Time to defeat my FSS?

Ferdy Mint

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I'm tired of that little sucker failing on me. I've already replaced it twice on our 1986 Bullnose 6.9 since I bought it in 2017. This last time I lost points bigtime with my wife, who was stranded under a railroad bridge on a little country road, barely any cell service. Of course she was armed, as always. This is Texas. I had to go pull her home on a tow rope. But as you married guys know, the FSS incident is my fault.

I can hear the electric pump start up but the FSS is not clicking with the key anymore, so I'm pretty sure the FSS is inop. Again. Unless you have an automatic tranny, I just don't see the value the FSS brings. If you want to shut off the motor, put the tranny in 4th and let out the clutch. Just like my old IH or Fendt tractors. Stall it out, problem solved.

Anyway, as a debugging measure I'm going out there now to wire it open, safety wire or wire tie etc. If she fires right up, maybe I'll drill and tap a hole in the top case for a screw that goes down from the top and holds the critter open. We run electric lift pumps on our IDIs, so fuel will probably seep out by the threads. Maybe some fuel resistant silicone would help. The fuel level in the 100g bed tank when it's full is higher than the FSS so it would sit there and seep out 20 gallons or so. Oh joy. Bite'm special agent armed EPA fedboyz might come shoot our dogs.

These Stanadyne IPs have been around since Moses and on most tractors they had a manual fuel shutoff with a cable link to the dash, where you pull it to kill the motor. I looked around the web to find one that fits the IDI but doesn't leak diesel if used with a lift pump. So far no luck. Anybody seen that?
 

Farmer Rock

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You absolutely need some kind of shutoff from the cab.
If something stupid happens like your clutch goes out, you're gonna have to start ripping off fuel lines. Just sounds like a recipe for disaster.
And not that an fss is going to stop a runaway, but I can definitely see the chances of a runaway increasing if you can't kill it immediately.
It's not hard to change out the fss, the biggy is keeping steady voltage to them.
Leaving the ignition on kills them.
But I too prefer a mechanical shotoff.
Check out an intake valve for oilfields.



Rock
 

Ferdy Mint

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Once I had to choke out a 6.0 that was running away with turbo oil. Just stuffed my fist in the intake then a rag with my other hand. Skinned my knuckles, hurt a bit but saved the customer's motor.

So .... Yes, I would like to have a cable shutoff in the cab. Blocking off air from inside the cab would be much harder. Like I said, these Stanadyne pumps are old as sin so there must be something I can adapt here. I bet some old timer here knows what to do.

>Check out an intake valve for oilfields.

What's that?
 

Farmer Rock

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This one's a pacbrake brand just to give an example.
You must be registered for see images attach

The simplest way to do this though, would be to make your own kill cable.
All it has to do is push the metering valve.


Rock
 

Ferdy Mint

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That looks like the perfect solution. Thank you, I had no idea such a device existed. I'd place it right at the snout mouth of the metal air filter housing, which won't collapse under vacuum. I think I'll put this on all three of our IDIs instead of replacing the FSS again. Just like electric choke pull-offs on a gasser carb, I don't like any device that sits there and consumes 12v all the time the ignition is on. Sooner or later it's going to give up the ghost, overheated by its own coil. It's usually a dumb bandaid smog control idea that was never fully thought thru for durability. Fuel bowl heaters on PSD, intake air heaters, I remove them all.

But I'm ranting again.

As a bonus the air valve you recommend will also prevent runaway, once I get around to converting IDI to TIDI. Maybe you've seen my other threads on that, where I'm still collecting parts to build a TIDI from a cavitation-holed 7.3 IDI block plus moving parts from a freeze-damaged TIDI block...that only had 7 good pistons/rods in it. I'm just about to give up on ever finding another good TIDI rod, and buy a set of those nifty machined PSD rods instead from R&D Diesel. Finding pistons is a lot easier than finding rods. The R&D website says they are finally open for business after their big move from Commieforegonington to Wyoming. Been there, love it, and Montana. But we settled in Texas because winters are not so harsh. Usually.
 

Ferdy Mint

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The simplest way to do this though, would be to make your own kill cable.

All it has to do is push the metering valve.


Rock

I've seen teardowns of Stanadyne pumps on themtube, but only remember seeing the throttle valve. Is that what you call the metering valve?

Or do you mean the lever that shuts off fuel, sitting under the FSS cap? That was my original idea, to put a cable on that. But given we run electric lift pumps, I'd need to seal up whatever cable reaches in there, to resist the 10 psi lift pump pressure in the cavity there.
 

