Off topic but still a Ford IDI

[jaluhn83]

Got an issue with a Ford 3500 tractor I'm rebuilding and wanted to get some thoughts. I know this is off topic but this seems the best place to get info. Mods, I'll delete this in a few days or move it.

The tractor is a 3 cylinder IDI ford motor, 172 CI with a inline injection pump (Simms Minimec) I bought it as a basket case with the head off and significant rust in the bores. Seems the head was pulled about 10 years ago and then owner deployed and while he was gone the cover blew off and it got rained on. Wound up needing sleeves in all 3 cylinders. The injection pump also looked like it was exposed to water. Injectors had some rust but mostly surface. I've got the engine back together and in the tractor now but I cannot get it run - as far as I can tell it's not actually injecting fuel.

I've got clean fuel to the pump, good life pump pressure and the low pressure side has been bled multiple times. I'm getting fuel delivery and I've bled the injector lines several times and cranked it a ton, even to the point of having it running on starting fluid for a bit. Still no sign of any fuel actually getting injected. With the lines loosened I get a good squirt of fuel from each line.

The injection pump did have rust problems in the delivery valves and I wound up having to disassemble the hydraulic head, clean the delivery valves and seats and lap to the valves. The actual plungers and bores were clean with no signs of rust or damage. They felt tight in the bores and all of the fuel flow ports were open and clean. All of the parts were put back in their proper locations and the plungers are engaging the rack properly. The rack moves freely and the governor seems to be working properly. After fixing the delivery valves I get a nice clean squirt of fuel from each port and the shutoff lever does stop fuel flow. The quantity of fuel *seems* about right though it's hard to say for sure. Should be enough to at least make some smoke anyway. The cams did have some rust on them when I checked but I can't tell if it's new or not and there doesn't seem to be enough damage to cause problems.

I also removed the nozzle holders on all 3 injectors and cleaned and inspected the nozzles and plungers. All were clean, seemed to fit well and were free. I don't have a pop tester yet so I can't fully verify proper function, but I didn't see anything that looked horribly wrong.

When cranking I get no smoke or evidence of any fuel injection. I even tried connecting on of the injectors sideways so I could see the tip and I saw no evidence of fuel.

So, any thoughts? Everything I've looked at has seemed ok. It would not surprised me if it was a bit off somehow, either from damage or from me messing up putting something back together, but I can't think of anything that would fit the symptoms. I'm definitely getting flow to the injectors, and it's making enough pressure to lift the delivery valve (1-200 psi???) and delivery a healthy slug of fuel, but yet apparently not enough to lift the injector. About the only thing I can think is I still have air in the system somewhere. However, with a much as I've played with it (probably close to 30 minutes total cranking time) I find it hard to believe there's not something else going on. On the 6.9 with a new pump, blown out lines and new injectors I don't recall it taking more than 1-2 minutes.

This things seriously starting to make me pull my hair out... and I don't have enough left to do much of that!

Thanks,
~John

 

[riotwarrior]

Send IP and injectors to MEL

I have no idea sounds to me like a pop tester is in order....time for a bottle jack build and find out whats what and whats going on or not going on. After that...it's send pump and injectors out for rebuild/inspection.

 

[Dave 001]

Can you jury rig a pressure gauge in place of an injector and see how much pressure the injection pump develops?

Also off topis: I have a '59 Fordson Power Major. Old tractors and engines are a hobby of mine.

 

[Dave 001]

Oh yeah...I forgot to ask.....Is it really an IDI? My Major has direct injection.

 

[jaluhn83]

Injection tester is in progress..... I ordered the pressure gauge yesterday and have the bottle jack. Just need to swing by the junkyard and scavange some lines and a deliver valve.

I haven't figured out a good way to putting a pressure gauge in one of the injection lines yet..... It'd have to be completely bled of air too otherwise it'd be a false reading.

I really don't want to send the pump out - from what I've seen it's $1000 for these pumps, and I'm betting it's not really worth rebuilding. Thing is I can't think of what would be bad in the pump to cause a completely lack of performance like this.... Wouldn't surprised me at all if it ran poorly or was hard to start, or missing, but no fuel at all to all 3 injectors is hard to figure. As far as I know it was running fine up till it blew a head gasket, and since it's just sat, so no reason for the injection pump to be screwed up aside from weather. And even then, I'd expect solid rust or major internal damage, not clean bright steal that fits smoothly but yet somehow doesn't work.....

It is IDI. Not as high of compression as the 6.9 motor, but definitely IDI.

 

[sassyrel]

jaluhn.. got some two stroke gas mix around??? put that in a 1 qt misting bottle,,and spray that in the intake,,to get it running..is NOT ******* the engine like either,,and you can keep it running till your out of fuel...have started many idi's and strokes this way...NORMALLY!!, long before you run the bottle out,,its running..

 

[jaluhn83]

Interesting idea. What makes it better than ether?

