how to check/tune ip timing on an OM606? - PeachParts Mercedes-Benz Forum

kickit · #1 06-08-2011, 01:12 AM

I've been hunting around for a good post on how to check/tune the timing on my IP for my OM606. I could not find it on the forum thread on the subject: Diesel Injection Pump Timing Device threads

The FSM says to use a Digital meter but I do not see one in the loaner thread.

Any one ever tackle this one? ...or should I just take it to my local MB shop?

Jeremy5848 · #2 06-08-2011, 01:16 AM

Why do you think there's a problem? IP timing usually doesn't change by itself, unless you have a great deal of timing chain stretch, which is another problem entirely.

kickit · #3 06-08-2011, 01:23 AM

New injector nozzles installed recently and there is a little white smoke in the exhaust now that wasn't there before. Timing chain is new as of 6 months ago.

KarTek · #4 06-08-2011, 05:25 AM

I've done a lot of pump work on my car and I set the timing by "ear". It's not scientific but it's worked so far. I was getting a burst of clatter upon initial acceleration which indicated far retarded injection so I just advanced it little by little until the clatter went away.

I'd really love to get one of those acoustic interfaces to do a proper job of timing it though but their several hundred dollars.

kickit · #5 06-08-2011, 08:27 AM

Quote:

Originally Posted by KarTek

I've done a lot of pump work on my car and I set the timing by "ear". It's not scientific but it's worked so far. I was getting a burst of clatter upon initial acceleration which indicated far retarded injection so I just advanced it little by little until the clatter went away.

Thanks. I have clatter too! I'm attaching the pages from my FSM. So it looks like I can loosen the securing bolts and just adjust the 30/1 screw?

Lowflyingbird · #6 06-08-2011, 08:31 PM

I have a 1996 E300 with 220kmi on it. I highly doubt the chain has been replaced, I also have some white/blue smoke when cold and a little too much clatter. My injectors were tested /shimmed, they are perfect. Tank cleaned, good fuel, no bubbles in lines. Runs very good when warmed up with a little too much clatter remaining. Power is a little weak at bottom end RPM, good as it builds more RPM.

Possible to try adjusting the pump slightly to improve? Please explain steps in doing so, Pics. if possible.
Thanks
Lowflyingbird

KarTek · #7 06-08-2011, 09:04 PM

That PDF is exactly as the procedure is. Use a 3/8" drive with a 3" extension and 13mm socket to loosen the front 3 and rear 1 bolt just a little, not super loose because the threaded tabs will fall off and you'll have a heck of a time putting them back on. (I also used a piece of bailing wire to pull and hold the radiator hose out of the way. Then, put an 8mm socket on a 10" or so extension and slip it down over the adjusting screw.

Start the engine and let it warm up completely. Grab the throttle and slowly rev the engine to around 2k RPM. If you hear a lot of clatter just off idle until about 1500, then turn the adjusting screw a half turn counter clockwise and repeat the rev from idle.

If you still hear the burst of clatter, turn the screw another half turn and repeat this process until you hear some improvement. Keep count of your turns because if you don't hear any change in the engine sound, you have another problem and you'll want to return the pump to it's original position. I went a little too far with the advance and the engine started making a soft "squeaking" sound from somewhere inside so I turned the screw a turn or 2 clockwise until the noise went away.

It's been running perfect ever since!

kickit · #8 06-08-2011, 11:36 PM

Evan: Perfect, thanks!!

compress ignite · #9 06-09-2011, 01:01 AM

Y'all Do realize Turning the Adjusting Screw 30/1 WITHOUT the Electronic Meter 001
TAKES the I.P. Outside the Parameters of the Factory Specs.
(FOREVER, as far as you're concerned!)

Only Crazy Owners adjust their I.P.s by EAR!

[For Me,this is like watching a Blind Man teach other Blind persons to fly,over the Internet.]

KarTek · #10 06-09-2011, 10:08 AM

Obviously it's better to do things according to spec but lacking the appropriate resources: funds/tools, we do what we have to.

Beyond the detonation due to far advanced injection, what are other dangers?

okto · #11 06-10-2011, 12:46 AM

Quote:

Originally Posted by compress ignite

Y'all Do realize Turning the Adjusting Screw 30/1 WITHOUT the Electronic Meter 001 TAKES the I.P. Outside the Parameters of the Factory Specs.

So does driving it 250,000 miles. I'm not that worried

okto · #12 06-10-2011, 02:03 PM

Having just done this procedure last night, I'm going to add some knowledge (mainly for noobs like myself):

1. The bolts for the IP are on the mounting plate for the vacuum pump, and kind of hidden Only two of them can be seen without removing the radiator. The FSM manual diagram is, as usual, only slightly better than nothing, giving the impression that the bolts should be both readily visible and easily accessed.

2. The IP bolts, at least on my engine, are EXTREMELY tight. Like, cheap-ratchet-breaking tight. Use a breaker bar and some PB Blaster, and don't be afraid to whale on it a bit. Mine took me most of 20 minutes to break loose.

3. There is a lot of stuff in the way of the IP adjustment screw 30/1. On mine, there's a fuel hose routed DIRECTLY over it. You're going to want to use a 1/4" drive socket and extender here, I can't see how a 3/8" extender could even fit into this space.

4. 30/1 is quite loose. I was expecting it to be slightly stiff, but it turns freely. Don't turn it too far. I ended up taking the extender off the ratchet and turning it by hand because the screw didn't provide enough resistance for the ratcheting action.

kickit · #13 06-11-2011, 12:36 PM

Quote:

Originally Posted by okto

Having just done this procedure last night, I'm going to add some knowledge (mainly for noobs like myself):

Thank you from a fellow noob!

I'm going to give this a shot this weekend and I really appreciate the input.

kickit · #14 06-11-2011, 08:38 PM

Guys: I've loosened the three 13 mm bolts that I could find, but I couldn't get the rear bolt loose. There's another device in the way and it's really hard to get a wrench or socket on it. Any advice here would be great.

I got the engine all warmed up and the 8 mm IP adjustment bolt goes just under 2 turns clockwise with my fingers like okto said, then it stops and is hard to turn even with a socket wrench. I do not want to break anything and I'm not sure if I loosened the correct three 13 mm bolt heads.

Can you take a look at the picture below and see if this is the top bolt to loosen? This is the one I am unsure of. It's between the fuel filter and the power steering pump and you have to use a regular open wrench to loosen it because of the pulley wheel. Maybe there's another bolt down below that I did not find?

sixto · #15 06-11-2011, 09:08 PM

That's not one of the IP retaining bolts. One of the square nuts is ahead and about the level of the IP lift pump. The other two are between the IP and block so just loosen the bolts. If you remove the bolts, you might never retrieve the square nuts. I don't know where the back end bracket is in a 606.

You need a good reason to move the IP, or more relevantly, the o-ring between the IP and the block, after 250K miles. That o-ring is just begging to leak.

Sixto
87 300D