Mitsubishi 4D32 diesel power unit in CAT 307SSR

[Delmer]

He push started the engine, let it run for two hours, then it let out the black smoke and ran fine. That's my take.

Looks like the glow plugs check out OK. The only way I know to check an injection pump is to hook one of the injectors back up and watch the spray pattern.

A leak down test would give you some info, you should be able to tell if there's a dramatic difference between the cylinders at least.

If it was me, I'd check all of the external banjo bolts for plugged screens, hook the lift pump back up the way it was originally, and do whatever it takes to get it started: use kerosene (#1 diesel), warm up the engine/intake, etc.

The last Cat from Hawaii started and worked with the timing 180 off, so this thing should start if it's getting any fuel at all injected.

 

[John C.]

That two way fitting usually has a check valve in it with a spring. The fitting hooks into the pump with the big hose going back to the tank. The small hose comes from the spill off from the injectors and goes back to the tank. I've seen crud in that check valve which lets fuel go back to the tank. All the Zexel pumps I've worked on have the screen in the banjo bolt at the suction side of the hand pump if there was one. I've seen the electric pumps before and most for were priming the system after changing the fuel filters. I've seen some machines with the plastic fuel tanks under the cab and there was a strainer there. The last possibility is that the pump drive shaft has slipped on the drive gear. Many of the injection pump units I've worked on had a key and a tapered shaft with a nut on the end that needed to be torqued to a certain specification and wasn't. The nut came loose and the key sheared off dropping the timing. Most of those units can be timed by removing the check valve below where the steel line for number one is hooked up. Find out the timing and back the engine to before that mark. Run your priming pump and turn the engine very slowly watching the fuel coming out of the #1 fuel injection line. When the fuel stops coming out of the line, stop turning and check where you are on the timing marks. It that is correct you will be on the timing mark. If not run the process again and if wrong you have a problem.

A service manual would show how all that is done.

 

[Pants]

Thanks, John C -

You're talking about a check-valve on the FILTER-return connection, then, built into that banjo with the two inlets on it ('2-legged banjo', from my relabeled photo below, yes?) That would make sense, especially if the check-valve spring is also configured to regulate lift-pump pressure into the IP, right? (If it free-flowed or was stuck somehow, I'd be losing most of my incoming lift-pump pressure there - maybe that's what you were saying?) I'll take it apart tomorrow just to check it since it's not too hard to get to.



If an unwanted bypass was happening, though, I was still getting something more than a tiny amount of diesel coming through the open injector tubes while I was (forever) cranking to bleed out suspect fuel. Any rough estimates of how MUCH fuel I should be getting for, say, 15 seconds of cranking, from one injector tube? I was keeping an old 35mm film plastic canister over the end of one tube so as to roughly check the fuel quality & assess whether I'd gotten new diesel through yet...I'd very roughly estimate a teaspoon came through after an aggregate of 2 minutes of cranking.

If it comes to pulling the pump out, I have mostly top access - with the photo showing my maximum view from the side of the pump (none to speak of below). Is it feasible/reasonable to get it out without other dis-assembly?

--Dave

 

[Mobiltech]

I don't think you're getting enough fuel. First check that banjo fitting. Next mount the injector you have out on the injector line and see if itis spraying fuel.
If you have one injector spraying it should be firing on one cylinder at least.

 

[Pants]

I don't think you're getting enough fuel. First check that banjo fitting. Next mount the injector you have out on the injector line and see if itis spraying fuel.
If you have one injector spraying it should be firing on one cylinder at least.

Thanks, Mobiltech. It's really rainy morning here so I might not make any progress with that banjo, but let me ask you this: I've got all injector tubes out now, and just one injector out. So if I can cobble up some way to connect the injector to an open port on the IP (without having to completely murderize one of the tubes to make both connections), would testing be meaningful, even with all other IP ports open? (I don't mind "messy"...just want it to be useful.)

On a more theoretical level: every time I struggle with a nest of injector tubing, I wonder why none that I've seen use high-pressure flex, eg braided-stainless over teflon. It'd certainly be more expensive, but would it not work? Maybe too springy under pressure? If I could come up with the fittings easily, I'd do it that way.

What cylinder cranking-pressure range would you expect, in case I can come up with a lay-around gauge to plumb in? Would 800psi cover it?

Mahalo - Dave

 

[lantraxco]

Yes, flex lines swell slightly like a balloon with each pressure pulse, so no good. Actually the steel lines do swell a tiny bit, and while I have never bothered to try and measure them, I was told to insure perfect timing that each fuel injector line is exactly the same length as all the others, which is why you see some really odd looking bends and U's in some of the lines.

