350SDL Injection Pump Problem - PeachParts Mercedes-Benz Forum

dick87 · #1 09-06-2006, 08:47 PM

Had a fuel leak at a couple of delivery valves. Replaced the O ring and seal. Followed the recommended torque procedure. Now one cyclinder does not have any fuel pressure from the delivery valve.

Anybody have any ideas?

mbdoc · #2 09-07-2006, 08:25 AM

IF the actual delivery valve came out of the pin of the main rack then that is the problem....did you do 1 at a time? did you use a magnet to get to the crush washer?

dick87 · #3 09-07-2006, 09:43 AM

I did repair one valve at a time and did use a magnet to retrive the crush washer. Reassembled according to the pictorial in the maintenance manual.

Can you remove the valve actuator, the lifter that rides on the injection pump cam? I am thinking that the fuel path may have gotten some crud in there which is blocking the fuel flow to the valve. Is this reasonable?

On visual inspection of the delivery valve there does not appear to be any obstructions.

dieselbeagel · #4 09-07-2006, 10:29 AM

Fuel leak is due to the worn out o-ring.

U do not have to change the crushed washer. It maybe better not to change the crushed washer. Removing the inner spring out of the hole may throw the timing off.

It is better to just screw off the top, slide the old o-ring off and the new one on and screw back the spline nut.

U may have thrown the timing off.

dick87 · #5 09-07-2006, 11:56 AM

I thnk my problems are worse than that. #2 injector is not getting any fuel pressure. I swapped the #2 fuel delivery valve with the #1 fuel delivery valve. Still no fuel delivered to #2 injector. I am beginning to think I have an injection pump issue.

As noted previously the car ran fine prior to the leak repair.

I suspect that I may have got some crud in the #2 hole. Any suggestions on how to clear the contaimination from the area below the fuel delivery valve?

mbdoc · #6 09-07-2006, 12:32 PM

Yes, if you used a magnet to remove the pintle below the spring, the actual delivery valve could have come out of the guide pin on the main rack. you may disassemble down to that valve & see if you can re-insert the valve back onto the rack..if not then the pump will need to see a BOSCH service repair center.

dick87 · #7 09-07-2006, 01:19 PM

M.B. Doc

Good call. I did use a magnet to remove the pintel. Can you access the delivery valve from the inspection plate on the side of the injection pump? Can you steer me to a pictorial of the valve and guide pin on the rack?

Any further advise on how to reseat the delivery valve would be appreciated.

BenzDiesel · #8 09-08-2006, 08:26 AM

Quote:

Originally Posted by dick87

M.B. Doc

Good call. I did use a magnet to remove the pintel. Can you access the delivery valve from the inspection plate on the side of the injection pump? Can you steer me to a pictorial of the valve and guide pin on the rack?

Any further advise on how to reseat the delivery valve would be appreciated.

To reseat the bottom half piston of the chamber into the rack, I take the magnet and rotate piston, slightly putting downward pressure as I rotate it, until it reseats. Insure that the barrell shaped piston is ALL THE WAY DOWN in the chamber. Put the top half back on. Put the copper ring in. Put the spring and the part that fits into the piston back on. Then tighten, using the splined tool. I've had success using one STEP. Turn the thing until it won't go any further. In other words, crush the copper seal. That three step method I used when I was new to the 603 injection pump, contributed to my RUN AWAY engine problem, I think. But do know that you don't want a RUN AWAY. So, tighten until you know the thing is tight.

BenzDiesel

mbdoc · #9 09-08-2006, 08:30 AM

That post (BenzDiesel) is EXACTLY what needs to be done! Be careful....

dick87 · #10 09-21-2006, 02:25 PM

The problem has been solved. When I reinstalled the fuel delivery valve I managed to push the alignment pin into the injectin pump housing so that I could not get the valve body key to align with the alignment pin. The remedy was quite simple. Remove the injection pump inspection plate. GENTLY tap on the alignment pin with a punch which pushes the alignment pin back into its proper position. You can then install the valve body so that alignment pin aligns with the keyway on the valve body.

Lessons learned. Do not use a magnet to remove the pieces of the high pressure valve when replacing the O ring and seal. Take great pains not to disturb the fuel delivery valve assembly.

jrgslg · #11 09-22-2006, 08:23 AM

Kudos to all,that was an awesome thread to read from start to finish. Good job