Fluctuating idle and stalling ck30 2005

[rcrcomputing]

This is probably a bit of a repeat of this thread by KiotiKevin. http://www.tractorbynet.com/forums/...uating-idle-stalling.html?highlight=idle+down

Symtoms are the same. Will start, rev up, maybe run for 5 minutes fine or 1 minute fine or 20 minutes fine. Then idle and rpms drop. It may even die, but probably not as long as I don't press the accelerator.

In looking at fuel starvation problems, I see two lines coming from the fuel tank.

Questions at the moment are:
How do I test the fuel pump.
Why are there two lines coming out?

I pulled each one separately, one that goes to the filter and the one that goes to whatever it goes to in the back.
When I started the engine, no gas comes from either line. I did not leave the tractor running like this in fear of the dreaded "run a deisel out of fuel issue".

Shouldn't gas come out?

In any event, I then took the line off that is on the right side of the filter, it does push gas out. Ok, then I put my finger on the filter side of this line and started the tractor. I was able to hold my finger on it, and when I let go gas spurted out quite a bit.

So what to do from here??

 

[rcrcomputing]

Opps, I forgot to mention, I did blow both the lines from the fuel tank back to the tank.

 

[ritcheyvs]

These are classic fuel starvation symptoms. The fuel system looks something like this:


The feed line from the tank is the one going to the filter. The other is a return line that sends excess fuel back to the tank. Some fuel leaks past the plungers in the injection pump and this is routed back to the tank. Also, when you bleed air from a new filter, the excess fuel is sent back to the tank. If you disconnect the hose from the tank to the feed pump, fuel should flow (slowly) by gravity (assuming the fuel level in the tank is higher than the open end of the hose). If it doesn't flow, I think you have a blockage in the tank or that hose. To check the feed pump you can insert a tee between the feed pump and the filter and use a gauge to measure the fuel pressure with the engine running. This should be a few PSI. You should also be able to measure a few PSI between the filter and the injection pump.

But before you go measuring any pressures, when was the last time you replaced the fuel filter? That's the first thing I would do. A single load of bad (silty or buggy) fuel can plug the filter. I have seen the silt settle when the engine is off but get sucked up and plug the filter media when the engine has run a bit. I have also seen this happen to the strainers that are commonly in the bottom of the fuel tank.

In case you don't know, there is a type of microbe that lives in Diesel tanks near the bottom of the fuel meets the water condensate that is always in the bottom of a tank. These microbes die and their bodies form a silt in the fuel which can plug a filter or do damage if it gets through the filter. If this happens you can usually see that the fuel is darker than the normal, almost clear, color of fresh fuel. This is mostly a problem in fuel that sits unused for a time, like over the winter. Biocide additives are available to prevent this microbe growth.

 

[oldpilgrim]

start simple.

Sounds like a plugged fuel cap vent. If air can't get in the tank to replace the fuel going out, the fuel won't go out. Take the 'gas' cap off and try running it and see if the same thing happens. If it does, clean out the vent hole in the cap.

 

[VictorW]

The delivery fuel line from the tank will go first to the lift pump which is mounted on the right side, towards the rear, of the engine block. This is a diaphram pump that only makes about 3-4 pounds of pressure. Just enough to push the fuel through the filter and to the injection pump. If you take the line from the lift pump to the fuel filter off and crank or start the tractor, you can stop the flow if you push your finger on it hard. With light pressure, fuel will spray. As mentioned, some members have had a fuel tank cap that stopped venting. Other checks are as ritcheyvs mentioned. My CK30hst is a 2004. I believe you have the same injection pump. These pumps didn't seem to have the problems that later models did starting around 2007 or 2008. Also, your fuel shut off solenoid should be fuel on with no power. It should only have power for about five seconds when you turn off the key. You probably won't hear it engage when the engine is first shut down but you should hear it click and re-open the fuel after the approximate five seconds when the timer turns off the power. So I think your problem is prior to the injection pump with starvation of fuel unless water got into the ignition switch, causing problems and possibly putting power to the fuel shut off solenoid. These switches are known to have gremlins appear when going bad and cause various problems.

 

[rcrcomputing]

Excellent, thank you!!!

I had already changed the fuel filter, but overlooked mentioning it.
So after carefully reading the reply's,

I took off the gas cap, it did not help, but I cleaned it up anyways.
I then, after looking at the diagram and reading over and over what I was being told,
removed the line from the gas tank to the fuel feed pump.
I had a trickle of fuel coming out. I then removed the gas cap and blew the line back to the tank.
This time, I head lot's of gurgling coming from the tank. (I'm on the right track now...
When I stopped, I got a full hose of fuel coming from the tank. YEAH!

I drove around while and the issue seems to be fixed!

Sooo, now I'm sure I have crap in my tank. How to resolve that?

Maybe let that hose drain the tank out?

 

[ritcheyvs]

Hopefully, someone who dealt with this problem can comment. Maybe a dealer on the list knows if there is a strainer inside the tank. By the way, is your tank metal or plastic? The reason I ask is that metal tanks can rust (there is always a bit of H2O at the bottom) and create a rust silt that can plug the bottom outlet.

There may be a strainer at the bottom of the tank, but I don't see a separate strainer on the parts diagram.

I once had a similar problem on a Diesel car but it had a large removable strainer at the bottom of the metal tank. In that case I removed the strainer (after draining fuel) and blasted it out with a pressure washer. The water and mucho crud came out the bottom. Then I dried it (for about 2 days) by blowing air through the tank with a shop vac.

In your case, I think removing the tank (so you can invert it) may be required. But before you do that, you can try draining out the crud and/or sucking it out (from the top) while agitating the liquid by blowing compressed air into the drain/feed hose. Diesel isn't very flammable but you still want to use an "explosion proof" pump to suck out the fuel/crud from the tank. A "topsider" style oil change pump would probably do the job. I would NOT use a shop vac to suck out the crud unless you have a death wish. All this assumes you can reach the bottom of the tank through the fill hole.

 

[VictorW]

I believe his tank is plastic like my CK30hst, 2004 model and there is no strainer or screen. Taking the tank out would be a pita, as it's between the engine and firewall.

 

[rcrcomputing]

I believe his tank is plastic like my CK30hst, 2004 model and there is no strainer or screen. Taking the tank out would be a pita, as it's between the engine and firewall.

I'll just drain it out the bottom and put a bit more in and do it again. Keeping things stirred up as I go.
As it was, I was able to get my work done the other day.

Thanks to you guys!
Thanks for the advice and the diagram.. I appreciate it!