My working knowledge and experience with injection pumps could land on the head of a pin. Much thanks to the help, knowledge and experience received from folks here, I'm gaining ground.

DO NOT TRY THIS AT HOME DISCLAIMER:
If by some chance this post isn't removed by the moderator and you've stumbled upon it, what you read below is mostly for entertainment purposes. It's crazy-wreckless, ignorant, naive, and may even alarm the Surgeon General. However... It's SO crazy it just might work or at least get you as far as I have.

I have a '78 240D that's been parked in complete neglect for more than 8 years. She started right up but went into a runaway. After ruling out oil in the cylinders I learned some basic theory of operation and sought professional help. I discovered repairs were cost prohibitive and buying a used pump was a gamble at best.

Given the circumstances of age and neglect, a tech at an IP service center suggested the rack was probably frozen. I opened the top of the governor. He was right. The rack was frozen solid and would not budge no matter how hard I tried.

I had nothing to lose and wasn't going to be able to purchase another pump anytime soon, so I set to work. I was all but certain my Pump was scrap but at least it would understanding of its inner workings so what the hell. I flooded the housing with ATF, dug into grandpas toolbox(He was a Greyhound Mechanic) and pulled out a monster sized flat blade screw driver, about 2' long. I know... it was wreck less but nothing else I used would budge that rack so this was the last ditch effort before proceeding with an autopsy.

Using an unholy amount of torque it moved, not more than a hair, but I felt it. I flooded the housing several more times and after about 20 minutes I had about 1/2" of travel. 30 minutes later I was reasonably sure that I had full travel and it was loosened up enough that the throttle arm inside was even moving it back and forth. I drained the ATF from the engine, flushed the governor housing with fresh oil, refastened the cover plate, and what the hell... I might as see if I got lucky.

Did it work? Did I further damage the pump, significantly shorten its life span, waste a gallon of ATF? Probably... I haven't a clue but the engine started, no runaway, and after she warmed up I got a good idle and was able to shut her down with the cut off. Pretty exciting, but by no means am I out of the woods yet...

Initially she wouldn't climb more than a few wraps above idle, a reciprocal of earlier event. It was, a welcome one for sure. Eventually she gained full tilt... I think. She still has a sluggish almost sponge like response but makes it there, so I'm pretty tickled. At the very least it's always a pleasure to hear the sound of a Diesel engine run.

Before trying all this I did lap the injectors, installed new heat shields, torqued them to spec, cleaned or installed new lines, tank, filters, and delivery pump, but forgot to tighten the primer pump down. I am pretty certain it was sucking air through there. After I secured the loose Pump I primed all lines to the best of my know-how and it made a difference but not profoundly.

I don't know if things will improve but I'll persevere. I'd love some suggestions, tips, or sideline help from anyone who has been patient enough to read this far. I don't know how to bleed the pump or if it's even necessary. I read about pump pressure and pump timing last night from the shop manual and the generously contributed step by steps instructions within this forum. I guess I'll start there and report back my findings, failures, and/or luck ridden success.

Again, Im full aware that suggesting this to anyone. But maybe, just maybe, it has worked for me, and will provide some penniless fool a crude chance of success in an otherwise hapless situation. Most probably not but I'm anxious to hear from the IP sages even if they tell me I'm an idiot and ban me from the forum. At least I'll have learned something if only by my failures. That's where I learn the most anyhow.

Run a couple cans of straight Lubro Moly Diesel Purge through the system couldn't hurt.

Do you think the rack was frozen due to something having to do with the fuel sitting in the IP or something to do with some other lubrication issue internal to the pump's mechanical space?

These old engines were built in the days of "normal" diesel. As such, the engineers relied on the high lubricity of the diesel fuel to lubricate the injector pump. Fast forward to today when we've outlived the low-sulfur fuel era and are now saddled with ULSD (ultra-low sulfur diesel) with comparatively no lubricity.

Do yourself a favor and add 1-2% two stroke oil to your fuel to restore lubricity and protect what's left of your IP - cheap insurance!

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Current Stable

• 380SL (diesel)
• Corvette C5
• Manx
• Baja Bug
• F350 Powerstroke
• Auburn Boattail Speedster replica

Based upon observation of the diesel polymers that formed in the rest of the fuel system, I suspect the pump suffered the same as it was working just fine prior to the last shut down.

