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Matt, Mechanical Engineer
Category: Car
Satisfied Customers: 22894
Experience:  BEng hons Mech engineering, in auto industry 22 years
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I have a renault 1.4 megane, it decides now and again to just

Customer Question

I have a renault 1.4 megane, it decides now and again to just cut out, hard to restart while it is movine, once stopped the engine will turn but not fire up, hae to leave it a while before it restarts etc, changed the idle control valve, can only think of crankshaft sensor or egr valve, but wolud either of these cause the car to cut out while driving along, thanks, Mike
Submitted: 3 years ago.
Category: Car
Expert:  Matt replied 3 years ago.
Hello Mike

a faulty crank sensor will certainly cause the engine to cut out

and this certainly sounds like an electrical actuator or sensor at fault .Usually when you can cycle the ignition key on / off and then restart the engine and the fault is gone temporarily this indicates that this is an electrical component causing this issue.

This could be a wiring issue as things tend to expand when hot and its possible a poor or partial electrical connection is being pushed apart on one of the major sensors so check the connection plug and wiring to the following;
Airflow meter
Crank position sensor
Cam position sensor
O2 sensor
Throttle position sensor

Also worth checking the connections to the fuel pump for the same reason - unplug each in turn and give them a good squirt of switch / contact cleaner - Not WD40

and also unplug and inspect the main power relays and fuses for signs of overheating or corroded terminals - so the ones for the ECU and the fuel pump

And also unplug the wiring loom connections in the engine bay one at time and inspect for corroded or recessed pins.
also check for any oil on the end of the sensor wiring looms as you can get the situation where oil enters the wiring from a component that is leaking, into the wiring harness andyou then have to replace the component and clean or replace the wiring
.Usually this can short out a data circuit or control circuit and can cause issues like this here

Check the resistance of the spark plug leads ( 13-15Kohm / metre) and replace if any doubt or high resistance - Also replace the spark plugs if any of them fail this checklist:
Customer: replied 3 years ago.



Theres a lot to do, thanks, shall check them all and get back to you, thanks

Expert:  Matt replied 3 years ago.
Hello Mike

thats how the site works

just get back to me on this post