Weird A/C induced stalling problem

sounds like a poor battery connection or earth lead to the engine. Check all the heavy leads under the bonnet, especially the engine to body or battery lead.

mrcheerful

Thanks. Come to think of it, there seems to be an undue voltage drop somewhere since the dashboard light intensity varies somewhat with the speed of the ventilation fan. But what part of the A/C system consumes so much current that the temporary voltage drop shuts the system off?

-Daniel

Either the compressor clutch (about 8-10amps) or more likely the cooling fans firing up (can be as much as 45amps)

i am not certain of the a/c strategy on the Megane- some cars fire up the fans at the same time as the compressor clutch, some wait afew seconds.

As Mr C said, check ALL the power and earth connections you can find underbonnet- this includes the maxi fuses in the engine compartment fuse box, and if there is one the nut/clamp which secures the battery feed cable to the e/compartment fuse box bus bar. These can work loose. (its a Renault after all!)

Tim..

the magnetic clutch pulls a bit, along with the extra fan that comes on (check that too), but it is probably enough voltage drop to lose the fuel solenoid, hence it stops so quick, as a test put a jumper cable direct to the fuel stop solenoid from the battery, if the engine then continues to run ok you know the fault is on the positive side, you can also try the same trick by adding a heavy earth wire from the engine direct to the battery minus, and test again.

mrcheerful

You were right on spot! It was the clamp in the engine compartment fuse box that apparently wasn't making proper contact. Thanks a lot!

-Daniel