The owner of the Ford Escort 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.  

Modern cars with all of their gadgets are great – when they work, trouble is the more gadgets on a car the more there is to go wrong. For instance automatic choke systems – most people have experienced automatic choke problems on a car at some time in their motoring life, but with the old manual choke system nothing much beyond .a worn out choke cable replacement was ever needed. Electric windows – another gadget that often gives more trouble than the manual system, expensive items to repair or replace. After the car is more than seven years old the non-essential gadgets are often left broken when they go wrong, because the cost of repair starts approaching the value of the car. The owner has to clamber into the car via the passenger door because the central locking on the driver’s door has packed up, sweats in the summer because the electric window and the air conditioning has stopped working, and suffers from backache because the electrically adjusting seats have failed at a position suited to a seven foot tall basket ball player. The owner of the Ford Escort Ghia that he brought to our workshop little suspected the cause of his high speed misfire to be caused by the manufacturer’s fuel consumption computer system that had stopped working a long time ago - and for that matter neither did we. The fuel flow transducer was the culprit, it restricted the fuel supply to one of the injectors causing the fault. Since the owner didn’t want the mpg computer working anyway the cure was very cheap – we removed the transducer and cured his fault. Devil of a job to find though, since the fault only occurred at high speed and without our Rollin Road Dynamometer to simulate these conditions virtually impossible.The owner’s regular garage had been trying to track the cause down for weeks.

Emissions failure.  The most common cause of rich running faults is the lamna sensor or the ECU (engine control unit) both of these parts are relatively simple to check, to check the ECU strip back the insulation onthe signal wire from the lamna sensor, this wire is usually black. Then hold the bare wire between you finger and thumb then touch your other hand on to the battery positive if the emissions come down then you have a faulty lamna sensor but if the emissions remain the same then the ECU is most likely at fault. For more information on ECU testing click on ECU

Hessitation, power loss. This type of problem can be one of the most time consuming faults to find because the problem often is only slight and the fault only shows up when the car is being driven under load.

One of the most commen causes of this is fouled or sticking injectors that can be reconditioned at less than tenth the price of a new set. For more information on injector servicing click on injector.