^^Just a re-cap for new readers^^

 

It could be residue from damaged O-rings or burnt out internal components. The fuel coming out of the IP should be the same color as the fuel going into it.

 

Eaton your on the ball mang!!! Good recap!!! Cant wait for the results..... as the thread is friggin getting good like a book lol

 

Great recap, and it is like a book. I hope it has a happy ending and Lunis dosen't get kicked out, and know car.

Chet

 

Thank you eatont9999

 

Oh I think it will have a great ending

I took the top off the IP today as I read in that article that if the IP has pieces of black plastic in it then it's no good
I didn't find any plastic or anything else in it except fuel
refilled it with diesel kleen and still nothing

I looked at some diagrams of the internals but still am unsure what exactly wears out in these pumps?
I understand there are really two pumps in there, and have heard if the truck gets hot a few times on an old pump it may kill it
As I said before the truck did get hot, not overheating, but hot going up a few mountains on the way here and when it did die finally it was at the top of Pequops mountain here
I suspect that and the viscous WVO combined to kill it methinks

Eaton could you tell me some info about the pump you sent??
possible mileage on it and if you know for sure it does work?

mine was a junkyard pick so it was an unknown when it went on there

Thanks again to all of you

 

Well guys I'm REALLY hating myself for not finding this thread sooner. I REALLY wish I had followed this one. I just spent 2 hours skimming over it to try and get an idea of what might be the problem. Apologies if my ideas have already been covered.

Linus, I'm Very sorry to hear about your troubles!

I have some PDF files for the 1985 model year that I can Email you. Its not the same as for the 7.3L but the fuel system is almost identical and there is some instruction on removing and installing an injector pump. PM me with your Email addy and I can send them to you so you can be ready for when your parts arrive. I tried uploading as an attachement but the forum won't let me for some reason

I think I might know what the diesel mechanic was offering to do (or rather CLAIMING to offer...). The idea was to pressurise the fuel tank and force fuel in through the low pressure lines in order to prime the high pressure injection system. Provided the low pressure return line was disconnected from the tank and the tank end blocked off, it *could* work. Its a similar idea to adding an electric pump to prime the system before you try turning over the engine.

However what you can do yourself, is check to see how much fuel is in the fuel filter. I didn't see any mention of this in 20 pages but I may have missed it. The filter must be full to the brim or the injectors will not fire. Period. They need about 1400 PSI to pop the pintle open (1400 used 1800 new generally).

If your low pressure fuel system has an air leak (very likely considering the amount of tampering in the area around those lines) then any time the engine is not running, the lines will drain back to the tank. So every time you try to restart the truck, it has all that air to go through all over again. Most likely draining your batteries before you can get through it all.

Thats my guess on whats happened here.

These engines will fire and idle on half the cylinders if everything else is as it should be. Not well, but they will do it. In other words, even if you did have one or even two completely dead cylinders, the truck would still try to start. However with no fuel nothing will happen no matter how much you crank.

If you have access to a wall outlet, use the block heater. Then if you know how to, disconnect the glow plugs. A warm IDI does not need glow plugs to start up, but if it has air in the fuel lines, you'll need all the battery cranking power you can get in order to clear the lines and allow the injection system to prime. Only after you have fluid in the line again, can the injector pintles be forced open for fuel to flow. Also crank with your foot to the floor, it will help purge the lines more quickly.

And if it hasn't already been mentioned, crank for no more than 20 seconds at a time (15 would be better) and allow a minimum of 2 minutes cooldown. The last thing you need right now is to have to replace a starter!

 

thanks David85 for coming in to help

both tanks, fuel lines, etc were fixed/replaced before I left
filter is always full

lift-pump shoots fuel clear across the engine bay so believe it is good

I too kind of understood what the diesel mechanic was talking about but do not believe that is the problem
fuel to injectors but no fuel through the injectors- all fuel seems to be going to return lines

believe IP is worn out though no visible evidence to support that

injectors replaced as well as filter and glowplugs

FSS works fine

block heater works great when I had only one battery and bad glow plug but no good for this

PROBLEM IS I AM GETTING FUEL TO EACH INJECTOR LINE BUT INJECTORS WILL NOT FIRE AT ALL, EVEN AFTER ADDING 8 INJECTORS FROM CHARLES

ONLY PART THAT COULD BE BAD IS INJECTOR PUMP AS FAR AS I CAN TELL

 

Yes I agree the injector pump is a possibe cuplrit in that case. Although generally there is some warning before they go...