 

[repowerguy]

Sorry about the confusion,I can be less than clear when I'm not think things through. Delmer nailed what I did,spot on. The starter would'nt spin it over fast enough to compensate for the leakage past the plunger. When spun up fast enough it ran weakly on the 5 cylinders. I have also seen plungers stick in 3208 Cat pumps that have set awhile ,had to take the top off and carefully pry them loose with a wooden dowel, maybe should have push started it.

 

[Pants]

Sorry about the confusion,I can be less than clear when I'm not think things through. Delmer nailed what I did,spot on. The starter would'nt spin it over fast enough to compensate for the leakage past the plunger. When spun up fast enough it ran weakly on the 5 cylinders. I have also seen plungers stick in 3208 Cat pumps that have set awhile ,had to take the top off and carefully pry them loose with a wooden dowel, maybe should have push started it.

Push-starting tracked equipment...gotta check out Youtube for that. I suppose if it doesn't work, there's an equal chance of becoming a viral hit somehow. Thanks for the info.

-Dave

 

[Pants]

Yes, flex lines swell slightly like a balloon with each pressure pulse, so no good. Actually the steel lines do swell a tiny bit, and while I have never bothered to try and measure them, I was told to insure perfect timing that each fuel injector line is exactly the same length as all the others, which is why you see some really odd looking bends and U's in some of the lines.

Thanks Mobiltech, too; following John C's descriptions I decided to look into the banjos for ball check-valves. Two spring-ball-checks exist in places where they make sense; one requires the filter-head outlet to overcome spring-pressure in order to return to tank, and the other is built into the bolt that's from the mystery-electric pump that's controlled from the rocker-switch in the cab. In taking the return banjo and the "mystery pump" banjo off, I was able to determine that they lead into the same chamber, with no restriction, so hitting the rocker-switch to get that electric pump going would have pumped unfiltered fuel into the return-port of the IP, with...help me out here...some, or all of it returning to the tank again? I'm still thinking the designers weren't silly enough to pump unfiltered fuel into the return-port for no reason, but I can't see what good this could ever do.

There was some orangey-rusty scum visible coating some of these passages, so clearly some rusty glop had made it that far.

Also following a few people's suggestions, I found I could fit up one injection-tube to an injector floating in the air outside the engine compartment, so I cranked it a bit while within a clear plastic container. Far from the fine mist I'd expected, it looked like an irregular "spiders-legs" pattern of radiating streams. Not good, right?

I've resisted every instinct to rotary-wire-brush it and examine the nozzle under magnification to see what I can see, having read at least one source that says not to use even a manual wire brush to clean them. Is there really such a taboo? If so, how can one safely clean them?

I also suppose it's not going to be just the external crud that's messing them up, but I'm game for disassembly and reassembly if that's not a guaranteed-to-fail process without specialty equipment. I'll be googling for this, but very interested in suggestions in this vein.

--Dave

 

[repowerguy]

Oops it was'nt a crawler it was a 3 wheel Ingram roller. I did'nt mention it because I did'nt think,sometimes whats in my head does'nt come out of my mouth or keyboard .Push starting crawlers was common before powershift trannies came along. I suppose you could push start a powershift if you could crank the engine enough to get clutch pressure, that's what I did on that old Ingram. Sorry if I took your thread on a rabbit trail I was just relaying a experience when a funny tale got in the way!

 

[Delmer]

The spiders legs pattern might be normal, irregular doesn't sound good. Look up some images, find ones of multi hole injectors, if that's what yours are.

Acetone and a toothbrush is how you clean them. Or something less aggressive if the toothbrush melts. If you take the injectors apart wear gloves, don't touch anything with bare hands, rinse everything in clean diesel and reassemble wet, no wire brushes. What do you have to lose?

800 psi is enough for a compression tester, you should get something like 400psi, and not much difference between the cylinders.

PS: don't try to push start a hydrostatic-planetary-reduction... just don't.

 

[Pants]

Thanks, Delmer.

I didn't see your message until I'd already gotten into cleaning the injectors, but I think I did OK. They did have a lot of slightly-greasy carbon buildup on the nozzles, and I might horrify you when I tell you I used 0000 (superfine) steel wool for the most part - toothbrush didn't do much, wooden chopstick helped with the recess just below the bulb. The jets/holes are much finer than I'd expected - way smaller than my smallest number bit, tip-cleaner...even a straight pin only fits partway in. I needed to probe some of the holes because they were (seen under magnification) really plugged with the same gunk. I'll tell you, acetone swells and shreds nitrile gloves even faster than lacquer-thinner...

