PeachParts Mercedes-Benz Forum - View Single Post - OM617 injector return fuel flow and rough idle

Theseus · #34 07-24-2022, 12:16 PM

UPDATES (search posts on my user name for more detail on related posts):

- I needed to replace my crank seal, so this gave an opportunity to replace more parts in the engine.
- Discovered I had 6 degrees timing chain stretch. 3 degrees after new timing chain. Then added 2 degree offset key (with dial indicator method) to get it within 1 degree of spec. I wish I checked this before getting the injection pump! So please check this first! IF you have and still have rough idle condition, please share this to the group.
- Sourced a very nice 85 CA model injection pump. However, I have regrets because of that emissions sensor attached to it. It requires a very tricky ways to access the top bolt simply to attach the washer and bolt to tighten, but it can be done.
- If you have that pump and don't plan on using that sensor, unbolt the cover and you can unscrew that component from the rack. Reseal it with "right stuff, black". Cut the sensor wire and permanently seal cut cable with RTV.
- I bought the M**********.com pump injection timing kit with drip tube and video. For all the criticism, I have to say that his video and kit was well worth the price.
- I sealed gasket with "permatex aircraft gasket sealer". Won't harden or leak, allows for future adjustments, which were invaluable.
- Got the 1 sec drip timed at 24 degrees and able to repeat it after tightening all the bolts on the injection pump.
- installed a pyrometer on the exhaust manifold

At this point - I have not started the engine. I have removed two potential sources of the issue - the injector pump and the timing. The timing was definitely off spec by 6 degrees.

If this engine runs smooth, I very curious to see if air still comes out of the injector pump return line after acceleration. If it does - I may assume this is normal. Remember, my original injector pump had evidence of corrosion inside.

That's it so far!