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-   -   Delivery valve internal leak as a cause of nailing? Yes? No? Maybe??? (http://www.peachparts.com/shopforum/diesel-discussion/363700-delivery-valve-internal-leak-cause-nailing-yes-no-maybe.html)

RunningTooHot 12-25-2014 10:35 PM

Delivery valve internal leak as a cause of nailing? Yes? No? Maybe???
 
Has anyone ever had a situation where the delivery valves were NOT leaking externally, but replacing the crush washer & o-rings resolved a nailing condition at idle? (Or has anyone ever encountered a broken delivery valve spring? (Assuming correctly or not that a broken or out-of-spec DV spring could possibly be causing nailing at idle?)

Reason for asking: My '98 E300 (OM606.92) has been nailing at idle on one cylinder. It's especially bad when cold, and it actually misfires under cold-start conditions. (The glow plugs all ohm out OK - but even if a glow plug was faulty, that wouldn't cause it to nail at idle while the engine is hot.)

I've pulled the factory original injectors out (to have Greazzer go through them) and I temporarily replaced them with a spare (used) set for the time being, but the nailing persists. Granted, I don't know the condition of the spare injectors, but the nailing is consistent – therefore my suspicion about the delivery valve.

It is definitely not a tank of bad fuel, as it has persisted through several tanks. (I also run Power Service at relatively high doses with every fill up.)

Any thoughts, opinions, conspiracy theories, etc. are much appreciated. Oh, and Merry Christmas too!!!

capflya 12-26-2014 01:13 AM

Curious to find this out as well. My 603 seems to have the same symptoms, yet no external leaking. I've also swapped injectors and it didn't seem to change anything.

compress ignite 12-26-2014 08:19 AM

The Master Shows how [Dieselmeken]
 
https://www.youtube.com/watch?v=-SW1dRGpHPU

compress ignite 12-26-2014 08:37 AM

Parrot of Doom's version
 
http://www.peachparts.com/shopforum/diesel-discussion/211801-om606-engine-w210-e300d-td-delivery-valve-seals.html

Mxfrank 12-26-2014 09:11 AM

It can't hurt to replace the delivery valve seals, but this isn't a likely cause. I had a problem like this on my 190DT (602). Turned out to be damaged valve seats, which required sending the head to a machine shop.

KarTek 12-26-2014 09:50 AM

Never at idle but at highway speed my car has had a nailing problem that I solved by re-torquing the DV holders. Also, tiny bubbles in the fuel lines can do it.

I also replaced the rubber line from the firewall to the fuel heater and that helped. I think it was sucking air somewhere along the line. Sometimes I get tired of chasing air leaks in that system.

capflya 12-26-2014 09:51 AM

I just had my head done at a reputable shop so I doubt the seats are my issue. I suppose it's possible but so is anything ;)

vstech 12-26-2014 10:05 AM

I like how the master cleaned the top of the IP BEFORE he removed the dv's POD's ip is scary dirty...

RunningTooHot 12-26-2014 11:19 AM

Thanks for the links Compress Ignite. And Vstech, I agree whole-heartedly!

KarTek: There are no signs of air in the fuel lines, even at higher revs - so that is not an issue. But the fact that re-torquing your DV's helped... that's encouraging!

MxFrank: Making sure that there are no mechanical deficiencies in the engine itself is something I will do when I've got everything apart - however considering the low mileage and easy life this car has had (90%+ highway use) I feel that it's very unlikely that there is a compression problem due to either a valve, ring, or head gasket issue.

As I typically do on any of my new (old) cars, when I "open up" an area, I just go nuts and replace every 'consumable' item so that I don't have to worry about it again for a long, long, Long time. When I have the manifold off I'll be replacing all the fuel lines, the DV seals, the SOV o-ring, and glow plugs. (If I've forgotten anything, please let me know guys!) I've already ordered Viton o-rings for everything even though I run only conventional pump fuel; I figure why not put the better material in. By the way, in addition to McMaster-Carr, believe it or not Amazon has viton o-rings available too.

I guess that I'm really looking for anyone's experience where there is verification / confirmation that the DV's can leak internally in some manner (past the crush washers?) and fixing that can resolve the nailing. :confused:

pimpernell 12-26-2014 01:41 PM

Quote:

Originally Posted by RunningTooHot (Post 3423158)
Has anyone ever had a situation where the delivery valves were NOT leaking externally, but replacing the crush washer & o-rings resolved a nailing condition at idle? (Or has anyone ever encountered a broken delivery valve spring? (Assuming correctly or not that a broken or out-of-spec DV spring could possibly be causing nailing at idle?)

