WDB202 250TD Engine Heater plug replaced - now non start.

[Gibralmoro]

Found one diesel engine (5 cyl) heater plug was open circuit, fitted new genuine item & reassembled everything removed to gain access but now engine will not start, it does not even try to fire. Everything lights up on the dash as it did before, the heater light does go out but engine will not fire or start. Is there a relay that needs resetting or an ECU fault ? I have treble checked all connections are in right place. Please advise.

 

[brianbrian]

Did you undo any fuel lines?

 

[Gibralmoro]

Thanks for your response Brian. No I did not undo any fuel lines or unions, but it is an 18 year old car and as a result of talking to a more experienced M-B mechanic this evening, the clear plastic fuel pipes and seals have never been changed, so I think I must have inadvertently disturbed a pipe or seal whilst taking the inlet manifold out of the way, causing air to get into the system, as a 30 year M-B technician he is at least 80% sure this is the problem. New Seal set ordered. If I am lucky I will get away with a new set of pipes from M-B Main dealer (expensive no doubt ?) I will advise results to forum.

 

[Westheath]

set of pipes @ 120.00

you only need to look at them the wrong way and they let air in

 

[mercedes13156]

Have you nudged one of the electrical connectors on the top of the engine, particularly the injector caps? Check they're all on tight.

 

[Gibralmoro]

Have you nudged one of the electrical connectors on the top of the engine, particularly the injector caps? Check they're all on tight.

Thanks for your suggestion but this is the agricultural OM 605.960 engine with minimum electrics to do with the Bosch fuel system.

 

[Gibralmoro]

SUCCESS

Problem found and solved. After changing all the o rings on the clear plastic pipe unions/connections, cleaning out the pre-filter (which was not bad at all and the main fuel filter was renewed in June this year) the engine still refused to start BUT it was noted that the only pipe that had a continuous string of air bubbles transiting from one end was from the shut-off control. This was removed, the "easy to get at "o ring which secreted itself within the pump body but was easily hooked out, was renewed and the valve body refitted along with all removed pipe connections. Engine started after the usual protracted use of the starter motor, air bubbles virtually gone, ran engine up to normal operating temperature, whilst carefully refitting the inlet manifold and attached pipework.
Proof of the pudding was "will it start after an all night rest or will the fuel have drained back ? " --- it started first turn of the key. Thanks to all contributors - the value of this forum is immense to those like myself with mechanical experience and knowledge, but not necessarily with Mercedes Benz - although I am an ardent enthusiast of the marque having owned my C 250TD estate virtually from new and prefer driving it to most.
Thanks again Mike