CAV injection pump preventive maintenance

[johnnmr]

I suspect the metering valve stuck closed in a cav pump on a no start Ford 4000 3 cylinder diesel. I gently rattled the pump body with an air hammer and got something freed up again.

This worked for me this time, I am not recommending anyone else try this.

My question is what can be done to prevent this from happening again?

I read here a guy said to run a quart of atf per 5 gallons of fuel to add some lubrication. I did that since it's labor day weekend and all the local diesel shops are closed. Took a while to get the throttle response back but it finally freed up. Is there a better product that will add the extra lube needed to keep this from happening again?

This is an acreage tractor used to mow weeds in the summer and push snow in the winter. I'm afraid if it sits that metering valve will stick again if he doesn't use it til it snows.

 

[Dieseltech]

I prefer two cycle oil over atf. Don't use Bio diesel unless it runs EVERY DAY, keep the tank FULL to prevent condensation moisture/water in the fuel Is the best way to stop metering valve and/or rotor plungers from sticking. With the engine fully warmed up, set the hand throttle wide open, now QUICKLY pull the stop cable off and back on, this will move the metering valve to HOPEFULLY get it freed up smoothly again.

 

[johnnmr]

I prefer two cycle oil over atf. Don't use Bio diesel unless it runs EVERY DAY, keep the tank FULL to prevent condensation moisture/water in the fuel Is the best way to stop metering valve and/or rotor plungers from sticking. With the engine fully warmed up, set the hand throttle wide open, now QUICKLY pull the stop cable off and back on, this will move the metering valve to HOPEFULLY get it freed up smoothly again.

What does 2 cycle oil have that atf doesn't? I'm not a 2 stroke guy, I don't have any serious experience with them.

 

[MARK ROBKE]

What does 2 cycle oil have that atf doesn't? I'm not a 2 stroke guy, I don't have any serious experience with them.

My understanding is ATF has friction additives (tiny amounts of grit!) and 2 stroke oil does not. I always thought old dexron was ok, but new fluids are different. Engine oil may be better than ATF. Mark.

 

[DanielW]

What does 2 cycle oil have that atf doesn't? I'm not a 2 stroke guy, I don't have any serious experience with them.

I was always made to understand two stroke oil is made to burn up cleanly during combustion (what you want), while ATF and other heavier oils don't burn up as cleanly and can contribute to carbon build-up. No idea how much truth is in that, but I always put a dose of two-stroke oil in the gas or diesel of all my old engines. I know some folks will say it's a waste of time, but I figure a little extra lubricity never goes amiss.

 

[Fritz Maurer]

ATF does not have grit in it. Enough grit to overcome glazed clutch plates would never get through the valve body without seizing the valve spools. More than likely these friction modifiers are of some chemical composition... like the Ford additive for chattering wet brakes when cheap oil is used is a certain amount of phosphoric acid... the stuff is like $80 a gallon. Im not a chemist and I don't know exactly what takes place , but whatever it is, it works.

GM had a friction additive in the days of the TH400 / 350 to correct clutch shudder or squawk and it was widely used in Ford C6's for towing / heavy duty when they were in for overhaul.

 

[Texasmark]

When I was a boy I played in sand piles with vehicles, in particular 'Rock Buckets" as one city cop called them but officially classified as "Dump Trucks". When I retired from my day job I decided to have some fun and bought one of those and drove it for several years. It was an older cab over International with a 400hp Big Cam Cummins diesel. Engine had a million miles on it when purchased and have no idea as to what had been done during that time.

Every day I would fill up 2 100 gallon tanks and each got a quart of ATF. Never had a fuel problem.

I have been running diesels on my farm since about '82, currently running/working 7, 25 to 84 HP. I fill up at one convenient store that has guaranteed clean diesel. I use 3 ea 50 gallon drums in an old Chevy modified truck bed trailer to go back and forth to town. Every time I fill up they get the recommended dose of Power Services additives and each gets half a quart of ATF to make up for the ULS. Other than purchasing a tractor with a leaking pump that I couldn't find the leak and bought a new one, I have had zero fuel problems with my diesels over the years. If ATF hurts them my diesels are unaware that they are being hurt.

