My 350SDL, 147k miles, original owner, is all of a sudden, very hard to get started in the morning. I have to crank it 8-10 separate times to finally get it started. After it warms up it restarts just fine.

Glow plugs and glow plug module were repalced a week ago and all was well for a week. Tried replacing glow plug module again, no change, it still has the cold start problem. Glow plugs are getting 12VDC from the module when key is turned on.

Any ideas?

Thank you.

Compression test?

Compression is fine.

Could be lots of carbon in the prechamber soaking the heat away from the plugs, or possibly the wrong plugs were installed (there are a few different length versions to fit the OM60x engine). Try letting them glow longer (10-15 seconds AFTER the light goes out) before cranking. In a cold climate, use synthetic engine oil (Mobil-1 15W-50) and this will make a HUGE difference in cranking speed compared to dino oil. I still suspect the glow circuit somehow, even if parts are new. The plugs should measure 0.6 ohms each with a meter. Just because voltage is present doesn't mean they are getting hot. If you had a shop do the work, bring it back!

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you should never have starting problems in Coldwater, FL with a diesel!

I'd suspect a fuel problem rather than a glowplug problem -- check the fuel lines for deterioration and replace the o-ring at the suction line to IP (lift pump) connection -- if this spot leaks, fuel siphons back into the tank rather than dripping unless the car is parked nose down on a STEEP slope -- even putting the rear up on ramps may not be enough. No way you are going to find a slope that steep in Fl.....

Also, replace your fuel filters if you haven't recently, plugged filters will restrict fuel pressure at cranking speed enough to cause hard startd due to fuel starvation.

Peter

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1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!

Peter,

Filters were changed recently. I'm getting a good bit of smoke out of the exhaust pipe when it is cranking which indicates to me it is getting fuel?

Hmm. Sounds like my old 220D, except that your compression is OK and mine isn't.

It may be a good idea to check the chain stretch, it may be getting long enough to make both valve timing and injeciton timing late. This will make for hard starts.

And verify that you have good power to the glowplugs, too -- a bad connection on the supply side will lead to low current flow to the plugs, so they won't get hot enough. I assume the fuse is good (glow plug light won't work if it isn't). Best to check the current draw on the plugs, and do make sure they are the correct ones!

Peter

__________________
1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!

Is the engine noisy after it starts and does it smoke?

rdanz. yes it is/does until it warms up a tad. This problem is a sudden onslaught, not something that has gradually come on.

Two things I would check 1. There are two o rings near the bottom of oil filter bolt that if damaged inhibit oil going to the lifters which might cause it.

2. Check your timing chain if more that 4 degrees out replace.

MB had a problem with quality with these chains.

Hope this helps Good Luck

Does the car run PERFECT (or at least as good as it did before) when it is fully warmed up, and does it always start perfectly when warm? So this is a cold start problem ONLY?

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gsxr,

My '87 SDL had a problem starting a few months back. The glow light would come inside, but no start. Turns out the glow plug fuse was cracked and not conducting enough current to engage the glow circuit ( it is an 80 amp fuse). It would conduct electricity (did not show as an open with an ohm meter), but was bad. My was .80 to fix, hope yours is a simple and cheap.

Chuck