SOLVED! Mule 4010 Fuel Injection Idle problems - running rich
 

After a year of my 2010 Mule idling terrible and engine dying when I let off the pedal at idle, I finally got serious about fixing the problem.

I read many posts on this and nothing suggested seemed to work.

Repair attempts:

1. Valve adjustment - I read that intake valves could tighten up a bit and cause pressure sensor to misread tricking the system to add fuel at idle causing the rich condition. I adjusted the valves and did find a tight intake valve and loose exhaust valves - but this did not affect idle problems.
2. Spark plug replacement - no change (they were completely black with carbon - but it still ran pretty good).
3. Fuel pump check - remove fuel line from fuel rail and place end into a measuring cup and turn key to "on" and check how much volume you get. Should be more than 1.7 oz. Mine was fine.
4. Fuel injector leaking check - Pulled the injectors and fuel rail, held it all together tightly by hand while assistant turned key to "on". No fuel leaking from injectors. Cranked engine and observed nice spray pattern onto a rag.
5. Throttle body clean - via spraying an entire can of cleaner directly into the throttle body while assistant has accelerator to the floor - seemed to work for 60 seconds and then back to terrible idling and engine died.
6. Last effort before taking it to the dealer: Removed throttle body (PITA), throttle body appeared brand-new inside maybe due to the throttle body cleaning step in #5 above. What I did different was open the electronic servo controlled throttle blade using my finger: full open and full close back and forth - sprayed shaft bearing area with WD40. While fully closed, and with all electrical connections hooked up: have assistant turn key to "on" position and watch the throttle blade - you should see it open slightly. If so - good to go. Put it all back together and start it up. SUCCESS (for me)

Mine idles like new and starts easy.

This is what worked for me. I also read about air temp sensor, but that wasn't my problem.

Thanks for the informative post. Glad that you are back up and running.

2012 mule 4010 idle problem
 

hey, i got a 2012 mule 4010 and when i got it back from the dealer for first service it started idling rough. it got progressively worse over time. i read your post and decided to try what you did before taking it back to the dealer again, cleaning the throttle body was what they were going to do anyway. it worked!!, and it's back to running as smooth as the day i got it. next thing I'll do, and i don't know if it will prevent it in the future, is to run pure gas no ethanol mix in it. thanks for posting you solution it kept me and the mule from being separated for three or four days, don't know if i would have survived!

2012 erratic idle on my kawasaki mule
 

:confused:My mule was running fine until I replaced the fuel pump and then the idle became erratic. When I first crank it idles slow but the rpm goes up and down like it wants to die. I reave the engine and let off and it runs idles perfect but when I drive off no matter how fast or slow when I stop the idle is slow again and acts like it wants to die and while stopped I can reave it up and let off and it will run perfect again. Any suggestions on what may be going on? All advice is appreciated. :confused:

I also have a 2012 Mule that wasn't idling well. I printed off this thread and gave it to a local mechanic but asked him to first check the fuel pump as I discovered bugs in the fuel filter housing on the bottom of the fuel pump. After testing the fuel pressure (which was fine), he noted that there was fuel in the oil - from running rich.

He removed the throttle body (as suggested here), sprayed carb cleaner on both throttle blades, manipulated both blades and re-installed.

Idles like it's new. As an aside, I only use ethanol-free gasoline so I can't blame ethanol.

You guys saved me alot of cash by posting your solution - thank you so much.

John

pictures man we need pictures ,, lol

No pictures but I do have a video of the repair work...Not sure how to attach it? Edit: The site has a 5 MB limit on file size - my movie is 300 MB.

In any event, this whole issue has become moot from my perspective:

I found that this "cleaning" of the throttle body, while temporarily effective, would last about 6-8 weeks...and then I'd have to do it again. One day, while at my Kawasaki dealer picking up an oil filter, I asked the service manager "What solvent do you recommend for my bi-monthly throttle body cleaning?"

He replied "Why on earth are you cleaning your throttle body every 2 months?". When I explained the issue, he said "There is a RECALL on the throttle body. Bring it in and we'll install a new one...no charge".

When asked why didn't I get a letter on this recall, he responded "Not everyone had problems".

I got a new throttle body and intake and all it cost me was gas money.

My final question was why this problem had happened. He replied "The routing of the crankcase vapors into the throttle body gummed everything up".

So...my advice...if you are having problems, call your dealer about the recall. If not having problems (yet), unplug the crankcase vent hose from the side of the throttle body and plug the exposed port. Just let the crankcase vent to the atmosphere.

thanks buddy !!! yesterday I got off in it ,, changed the little fuel tank filter and then just took the intake tube off just aft of the airfilter and revved the motor to full throttle and sprayed gumout till it would almost die then let it come back up to rpm and do it again after about a half a can she was running good ,, but i'll chk out the recall and plug that vent tube ,, thanks for the help mate
bobby allison !!

I just purchased a used 2009 Mule 4010 and it has the same idling problem. Does anyone know if there is a recall on throttle body for 2009 Mule 4010?

If your question is whether the recall covers a 2009, can't answer....but a dealer can.

