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Matt
Matt, Mechanical Engineer
Category: Mercedes
Satisfied Customers: 21991
Experience:  BEng hons Mech engineering, in auto industry 22 years
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E240 engine replaced. Turns-over but no spark and have dry

Resolved Question:

E240 engine replaced. Turns-over but no spark and have dry plugs ? Computer says that the car is fine ?! I still have the original engine - oilpump failure .
Submitted: 3 years ago.
Category: Mercedes
Expert:  Matt replied 3 years ago.
Hello

If there is a spark and its still not starting then its likely that the ECU isn't opening the fuel injectors, if the injectors are working you can hear them click - its difficult to hear them with background noise so use a long screwdriver like a stethoscope, placing the handle end in your ear and the metal tip against the body of the injector whilst your assistant turns the engine over.
If you can't hear anything check the ECU power is present by measuring voltage at the fusebox and on its relay socket if OK then check the connections to the crank speed sensor and consider replacing this sensor if the wiring / connections look OK

If the car will start using a squirt of quick/ easi start into the intake then this confirms the problem is lack of fuel

Also its worth checking that the electric pump that feeds the injectors is working correctly, it should run for a few seconds then switch off when you first turn the ignition on. If you remove the filler cap to the fuel tank and listen inside while your assistant flicks the ignition you should hear it clearly
If the connections to this are corroded or damaged then the pump could stop at any time. Check that its relay switches in and out and the relay contacts are clean and bright – replace the relay if in any doubt and do the same for the fuse, ideally measure the voltage at the pump and check its getting 12V.
You should be getting around 3 bar measured at the injector rail check to see if the plugs are getting wet indicating fuel is flowing – if not and the injectors are opening then there’s a problem with the pump or the filter or even the pressure regulator
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Customer: replied 3 years ago.

Thanks for that , Matt. The thing is , there is NO spark AND the plugs are dry. There's good fuel pressure at the injectors' supply pipe. I swapped the torque converter as well - a guy told me that l'd messed with the timing because l bolted it back as it went on ! I didn't see any marks ? Sorry to muddy the water . Bloody Brits ! Haha !

Expert:  Matt replied 3 years ago.

Hello Clive

Ok

measure for power to the ECU 1st as I mention above and if you've got 12V at the fuse then replace the crank speed sensor

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