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300SD has problems starting

Started by ziper1221, 11 June 2012, 11:15 PM

ziper1221

My 300SD has trouble starting, it cranks over just fine, but it can take up to 30 seconds for ignition. I dont think it is a glow plug problem, because it has this problem even when it is 90 degrees outside. Any ideas?

ckamila

Hello ziper - Think we need a little more info to help:

How long have you owned the car?
How long have you had trouble starting?
Valves adjusted?
Compression test in the recent past?
Fuel filters changed? - 3 in total; inline, screw on and the filter/screen in the tank
If poor compression you might still need glow plugs to get her going.....

chris
If it's not broke i haven't fix it yet...


1980 300SD, 170K
1985 300D, 235K

ckamila

ziper - looking at your other post http://forum.w116.org/test-drive/my-1979-300sd-9311/ did you "fix" your vacuum problem and then the starting problem happened after?

Do you have a good diagram of the vac lines and where they go? I assume its possible to mess up the fuel shut off vac line so vacuum is always applied and not letting fuel flow.

Please provide some history to this problem.

chris
If it's not broke i haven't fix it yet...


1980 300SD, 170K
1985 300D, 235K

ziper1221

Thanks for the help, I replaced two of the fuel filters and adjusted the valves (wasnt sure if I did them right, but... it still runs) and although it runs somewhat better, the starting was unaffected. I have only had it for about 3 months and the problem has been consistent.

So far I have left the vacuum system mostly disconnected, with just a couple hooked up, one of which was the engine cut off. In the morning I will check and post back.

How much should I pay for a decent compression tester?


Tony66_au

If your compression is down on a diesel to the point where it affects the running then you will get diesel vapor out the tailpipe which smells like kerosene and will look like steam.

This is fairly noticable and may drop off as the car gets to operating temp so i wouldnt be too fussed about checking compression (This is difficult with Diesels anyway).

Try checking the glo plug circuits, I am not familiar with which specific diesel is in your model as we dont get the Diesel 116's in Oz but there are 2 distinct type of glo plug system I know of.

One system where its all or nothing and if one glo plug fails they all fail and the other where if one fails the other 5 or 6 continue to work just fine.

there is also a great site on Diesels which has a few nifty tricks for solving some common issues the OM oil burner range suffer from as well as some great tutorials on fuel system maint etc but I cant for the life of me find the damned link, maybe someone else can help out.

The OM range is fairly hardy and will give years of life so unless you have seriously messed up the valve settings id think it is a pre heat issue.

I did sort a friends 300D (W123) and the main issue with his was Glo plug circuit, filters and ancient alpine diesel in the tank, once sorted the car went on to rack up 50'000 km a year without so much as a hiccup between oil changes.

Good luck!

Tony