Engine replaced on boosted NB 1.6, do I need a new tune?

  1. My model of MX-5 is: 1998 NB 1.6
  2. I’m based near: North London
  3. I’m looking for technical help or recommendations on: whether I need to get new tune/dyno run after engine replacement.

I managed to crack a head after a coolant loss on my turbo NB 1.6, and after a head replacement, needed to replace the whole engine. The car runs fine, but feel a bit flat compared the previous engine. I am also now getting pops and bangs on over run, which I did not get before on the old engine. Would this means the fueling is slightly different? I don’t have an AFR meter.

Before engine was swapped, out on new coils, leads, plugs, Cam and Crank sensors.

I suspect the previous engine had been on the way out prior to final tune I had, and also may of had some slight vacuum leaks that were sorted during the fitting of the new engine (old engine 144k, replacement 82k) The ECU is a ME221, is there anything I can check (logs?) to see if fueling is correct?

Any help or things to check is appreciated. Or anyone near North London who could have a wee look to see if anything obvious before I find a tuner (original guy not is business now, mechanic who did engine swap not really a performance shop)



What kind of o2 sensor do you have? Factory or aftermarket? Seems you are running rich and in a one way ticket to chocolate rods.

Thanks for the reply. Not sure on o2 sensor. Discovered the manifold developed a large crack, so that would of been throwing the o2 mix off. Car is at mechanics getting MOT and manifold fixed, will get it back on a dyno to check the mapping once I get it back.



What ecu do you have?

I have an ME221