Hello to all. Car is a '92 300D 2.5 Turbo with 110,000 miles. I decided to have the injectors rebuilt because the engine was running rough. Before removing injectors, the engine was quite. Now after having the injectors rebuilt by a repair shop that specializes in diesels, the engine is nailing at idle but doesn't at higher RPM. I placed new crush washers at the bottom of the nozzles. What can be causing this?

Thanks

If you mean your car now sounds like a Ford powerstroke tow truck, this isn't unusual following an injector rebuild.

It will clear out with driving.

If it's worse than that, really banging, that's outside my experience.

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Mac
2002 e320 4matic estate│1985 300d│1980 300td
Previous: 1979 & 1982 & 1983 300sd │ 1982 240d

“Let's take a drive into the middle of nowhere with a packet of Marlboro lights and talk about our lives.” ― Joseph Heller, Catch-22

Define "rebuilt."

I took my old injectors to a company specialising diesel equipment and told them to rebuild the injectors. I imagine they replaced the guts of the injectors because they said they had to order some of the inside parts like the needle.

Injector nailing is caused by injectors that pop open to soon causing fuel to pre-detonate in the cylinder. Which causes that nailing or hammering sound.

Rebuilt injectors that have just been taken apart cleaned re-shimed to the proper pop pressure should sound just the same as the old. If this is the case than someone didn't rebuild the injector properly.

Rebuilt with new nozzles will make more noise for a short while, and it's normal. If this is the case I'd drive it for a 100 miles and see if the noise goes away.

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Some of the Members have said a several things:

The Nailing goes away after 100s of miles of driving

In use Injector Pop Pressure gets lower; and, raising the Pop Pressure during rebuilding retards the time when the Fuel is actually being Injected.

(Nailing can be caused by too late/retarded of Fuel Injection Pump timing and also too much advanced timing.) It may be the Fuel Injection Pump needs to be retimed.

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84 300D, 82 Volvo 244Gl Diesel

It might be a bit rough until you log a few hours IF the nozzles were replaced. I had the local Bosch boys rebuild a set w/o replacing the nozzles and it ran better then before. They did tweak the shims or spring preload. Dont know about you, but I got all anal about rinsing out the hard lines before I put the injectors back on. I had simply left them sitting,a dn you wouldnt think anything could happen but..... I had a bugger of a problem once with a Holley carb I literally set aside while I swapped a motor ( an hour back as a kid). well, somhow a piece of crud endied up getting in there and blocking an air bleed. A Holley carb is a crude piece of equipment as comapred to an injector OR an IP.