starting probs for 1981 240D

[brohndog]

i have problems with my older 240D starting. Changed glow plugs (used a reamer), changed glow plug relay,starter,fuel filters (have not checked sock in tank yet); question is why would does it start right up some times...then not start later in day after use. When it runs i can drive all over the world no problems (including hills) --somebody said could be valves too tight? i also read some things to suggest i could use a stronger starter than the one that is supposed to be for that car? thoughts?

[leathermang]

It may seem funny to suggest this.... but I think you need a new starter...
My 80 240 had those same symptoms.... I decided to just throw $108 dollars at it... and it solved the problem.... since I also had the old one I asked the starter shop to show me what it looked like... the brushes are huge and were in fine shape.....but the three little screws which hold on the framework for the inside stuff had loosened enough to be arcing... only sometimes...with no rhyme or reason to when...

You need to start by doing a compression test.

Good luck,

[JimSmith]

brohndog,

Try using the search function. Starting these beasts under certain circumstances is a challenge we all have in common. In general the problems, assuming the piston to cylinder wall interface is good and compression is acceptable, usually lie in the glow plug system, the starter and electrical system, or the fuel system. With glow plugs the issue is usually a bad plug, in which case you typically but not always, get a signal from the glow plug indicator light - it will light inconsistently or blink or do some other abnormal lighting event. If the problem is with the starter it is usually because the starter is aging and with the design voltage will not produce the design torque to crank the engine over at the design speed. Low speed on the starter means the heat of compression is sucked into the block before the air temperature reaches a value high enough to support ignition of the fuel. This problem can be more of a problem in warm weather than cold weather depending on the way the starter motor is deteriorating. Real age is an insulation abuse state from accumulated long starting cycles of the starter, and this gets worse with temperature. If the charging system voltage is low while starting, you have a bum battery or a bum alternator. And, if the fuel system is leaking at all, you likely are getting air into the system, and the fuel system is not prepared to deal effectively with air instead of Diesel fuel. The system must purge itself to work correctly and it is very inefficient at doing this by cranking the engine with the starter. This problem goes unattended to and pretty soon the starter and battery are weakened.

All this stuff is interrelated. A borderline starter will work ok if everything else is top notch. But any combination of weaknesses can lead to starting woes that are very difficult to get your arms around. A new starter will not, for example, fix a starting problem if the glow plugs are not functioning and you have a small air leak. Or a bad battery. And so on.

Try the search function. We have experienced nearly every possible system weakness permutation and posted about it here. Good luck, Jim

[brohndog]

thanks for the very good and quick responses..i guess i was just needing moral support
you guys confirmed i have to go down a rather lengthy check list (and rightly so.) i'll go buy some more blue gloves!