car wont start
 

I have bad glow plugs and I foolishly havent started my car in a couple days. I tied to start it today and I cranked it for at least a minute but It would not turnover. Primed the injection pump but still nothing. I got home later in the day when it was a little warmer and tried again. Still the same result. I'm gonna take my battery to have it tested\charged since its still under warranty. What else should i try to do? Thanks a lot

Get the glow plugs fixed, you will fight it forever until you do.

Peter

Fastlane sells for glow plugs + a relay for about 100$. The gps are bosch so I'm gonna guess that these are good quality. Anu objections?

Do you need the relay? GPs run about 50 for a set.

I'm not sure yet I haven't checked the glow plugs for voltage and resitance yet. The light on the dash does not come on though when the glow plugs should be charging. How hard is it to change glow plugs anyway?

adiaw83,

I think you should check the glow plug relay fuse. There is a couple of inches square size black plastic box on th driver's side inner wheel well. This thing has a snap open cover and inside you should see a stamped out, stainless steel, sheet metal looking plate, with two screws, one at each end, holding it down. This is the fuse and you should take it out, check it out and make sure it is not cracked or broken in half, and replace it if it is bad.

I am a believer that with production methods as uniform as they are, when one plug goes, the rest are closing in on the day they will quit too. So I replace them in sets. There is nothing wrong with having a set on hand, so I would go ahead and get them. I would not get a relay until I knew I needed one as I have never replaced a relay, and I have abused my glow plugs in Winter months in the past.

Good luck, Jim

Adiaw83,

First you stated that you have bad GP. Then you tell us you tried other remedies to try to start the engine and you seem to wonder why it wouldn't start.

Elementary, my dear Watson. You have to fix the problem, not something else if you want to your engine to start.

First do a voltage test on each GP. You should have ~12 volts at each one for ~45 seconds after the key is turned to the run position. If there is no voltage at the GP, either the fuse is open or the GP relay is not working.

Does the GP relay click when key is turned to run position. If not, try R&R the smaller cable connector on the relay 10 times to clean off the corrosion on the contacts.

Let us know your results.

P E H

BTW, the fuse Jim refers to s/b 80 amp - you can also get them in 30 amp and 50 amp for other applications, but 80 amp is the right one for your 300SD.

80 amps! That's a lot of current! Probably makes sense to replace it every 15k service.

Thomaspin,

Replace a fuse as a maintenance item, I don't think so.

If a fuse is rated for 80 amps then it won't be harmed at currents up to 80 amps. At currents over 80 amps it is supposed to melt and open the circuit to prevent damage somewhere else.

Do you replace any of the other fuses at 15,000 mile intervals? Why would they be any different?

The same 80 Amp fuse has been in my '80 300SD for the 13 years I have owned it and maybe it is the original. I carry a spare but I'm not about to replace it until it goes open either by a crack or melt.

If it ain't broke, don't fix it.

P E H

I carry a spare. If I did not, I would replace it. $2 beats being stranded. Frugality ia a net cost concept, no?

Thomaspin,

I carry a spare too. Seems I remember they cost $.37 from Fastlane but it might have been something else I bought .

P E H

Even if all the glow plugs and the relay are shot, the car should start eventually. Failure of the aforementioned parts shouldn't make it impossible to start...

Since it would be quite unusual for all GPs to fail at the same time, I would assume the engine would start, or cough close to starting, with even three working, right?

Then, can't be GPs ... relay or wiring or ignition (not exactly accurate for a diesel), then?

I thought a 300SD should start with 3 good and 2 bad GP but it wasn't so. The engine wouldn't even sputter. Temp was less than 30F. The two bad GP were in firing order sequence.

I replaced the 2 bad GP and engine started instantly. I have no explanation why the 3 cylinders with good GP would not fire, even if not enough to get the engine running.

P E H

I got the car started the other day after charging the battery. It hasn't started since then though. I fiddled wit the fusese the other day. Took out the big box ones in the back of the fuse box the check them and but them back. Since then the gp will come on for about 3-5n seconds the car still isn't starting.