Hello All,

I bought this 81-300sd w/ 215K about two months ago for my wife...she loves it. It has always started immediately. I have changed the filters (air, oil, and spin-on fuel) right after I bought it.

Today, the engine turns over quickly and strongly, but nothing is firing. I checked the glowplug strip fuse and obvious vacuum hoses, and nothing. The fuel in the plastic filter seems clear and very little bubbles. I am running on regular diesel.

We had a wicked thunderstorm and about 5 inches of rain yesterday, if that would make a difference.

What could be the culprit? It started great just last night.

Thanks, Don...I will check back often for any follow up questions.

I left the wiper switch on overnight...could that have run down the battery just enough to make it slow on start? I did not think the wiper switch would do that, but... I don't know this car that well.

Thanks, Don

OK, I tried to jump it and it still want to fire... What is the next step?

Don

Is your glow plug light illuminating ? You need that to work or car wont start.Check your fuses,Johnny

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85 300sd SOLD ,85 745i,95 740i,1972 Suburban,1938 International

Johnny,

Thanks for the reply. The glowplug light is working as normal. None of the fuses are blown, but I am not sure what the relays are in the fuse area, as they are not marked. I may try taking out each fuse and cleaning them and the contacts.

Don

Is there any way you can put a meter on the glow plug to see if your getting voltage ? I think there is a relay for the glowplugs,it may not be working.does the glowplug light go out or des it stay on? Johnny

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85 300sd SOLD ,85 745i,95 740i,1972 Suburban,1938 International

The glow plug light comes on normally (for about 2-3 seconds) and goes off. I have a simple volt meter, I just am not sure where to put the leads. Also, is the relay with the glow plug strip fuse?

Don

Not sure of the location,let me check something.Johnny

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85 300sd SOLD ,85 745i,95 740i,1972 Suburban,1938 International

Here is a link that I came across(thanks Brian ) Ithink it will have all you need ,Johnny http://mb.braingears.com

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85 300sd SOLD ,85 745i,95 740i,1972 Suburban,1938 International

Johnny,

I am on a dial-up ISP, so I cannot open the PDF file, Thanks anyway. I know where the glow-plug relay is, so I will check for continuity and check for power at the glowplugs the best I can figure out.

Should I change out the plastic fuel filter? I changed the spin on one, but not the plastic one. Would that stop enough fuel to prevent firing up?

Don

If you changed the spin-on filter you need to prime it with the hand pump or it will not start. Have you primed it? It's worth changing both filters just to be sure.

1984 300d Turbo 139k
Open A Fuel Line Or Turn The Main Filter So It Leaks Fuel When Using The Hand Pump Its Full Fuel And Will Start If All Glow Plugs Are Good No Open Glow Plugs Remove 5 Pin Plug, Relay Box On Left Side
Of Engine Check Ea To Ground.

Craig,

I did prime the spin on pump and have driven it for over three weeks since I changed the spin on filter. I will change the plastic filter anyway.

Raymond,

If I understand you correctly, I will check the fuel flow by loosening the spin on filter and then I should check the glow plug connector at the relay.

If they all check out, what next? Would the connections at the power stage make any difference? They looked like they needed cleaning.

Don

Disconnect the Vacuum hose from the shutoff valve on the IP in case your ignition switch or shutoff valve on you IP is the problem, Have you verified their is fuel being sent to the cylinders.

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1979 300D.

dazsa,

2 to 3 seconds for the GP light to stay on is not normal. It should be on for about 10 seconds in warm weather or if the engine is warm and longer in cold weather.

As soon as U energize the starter, the GP shut off. So they may not have been on long enough to get red hot.

Try waiting longer for the GP to get hot before U turn the key to the start position.

P E H