Do I think it's going to start up and purr? Not really...bad as the injectors were, I don't really believe they just suddenly took a crap and stopped being able to do their jobs entirely. But at least I can kinda-sorta rule out injectors as a problem.

I'll try to rig something up for a compression-test tomorrow during the process of putting them back in, hopefully to rule that out, too. Also, I will take my best guess at checking the IP timing while I am at it...still waiting for the manual I found online to arrive.

--Dave

 

[Pants]

I did compression-testing this AM. Since I don't own a kit for this yet, I had to make up a glow-plug-replacement bolt with a flare-fitting brazed into it, to connect a pressure-gauge, which in this case is an A/C gauge with an adjustable zero on a conveniently-long hose. I don't have anything to use for a check-valve on hand that I can think of, so I was simply staring at the gauge while cranking in order to observe the approximate peak psi, this being a relative test anyway.

I don't have anything to compare this to, but my results seem way low: ~130psi on 1/2/3, ~140 on 4.

Do I need to retest with better setup, eg a check-valve included somehow? I can't imagine that would make a huge difference.

Can't find cyl compression specs (or much of anything at all) online for this engine...but getting a bit depressed about it now because this seems more like gasoline-engine compression test results.

I did test each injector after cleaning them all yesterday - all produce similar spray pattern now, but that compression...

--Dave

 

[Delmer]

Don't get worried yet, that long hose is throwing your results way off. Use a short hose, or a check valve to let it build up pressure. One compression stroke doesn't have enough time to push the air all the way through that hose, that's my guess.

It would be very odd for the results to be that low, but that uniform at the same time.

Did you find any pics to compare the injector pattern to? Or were the streams uniform enough on each injector and compared to each other that they seem to be good?

We didn't ask, but has the engine been turning over at a decent speed the whole time?

 

[Pants]

Thanks again Delmer...

I can put the gauge right on the fitting, I suppose, but can't see it from that position. I keep wishing I had a remote-starter. Might have to drag the one I married out there...

I did see some spray-patterns on Youtube videos that make me think mine are about normal, at least now that the gunk is gone, but maybe not as far off to begin with as I'd thought before. I'd thought injectors were capable of much finer atomization, but apparently not. They fire in what I think is a five-stream pattern spaced evenly around the circumference of the bubble, and with the 'jets' at various azimuths as you twirl the nozzle - probably pretty typical for this class (though completely different than those on my old Benz.)

I've been doing a lot of guesswork since I'm in the dark as to specs - not just about the compression-testing. Reassembly torque for the injector bodies was one of those guesses. Since they'd "cracked" on disassembly, I was thinking I'd feel a hard "stop" on reassembly, but not so, and I quickly got into that "oh-crap-I'm-about-to-strip-this"-zone. Same for the injector retainers - they cracked loose, but seem to be daring me to strip them out on reinstallation.

One of my glow-plugs is getting swollen, but they all glow relatively uniformly. How quickly will I regret not replacing that one, or all of them?

Alright, back to it...

--Dave

 

[Mobiltech]

You do need a gauge with a check valve to get a good reading and definitely don't want to use a long hose. It will take about 4 good compression strokes to get a stable reading. A diesel will fire down to about 250 psi depending on intake temp. The minimum I would want to see is 300 psi.
The injector spraying in a spider pattern says you're getting fuel and the pump is pressurizing it although you could have injector valves sticking open. Do the injectors drip a bunch after spraying or was it a sharp cut off of flow after the spray pattern?
Are you seeing about 200 rpm while cranking or much less.
Have you tried any starting fluid yet. That would tell you if you have a compression , cam timing or air supply problem.
I wouldn't mind a "road trip " to look at it but I had my Hawaii trip this year already.

 

[Pants]

You do need a gauge with a check valve to get a good reading and definitely don't want to use a long hose. It will take about 4 good compression strokes to get a stable reading. A diesel will fire down to about 250 psi depending on intake temp. The minimum I would want to see is 300 psi.
The injector spraying in a spider pattern says you're getting fuel and the pump is pressurizing it although you could have injector valves sticking open. Do the injectors drip a bunch after spraying or was it a sharp cut off of flow after the spray pattern?
Are you seeing about 200 rpm while cranking or much less.
Have you tried any starting fluid yet. That would tell you if you have a compression , cam timing or air supply problem.
I wouldn't mind a "road trip " to look at it but I had my Hawaii trip this year already.

I'll buy you another ticket, Mobiltech...

I should have known better than to use the hose, but hadn't really thought it through, and it seemed knee-jerk convenient so as to get myself near the starter-switch. Later I began to realize it's not only elasticity of the hose that's a problem, but it's like I added a bunch to the combustion-chamber volume, so it would really mess things up.