I was told that my repair work would have cost $1,700 if not covered by the recall. So be persistent.

Ah...your question is whether it covers a 2009. Can't answer that but a dealer can.

Thank you Snakebit.. I will check it out..

Great thread. I have had this same issue for the past year on my 4010. It is a 2010 model but has only 990 hrs. I have submitted a question online to the selling dealership as to its eligibility for free repair. I am hesitant to take any of my units (I have 3) to the local dealerships having nothing but bad repair experiences at both that are local to me (Austin TX area). Anyone have any suggestions as to where a Kawasaki product can be dependably serviced? I've thought about just buying the service manuals and taking the units to my local (very dependable) auto repair shop and let them work on them? I wish they were still building the 1998 mules (yes carburated) but VERY dependable. My old 'dependable', while small, is a real workhorse. And for those wondering why I'm not doing the repairs myself? Old age and agility have taken their toll.

I had same rough idle develop with my 2011 4010 with only 250 hours. Repeatedly cleaning the TB was a temporary and unreliable fix. Dealer fixed under extended service (two trips) , then it got rough again about 100 hours later. Like many I was fed up with the fuel injection design. Then I realized that cleaning the throttle body was treating the symptom and not the cause. Inspecting the TB revealed that there are only three things going into it, filtered air, fuel and vapors from the crankcase (EGR). Another forum suggested disconnecting the EGR completely, after the frustration I'd gone through it seem worth a try.
I cleaned TB again and disconnected/plugged EGR tube from the TB. Results were not immediate, but got progressively better and now runs great! 150 hours later it is still running smoothly. To "rhaus" i would say this is a very simplistic repair, 10 mm wrench, socket, carb cleaner and a shop towel to plug the holes. Truly a low skill, low effort repair. 20 minutes tops. (don't remove TB, just loosen it enough to access both ends. spray carb cleaner and wipe with towel or toothbrush)
Good luck.

Engine Perkins 403C -11 bolt up to a Kawasaki mule 4010 with a three cylinder diese
 

4010 Throttle Body repair - FREE
 

A BIG thank you to 'Snakebit' for the hint. I took my 2011 4010 to the dealer and had them verify that the problem that I was having was due to the throttle body issue discussed in the forum.Two weeks later (the first parts that were ordered were for a California model and had to be reordered) I have the mule back and it runs like new. And the repair cost, including new plugs, $0.00. Can't beat that!

That's what forums like this are for...glad to be able to help.

2012 Kawasaki mule 4010 throttle body
 

So I finally bit the dust and disconnected the crankcase breather tube on the ol' mule. It started running better almost immediately. It got better the longer it ran and I didn't even clean the throttle body. By the way I did check with the local dealership where I bought it from, they ran the vin number and came up with no recall on the 2012 model throttle body. So here's where I'm at, I routed the breather tube back around behind the fuel rail shortened it so that it turned downwards so I didn't get any water in the crankcase when I washed the engine or drove it thru a large puddle. Now comes the problem, after driving it full throttle down the road the breather tube started to blow oil onto the engine block. So now I'm back to the drawing board, there has got to be a better way to vent the crankcase than back thru the throttle body gumming up the butterfly valves. I thought about going to the local auto parts store and trying to find an old style breather cap that would go over the end of the hose and routing the tube to a different location. Anybody got any ideals? I tried to attach a picture of the current setup but it didn't work. As many people on the forum here with the same problem i figured maybe someone has come up with something I haven't thought of yet.

2012 Kawasaki mule 4010 throttle body
 

Ok, I learned something new. The pictures I uploaded can be viewed by going to the three bars in the upper left of screen click on them and select gallery.

locorob, I am in the exact same boat... No recall on 2012, disconnected breather, seems to help but I don't think the blow by gasses vent without the vacuum from the intake. With the crankcase breather disconnected from the intake and the engine running it feels like there is vacuum on the breather tube. I just left it disconnected anyway, but now I am getting fuel in my oil so I am going to try a catch can. It should allow the vacuum from the intake to draw the blow by gas out of the crankcase, but allow the gasses to condense in the catch can instead of gumming up the throttle body.
Anyone have any experience with catch cans, or advise regarding this application?

I am not sure that this is helpful but...

Before I discovered the recall, I disconnected the breather tube, inserted a cheap cloth filter in the open tube opening and taped it facing downward to the frame. I effectively vented the crankcase to the atmosphere (albeit with a filter to minimize my guilty feelings). I plugged the open hole in the throttle body with a rubber radiator plug. I ran this way for a few months without any issues before I had the throttle body replaced. I did wash out the filter a time or two.

Cannot speak to the vacuum issue but can say that I was getting fuel in the oil in the original configuration of routing the crankcase vapors into the throttle body. What a terrible engineering design.

