87 300tdt quit running, now glow plug relay light out - PeachParts Mercedes-Benz Forum

Comanche · #1 11-22-2019, 05:27 PM

Hi, I am new to this forum thing, and recently wound up with my first Mercedes. Drove it home, ran fine. Went to start in the morning and cranked but no start. Charged the battery back up, replaced blower motor fuse, went to start it, glow plug light came on and then timed out, engine cranks, no start. Went to turn over ignition switch again, no relay light came on! Fuse on relay is good, I figure there must be other issues I'm dealing with. Has 190k miles but hasn't been properly maintained. I notice it has been sitting awhile also. Any help is greatly appreciated, thanks.

Diseasel300 · #2 11-22-2019, 08:03 PM

Sounds like a fuel delivery problem, probably air in the system. An OM603 will start even without glow plugs, you have to crank a bit, but it'll start. Make sure the "Stop" lever on the injection pump is raised up with the key on, it's possible that there's a vacuum issue keeping it held down.

Comanche · #3 11-23-2019, 10:52 AM

Thanks for the wisdom, it is currently 21 degrees out so will wait for it to warm up. I noticed the stop lever but not sure what it was for. I ordered some manuals but waiting for them to arrive after Thanksgiving. Lever is up when the key is off, will check it out.

barry12345 · #4 11-23-2019, 04:12 PM

Was the the temperature gauge up when you picked it up or at the bottom?

Comanche · #5 11-24-2019, 01:03 PM

I tested yesterday, the fuel lever was up with key on, tested glow plugs, 5 of 6 are bad. Found 2 loose fuel line connections, and battery appears to be bad. When I drove it home from purchase/trade, the temp gauge was working, half up. As soon as it warms up, possibly tomorrow, will replace the glow plugs and install the battery for further testing. What would the temp gauge have to do with starting? Thanks for taking the time to respond. I greatly appreciate the assistance.

dlssmith · #6 11-27-2019, 12:57 PM

The temp gauge question is about whether it is working or not. From your comment it seems like it is. If you can get it inside in a 60 or 70 degree building she will start without the glow plugs operable. It will take some cranking but a 603 will start without glow plugs - though not likely if its 20 degrees ambient temp.

barry12345 · #7 11-28-2019, 08:46 AM

The temperature gauge question was based on. If the temperature was already up when you picked up the car. It could have been that way because it was very hard to start cold by the vendor.

In any case like that usually you want to do a compression test. Although it sounds like your lack of glow plugs was the issue in your case probably.

I do not know a lot but with cars. You really have to be careful when buying. I feel ethically bound to tell people what I am selling them. If it is intended for use. Beyond a certain condition I will have it scrapped instead.

Times have changed and some of the newer generations know nothing about cars. There are probably many factors for this including how complex the cars have become over my lifetime.

Comanche · #8 12-01-2019, 11:11 AM

Thanks for the input. I traded for the car, received it when it was warmed up ans running. Was in the original family aince new, 190k miles, has spent a lot of time sitting. 1 glow plug tested good, battery is replaced as the prior one kept running down. I don't have a warm place to put it in at the moment. Paranoid of changing glow plugs due to cold-don't want to break them off!

dlssmith · #9 12-01-2019, 07:21 PM

Quote:

Originally Posted by Comanche

Thanks for the input. I traded for the car, received it when it was warmed up ans running. Was in the original family aince new, 190k miles, has spent a lot of time sitting. 1 glow plug tested good, battery is replaced as the prior one kept running down. I don't have a warm place to put it in at the moment. Paranoid of changing glow plugs due to cold-don't want to break them off!

I was in a cold place away from home one time when the second or third glo plug failed on my 603. I kept the car running for about 4 days until I could get it into a place to change the glow plugs. But they sip fuel when idling and what could I do? It was about 15 below zero then and she just wouldn't start without glowing at that temp. When it got below minus 15 f she would barely start even with 2 or 3 full glow cycles and all six glowplugs functioning. Seemed like minus 15 f was her cut off point - Above that she always started. I have always been warned away from using starting fluid with diesels with pre-chambers so that's not an option.

Comanche · #10 12-03-2019, 10:25 AM

Thanks, I agree and don't want to use starting fluid of any kind. It is suppose to be nice today, around 40f so will attempt to change some glow plugs!

dlssmith · #11 12-09-2019, 06:16 PM

I changed glow plugs this week in the 603 and was reminded that it isn't a bad job at all. Removing the intake is the hardest part and that isn't the worst part if you have the swivels and ball end hex and so forth to get into the crannies.