My fuel injector pump went-out -- 2 years after replacing and relocating one of those now infamous PMD controller boxes -- to the cooler fender-well (so I do believe it's the actual injector-pump now).


Bottom-line -- it looks impossible to remove and replace the pump without removing the engine! The video link here shows that the pump must have been bolted on before the engine was dropped-in at the factory.


I may have to scrap the 'ol Hummer if I can't get the pump replaced -- unless I can pay big bucks to a shop to do it for me.


Please look at the final issue -- with "knuckle-space" -- and offer any tricks you may know. This may also help you if you come across this problem on your H1. Thanks in advance!
My YouTube video->

 

Doh! -- an "S-Type" wrench (see attached) might just solve my problem. It might just do enough "reach around" to do the trick.


I'll need to cut an small opening on the end of the "box-end" to get around the tubing -- just as I saw on YouTube for the same issue -- for a straight box-end wrench.


I'll update later.

 

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Removing and replacing an injection pump is a PITA but it shouldn't take more than a few hours. Being in the valley of the block it is not in the easiest place to reach. You can have yours rebuilt, buy a reman or buy new. I have had mine rebuilt. You do not have to pull the engine to get them out.

 

Whew! No luck with my custom "notched" S-curved Box-End wrench -- shown above.

Opening the wrench's box-end (by cutting a tube-sized notch in the box-end) made it too weak -- it bends/warps under high torque and slides over the nut


An "open-end" S-curved wrench is only found on antique websites!


I am off to buy a set of "angled" open-end wrench's at Northern Tools. I may yet need to find a real blow torch to make a curved wrench.


What tool did you use?

 

Sears sells the curved S wrenches

 

I hope your right! That would be soooo nice.


I had already scoured the Sears website only to find their S wrench's are all "box-end" -- i.e. won't pass thru the fuel line tubing without notching the box-end -- apparently weakening it too much. Incredibly -- Google shows ALL s-curved wrenches are box-end -- except for some antique ones


I am tempted to stop-off at a physical Sears anyway and see if maybe their website just doesn't include a open-end S wrench. That would save the 45 mile trip I'm about to take to get a mere angle-end wrench.


Thanks for the help guys! I think this is gonna work after-all. Stay tuned.

 

FIXED!!! -- it was that infamous PMD controller box AFTER-ALL!!!


I did replace the injector pump first -- and it was hell! I was forced to splice the two bottom fuel lines after using a tiny tube-cutter to [finally] cut them. The 1/4" tubes were really thick -- took a while to cut em. I used the "Dorman 5000 psi 1/4" Hi Pressure compression unions" to tie them back together (whew!) I needed my wife's tiny hands to start the 2 bottom pump mount nuts -- on the existing studs.


I wound-up purchasing every type of wrench known to man


Bottom line -- and as the prevailing wisdom had warned me -- always replace the PMD first -- even if you've already done that -- and as in my case -- even remote mounted it just 2 years ago.


My "baby" is back! I'm going to retire this '96 Hummer now. I'll drive it on weekends around town you know. I should get another 20 years out of it like that

 

Congrats. Glad it turned out to be the easy fix, even if you did the hard fix also.

 

I really wish it was my PMD. I'm in the sticky situation of tackling the injector pump.

 

Are your SURE it's not the PMD? It's a $650 vs. $260 question. Actually, you'd want both if it is the pump. You'd want the remote PMD mount kit also if not already installed.


If you must change the pump yourself -- and even though mine runs fine now -- I just discovered a "lukewarm" hard-start issue.


"Walt" at SSDieselSupply.com -- where I bought the pump online -- says I must still use a Tech2 "learn" procedure to set the TDC. I don't know what I just said


So, I just dropped off my H1 at a local diesel shop to have the pump TDC adjusted.


SSDiesel was kind enough to send me 2 pages of instructions on how to set the TDC. I can attached them here if you need it.


BTW SSDieselsupply.com deserves my compliments and recommendation.