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V6 transmission (2002) km to mph
Posted: Wed Aug 18, 2021 6:15 am
by Piers
Hello all.
New to the forum.
I believe the change from km to mph when I imported has effected the top rpm gear change. It seems to over rev by about 500/700 before changing up a gear. Can anyone advise on a remap to correct it? Perhaps a second hand unit that has already been modified? Or does this need to be done in situ? I've had a look at other posts as to where the unit is located but I think they referred to diesel. I can source an adaptor to read from the ECU passenger side but is that access to the transmission?
A lot of questions, I know
Any help greatly appreciated.
Re: V6 transmission (2002) km to mph
Posted: Wed Aug 18, 2021 8:40 am
by g8dhe
I've wondered about this myself, the pulse rate is reduced by the chip so that the scale reads correctly, but this also affects the pulse rate to the ECU. I've not seen any discussion of this previously and its only since getting a new V6 with chip fitted since July that it has occured to me as the "feel" when changing up the gears feels significantly different.
Given the age of the vehicle mapping isn't a possibility as its held I believe in a ROM rather than any form of programmed storage which can be changed.
Re: V6 transmission (2002) km to mph
Posted: Wed Aug 18, 2021 10:34 am
by Piers
Okay, that's good info.
But.. I was assured at the time of import that they didn't chip it..
Also I believe ROMs can be modified going on the same principle that computer ROMs can be but that's more speculation..
Re: V6 transmission (2002) km to mph
Posted: Wed Aug 18, 2021 11:00 am
by g8dhe
If your Odometer reads in Miles and not KM's then you have been chipped!
ROM - Read Only Memory - cannot be altered its created by the masking of the metal layers within a chip, there are also;
EPROM and FLASH memory, these can be reprogrammed, however the ECU in a Bongo uses ROM not EPROM and was designed before FLASH had even been thought of

Re: V6 transmission (2002) km to mph
Posted: Wed Aug 18, 2021 5:31 pm
by Piers
Ahhh..
So unchip it? And put a kph with mph odometer on?
Re: V6 transmission (2002) km to mph
Posted: Wed Aug 18, 2021 6:57 pm
by g8dhe
Yup that would work, consider removing the chip and using the nice Plasma displays
https://visual-performance.co.uk/mazda-bongo-200-c.asp just make sure you get the right style!
Re: V6 transmission (2002) km to mph
Posted: Thu Aug 19, 2021 5:30 am
by Piers
Thank you for your help . I think we can close this topic..