Just be careful about removing the top cover. Incorrectly reinstalling it could result in a no start condition or a runaway engine.

 

I think the IP is the only culprit it could be:

Picked up some veggie oil from Mexican restaurant in Illinois I think
all veggie filtered thru 5mic whole house filter using 12V utility pump
Believe Mexi veggie had something very bad in it....

First broke down in Nebraska I think, truck got "hot" or hotter than it's ever been since I had it (needle at the L in NORMAL) also changed filters at this point.

Broke down again in Wyoming I think, this time truck started going slower and slower and I figured a filter change, filter change did not last long and truck conked out at rest area...did not start again for 2 hours.

Broke down again in Utah, same as above, would not start for 2 hours or more

After Utah truck could not maintain 55mph even with clean filter, and steadily slowed down even on the straights.

Reached the top of Pequops Mountain (7K elevation) and truck died as soon as I let off gas.

Truck has not started since...

My only diagnosis I can think of is that due to elements in the Mexi veggie which somehow passed thru the pre-filter and clogged my truck filter, which caused the IP to overheat from fuel starvation

 

Yeah that sounds a lot like the injector pump. The no start for 2 hours after a hot shut down is a typical heat soak condition from worn out internals. When the pump cools off, the parts shrink slightly and take up some of the extra slack caused by the wear & tear. Fuel is also thicker, which also helps build pressure more easily.

This happened to my Dad's 93' GMC but much more gradual. His never failed to start, it simply took up to 2 full turns to get the engine to fire. In his case there was a 45 minute window after hot shutdown where it hesitate to start.

I replaced the pump with a rebuilt before it could get any worse.

There must have been some nasty stuff in that fuel to kill it that quickly.

Stalling when letting off the pedal is usually a stuck metering valve, but in most cases an immediate restart is possible. Your pump probably just can't build enough pressure to pop the injectors anymore.

 

thats what I was
thinking too

I plan to remove the bad IP tomorrow and would like to know if there would be anything external that would indicate wear/malfunction?

I would also like to disassemble the pump completely and discover what effect 10K miles of running wvo/wmo/atf/etc had on this IP??

anyone know if it is easy/hard to disassemble these pumps and the procedure?

thanks guys!

 

The pump was on my truck when I bought it. My truck ran fine and it ran smoothly. I decided, in my relative ignorance of the IDI engines, that I should replace the IP and injectors since I did not know their age. I later noticed my old IP (the one you are getting) has rebuilder's paint on it. (The anti-tamper red paint on certain bolts). My truck had as an educated guess, when I bought it, 150K on it. Judging by the interior, suspension and other related components, I fully believe my truck had about 150K on it. If the IP was rebuilt, it was likely within the last 50K at the most.

You can burn almost any kind of oil in the truck but WVO is the most particular type. You must have it pre-heated before it enters the primary fuel filter and IP or you WILL have issues. Anything petroleum based is not as picky but proper mixing will help poor burn quality. Mixing petrol based and veggi/animal based fuels is a huge no, no. Mixing may have hurt the IP enough to lose tolerance and later fail. If you ran straight, un-heated WVO, then guarantee you that this killed the IP. WVO has to be heated, dewatered, filtered and heated again before entering the IP for it not to cause damage to an IP. Anything short of that process, is likely why you are stranded now. Live and learn but don't repeat past mistakes. I'm confident you have learned not to mess with WVO for now, so I feel the IP will serve you well being run on D2 and a proper dose of Diesel Kleen for cetane boost.

 

If you disassemble the pump, do not expect to get it back together or working again without a full rebuild and a pump testing station.

We may be able to tell if there is obvious wear or an obvious failure point but if you replace the IP, and the truck runs after that, we can be pretty sure the IP was the problem. It is possible that the IP died on its own accord or that WVO had something to do with it. It is really hard to tell unless you see something obvious like rust or WVO gelling on certain components.

 

Linus, Are you familiar with how to remove the injector pump?