When I reconnected the gauge with minimal fittings, directly to the glow-plug ports, having soldered a Schrader-valve into the inlet of the cobbled-up tester, I got much more encouraging results. Something like 380/360/360/390 psi, cranking maybe more than four cycles, probably not more than 8 - I just cranked until it had apparently maxed out. I've kept chargers on the two batteries (24V) to make sure they stay up, and it sounds like it always did when trying to start; it doesn't sound like it's dragging as long as I keep the chargers going.

Injectors did NOT appear to do any post-spray dribbling. But now that you mention it, when should I start seeing diesel filling the return-branch daisy-chain? I put some of that transparent blue fuel hose in to replace the original 1993 stuff, and I noticed that no matter how much I cranked, I never got any diesel coming back through the returns from the injectors. Does that not happen at cranking speed, maybe?

I then installed the cleaned-up injectors etc, bled all lines through to the injector nuts, and hoped for the best. And nada - zip - not even the ghostly wafting exhaust I had seen previously.

I ended the day by hand-turning the engine to see if I could verify IP timing crudely - looking for a jet of fuel somewhere around #1TDC. I was checking TDC by using the glow-plugs as if 'corks,' loosely fitted into their ports, so as they hissed/popped up in the ignition sequence, I could anticipate when #1TDC was coming around again. Doing this, I passed TDC a number of times with no clear indication of any change in the 'lens' of diesel that was pooled in the top of the open injector port for #1. D'oh! I then realized that I'd wasted a lot of hand-cranking effort, since if the keyswitch is OFF, I should NOT get anything from that port. Sigh. I then cranked it a few times with the starter, again verifying that I saw a jet of fuel spurt up from the #1IP outlet, left the key on this time, and returned to manually rotating the engine. I finally got a little bubble coming up at about #1TDC - at least SOME indication of timing being correct - but never a distinct 'shot' of fuel. Should that happen at hand-cranking speed, too? (I figure if I need to do this method more precisely, I will have to make up some kind of barbed adapter to get me from the IP outlet to a small-diameter clear tubing, so I can better see the fuel moving through the tube).

**Starting fluid isn't a no-no, then? Ether? (If it matters, it's not a turbo). Can I do that with the manifold NOT connected to the air-cleaner, maybe with an old sock or something over the intake as a catastrophe-preventer, just for testing period?

Other than the starting-fluid, anything else to try? Cam timing would be OK based on my new compression-test results, right?

Mahalo - Dave

 

[Mobiltech]

Yes you can try starting fluid . You do not need a sock in the intake. Spray an atomized mist of starting fluid at the intake manifold inlet holding the can about 2 feet from the inlet while the engine is at a good cranking speed with the starter.
You will probably want to put all the glow plugs and injectors in and have the engine ready to run for this because from what you've said so far it should start up briefly on starting fluid.
If you feed it too much ether it will lock up but will start cranking again if you leave it sit for a while. Try to shoot the ether in short bursts, just enough to keep it running.

 

[Pants]

Yes you can try starting fluid . You do not need a sock in the intake. Spray an atomized mist of starting fluid at the intake manifold inlet holding the can about 2 feet from the inlet while the engine is at a good cranking speed with the starter.
You will probably want to put all the glow plugs and injectors in and have the engine ready to run for this because from what you've said so far it should start up briefly on starting fluid.
If you feed it too much ether it will lock up but will start cranking again if you leave it sit for a while. Try to shoot the ether in short bursts, just enough to keep it running.

Thanks again for the confirmation - Gonna head out in search of the starting-fluid this AM. IIRC it can be hard to find here, like black ice and sleet, but I have seen it. (Why do some engines, eg the Cummins in my Dodge...I think...come with warranty-void-if-you-use-starting-fluid warnings? I'd gotten the idea that it was appropriate for gasoline engines, not diesel, but I'm not worried about any warranty anyway now, and it's obviously something you're accustomed to using.)

So just to keep me thinking - let's say it springs to life briefly with controlled bursts of ether and dies out as soon as I stop providing it. Will that mean my IP is toast? Too soon to jump into another rabbit-hole? From my web-searches, I'd probably be looking to buy one from China - not unexpectedly, really; just seems they almost don't exist in the U S of A...

Mahalo - Dave

 

[repowerguy]

If you do need a IP, you won't need a new one, just a good pump shop to do a overhaul on it. I'm sure the west coast has a good pump shop or two out there. Here I send stuff to Columbus Diesel Supply ,nice guys who will phone coach you if you ,and I have, get stuck.