Air Flow Meters, Question on different models

[tvrjohn]

The standard fitment model on TVR Rover v8 engines seems to be the
5AM Model.
The 3AM Model fits the jaguars, does this model give better performance results ?

Just that mine on a 4.3 Griff has started giving me drastic over fueling problems, and i need to replace.

[HarryW]

Best check with the likes of Mark Adams first, but if you have a 3AM fitted then the ECU fuel map scaling will be set to 3volts max. The 5AM gives 5 volts max so would not work without a replacement 'chip'. You can get a replacement TVR chip from someone like TVR Power, but then again it might not work with the earlier ECU .
I think best you speak to Mark Adams or Dom at TVR Power.

Harry

[Toffer]

Could be a nightmare! Get good advice and then keep things standard!

[griffter]

Lots of confusion over afms and nobody seems to some forward with the definitive answer. AFAIK the precats should have a 3AM (My 4.3 has a 3AM), the 5AM being fitted to the 500s. There's a book on the V8 (Speedpro/Hammill) to which I believe MA was a contributor, which states that 3AM and 5AM are interchangeable. Another source has been told by RPi that 3AM and 5AM are 'functionally identical'. So where the 3v / 5v comes from, whether it's true, and what effect if any the CO trim adjuster has is, and it seems will, remain a mystery.