Can I find that product locally or is only available online? Dissolving the polymers from the rest of the system was a cinch with 92% Isopropyl Alcohol. Obviously purging the pump with alcohol would be a catastrophic exercise during engine operation but I wonder if it would benefit or harm with the injector lines disconnected and then purged with fresh diesel.

I like the 2-stroke oil idea! I have a couple quarts in the shop. I've heard Others swear by all sorts of additives: Olive Oil, MMO, SeaFoam, Tinkerbell's Pixie Dust. I certainly agree that some slick stuff should be added. How about used engine oil? Only kidding! I read somewhere that hours and mileage aren't really the standard unit of measure considering the absence of sulfur. Engineers are rating and projecting longevity units of fuel consumed by the engine.

I should point out that I owned and operated the car for about a year prior to parking it and I only ever used biodiesel(B99) for the added lubricity. In fact I was running B99 when I parked. I drained the tank and kept the fuel(@ 15 gal.) It didn't polymerize in the Jerry cans I stored it in though it does have a slightly different odor. B99 in the IP may have saved it, may have ruined it. I'll never know for certain. I've never used and probably never will use WVO based upon what I've read thus far. I understand through research that Petro-Diesel begins to break down into polymers 90 days after distillation.

I had a rack stick in the stop position on a Lucas rotary injector pump. Took the top cover off and used carb cleaner to help free up the linkage. Ran just fine after that.

I didn't mean to imply that 2 stroke oil was the be all and end all of lubricity restoration. 5 % or more of bio diesel mixed in will do the same thing. Straight bio diesel is OK too, but will cause stock rubber fuel lines to disintegrate and start to leak so will need to be replaced with upgraded lines.

__________________
Current Stable

• 380SL (diesel)
• Corvette C5
• Manx
• Baja Bug
• F350 Powerstroke
• Auburn Boattail Speedster replica

I didn't take it that way all. I thought it was a good suggestion and I'm getting rid of my old 2-stroke oil I have no use for. Thanks for the suggestion. If anything I was more poking fun at all the products on the market that promise jaw dropping performance and longevity to your engines fuel system.

Yeah, that would have worked better more than likely but all I had available to me was rubbing alcohol and ATF.

Rack internals are not fuel lubricated... they are engine oil lubed... so... why did it lock up? Water in the oil?

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John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!

I've completely disassembled and put back together a Bosch rotary pump and there was no rack. Are Lucas rotary pumps that different from Bosch rotary? A rack is a long bar with gear teeth cut along its length, e.g. like in a rack and pinion steering. Isn't it true only inline pumps have racks?

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85 300D turbo pristine w 157k when purchased 161K now
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

Is rack still binding a little or not? It has to move easily I would think. One thought I had was if WVO was used as fuel in the engine and the base oil was polyermised. Not being changed enough because of the product going past the rings.

Over a long term siting situation it could have gummed up the rack. Plus might have impacted other things. I might soak both the portions of the injection pump in laquer thinner as it would dissolve any gum. WVO products and by products turn into a strong glue with time. I was thinking the govenor might need the cleaning as well.

Eight years ago was probably when the use of wvo peaked. You know people put almost anything in the fuel tank then and though things would be fine. A used pump cheap enough can also be found if the need became obvious.

Also check the valve clearances because back then many people never bothered.

I called it a "rack" in generic terms. I'd have to look at a diagram again to see what it operates.

Here's a post with a good diagram:
so, what does that rack damper bolt (617) actually do?

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85 300D turbo pristine w 157k when purchased 161K now
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

I get full throttle rpm but it just takes awhile to get there which means there's probably still some sludge in there. It doesnt seem to be hanging up. It improves when it warms up but still much room for improvement. I don't know why but it had never occur to me that the PO could have burned WVO which would account for something.

As for the lacquer thinner... I'm a little reluctant to use it. I'm nervous about damaging any composite materials, swelling, and or cracking seals. Do you think another solvent could be used? I've had great success with 92-99% isopropyl alcohol on petro-polymers. It's less expensive, available everywhere, and a less noxious. I don't have experience removing bio-polymers with alcohol.