Having some issues w/ cold starts ... Seems TOTALLY backwards than all the postings I've read.

My car starts when the GP light does NOT glow, hesitates badly when it does!

When the GP light does not come on, I simply wait for the relay to click off, and the 240 starts right up. When the GP light glows, relay won't "click off" and I rely on compression and cold cranking power to turn the engine over.

Batt fairly new, new Berus as of the fall, all batt terminals clean and grounding straps pulled and polished. Any ideas???

__________________

You will have to go throug the full troubleshotting proceedure. Do internet search for the Diesel Gaint site he has a good pictorial of trouble shooting the glow plugs. I do not know which models have which equipment but some engines have a temperature sensor; located I believe some where on the cylinder head and it is part of the glow plug relay circuit.
Also the Diesel Gaint site deals with a glow plug relay located on top of the engine compartment fender well on the drivers side. If you glow plug relay is inside the car, to the Left of and under the instrument cluster. Trouble shooting is different.

__________________
84 300D, 82 Volvo 244Gl Diesel

If the pre-glow light won't go out, the relay is telling you that there's a problem. The fact that the relay works when the light doesn't illuminate is a second and probably related sign of trouble in the relay itself. If you have checked all of the glow plugs (even though they were new last Fall) by measuring resistance with an ohmmeter at the cable where it plugs into the relay and they are all 1 Ohm or less, then there is most likely a problem with the relay itself. Swapping in a known good relay is the only way, AFAIK.

Jeremy

__________________

"Buster" in the '95

Our all-Diesel family
1996 E300D (W210) . .338,000 miles Wife's car
2005 E320 CDI . . 113,000 miles My car
Santa Rosa population 176,762 (2022)
Total. . . . . . . . . . . . 627,762
"Oh lord won't you buy me a Mercedes Benz."
-- Janis Joplin, October 1, 1970

The operation of the light is essentially unrelated to the operation of the relay. Both are controlled by solid state circuitry in the timer device, so the problem is most likely with the control circuitry, not the relay itself. In any case, continuous operation of the light is not one of the programmed diagnostic indications.

An '83 uses ambient air temperature to determine the duration of the glow plug indicator light operation.

When I had one plug go bad, the light quit working. The engine started, but not as easily as normal...it sputtered for a few seconds and then smoothed out. Then the rest of the plugs went out a few days later and the car wouldn't start for anything, but the light worked just fine . It came on, went off after a few seconds, the relay clicked and everything. I just had 5 bad plugs. So it seems like my light only works when all of the plugs are good..or bad.

Here's diesel giant's troubleshooting procedure:
http://www.dieselgiant.com/glowplugrepair.htm

__________________
1985 300TD-euro 352,000 mi
1974 240D (1?)52,000 mi - has a new home now

The light is controlled by a coil that amplifies the current to glow plug #1 by a factor of four, then balances that against the combined current to the remaining plugs. If none of the plugs work, there is no imbalance, so the light will operate as if there is no malfunction.

Think I just found out what happened to mine.

See this thread.
Help please. Car won't start in cold.

When I tried to start it Saturday night in the cold the light stopped working. Then went back to it Sunday morning and the light started working again. I tested all 5 plugs today and all tested infinite.

So a few quit working and the light went out. The others burned out and the light started working again Sunday morning.

Getting 5 new GPs today. Hopefully this will start 'er up.