Drip timing - OM617 - CONFUSED?? - PeachParts Mercedes-Benz Forum

rgnprof · #1 06-17-2008, 01:17 PM

I am trying to time my engine after my recent trip home (2200 miles) - car is pinging/knocking after installation of new, Monark injectors.

I am using the drip tube and I can't quite figure out the procedure when pumping the primer pump. With my car at 24 degrees BTDC, cam lobes up on cylinder 1 - I pump the pump and fuel flows pretty freely - stop pumping - and then fuel flow eventually slows down to one drop per second, but then stops all together. Should I be getting only drops WHILE pumping (not a steady stream), with car at 24 BTDC? Do I continuously pump the primer?

Does the following procedure also apply to OM617 engines?

http://www.peachparts.com/Wikka/OM615OM616InjPumpTiming

Ryan

tangofox007 · #2 06-17-2008, 01:24 PM

You want drips while pumping the primer. If you have continuous flow, you need to advance the timing until the flow changes to a drip. The flow will change from "all" to "nothing" very quickly as the IP is rotated. You want the spot right between "all" and "nothing."

rgnprof · #3 06-17-2008, 01:28 PM

Which way do I rotate the pump (away from OR toward engine) to advance timing?

ryan

tangofox007 · #4 06-17-2008, 01:28 PM

Toward.

rgnprof · #5 06-17-2008, 01:34 PM

In the FSM, it says to loosen the vent bolt (banjo) on the fuel filter, but the procedure described in the sticky does not mention that. Do I loosen the bolt, and if so, once I have primed the pump, do I leave it loose - or do I tighten i back up?

ryan

tangofox007 · #6 06-17-2008, 01:39 PM

I can't see any need to loosen that bolt in the first place.

#7 06-17-2008, 01:44 PM

Once you pump up the system, the residual pressure will let it drip for quite some time.

rgnprof · #8 06-17-2008, 01:50 PM

So FI, do I not need to continuously pump the primer?

I loosened the bolt and left it loose (and so that might change things some), but I think the FSM describes this step because it is assuming - I'm guessing here - that their is air in the system and that you are timing a pump that is being installed, or at least not on what has been a running car.

ryan

#9 06-17-2008, 01:57 PM

Quote:

Originally Posted by rgnprof

So FI, do I not need to continuously pump the primer?

I've never had to.

dieseldan44 · #10 06-17-2008, 02:01 PM

From my experience - once you are in the right spot - that point right between open and closed - you will not need to pump the primer to get 1 drip per second.

If you are off and the valve is too open you will need to keep pumping to see fuel flow through. So to get to the right spot i needed to have an assistant keep pumping while rotated the pump.

dd

tangofox007 · #11 06-17-2008, 02:24 PM

Quote:

Originally Posted by rgnprof

So FI, do I not need to continuously pump the primer?

The IP needs to drip when the fuel is under pressure. The "drip" that occurs at the "end of the stream" is not what you are looking for.

Think of it like it was a water faucet. If you turn a faucet off after it was running, it is going to drip for a bit. That's a different kind of drip that occurs when the faucet is not completely turned off. You want the continuous drip under pressure that happens when the IP is almost "turned off."

rgnprof · #12 06-17-2008, 02:44 PM

So, I keep pumping the primer, right....?

I have the 4 nuts loosened, but I can't budge the pump in either direction...pry bar? rubber mallet? Needless to say, I'm a little concerned about breaking something...

ryan

tangofox007 · #13 06-17-2008, 02:46 PM

I would vote for removing the other four hard lines.

rgnprof · #14 06-17-2008, 03:28 PM

Tango,

Thanks a million - your advice has been VERY helpful. Loosening the other 4 lines did the trick and I was able to move the pump easily. I have noticed a couple of things: 1) the pump was about as far away from the engine as it would go, 2) rotating it closer to the engine effected the flow, but I have fuel coming out of the primer now as I push it. The more I rotate the pump toward the engine, the stream stops and I get drips, then nothing - if I am still pumping then, the fuel spills out the primer (quite messy). Is this right?

ryan

winmutt · #15 06-17-2008, 04:36 PM

Quote:

Originally Posted by rgnprof

Tango,

Thanks a million - your advice has been VERY helpful. Loosening the other 4 lines did the trick and I was able to move the pump easily. I have noticed a couple of things: 1) the pump was about as far away from the engine as it would go, 2) rotating it closer to the engine effected the flow, but I have fuel coming out of the primer now as I push it. The more I rotate the pump toward the engine, the stream stops and I get drips, then nothing - if I am still pumping then, the fuel spills out the primer (quite messy). Is this right?

ryan

Pretty much, you should replace that primer pump when you have nothing else to do

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