another 92 OM602 running rough after replacing delivery valve seals - PeachParts Mercedes-Benz Forum

diesellover 92 · #1 08-29-2017, 08:33 PM

So i pulled the intake manifold off and decided to tackle a few of the various orings that have been leaking. Lately i have been getting a rough start that smooths out once everything bleeds.

Anyways i cleaned the area and did the valves one at a time. Both crush washers and o-rings. On the very first valve with i pulled it up a small part was stuck to the bottom of the spring and the spring came out in the valve. I didn't pay much attention to it and dropped the small part with a spline back in the hole. I torque the seals 2x 35nm fired it up with the intake off. Took a while bleed to get it to fire, once it finally smoke out i was getting some backfire out of cylinder 1x and i see that i royally messed up.

any advice, i see i can check for a pin on the side of the pump if i pull the cover. should i have the ip timing tool in place when i do this?

engatwork · #2 08-29-2017, 08:46 PM

Quote:

i see i can check for a pin on the side of the pump if i pull the cover. should i have the ip timing tool in place when i do this?

You are on the right track. There is a pin that gets boogered up when you put the part that stuck to the spring in the wrong way. Fix is to remove the part that stuck and push the pin out a little to pick up the slot (after removing the cover plate on the side). I did this one time and ended up pulling the IP and taking it to an injector shop for repair. You should not have to lock pump down if you don't remove it from the engine.

diesellover 92 · #3 08-29-2017, 09:32 PM

i pulled the cover off, i can't see anything in there. All the parts are covered black from the leaking alda i also replaced. might need to get a locking tool and pull the pump to see better.

Diseasel300 · #4 08-29-2017, 09:54 PM

Changing the D/V seals has no effect on timing at all. If your timing is off, your D/V procedure had nothing to do with it.

More likely than not, you have dirt or something in one of the delivery elements or an improperly torqued D/V holder. FSM says to torque to 30, release, 30, release, then final tightening to 35nm. The idea being to get everything seated before applying final torque.

Backfiring out of the #1 cylinder suggests you have valve seating problems as well. Time for valve guides? They were shot on my SDL at 176K. Iron valve guides don't enjoy long lifespans. The replacements available are bronze which should likely last the life of the engine.

diesellover 92 · #5 08-29-2017, 10:23 PM

Quote:

Originally Posted by Diseasel300

Changing the D/V seals has no effect on timing at all. If your timing is off, your D/V procedure had nothing to do with it.

More likely than not, you have dirt or something in one of the delivery elements or an improperly torqued D/V holder. FSM says to torque to 30, release, 30, release, then final tightening to 35nm. The idea being to get everything seated before applying final torque.

Backfiring out of the #1 cylinder suggests you have valve seating problems as well. Time for valve guides? They were shot on my SDL at 176K. Iron valve guides don't enjoy long lifespans. The replacements available are bronze which should likely last the life of the engine.

perhaps is it related to no final 30nm torque, but outside of the rough running fuel issue for the first 20 sec after sitting for a day its ran excellent. I was getting between 29 and 33mpg and have not burned any oil. Just decided to do the leaking dv orings and replace the alda oring. Based on what i have read when the smaller top piece came out it disturbed the timing on the lower barrel.

Diseasel300 · #6 08-29-2017, 10:30 PM

Quote:

Originally Posted by diesellover 92

Based on what i have read when the smaller top piece came out it disturbed the timing on the lower barrel.

Highly unlikely. The M pumps that the OM60x engines use are not like the earlier MW pumps on the 61x engines. You can remove the entire delivery valve assembly (both the plunger and the barrel it sits in) without disturbing timing or injection settings. The injection elements are down below the delivery valve, you have to really reach down in there to get into anything that you can screw up.

diesellover 92 · #7 08-29-2017, 10:40 PM

hope you a right, tomorrow i will try the final torque sequence and see if that clears up my issue. It just seems odd that the cylinder that small splined piece came up out of is the one that backfired. I was also getting a ton of smoke when it did finally fire up.

Diseasel300 · #8 08-29-2017, 11:35 PM

It's worth checking that you made sure the top of the IP was "surgically" clean before you started right? If any crap got down in the delivery valves while you had it apart, you could have an injector hanging up or a delivery valve not seating properly.

