Sprint New engine, low MPG

XT Bloke · Mar 27, 2017

Hi
I have fitted a 2007 engine to my 2005 Sprint and kept the '05 ECU.
The MPG seems low and my rucksack smells of exhaust fumes, I am getting approx. 42 MPG at 80mph ish on motorways, this seems low and maybe it's running rich, as it is all controlled via the ECU what would cause this?
It has a new air filter and stock exhuast.

I did look at the std maps and the name is the same for both years so not sure if that's the cause.
Thanks in advance.

thebiglad · Mar 27, 2017

Hi XT,well for a start 42 mpg at 80mph is not really that bad. However if when you check the plugs and they show the motor is running rich, then I would be looking at :

1. Condition of air filter;

2. Condition/function of IACV (Idle Air Control Valve) as this feeds info to the ECU for fuelling calcs;

3. Check/change plugs

etc etc

austin · Oct 10, 2017

at 80mph i reckon thats not bad i have only just got my sprint so cant saywhat its going to do however i had a 955 a few years ago and it could get 60mpg but that was cruising on a rds at 60mph