Reason for asking: My '98 E300 (OM606.92) has been nailing at idle on one cylinder. It's especially bad when cold, and it actually misfires under cold-start conditions. (The glow plugs all ohm out OK - but even if a glow plug was faulty, that wouldn't cause it to nail at idle while the engine is hot.)

I've pulled the factory original injectors out (to have Greazzer go through them) and I temporarily replaced them with a spare (used) set for the time being, but the nailing persists. Granted, I don't know the condition of the spare injectors, but the nailing is consistent – therefore my suspicion about the delivery valve.

It is definitely not a tank of bad fuel, as it has persisted through several tanks. (I also run Power Service at relatively high doses with every fill up.)

Any thoughts, opinions, conspiracy theories, etc. are much appreciated. Oh, and Merry Christmas too!!!

When my 96E300 d delivery valves started leaking externally, I decide to repair them. Prior to me doing the repair, the engine ran smooth as silk at idle. The first time I did the repair, I did not change out the copper crush washers. A number of posters indicated it was not necessary to do so. The leak was fixed, but when I started the engine, it was nailing, which it had never done before. After driving the car for about 100 miles, the nailing was still there, and I decided to do the delivery valves again, only this time changing out the crush washers. Long story short, the idle was back to normal and smooth as silk.

RunningTooHot 12-26-2014 08:37 PM

Pimpernell,

Thank you! That is a VERY encouraging story, as it seems to verify that the crush washers themselves could cause nailing if they aren't sealing completely.

If your crush washers weren't sealing after you first replaced your o-rings AND that high-pressure leakage didn't blow out the new o-rings, then it logically follows that any crush washer leakage has an alternate path back out of the pump. Therefore (in theory) my pump's crush washer(s) may be leaking internally while still allowing the o-rings to remain intact and not cause external leakage. Good news indeed!

I sure wish that I had an old pump to dissect so that I could simply look at it to see how it functions - that would answer a lot of questions...

Diesel911 12-27-2014 12:00 AM

I have one Cylinder that has 50 psi lower compression then the rest and it nails slightly when hot and more so when cold.

When I used to rebuild Fuel Injection Pumps in a Shop Delivery Valve Spring breakage was rare but I have seen it a few times.

What is going to be fun in this case is that if the Delivery Valve Seals are replaced people have said all of them nails for a few 100 miles.

Some People have claim issues with the Delivery Valves themselves that were solved by replacing them but I don't remember the specifics of the symptoms they were having.

RunningTooHot 12-27-2014 01:34 AM

Thanks Diesel911, your input is always appreciated - especially in light of your shop experience.

I've read about the post-seal replacement nailing issue, so I won't freak out unless it persists for several hundred miles. I guess we'll find out the answer once I receive the 33-point socket and all the other bits & pieces.

compress ignite 12-27-2014 09:13 PM

One thing I did notice...
 
D.M. only Torqued-Released-Re-torqued ONCE.

And the 605 idled perfectly.

(We've always been cautioned about the NEED to release and re-torque
Three (3) times .)

gmog220d 01-24-2017 11:15 AM

Reviving this thread because the situation I have is just about identical to the one described in post #1, with the main difference being my car is not turbo-charged (1996 E300 with OM606, 184K miles). I've got a persistent nail at and a little above idle, and rebuilding the injectors made no difference. Searching led me to this and other threads about delivery valves being a possible culprit.

RunningTooHot - Did you ever resolve your idle nailing issue? I've got pretty much the same thing going on:

- One cylinder always nails below 1300/1400 or so RPM, worse when cold to the point the engine misses a little until warmed up.
- IP is dry - no leaks.
- Replaced all fuel system o-rings - no air.
- Replaced return and supply fuel hoses between engine and chassis.
- Replaced main and pre fuel filters.
- Pulled injectors and had all the nozzles replaced, and adjusted to pop within 5 bar or so of each other.
- One cylinder took a lot longer than the others to purge the air, and it made some nasty knocking noises in the process.

The engine runs better but the nail persists as if rebuilding the injectors did nothing for it. Under power the car is smooth and quiet. With no load the engine is quiet over 1300 - 1400 RPM but I do feel a subtle engine shake up to around 2500 RPM.

Here's a video I shot of mine and its nail. The engine was at operating temp after a drive. It's generally clattery around 1000 RPM and below, but there is one cylinder that nails consistently to about 1300 - 1400 RPM.

https://www.youtube.com/watch?v=vlmywW0wXmI&feature=youtu.be

Does my engine's nail sound consistent with what others have fixed by re-sealing the delivery valves?


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