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Old 05-02-2002, 01:26 PM
Registered User
Join Date: Nov 2000
Posts: 168
Not starting like it used to.

Over the last few months I've noticed that my car doesn't fire up as quickly as it used to. Before, I would turn the key after the glow light went out and the engine would fire up before the engine completely turned over. Fast! Now the engine starts up after a couple of seconds of cranking(maybe 2-3 turns of the engine). The engine runs great. Really smooth, doesn't burn any oil... I have run bio-diesel a few times and I have replaced both filters. I'm not sure, but I think my fuel economy has gone down a bit also. Any ideas? andy

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Old 05-02-2002, 06:24 PM
Join Date: Jul 2001
Location: Woolwich, Maine
Posts: 3,598

How many miles and how long since the charging system and starter have been checked? Sometimes, as the battery ages the drain of the glowplugs can reduce a weak battery's Voltage to the starter enough to prevent the engine from spinning fast enough to start as you expect. The starter can deteriorate too, by having the insulation break down on the windings, with a similar effect - slower than normal turning leading to difficulty starting.

Since the engine runs on the principle of heat generated by the compression of the air achieving a temperature that is great enough to ignite the Diesel fuel when it is injected, anything that lowers this temperature can adversely affect running and especially starting. Slow turning of the engine gives the heat generated by compression time to get absorbed by the block and head (usually cold at start up). Consequently the engine will not start right away. A few seconds of cranking and the immediate area around the combustion chamber is warmed up enough so there is sufficient heat to support ignition.

Glow plug issues are usually accompanied by odd behaviour of the glow plug light on the dash. Like it won't light up the first time you twist the key to the normal glow plug lighting position, or it blinks or some other event. You did not report any glow plug anomolies so I am presuming the glow plugs are ok.

So, I would check the battery Voltage before you start, while the glow plugs are on , while it is cranking the starter and after it is running. In general, the battery should be over 12.5 Volts just sitting there, and, with the engine running the system Voltage should be at 13.6 or slightly higher. If you are not within these ranges, either the battery or the charging system is at fault. If the battery and charging system are ok, I would suspect the starter. You can take it out and have it checked, but if it is weak, I would get a rebuilt one from FastLane. Diesels are hard on the starter and battery.

Good luck, and I hope this helps. Jim
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

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)
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Old 05-02-2002, 07:36 PM
Senior Member
Join Date: Jul 2001
Location: San Antone
Posts: 408

The engine firing after 2-3 revolutions is pretty good. In addition to what Jim suggests I would add that if the valves have not been adjusted in the last 10,000-12,000 miles or one year then that can also cause starting problems because the compression will not be as high.

Good Luck!
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1977 300D: 300,000+ miles

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Old 05-06-2002, 07:17 PM
Registered User
Join Date: Nov 2000
Posts: 168
Thanks for the hellp. The glow plugs are good and the valves were adjusted about 6000 miles ago. I replaced the battery about 6 months ago. I think it might be the charging system. Sometimes after I start my car the battery light stays on. A quick rev of the engine and it goes out. This has also happened a couple of times while letting the car idle. I'll get the voltage checked. I'm just used to the instant start up. Thanks. andy

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