Hello all, I just signed up. Got a question for those who may know. My 80 240D preglow light flashes for about 30 seconds every time i start the car. I can detect no problems that it may be indicating. I have had the car only 2 weeks now, all my previous auto experience is in varoius Mopars, some of which i still have. Thanks for any help there may be. Jerry Hoback

Welcome to the forum.... I also have a 1980 240d....
Does your car have the pencil type glow plugs ?
Is this flashing a regular timed flash or sorta flickering randomly ?
How long do you glow before hitting the starter ?
Is it a solid light up until you hit the starter ?...while you are glowing the plugs before you hit the starter ?

i allow the glow light to go out before i crank the starter, the car starts Very nicely, then the light flashes a regular code-like deal. I'd say about 1 per second for 15 to 30 seconds. I dont know which kind of plugs they are. I havent removed them as I didnt see they were broke.Hahahaha. Jerry

Ok, that sounds like it is trying to tell you something...
I will have to check my manual ... but someone will probably know this off hand...
It may be saying that one or more glowplugs are bad.... and that you should check them before all of them go out and strand you the first cold weather that hits...

Just fixed this problem on mine. The flashing indicates a fault in the glow plug system, usually a burned out glow plug. The systems compares current draw among all the plugs, and if it finds one that is out of specs, it flashes the light. There could also be one plug that has a higher resistance than it should, causing the error.

To see which one it is, unhook the multiplug connector going to the glow plug relay (located on the left fender well). This will be the main wiring harness going to the engine. Then take an ohm meter and place one prong on the wiring terminal of the glow plug you want to check, and ground the other end to the engine. The reading should be 1 ohm or less. If it shows infinity, it is burned out. If it is higher than 1 ohm, it is out of spec and might be triggering the fault indicator.

great, thanks, It looks like ive got 2 bad plugs, onw with 4 ohms, one with varying 10 to 1000 ohms. Off to the SALVAGE yard!

Don' get GPs at the salvage yard, order from FastLane above, or go to a dealer. They are not all that expensive, and they are new!

Best Regards,
Jim

I have a box full of used ones that I will make you a great deal on. And I can give you great price on some used oil filters!!

All kidding aside, take Jim's advice. (Well, except for the part about going to the dealer.) Buy some new ones. The typical parts store will have the pencil type. Replace them all while you are at it.

Hey guys,
Must extend a thanks for the advice, regardless of where I got good glow plugs. The flash is no more! On to the next little malfunction.....