There is a slight ping when I start my 81 240D after it has been setting for 8 hours. After about 5 mins the ping goes a way.

I know that I need to replace the glow plug relay,because sometimes it doesn't work at all. I wait tell I hear the "click" to start the car. Sometimes the relay will turn on and right off, so I only start the car after one cycle is over.

What a diesel purge do anything to help the ping or could be the relay not giving any power to one or more glow plugs?

How do you do a diesel purge?

__________________
1981 240D
Click Here To See My Mercedes

Its normal. That is the detonation of fuel your hearing, the excess pinging is caused by a cold engine.

__________________
1981 300SD 512k OM603

Thanks for the info. One last question. What controls the glow plug light on the dash. Does the relay control this?

__________________
1981 240D
Click Here To See My Mercedes

The relay and a temp sender in the engine control the light. Having your injectors checked for spray pattern would not hurt, and could give you a bit more power. Nailing is often caused by a poor spray from old injectors.

__________________
1979 240D- 316K miles - VGT Turbo, Intercooler, Stick Shift, Many Other Mods - Daily Driver

1982 300SD - 232K miles - Wife's Daily Driver

1986 560SL - Wife's red speed machine

My experience is DP stops nailing when it's actually being burned but doesn't make it go away long term. Good spray pattern and pop pressure fixes it.

__________________
1987 300D (230,000 mi on a #14 head-watching the temp gauge and keeping the ghost in the machine)
Raleigh NC - Home of deep fried sushi!

That has been my experience too.

__________________
1979 240D- 316K miles - VGT Turbo, Intercooler, Stick Shift, Many Other Mods - Daily Driver

1982 300SD - 232K miles - Wife's Daily Driver

1986 560SL - Wife's red speed machine

What is the cost to replace the injectors? Or can they be cleaned? Would a purge help any?

__________________
1981 240D
Click Here To See My Mercedes

I have very good news for you......

I took an injector from my 1977 240D apart last Saturday.

You need a 27mm deep socket (Mine a Craftsman) to remove the Injector and the torque is high so I have a 2 ft piece of pipe to extend my ratchet handle.

I simply put the removed injector in a vice, opened it up, and there are just about five parts in a serial assembly. The pintle is on bottom.

I used a bath of solvent (degreaser) and voila....

When it went back together it was perfect.

This is a very easy task and anyone can do it.

Make sure the shim is put back on top of spring the way it came out.

I was expecting something way more complex and difficult based on narrative on various groups. I see no need to take it to a shop but I am sure it does not hurt. You can see that it is clean by visual inspection. I do not have a cleaning kit.

Go for it and let me know how you are doing.....

__________________
Dionysius

I might give this a try. What about doing a purge?

__________________
1981 240D
Click Here To See My Mercedes

A purge is like using liquid plumber versus a power snake.

I never got a fix out of a bottle other than Whisky!!!!!

Use a purge to keep a system running great....not to fix a system.

Please let me know how you did....

__________________
Dionysius