 

[hce]

I have a ford major with a simms pump. It will not prime no matter how long it is cranked or ran on oil. There is a bleed screw on top of the pump that has to be opened while the engine is cranking. Once fuel comes out the pump is now primed and push fuel to the injectors. From the parts catalog it looks like there may be bleeders on yours. I will see if can find a manual to verify this.

 

[jaluhn83]

I have the screw on the front of the hydraulic head to bleed the system and that has been done multiple times. I've got clean fuel to the pump.

My guess at this point is that I've got problems with the delivery valves still somehow and that's either preventing it from priming or building proper pressure. I'm working on putting together a pop tester and then I'll go ahead and check the injectors but my gut feel is they're ok. I think I'm probably going to pull the pump off the engine and tear down the hydraulic head again and see what I can find. With it on the bench I can do some more testing.

I'm thinking I may wind up trying to build a pump test bench. The fittings on this thing are the same size as a IDI, so whatever I gin up can work for those pumps too.....

 

[hce]

Found the manual, pm me with your email if you would like the pages on bleeding the pump.

 

[jaluhn83]

And the verdict is.......
.
.
.
.
.
Someone turned the fuel screw all the way in, ie minimum fuel! So everything was actually working correctly!

My guess is that someone was trying to troubleshoot whatever problem is was that led to pulling the head and though maybe it was a fuel issue, so they tried turning the fuel, not realizing that screwing it in actually gives you less fuel.

So after the better part of a month scratching my head and cussing vigorously it turns out to be a 30 seconds fix. Luckily I figured it out before spending the $400 on plungers, barrels and delivery valves like I thought I was going to need to. Also learned quite a lot about inline injection pumps and how to rebuild them. Turns out it's pretty easy. I even made a homebrew injection pump calibration bench but it didn't wind up working as well as I'd hoped. Still a nice way to see how things actually work.

Once I got it all put back together and turned the fuel up a bit she fires right up pretty as can be. Amazing how little things are important.

Also, I was wrong, this is actually a DI engine, not IDI.

 

[79jasper]

Good work! Sounds like a video is in order.... :roflmao
Also you mind sharing how you built that test jig?

 

[jaluhn83]

No videos, but I did get some pictures of the pump work and was going to do a write up on it... eventually.

The test rig is the typical cobbled up piece of gear. A real test bench is pretty simple - a fuel supply system, system to drive the pump at a given rpm, various pressure gauges and such, a revolution counter for flow calibration and a set of injectors with lines and volume measuring gear. My theory was that I could duplicate most of that using the stock lines and injectors and some way of driving the pump. Turns out on this pump a socket with a cordless drill worked pretty well for turning the pump, though I doubt it was very good for the drill. The frame is just some 2 bys nailed together to hold the pump. I was originally going to set up a rev counter on the pump shaft and try to measure the output volume but I gave up on this in the end. Couldn't get the counter to work right and I had an injector line that didn't want to seal quite right so it was leaking a bit. Then of course I didn't really have accurate specs for the unit, and the correct procedure uses calibration fluid and special injectors. Should work to give some idea of the injector balance though. I finally decided to just use the smoke calibration procedure once I got it back on the tractor. It did work well to verify that the governor and fuel shutoff worked correctly.

The inline pump is much easier to calibrate than a rotary. To properly do a DB2 pump requires a whole lot more adjustment and measurements. Most of the adjustments require certain speeds too and would be much more sensitive to the fluid used.

For a ranch tractor pump rebuild this worked out pretty well. I' be hesitant messing with a truck pump too much - much more at stake if it breaks.

I do have an industrial DB2 to do some work on before too long so I'll try to take some pictures when I do that one. We'll see how many times I have to redo it. Seems like it usually takes 3-4 times to actually get it working right.

 

[79jasper]

I'll wait until then. I'm just looking to play around with some old pumps and injectors just for the heck of it. I sorta thought about setting something up before and figured on using a 110v ac motor. But that's about all I got. Lol

 

[jaluhn83]

First pumps I messed with were Bosch VE type, had a couple that had the input shaft seal leak and didn't have the $$ for a rebuild, so I found a good article online and it was pretty easy to tear down and reseal. Took a few tries to get it working right though. (hint - putting the vane pump in backward makes it run very poorly )

From what I've found most of this pump and injector work is actually very easy if you're careful and have attention to detail. It's not really much different than an engine rebuild, just more precise. I also think that the common conception of how sensitive these systems are to contamination is a bit over emphasized. Sure it's important to keep things clean, but you don't need a clean room or anything. I've got a DB2 pump on my welder that has significant rust inside the pump and it still works reasonably well though I do need to overhaul it. The Simms pump on the tractor sat for 10+ years with the injection lines off and completely uncovered for part of that time and it was restorable. Likewise the injectors had some pretty nice rust on them and they cleaned up well too.

Not going to say that it should be taken for granted, but fuel injection systems aren't a sealed black box that only a phd can work on.... especially when it's a ranch tractor or similar that doesn't need to work that hard and it woln't be a catastrophe if it breaks.