I am hoping someone may be able to offer some suggestions to my "little" issue...!
I have a 1990 MX5 BBR Turbo, which has been Megasquirted by its previous owner (amongst a number of other things inc larger injectors, one piece exhaust, oil cooler, intercooler etc) up to approx 198 bhp.
The previous owner also fitted a 94 engine (still 1.6)... I recently ruined that engine by running very low on oil - the oil pressure gauge appears to be faulty.
Now the issue - I have just replaced the engine myself (with my bro's help who knows a fair bit about cars, I know a bit but am certainly no expert) including new gaskets where required (obviously), and though the engine starts with no issue and sounds pretty smooth it lurches at WOT from about 4000rpm under load... So obviously all is not well.
The replacement engine comes from API who appear to be well respected, so I don't doubt the engine itself is good (it is of the correct type and age to directly replace the one I inadvertently knackered), and all the ancillaries and manifolds have been transferred from the previous engine (including injectors of course). I have also transferred the coil pack and CAS over as the new CAS was a bit squashed and the coil pack looked a bit corroded in places.
I have just set the timing with the MegaSquirt instructions after changing the CAS, so that should now be correct (set to 10deg BTDC fixed, then -10 to enable spark advance).
I realise that all engines are a bit different, so is this potentially the cause and it just requires retuning (which I would not do myself but find a professional to do this for me, in which case can anyone suggest a tuner who knows mx5/miatas and MegaSquirt, near sth London/Surrey UK???).
Or does that sound unlikely in which case are there other things I should check before going that route?
Any pointers much appreciated!