For what it's worth, I've had the delivery valves entirely removed from my IP (there's a thread running somewhere in this forum chronicling that adventure) for polishing the faces to stop a persistent nailing. They can be removed and reinstalled without affecting anything else in the fuel delivery system. If all you had out was the plunger, I don't see how anything could be damaged or thrown off fuel-wise.

diesellover 92 · #9 08-30-2017, 06:18 AM

Quote:

Originally Posted by Diseasel300

It's worth checking that you made sure the top of the IP was "surgically" clean before you started right? If any crap got down in the delivery valves while you had it apart, you could have an injector hanging up or a delivery valve not seating properly.

For what it's worth, I've had the delivery valves entirely removed from my IP (there's a thread running somewhere in this forum chronicling that adventure) for polishing the faces to stop a persistent nailing. They can be removed and reinstalled without affecting anything else in the fuel delivery system. If all you had out was the plunger, I don't see how anything could be damaged or thrown off fuel-wise.

"surgical" Hard to say. I sprayed it down with a can brake cleaner and wiped the areas down before removing each delivery valve only one at a time. It is possible something fell in. I didn't see your thread on the ip pump is it a 602 or 603 ? I plan to run a can of diesel purge to clean it, and i also saw it mentioned somewhere about measuring heights of the DVs after being torqued.

Maxbumpo · #10 08-30-2017, 08:37 AM

My advice: try again with #1, either use a new copper washer or re-soften the current washer by heating to a glowing orange with a propane torch, and then clean it off really well.

Sounds like you may have a couple things going on. Clean clean clean, surgically clean, is a MUST DO. Any contamination into the open DV area can damage both the DV and the injector. Remove the DV cylinder and plunger and closely inspect, and look down into the well to see if any grit is in there.

The torque procedure cannot be ignored.

Slight correction to Diseasel's post on the procedure: Torque to 30 Nm, release, torque to 30 Nm, release, torque to 30 Nm, and then torque to 35 Nm.

Diseasel300 · #11 08-30-2017, 10:27 AM

I've seen the torque spec show tighten both twice and 3 times to 30 before final tightening to 35. I've done both two and 3 tightenings to 30 and with new copper washers it doesn't seem to make any difference.

The key is proper preparation. I tend to rub oil on the O-rings before I install them with a bit of oil in the threads as well. The first time I did the DV seals i had an O-ring grab and make me think it was seated, but wasn't. Cleanliness is next to Godliness in this procedure too, since you're post-filter, if there's anything that gets in the DV chambers, it's going right to your injectors. There's such tight tolerances involved that ANY filth that gets through will cause scoring or hanging up. I generally don't clean the IP until after I take the retainer rings off, there's a ton of crap that likes to hide under there.

The very long running thread (a true cure for insomnia) on the DV nailing can be found here: http://www.peachparts.com/shopforum/diesel-discussion/363700-delivery-valve-internal-leak-cause-nailing-yes-no-maybe.html

diesellover 92 · #12 08-30-2017, 11:08 AM

So i can remove the spring under the plunger without worrying about untiming the ip?

Maxbumpo · #13 08-30-2017, 02:38 PM

Yes, you can remove the spring, see this video for as far as people normally go when replacing the copper seals:

https://youtu.be/-SW1dRGpHPU

You can take two more parts out after the spring and the washer, see pix here:

http://www.peachparts.com/shopforum/3704481-post97.html

These are the actual parts of the delivery valve. Pay close attention to orientation, don't take the small plunger out unless you really think you need to. Note that the biggest risk will be getting dirt into the IP at this point.

diesellover 92 · #14 08-30-2017, 03:02 PM

The smaller piece on the left is what came out with my spring.

diesellover 92 · #15 08-31-2017, 07:43 AM

Update. Pulled the delivery cap cap off and noticed not alot of fuel in chamber. Took an airgun and blew across the top with my finger on the plunger. Lots of fluid came out and fuel started running up. Replaced the brass washer and retorqued. Fired right up, Still seeing air in the lines between injectors. Going to pull the lift pump and replace those seals along with the emergency shutoff. I am already bypassing the fuel heater but might pull that replace those orings since i have them.