2012 Kawasaki mule 4010 throttle body
 

First off, thanks for the responses. I posted pictures in the gallery on my second attempt. I went to O'Reilly 's auto parts and gathered my supplies. I got three feet of 3/8" i.d. Hose, should have been half inch cause it would not go over the nipple on the crankcase so I had to use a short piece of the original hose with a 3/8'' barbed nipple to connect the two. I then routed the hose along the roll cage bar to the left side where I turned it upwards a bit so any oil that entered the breather tube could drain back into the crankcase. On the end of the hose i bought a breather cap from O'Reilly. It's part number elderbrock 43510. It takes another 3/8'' barbed nipple to connect to the hose.

I like the idea that OIIIO suggested with the catch can it would look more professional. I did notice after i started the engine vapors were coming out of the breather cap so i know its venting crankcase pressure without vacuum. My only concern in venting crankcase fumes back into the throttle body by any means is going to lead back to the original problem of the engine running to rich again. Thats just my thought. OIIIO, let me know if you have any luck with the catch can setup. As far as gas in the oil i haven't experienced that yet but I'll keep an eye on it, thanks.

I agree snakebit12 it was a poor design on kawasaki's part.

11/20/2018
I posted an update on this topic but it said it had to be reviewed by (a)the moderator before it could be viewed. Maybe it will show up eventually. It didn't turn out well.

01/25/2019
Update on my mule. I followed snakebit 's advice and took it to the dealer. They contacted Kawasaki and they agreed to pay for the new breather kit and throttle body. I was out the charge for adjusting the valves. Bumped the compression up from the low 190's to 200 psi. Cost was $110 and a month without the mule. Been driving the fool out of it since and it still runs as good as new. Thanks snakebit12!

2013 4010 Mule idle problems
 

I have had the same problem with mine. Carried it to dealer three time for it only to not last very long before the idle starts increasing and running rough. When it does this and in Low it is hard to go back to neutral and soot in exhaust pipe . The TB and vent line was upgraded the first trip to dealer. They suggested running a fuel additive but with no cure. I am going to try the disconnecting the crankcase hose and running it to the outside of engine. Thanks for all the insight.

I did exactly this disconnect the vent hose , and it runs great , I
 

I tried this fix and it did not work.
I thought this was the issue too, so I got some rubber fuel line and ran the hose off of the crankcase port and connected an in line PCV valve to it so that crank case presser could escape, but it would not allow outside air to enter if no pressure was being released. Plugged the connection port on the throttle body pipe.
It might have bought me an extra week, before having to clean it again.
Not the fix I was hoping for.

As a follow-up on my situation...

Following 4-5 years to trouble-free operation after the TB/Breather replacement, I recently took my 4010 in to address another (supposedly unrelated) issue.

The engine would start and idle all day long. However, it would consistently die when you took your foot off the gas...especially on a hill. I suspected the fuel pump.

When I brought it in, my dealer told me that the TB/Breather was "treating the symptom" but not the cause. Not entirely sure about that as routing crankcase vapors into a sensitive TB seemed like a pretty bad idea to me. Anyway, he stated that Kawasaki has continued to have problems with these engines and that the real "culprit" was the ECM module which was causing my current issues.

Like with the TB & Breather, he replaced the ECM free of charge and the Mule is once again running like a top.

We love our 4010 Trans and consider it the most valuable piece of equipment on our 100-acre farm. The ability to fold down the 2nd bench seat to increase bed capacity isn't something that I can recall seeing anywhere else. And my dealer has certainly taken good care of me.

But I do find these engineering issues concerning... and would probably at least consider other manufacturers if we ever decided to expand the fleet.

Interesting to know, thanks for the update.

so you took a 12 year old mule to dealer and they fixed for free?

I am interested, also. I had a '88 Mustang that the Ford dealership repainted for free do to a recall, may be the case here.

My mule is a 2012 (earlier typo) so it is technically 10 yo.

But, yes, the dealer (Valley Kawasaki in Harrisonburg VA) installed a new TB in 2014 and a new ECM this spring at no charge.

Long Term Solution
 

I have a 2014 Mule 4010 with approximately 900 hours that I use most every day. After a couple of hundred hours, it didn’t idle very well and would often die when starting off. I read about cleaning the throttle body, and that helped for awhile. I change the oil every 100 hours, so my routine came to include removing and cleaning the throttle body every time. Then , I read about Seafoam fixing the problem. Started adding an ounce per gallon every time that I added fuel, and that has solved the problem for the last 300 hours, or so. No more throttle body cleaning!!!

Good Stuff
 

I had a Porsche that I bought used with 20,000 miles cheaply, I found out why when on about the third fill-up, it began to lose power. I spent close to 4 grand on repairs, after 3 tanks same problem. And repeat. I finally had an old mechanic tell me to use Seafoam. Fixed it, been using it ever since, I buy it by the case! GREAT STUFF!

Kawasaki checked my Vin number, no recall for my unit. 2 area dealer would do nothing.
Problem was in the throttle body cross shaft.
I got tired of pulling my throttle body apart and cleaning/lubing the butterfly shaft. As time went on, it was shorter time between cleaning. Got to where it was less than 10 hrs between cleaning. I suppose I could have drilled out the shaft holes and fitted/installed some brass bushing, but decided to replace the throttle body with an updated version.
Warning! this part is very expensive.