 

[MARK ROBKE]

I was always made to understand two stroke oil is made to burn up cleanly during combustion (what you want), while ATF and other heavier oils don't burn up as cleanly and can contribute to carbon build-up. No idea how much truth is in that, but I always put a dose of two-stroke oil in the gas or diesel of all my old engines. I know some folks will say it's a waste of time, but I figure a little extra lubricity never goes amiss.

That actually makes more sense. And thinking about it, what Fritz says is something I should know, about the friction modifiers in the oil. I think you could use engine oil for added lubricity also. Mark.

 

[Wdj]

I prefer two cycle oil over atf. Don't use Bio diesel unless it runs EVERY DAY, keep the tank FULL to prevent condensation moisture/water in the fuel Is the best way to stop metering valve and/or rotor plungers from sticking. With the engine fully warmed up, set the hand throttle wide open, now QUICKLY pull the stop cable off and back on, this will move the metering valve to HOPEFULLY get it freed up smoothly again.

Do you recommend the stop cable technique as a preventative measure or a fix? Or both?

 

[JIM MN]

Two Cycle oil does work. You need it since suppliers took the lubricant out of the diesel fuel! If the injector pump has a metering valve and manual cable shutoff, then get in the habit of pushing in the stop cable to the run position after the engine has stopped. That puts the metering valve back to the run position, ready for the next start. This works!

 

[Fritz Maurer]

Specifically, why two cycle oil and not motor oil?

 

[Destroked 450]

The metering valve in a CAV is lever stop and spring open for run
It’s often said that once the engine dies to push the stop lever back in to help prevent the metering valve from sticking in the off position

 

[sotxbill]

I suspect the metering valve stuck closed in a cav pump on a no start Ford 4000 3 cylinder diesel. I gently rattled the pump body with an air hammer and got something freed up again.

This worked for me this time, I am not recommending anyone else try this.

My question is what can be done to prevent this from happening again?

I read here a guy said to run a quart of atf per 5 gallons of fuel to add some lubrication. I did that since it's labor day weekend and all the local diesel shops are closed. Took a while to get the throttle response back but it finally freed up. Is there a better product that will add the extra lube needed to keep this from happening again?

This is an acreage tractor used to mow weeds in the summer and push snow in the winter. I'm afraid if it sits that metering valve will stick again if he doesn't use it til it snows.

ALWAYS push the stop cable back in as you remove the key!!!!!!! to stop this from happening in the future.

 

[Ultradog MN]

Agree with Destroked 450 and Sotxbill.
Make it a firm habit to push the stop cable back in whenever you shut down.

 

[Fritz Maurer]

That seemed like a good idea at first, but if it's gonna stick, it's gonna stick. I think id rather have it stuck shut than have an uncontrollable runaway.

 

[Texasmark]

The metering valve in a CAV is lever stop and spring open for run
It’s often said that once the engine dies to push the stop lever back in to help prevent the metering valve from sticking in the off position

Not sure where I picked up this information but decades ago I read that when you shut off a Ford (was reading somewhere in that brand) leave the "kill" lever in the kill position. Said something about how the pump can fail if you kill the engine and then push the stop lever back in. So I have always done that and I guess it is a good idea.

Edit: Well reading more of this post I guess you guys have told us the "why"! On CAV pumps, I don't know how many other mfgrs. use them. I know some Fords have Simms inline pumps. Wonder if they have the same concern? All the Fords (numerous) I've had over the decades had the CAV.

 

[Destroked 450]

Metering valve doesn’t cause a runaway and I’ve never heard of one sticking open in the run position because the stop linkage mechanically closes it, the issue is that when held in the closed position for extended periods of time they can stick enough that the little spring can’t pull it back open
The only issue with pushing the stop lever back in is if parked on a grade in a high enough gear , there is a possibility it could compression roll and fire back up resulting in a runaway tractor
Setting the parking brake and insuring the transmission is shifted into a lower gear will prevent such an event

 

[Fritz Maurer]

Even if that were the case, once the governor forces a sticky valve closed, the motor is still dead because it's no going to open again. So whether or not the stop cable is pushed in is pretty much a moot point. Would be better to solve the problem since there is a significant number of pumps with ESO's, which hold the valve closed when no power is supplied.

 

[TomA in CA]

I have always used non detergent 30w motor oil as an additive for diesel when I can find it.

 

[Non-farmer]

I have always used non detergent 30w motor oil as an additive for diesel when I can find it.

TSC has it for $4.79/quart. They used to have it in 5 gallon too, but I can't find the pails on their website now.