430 Case skid Steer runs rough

[RFD]

My 430 Case skid steer runs fine on idle. When you give it fuel it starts spitting and smoking. If you back off fuel it clears and may run and may not. It is not burning any oil. This does not happen all the time. It has done this since it was new in 2006. Dealer kept saying there was nothing wrong. Sometimes when running and you put a load against it, it starts spitting and loses power. If air cleaner gets any dirt at all, it is really bad. If fuel tank is not clear full it is worse. Any suggestions?

 

[GaryHoff]

The most likely issue is a bad fuel lift pump, or a cracked plastic fuel line. The lift pumps are prone to failing. The plastic fuel lines crack, and will suck in air, this is tricky because fuel will not leak out. Also check your fuel cap. If the fuel cap cant breath, then you will also get fuel issues.

 

[RFD]

Thanks Gary I know it is now the fuel cap have checked it. I had thought about the pump but since it has been doing it since it was new I thought it would have gone out by now if it was bad. Have ran my hands down the fuel lines to try and see if they were cracked but couldn't feel anything. Guess I will have to do a little more than that to see if they are drawing air. I unplugged the fuel regulator box and it did the same thing. Dealer said he thought was the fuel advance. Of course that is around $3000 to fix if that is actually the problem. This thing has had me puzzled for years don't know where to go next except to trade but that is really expensive too thanks for any suggestions anyone might have

 

[bartelbe]

The fuel advance the dealer is referring to is called the ksb solenoid, if this is the culprit 95% of the time it would run great when cold, another easy test is when it starts to exhibit the problem jump 12v to the solenoid and see if the engine clears up. Also if anyone ever had the injection pump out and didnt correctly time the injection pump upon re installing then it would also give the same issues your having. You could also verify the timing is correct, Any decent tech should be able to check the timing of the injection pump in a couple hours. if memory serves non turbo was .95 and turbo was 1.27. There was also a pip that had the pump case pressure increased which involved having a authorized bosch tech come in and adjust the relief .

 

[Jeepwalker]

I wonder if there could be anything on the airside? Is it a turbo unit? If so, I wonder if there could be a leak (crack?) in any of the turbo pipes or connections? That can happen from time to time -- it screws up the air/fuel regulation, sucks air from the wrong place. If it is a turbo unit, I've check turbos on other rigs by removing the hose/pipe ends , blocking off with a PVC pipe caps and hose clamps ....and screw a spray paint gun regulator into one of the PVC caps so I could apply 10 psi on the system and listen for air leaks (I've found a few in the past, and at other times ruled out any turbo leaks).

Also as another thought, I don't know if your skid steer has a snow or bug screen on the air intake before or after the air filter, but I've seen them on other diesel rigs where there's a fine mesh screen in the intake pipe. They can become partially plugged up if a leaf or some bugs get in there. The added resistance can screw up the airflow. It's a bugger but the screens, when they exist, can be hidden and you'd never know they existed if ya didn't remove the air intake system and look into the air intake pipes. Not saying your Case has a screen, but just trying to throw out ideas if the fuel ideas others have thrown out don't fix things. Maybe others can chime in who know the machine a little better, or you could drop by your dealer and ask a mechanic.

Let us know what you find.

 

[GaryHoff]

As bartelbe suggested the ksb is not likely the issue. A failed ksb sender will cause the engine to smoke excessively (white smoke)
For the timing to be the issue, it would have to be very far out of time to cause a rough running condition, which is possible. Usually timing will just cause smoke. If the timing is too far retarded you will have low power. If after the other checks you suspect the timing is the issue, then you can rotate the pump towards the engine slightly. (Mark the pump position, and rotate it 1/16")
It may be the pump regulator, but that should have been checked/repaired while the machine had warranty.

Start with the easy things first.
The fuel lines generally crack near the fitting, and you may not visibly see the leak. You only need to replace the lines from the tank to the lift pump. Lift pump pressure should be 5-7psi even under engine load.

 

[mountainlake]

Also check both the intake and exhaust for any blockage, had mice build a nest in the intake pipe on my Volvo MCT125c . On my old M5 Moline I had the air cleaner off for a while and they stuffed the whole intake manifold full of acorns, it didn't rev up at all. Steve

 

[RFD]

We did as you suggested and jumped 12 volt to the solenoid. It cleared right up. Can you unscrew the ksb solenoid and replace it or do you have to replace the whole pump?

 

[bartelbe]

No the solenoid is not the issue , All the solenoid does is advances the injection pump timing. Once the engine temp reaches a certain temp power is taken away from the solenoid which then retards the timing. The dealership fix which i am well versed in is to remove the pump and send it to a authorized Bosch dealer to be gone through. But before this is done it is a good idea to check and possibly re-time the injection pump since i have seen some that come out of time most noticeably after installing since the pump shaft to driven gear a not keyed shaft fit and when torquing the nut that hold the tapered shaft to the gear the shaft can rotate out of time. It is critical that certain steps are followed when torquing down this nut and even then its a good idea to double check the timing afterwards. So with that i am sure your next question is going to be how to check the injection pump timing?. Well there a couple special tools needed, a dial indicator, intake valve compression tool and a extension adapter for the dial indicator. if you are not very familiar with injection pump and engine timing then this would be best left to someone that is. I would say your dealership should be able to do this fairly quick 2-4 hours but would depend on how knowledgeable the monkey working on it is.

 

[RFD]

Thanks for the help. Will call and set up to have timing checked. It looks to me like someone has moved the pump toward the engine already. There is a mark about 1/16th inch from where it currently is. It does run better when you remove the air cleaner. It is not perfect but is better. If it is the timing would it run fine part of the time? There is no one scenario that causes it to run rough, It is just random.

 

[thepumpguysc]

It sounds like a timing issue.. you've already proven it clears up when the ksb is energized. You basically moved the timing "manually"..
Its either just a timing issue OR the internal roller cage has grooved the main pump hsg. and the advance is sticking..
I've changed about 300 pump hsgs in the last few years due to the hsg being grooved..
It gets grooved from lack of lubrication from the fuel..

 

[bartelbe]

Most I have seen tend to exhibit rough running at high rpms when engine temp is at operating temp. When cold they run as should but this is due to the ksb affecting timing. So have em check timing spec I believe for non turbo'd is .95 mm at tdc and 1.27 mm at tdc for turbo'd . Also would be a good idea to check lift pump pressure for some reason 5-8 psi comes to mind and if there's excessive air bubbles in the feed line to the pump. As the pumpguy stated lack of fuel lubrication and air ingestion will take these pumps out .