Black dawg

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Anybody else have ANY failures of FSS?

Over the course of owning, driving, working on these, I have seen one fail.....

I do like the idea of a manual FSS, but the electric one has been a non issue.
 

Nero

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I've had three idi's over the years. Not once have I had one failed. I have a good friend of mine who worked at a Ford truck dealer for years. Said he only replaced a couple out of all the Idi's he's ever worked on. Why reinvent the wheel? Constant 12v is normal and you shouldn't be too worried about it. Just my 2¢
 

Farmer Rock

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I've seen teardowns of Stanadyne pumps on themtube, but only remember seeing the throttle valve. Is that what you call the metering valve?

Or do you mean the lever that shuts off fuel, sitting under the FSS cap? That was my original idea, to put a cable on that. But given we run electric lift pumps, I'd need to seal up whatever cable reaches in there, to resist the 10 psi lift pump pressure in the cavity there.
The valve right under the IP top cover.
Why are you running 10psi? That's over twice a stock lift pump.
I don't know what all you have done to the engine as far as timing and mods, but that's gonna mess up your timing a bit.

Like I said before, the only reason for premature failure, is leaving the ignition on while the engine ain't running.


Rock
 

Nero

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Ignition on while engine off could definitely cause it to fail. Solenoid gets hot, and no fuel movement to cool it.

What is stock lift pump pressure? I thought it was 4-7psi?
 

Ferdy Mint

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By stock lift pump you must mean the mechanical one that runs off a camshaft lobe. I don't know its pressure but on gassers they're usually around 7 psi and fail often. I don't much like them.

My mistake, actually I gave that 12-15 psi Facet pump to my son @Minty Ferd for his 7.3 because he read on oilburners that 14 psi will be better for his turbo setup (still in his head so far). The other two IDIs are running a 9-11 psi Facet lift pump.

Injection timing is advanced a bit on this motor. The PO did that and I've left it, don't have that nifty little timing tool, but a local mechanic nearby does if I needed to check it.
 

Ferdy Mint

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I just found this in my files from a few years ago. I got this here or on FTE, but the guy didn't know where I could buy one. This would work fine to shut off fuel. But that air vane shut off is even better because it will stop runaways too.
 

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Ferdy Mint

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Like I said before, the only reason for premature failure, is leaving the ignition on while the engine ain't running.

My wife forgets everything and drives this 6.9 often. She likes it. So yeah, you can bet she left the ignition key on forever. And she'll do it again.

Our daughter is a lot more mechanically minded. But then I had her changing brake pads and stuff like that with me when she was 5 ... She built this Bully up from a no-crank roller and flipped it for good cash. PO had the firing order 180 off, burnt up the starter trying anyway, then just gave up and sold it for $600, SMH. It was a 351W so a gas hog. Sons and I helped her of course, but she did a lot of the dirty work under it.
 

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hacked89

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The valve right under the IP top cover.
Why are you running 10psi? That's over twice a stock lift pump.
I don't know what all you have done to the engine as far as timing and mods, but that's gonna mess up your timing a bit.

Like I said before, the only reason for premature failure, is leaving the ignition on while the engine ain't running.


Rock
I’m running 10psi to inlet and I’m having IP funkiness that I don’t know if it’s caused by it or not. Ive watched and read plenty on a rotary injection pump design but my understanding originally was that this would just affect the dimensions of the hydraulic advance curve. I am told today by a pump builder that inlet psi exponentially affects transfer pressure. What does that mean to me? I don’t know right now. You can read books all day but nothing beats hands on experience. I have extra IPs Im going to have to take one apart piece by piece.
 

Ferdy Mint

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The guys at Classic Diesel Design in San Anton TX live and breath them IPs. They have a 250cc version for sale! For reference, 238cc is good for over 1000hp in a 7.3 PSD.

I bet they could answer your question. But ifn you was to ask me, I would call on my vast and deep experience from watching several themtube videos about Stanadyne IPs. I could be a CNN commentater like Brain Stelter with all that knowledge. I'd bet that all higher inlet pressure will do is raise output pressure at the injector. Unless you're seeing a lot of smoke, probably no problem. But that is just my hunch.

Now if as you say it affects the advance curve, I haven't any info on that. But for the PO of my 6.9 - who is a heavy diesel mechanic all day long - warned me that some folks get scared about advancing the timing but in his experience a little advance is harmless and gets better fuel mileage. So he did it to my truck and I never changed that.

An exponential increase in transfer pressure? I wish I knew more. What IP funkiness do you have? Some say IPs should be rebuilt every 100k when you do injectors. We go more like 200 or more.
 
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