Hi Ride Drive,

I have a 1992 Griffith 500, which I have owned for 2-years. I have noticed recently that when driving at low speed, such as in a town area, the car does not run cleanly and appears to be almost miss-firing, but not quite. I have had the fuel tank drained and the lines cleaned, none of which made the slightest difference. New spark plugs and leads also didn’t help. I am puzzled as to what it is.

Matthew Burley,

Little Tring,

Herts

Reply:

The first question would ask would be what has been done with the fuel pump? The TVR Griffith, like all TVR’s of that era, are fuel injected, which means fuel is pumped from the fuel tank, through the injectors, where some is taken off to feed the engine, and the surplus is returned to the tank. At wide throttle openings most of what leaves the tank is used by the engine, which means very little has to return to the tank, whereas at small throttle openings there is a similar volume travelling both ways. This also means that when you are travelling through town the pump is having to work much harder.

When working hard, the fuel pump, which is an electrically driven device, gets very hot. That is why it is mounted on the chassis and in the air stream flowing beneath the car – keeping it cool. The side effect of this is that it also gets all the muck and grime that is flying around underneath spread all over it, which can form a nice little insulation jacket around it. This will hold in more heat causing a further deterioration of the unit.

I would suggest you have the fuel pump checked out, either at your local dealer or you are quite welcome to bring the car to us. If it has been on the car a while it could well be on the way out. The initial symptoms can be poor running at low speed, but the next stage will be that it will give up altogether.

Colin Bowler
Racing Green Cars