3B Injection Pump won't prime (1 Viewer)

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The only thing I have to add to this thread, is that I expect the Mercedes are a Bosch VE pump, and so the fuel coming out of the pump would be at something like 1500 PSI, right? I know it can be lethal if your flesh gets hit with an injector pumping diesel, but should we be similarly worried about the pressure out of the pump (because it's not atomized like it is out of the injector nozzle)? Just for my own knowledge.

A good point well made.. I definitely wouldn't be putting fingers near any injection line or delivery port thats operating and possibly leaking.

2H/12HT crack pressures are ->


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3B almost certainly much the same.
 
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You could remove both flexible hose from the throttle body and blow air in it (not 90 psi!!) . I guess you can hear the diaphragm moving (slide the fuel rack), I didn’t try myself, just an idea.
There is a bleed screw on the IP 3B pump
I don’t have an IP near now…the diaphragm control the fuel rack but only from 600 to 4000rpm (if well adjusted) so I don’t think the diaphragm cause your problem.

Can you move freely the stop / run lever? This lever move the fuel rack to 0 rpm

I’m not 100% sure but would should be able to push diesel to the nozzle with the hand priming pump and injectors loose

You confirm that when pushing the hand priming pump, you see diesel out of the filter with the bleeder opened?
 
If anyone could use either of these for spare parts / troubleshooting, I noticed these for sale in the diesel section:

Injection pump cores.
 
Hi. Well after being away from the 3B for the past 2 months, I'm back and just finished tinkering on it> Turns out the rail in the injection pump was stuck in the off position. I determined this by first pulling the observation plate (2X 10mm bolts). This confirmed that when the stop>run>"extra fuel" lever rotated the rail did not move. I then pulled the diaphragm cover off (4Xscrews) and pulled the diaphragm out as far as possible without disconnecting it. This allows you to see the end of the rail. Pushing on it with a finger further confirmed it was stuck. I was able to tap on the end of the rail with a small flathead screwdriver + hammer. It's tight but you can get at it. I drove the rail in that way and back out by gently tapping on the fuel shut off lever. Rail in =s lever counter clockwise, rotate and tap clockwise to get the rail to push back out. I sprayed the upper top area of the observation window with WD40, kept working the rail back and fourth until it moved freely. Once free you should be able to depress the center of the diaphragm to push the rail in and rotate the lever by hand to push it back out. Mine is now moving buttery smooth.
Thanks for the help, links to videos and support, don't think I would have known where to start without that info

I'm looking forward to trying to prime this injection pump again, it's no wonder it didn't work before.
 
Hi. Well after being away from the 3B for the past 2 months, I'm back and just finished tinkering on it> Turns out the rail in the injection pump was stuck in the off position. I determined this by first pulling the observation plate (2X 10mm bolts). This confirmed that when the stop>run>"extra fuel" lever rotated the rail did not move.

Nice find and great that the rack freed up successfully. That 3B will be rattling away nicely before long!
 
It's alive!
YouTube short of the fist start.
Thanks again for the information and support. So stoked to hear it run, I bought this truck as an incomplete diesel conversion project. Was told the motor ran 10 years ago when pulled from a different Cruiser. Still lots to do but this felt like the most daunting part.
 
It's alive!
YouTube short of the fist start.
Thanks again for the information and support. So stoked to hear it run, I bought this truck as an incomplete diesel conversion project. Was told the motor ran 10 years ago when pulled from a different Cruiser. Still lots to do but this felt like the most daunting part.

Video is set to "Private" cant watch :(

Edit.. all good its fixed
 
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Excellent! Sounds good.. its rattling a lot and this may be indicative of poor spray patterns on the injectors.. not urgent, but may be worth considering getting them rebuilt at some point.
 
Hopefully it smooths out a bit. It was 35 degrees out, motor was stone-cold and running off a can of old-ish diesel. I haven't even looked at the motor mount situation closely ... or the coolant/radiator.... or the charging system. Felt like I just needed to see some sign of life in the motor before anything else. I did already ensure the clutch and throw out bearing were good as well as install new clutch cylinders and lines.
 
Hopefully it smooths out a bit. It was 35 degrees out, motor was stone-cold and running off a can of old-ish diesel.

Oh for sure.. that's not ideal, a good italian tune will assist no end! A fang around the block a few times at high speed! :)
 
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Much smoother after a couple laps around the block. Still have a few loose ends to sort but I’m stoked it’s running. Thanks again for the support and information.



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