Power loss under load..

[2TonCommon]

Greeting all.... I need your help. I've got a Mahindra 2816 HST with 200 HRS on it that just can't seem to stay in the power band under load. I've changed the fuel filters twice, bled the air both at the fuel filter and at the injector banjo-fitting (also twice), installed a new OEM air filter, drained the fuel tank and blew it out w/ dry, compressed air and have religiously followed all the other Mahindra maintenance requirements.

Despite all of that, when I go to re-grade my driveway with a box scraper (about a 10% grade) I'll be at 3000 RPM in low range (and 4WD but not w/ the rear diff locked) with the box less than 1/2 full, headed up hill and about 1/3 of the way up, the engine will suddenly lose power and the RPM's will drop to between 1800 and 2000. If I raise the 3 point and let go of the gravel the RPM's will go even lower yet for a few seconds while the hydraulic pump works, then the engine will come back up to full RPM. I realize the first thought is that I'm overloading the engine and causing the problem myself. However, last year this tractor had absolutely no problem tackling the same situation as above and the box scraper was overflowing with wet gravel. So I KNOW this tractor can do what I'm asking of it.

This sudden drop in power also happens on occasion when I'm in medium or high range and try to go full throttle..... it will bog, drop RPM's then recover. I've worked on gasoline vehicles for over 45 years but have very limited experience w/ diesels. My gut is telling me this is a fuel starvation problem but I honestly don't know how to go about figuring out which component is the bad-actor. Any help or insight will be appreciated.

 

[TnAndy]

I think your gut is right. Fuel starvation.

My Yanmar came with plastic drill shavings in the tank that would float around and block the fuel outlet causing nearly the same thing.

Since you've already cleaned the tank, you can 'probably' eliminate that as an issue.....so look elsewhere.

Is the tank cap vented ? Could it be on so tight you're getting a vacuum in the tank ?

IF have a plastic fuel filter housing, and can see it when this happens, see if it looks like it is trying to cave inward ( Mine did.....that was the give away to look at the tank ) as the pump sucks fuel.

Also, IF you have a booster pump ( you should hear it run when you turn the key to the "on" position, but engine not running ), make DANG sure to check and see if there is a filter in it. I have a Mitsubishi dozer that suffered the same problem....changing main filter did nothing. Finally got to reading the parts book and found an "element" in the back of that little booster pump. The back of the pump housing twists off, and there is a filter about the diameter of a 50cent pc, about 1 1/2" tall that gets the crud from the tank FIRST, and when it's blocked up, RPM goes to pot when you load up the engine.

AND the booster pump may not be working either ( I just looked online for a parts breakdown http://www.duntonfarms.com/tractors/Mahindra_2816/2816_parts.pdf and it does appear you have a booster pump. )

Look for all the simple stuff first.. and that is most likely the problem......barring that, you may have injector pump problem or a governor problem.

 

[DarkBlack]

Fuel restriction. Somewhere something is being sucked in the way during high fuel usage.

 

[jjlite]

I am having he same problem . Found what looks to be plastic drill shavings in the top of the fuel filter and in the line coming from the tank. I drained the tank and changed filter blew out feed line. Worked good for a while but I must not have got all of it Looks like I will be pulling the tank out to clean.

 

[kneedeep]

Suggestion-
Drain fuel out of tank as much as possible and rig up a rigid tube on a shop vac and suck the debris out of the tank

May work :confused3:

 

[foreman Etexas]

I was having same issue with my tractor and it ended up being a small piece of plastic that came off a plastic fuel can nozzle from filling. Mine was an easy fix at the filter,pulled a screw out of the housing to get to it. http://partstream.arinet.com/Image?.../www.hartleyenterprisesllc.com/pages/OemParts , my guess on yours will have to pull 2/3/4/5 out and it will be in there. Make sure line back up the same way took out so your fuel cut off will work right.

 

[LAWALLSTRACTOR]

Don't ask me how, but I have had 2 2615s that I found a restriction in the fuel line between the fuel pump and the banjo at the injection pump. I just disconnected it at both ends and blew it out. Quite a bit of black crap came out and it solved the problem. Just how it got there after the filter, I don't know. I would give it a try.

