this is my first MB experience, bought the 80 300CD with new glow plugs, has a cold start issue, needs starting fluid even in the now warm weather. I like to do my own work, even major rebuilds and have experience with diesels (off road). Most likely an electrical problem here, should check +and- (wiring), relay(s), is there a most frequent issue here to look for. Appreciate any help I can get here, thanks in advance.

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80 300CD new to me

Have you checked engine compression?

How warm is warm weather? Sounds more like a compression issue to me. Buy a cheap multimeter, search this forum for glow plug testing. If the weather is warm enough, it should eventually start with enough cranking, without glow plugs. Could be a valve issue, maybe.

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1989 300E 144K

By the way, welcome to the board and your new obsession (don't believe me? Give it a few months.)

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1989 300E 144K

Yes, the most frequent issue to look for is a cracked strip fuse in the glow plug relay. Follow the wires to the black box on the driver's side of the engine bay. The fuse is inside and looks like a piece of metal held down with 2 philips head screws. It can be cracked and look fine, so remove it completely to check. Be careful, because one of those terminals is hot all the time.

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Rick Miley
2014 Tesla Model S
2018 Tesla Model 3
2017 Nissan LEAF
Former MB: 99 E300, 86 190E 2.3, 87 300E, 80 240D, 82 204D Euro
Chain Elongation References

Welcome to the forum.

Following up with Rick's recommendation.............

He's thinking the glow plugs are not functioning whatsoever. I agree with this.

Find a voltmeter and look for 12V at one of the glow plugs immediately upon turning the key to the #2 position. If you do not have 12V, then, it's very likely that the fuse cracked, or the relay is not functioning properly.

BTW.......do not use starting fluid on these engines. You run a serious risk of damage.........they are not like your garden variety Cummins.

When was the last time you checked the valve adjustment?

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Sam

84 300SD 350K+ miles ( Blue Belle )

I felt that there was most likely something common like most of you described.

About the compression and valve adjustments, no doubt it will need to have the valves checked, but if the compression and valves are so bad it will not crank readily, then would it not (in my other experience) not run out well, and would I not have nasty gray and or white smoke, such is not the case here.

As far as temperature, in the low 70's, but have not been interested in cranking the starter for an extended period, which in my experience with diesels only guarantees starter failure. Just wondering.....................

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80 300CD new to me

I belive I have a fuel leaking issue, and my glow plugs do not work. I have been cranking it like this for 3 months this year, and when I drove it in 2000 I cranked it this way as well... I know this is not good for the starter, but It is working well for me so farr....... I know I know, fix the glow plugs... I did buy a running parts car so I will be fixing it up soon.
John

From personal experience, and many others here, will attest that this is not the case. I've never had any smoke to speak of, minimal with a very cold start up. Adjusting the valves has definitely improved starting and I don't see how you could get a very accurate compression test without it.

Are you saying that the starter seems to crank slowly? If so, a problem that I ran across was a loose engine-to-chassis ground strap (actually the bracket it attached to was loose). Or are you saying that the starter is cranking over like mad and still no start? Which would point to valves, compression, glow plugs or fuel.

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Sam

84 300SD 350K+ miles ( Blue Belle )

Welcome to the forums!

Try some of the tips in the glow plug pictorial.

http://dieselgiant.com/glowplugrepair.htm

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1981 300D 147k
1998 VW Jetta Tdi 320k
2001 Dodge Ram 2500 141k
1979 300D 234k (sold)
1984 300D "Astor" 262k(sold)
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