I am admitting now that I am not a MB diesel tech. but I have worked on them before and I was a ASE cert. tech before I changed my career in '97.

200,000+ miles...well maintained.
Car has been sitting for around 4 months.

The car is in Houston Texas and the outside temp. is between 40 and 60 degrees F.

Glow plugs are coming on when checked with a test light and the glow plugs have a resistance of around 2-4ohms....#1 was replaced recently.
The preglow indicator does not work on the dash but you can hear the relay click on and then off after around 1 minute and this is verified with the test light.
We did get it started after several tries but after sitting overnight it was reluctant to start up again.
It seems to run good once it's running and will start right back up when the engine is warm.
It acts like low fuel to the cylinders. Could the fuel be weak?

It does need the oil changed.

Any ideas?
Thanks in advance.

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kyle300SD Turbo

if your location was listed we could at least guess at ambient temps

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'82 300SD - 361K mi - "Blue"

"Good judgement comes from experience. Experience comes from bad judgement."

listen, look, .........and duck.

It sounds like a glow-plug problem.

To test, disconnect the glow-plug wiring harness at the glow-plug relay module, and apply 12V directly to each glow-plug wire. One at-a-time.

If the glow-plug, and its associated wire is good you should see a hefty spark. Otherwise that glow-plug, and/or wire is defective, and should be replaced.

Phil

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'95 E300 Diesel, 264,000 Miles. [Sold it]

I would check those glow plugs again. Last time I changed glow plugs a new one, or an installed one that worked, showed about 1 Ohm, or slightly less. How did you check them?

Next, I would check the oil. If the oil is a heavy viscosity it will drag the starting rpm down. A Diesel needs a pretty high rpm to start reliably. A good, Diesel rated oil, like Delvac 1, or other brands that are either synthetics or show a better low temperature flow capability will help a lot.

Next, or not necessarily the last step in the cheap options sequence, is to check the battery to ground connection at the battery and at the ground connection to the car's frame. Also clean the positive terminal on the battery and the clamp, as well as the connection to the starter.

Now things start to cost money. How is the health of the battery? Leaving a car sitting with the battery installed is often a path to a damaged battery. With the battery installed, certain functions in the car continue and draw power. Maybe not much but they get whatever they use from the battery. If a battery is getting old, it may not survive a really deep cycle that can result from such a scenario.

If the battery is ok, check the starter for response. It must turn the engine over at a good clip or the heat of compression is absorbed into the block and starting becomes too dependent on the local heating of the glow plugs. A tired starter usually gets more work because it is not starting the car quickly, which further weakens the starter, which subsequently becomes incapable of starting the engine. If you determine you need a new starter, I highly recommend the FastLane or Parts Shop starters. Call Phil there (buttons across the top of the page) and make sure you get the most powerful version that fits your car.

Finally there are potential fuel and/or air leaks that can add to starting woes. Any visible leaks or puddles of Diesel around the car? Air getting into the system will preclude fuel from getting into the cylinders, which precludes starting. In most instances, if air can get in, fuel can get out and you will see evidence. Hope this helps, Jim

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Own:
1986 Euro 190E 2.3-16 (291,000 miles),
1998 E300D TurboDiesel, 231,000 miles -purchased with 45,000,
1988 300E 5-speed 252,000 miles,
1983 240D 4-speed, purchased w/136,000, now with 222,000 miles.
2009 ML320CDI Bluetec, 89,000 miles

Owned:
1971 220D (250,000 miles plus, sold to father-in-law),
1975 240D (245,000 miles - died of body rot),
1991 350SD (176,560 miles, weakest Benz I have owned),
1999 C230 Sport (45,400 miles),
1982 240D (321,000 miles, put to sleep)

Kyle,

How did you measure the resistance of the GP?

Did you pull the GP wire connector out of the GP relay when you measured the GP resistance? What type of ohmeter did yu use?

2 to 4 0hms is too high, each GP should be about 0.7 ohms.

P E H

agreed. Also, if glow plug#1 is even a little bad, like it's 1.something ohms and the others are less than 1 ohm, the glow plug light won't glow because the relay measures the current through #1 and compares it to the average of #2 to #5. It's also a good time to check the flat strip type 80 amp glow plug relay fuse. These can crack and fail PARTIALLY, so look carefully.

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'82 300SD - 361K mi - "Blue"

"Good judgement comes from experience. Experience comes from bad judgement."

listen, look, .........and duck.

We'll replace all of the GP's and also change the engine oil.
O'Reilly said they can get the AutoLite brand for $9.89 ea.
Is this a good brand and if not then what is?

I'll post back later with the results.

Thanks again.

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kyle300SD Turbo

Kyle,

There seems to be a general consensus here to stay with Bosch GP.

P E H

Reported in other threads: Autozone has the Bosch GP for $7.99 each.

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Alan the Radio Guy
--------------------
Amateur Radio Station N7CEU
1985 300CD 199,000 and still rolling

Thank's for the help with the hard starting problem.

We replaced the glow plugs with the Bosch parts and the engine starts right up every time now. The glow plug indicator is also working now.

This site is great.

Thank's again.
Kyle

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kyle300SD Turbo