Quote:
Originally Posted by RunningTooHot
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!!!
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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.