 

[RalphVa]

Had it happen on my JD 4010 one winter. Turned out to be globs of wax mostly blocking the outlet line from the fuel tank. Had to siphon off the fuel and then use a fish tool to get the globs out.

Wax will drop out of ULSD if the winter nights get below 10 F.

Ralph

 

[2TonCommon]

Thank you all for the very good ideas and suggestions. I will take a turn on these over the next few days and report back any success.

 

[Tkblacktail]

I don't have a large fuel-supply tank set up (just yet),

I'm still using two new 5 gallon yellow fuel containers to refill the tractor tank (the .30/gallon HWY tax really hurts too).

The point: I was digging little flakes of plastic from my 3016 water separator/filter and traced them back to the yellow fuel containers; they had a lot of left-over plastic molding flakes in them. You may look inside the plastic and not see them but they are dangling on the seams like the leaves on a sweet-gum tree....:mur:

I also ran the fuel I had through screens and cloth filters several times before going into the tractor; can't trust what comes out of the commercial pumps because we citizens here in Oregon, cannot be trusted to fill our own fuel tanks at those retail pumps.

 

[2TonCommon]

Quick update: After much diagnosis, all indications are that the electric fuel pump is the bad actor. I blew out the supply lines between the output side of the pump and the banjo-fitting at the injector group, then reconnected the hose to the pump only and when powered up, the fuel pump sputtered, snorted and belched mostly air and very little fuel for about 3 minutes. My guess it's a broken diaphragm inside the pump.
The Mahindra dealer has agreed to test it to see if it meets spec for output volume and pressure and to replace it under warranty of it doesn't. It went out in the mail to him today. I'll keep y'all updated until this is resolved in case someone else has the same problem.

 

[2TonCommon]

Problem solved! Well, I'm embarrassed to admit it, but to save someone else the grief of figuring this out the hard way..... here's what I learned. Yes, this was a fuel starvation problem. And during my search for the culprit, I noted in my maintenance log that my fuel filter only had 5 hours on it..... so I kept telling myself that just couldn't be the problem. After the dealer informed me the fuel pump was just fine, I hooked it back into the system and then decided "what the heck, let's change the fuel filter while we're here." Lo and behold, all my issues with trying to evacuate the air from the system, the sputtering of fuel from the tank, through the pump and up to the banjo fitting all went away. The tractor runs like a champ now. The moral to this story is even if you've changed the fuel filter within a few running hours but you notice a performance problem..... start your problem-solving journey by replacing the filter again and keep 2 or 3 on hand. I didn't realize these engines were so 'touchy' when it came to any reduction in fuel flow, but I do now!

 

[mguitas]

So what was the problem with the 5 hour filter that you could see. Dirty.

 

[MarkF48]

Did you perhaps have a cold snap that gelled the fuel and plugged up the filter. This happened to me during one of our cold spells that I had to attempted to remove snow and had power loss to the point of a stall. Put additive in now.

 

[2TonCommon]

So what was the problem with the 5 hour filter that you could see. Dirty.

There was no outward sign that the filter was clogged. No dirt or water that I could see either in the bowl or on the filter. That's why I was actually so surprised when the darn thing started moving fuel in a steady stream. Bottom line, filters are cheap.... so from now on if I have any fuel performance issues, that's the first thing that will get changed out regardless of how short of a period it's been in service.

 

[2TonCommon]

Did you perhaps have a cold snap that gelled the fuel and plugged up the filter. This happened to me during one of our cold spells that I had to attempted to remove snow and had power loss to the point of a stall. Put additive in now.

Mark: Good advice and I always use a high quality fuel additive. We did have a cold snap and you may be on to something with the gel-up. That would explain why I could not see any obvious signs of blockage like dirt or water. I will look to see if there's a quality fuel additive that addresses the potential for gelling. Thanks again.

 

[robbieo11]

Ya i gelled her with and with out additive

 

[mguitas]

There was no outward sign that the filter was clogged. No dirt or water that I could see either in the bowl or on the filter. That's why I was actually so surprised when the darn thing started moving fuel in a steady stream. Bottom line, filters are cheap.... so from now on if I have any fuel performance issues, that's the first thing that will get changed out regardless of how short of a period it's been in service.

Someone on the massey forum just had a problem with starting, the massey gc2600 needed a filter change also. They check everything but that.