

[wilmart01]

This is the exactly problem I have, where did you buy the new fuel pump and how can I replace?

 

[silverstate55]

I get most of my Detroit parts from Powerline Components in Wyoming; they’ve always come through for me, especially if you ask Sales for Joe.

Be sure to have your engine model number & serial number handy, in order to be able to get the right parts…unless you can verify the exact part number from the -34P…there are various fuel pumps available.