1987 300D Turbo Glow plug light out. hard starting
 

Hi all! Another problem has arisen. My glow plug light on the instrument cluster has gone out. The car is hard starting in the cold. I assume that there is no cirrent flowing to the glow plugs. Is there a fuse anywhere? Or a relay? I get some white smoke on startup and when accelerating, but it is not excessive. Any help greatly appreciated.
Thanks,
Joe.

If the car starts, but runs rough, you may just have a glow plug out. If the glow plugs weren't working at all the car would be almost impossible to start (cranking for 30-60 seconds, in SUMMER weather.) The glow plug relay is in the engine compartment, on the driver's side fender, near the ABS pump and alarm horn. There is an 80A flat fuse in there that should be replaced every 5 years or so since it gets thermally stressed. Glow plugs should measure 0.6 ohms each, any more than an ohm or two and they're very likely bad...

White smoke isn't a good sign. Are you losing any coolant or oil, or have any oil in the coolant (or vice versa)?


Regards,

JF,

Here's a quick test to see if the GP are working:

Turn on the ceiling light and watch it when you turn the key to the GP position. It should dim slightly. If it doesn't, the GP are not working.

First check the fuse in the GP relay. If this OK try extracting and inserting cable plug that goes to the GP a few times. This fixed my '79 300SD when the GP didn't work.

I actually had no problem starting with the temp down to 40F when my GP were not working. I just had to crank for about 5 seconds instead of the usual 1 second when the GP are working correctly.

P E H