Dodgy Speed Sensor

[CJ]

I have a silly problem that is confusing me. Recently, the car has had the red triangle and engine warning light (the orange one on the uper right of the dash display) come on after a few miles. I was down at Matt Harwood's place last week and we found a Blitz Delimiter that seemed to be wired in correctly but when we checked the flashing lights off the diagnostic port they pointed to this being the problem.

 

I then tookthe car out to see if it occured at a given speed and it came on at around 60mph. But I then stopped somewhere for a while, took someone out for a very spirited drive, and it didnt happen despite hitting 140 mph on a private road. Although soon afterwards it came on again at a lower speed

 

Now, I am confused as if it is a joint FCD and TSD and is faulty, shouldn't I be hitting fuel cut and/or the 112mph barrier?

 

Would the best bet be to just ditch it and get a new one?

[Ben-san]

Col, I've read somewhere on here that Blitz converters are a little unreliable. I've got a TRL unit that does both things, but I fear that the speedo is at least 10 to 15 mph off. I know Thor units are adjustable to compensate +- 10%, so if I were to replace it I'd go for that. I suppose having separate FCD / TSD would make things easier to diagnose problems with, AFAIK there the two functions run independently even if it's a so-called all-in-one solution.