Evening post/motoring article

by David Peacock,

Ford Puma 1.7i 16v(MHA)1997 - 2002

     The owner of this Puma knew that something was wrong from the lightness of his wallet. At 200 miles per tank of petrol instead of the normal 350 it would be cheaper to run a Jaguar. The problem had started after his car had been serviced so he suspected that the garage had done something to cause it. They hadn’t , it was a fault that would have occurred anyway , but the garage trade is well used to the “It was all right until you touched it”. A car is bound to go wrong at some time , and if that happens within recent memory of someone to blame then they get it in the neck.The car ended up with us since the garage concerned felt that the fault needed more specialist attention than they could give. Our first line of investigation for any engine management fault is to look at the fault codes that the car may have left in it’s electronic control unit. (Ecu)These should tell what is wrong with the car – but often they don’t because a lot of faults elude the system. If they work then fault codes are great, saving sometimes hours of time in tracing faults. but all to often they come up with a fault code of “No fault found” while the car is left hacking and coughing itself to death on the workshop floor. In this case no fault codes were found so it was on to the long route of checking signals in and out of the car’s brain (Ecu), and checking it’s fuel pressures. We found a fault with the signal in from the air flow meter , which made us suspect a faulty unit, but on closer investigation found that the unit itself was Ok, - good since it cost telephone numbers – it was caused by a fault with it’s earthing circuit. Sorting this out fixed the problem. We often find though that with faults of this nature parts are renewed that don’t need to be.