On my 84 300SD I have developed a problem with restarting a hot engine. Cold start is immediate. On restart after short shut down glow plug indicator light is as usual but have difficulty restarting. It almost seems like it is not getting enough fuel. Filters are all new. Glow plugs check out at less than 1 ohm. In doing a little trouble shooting I noticed that if I pump the primer pump it is blowing a lot of fuel out. The pump is the original unscrew, pump and screw down the handle type. I ordered the new Bosch pump that bleeds air without the necessity of screwing open and closed the mechanism. I don"t know if I am on the right track. I have worked out all of the cold start problems over the last 300K miles ie glow plugs, valve adjustments, relays etc. This one has me stumped. Any thoughts would be appreciated. My wife is starting to complain about leaving it running to run into the store. She has now resorted to sneaking off with my 560 SEL and threatens to continue until I fix the problem. Help

John Olszewski

Things to check: battery failing, starter not turning engine fast enough, fuel clogged at filter screen in fuel tank (debris, algae, etc.), fuel line kinked/clogged, compression low, injection pump start of delivery is off, IP element sealing washers leak, faulty injection nozzles, fuel pump pressure not high enough, fuel pump check valves leak and/or springs weak, IP fuel return check valve spring has collapsed (common, stretch to 25-27 mm), air/water/dirt in fuel system, bad fuel - this list should give you an idea what to look for.

Good Luck!
Tom

__________________
America: Land of the Free!

1977 300D: 300,000+ miles

American Honda: Factory Trained Technician & Honor Grad.
Formerly:
Shop Foreman;
Technical Advisor to Am. Honda;
Supervisor of Maintenance largest tree care co. in US for offices in Tex.

I suspect you are on the correct trail with the leaking primer pump -- air gets drawn into the fuel system when the pump leaks. This can result in hard starts, although usually cold starts are bad, too.

Check the starter motor for current draw and for proper engine RPM -- engine must turn at least 100 rpm or it will not start, period.

My volvo does the same thing -- immediate restarts are fine, but if it has been sitting for a while (15 minutes or so), the glow plugs don't appear to run (no dash light), and I have to crank for a while to get it lit. Rattles then goes fine, with a blast of white smoke. Has 215, 000 plus miles with no evidence of starter replacement, so I cannot complain!

Otherwise, check the fuel system -- clogs, plugs, leaking lines, and a plugged restrictor or pressure valve in the fuel filter or the retrun line from the IP can all cause hot start problems from improper fuel delivery.

So can iffy glow plugs, buy the way -- how old are yours? If they are three or four years old, they may be heating slowly, and not getting hot enough when the engine is warm!

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!

I had the same thing happen to over 2-3 months. I ended with a dead battery. I replaced the battery and the alternator regulator and brush assembly. Now all is fine. When the engine was cold, compression was low enough and the oil wasn't up to temp to help compression so starting was fine. When the engine was warm it took prolonged cranking to start. After replacing the bettery and alternator bits the starter turns faster and the car start right up when warm or cold.

__________________
Fred Johnson
1977 240D
1983 300SD