UK Car Repair: Engine cut out while driving, renault clio 1, loose cables


Question
Dear Howard,

I have a renault clio 1.2 (1997) and recently has been giving me a bit problem.  I had my car a full service 2 months ago and since then it has gone wrong. I had to return it back a week later to the garage as the car was running heavily. He said was due to one of the cable punctured and he replaced the cable with a new one.

Three weeks later, while driving the engine suddenly cut out. It almost always starts right away when I turn on the ignition key again. There is no sign of rough or shaky before it cuts out. Normally it happens after changing the gear and press the gas. I use this car daily to work ( 3 miles). Sometimes it happens only once/twice a week but recently is getting worse. This car never had this probelm before.

I decided to take back to the garage. On that day the engine cut out about 10 times just to get there (4 miles distance). However the garage could not find the problem and he said nothings wrong with my car. He drove the car and it did not cut out at all.I took it home and it was ok then but three days later it cut out again. I called an AA and they checked it offside the road. He could hear that the engine sound a bit different and thought could be some of the cables are loosed. However he could not find any loose cables though. After 10 minutes checking,  the sound has dissappeared. I drove home, was ok but two days later it cut out again. As far as am aware off the engine sound looks normal and the car run smoothly apart that you never know when the engine is going to cut out.

I do not know anything about car and would like  help of the expert to advice me on what possible cause it might be? Thanks in advance.

Regards,


Hendry  

Answer
Hi Hendry,
My expertese is MG /Triumph / Jaguar but the problem you are having may have nothing to do with what brand your car is. All piston engines operate the same. They all need compression fire and fuel and when you have an intermittent cut off, you must check which has been lost, Igintion or fuel. If compression was gone it will not return. It is easy to test for Ignition. Purchase a inexpensive timing light, read the directions if you don't know how to use it. They are simple. Connect the pick-up lead to any spark-plug wire. Now tape the timing light to the windsheild or the rear window (if this is a rear engine Renault) Tape a piece of cardboard over the light end of the light so you can see it in the daylight. If the light has a trigger control, tape the trigger down so it is on all the time. Now drive the car untill it cuts off. Don't depress the clutch when it cuts off, just let it coast down. Quickly note if the light continues to flash all the way to a stop. If the flash cuts off and the engine is still coasting down then you for sure have an intermittent Ignition failure. If you are not a mechanic then take it back to another shop (one who cares what they do) and tell them you have an intermittent Ignition failure and to fix it and tell them how you made the test.

If the light continues all the way to a stop, then you should tell them you have an intermittent fuel loss and tell them how you eliminated Ignition as a cause. This will at least isolate the problem into a smaller area so the problem can be found.

I hope this helps you,
HMF