Well, i decided to give a new life to this old thread.

Last summer i've overhauled the engine @52k km. It took a month.

New rotor housings, new Mazda apex seals + all springs are new.

Engine started straight away from the first try and it was running so smoothly! The jerking/bucking problem was gone and it had a lot of power down there!!! I was very happy with that.

Now it is 4k km past that and the problem gradually returned. It is exactly how it was before the overhaul and the power output is down (with my butt dyno).

It looks like something dryed up or something, while the car was disassembled, but it eventually got to the condition where it was before the overhaul in 2-3 months of car usage.

I've checked most of the things came to mind, like spark plugs, wires, coild, air filet, air leaks, etc. Probably the only major thing left is to check the fuel pressure.

New log attached.

What bothers me is that i see some ridiculous changes in Lead / Trail ign. advance time, like at a time it is 37 / 6 (lead/trail) and next moment it is -5 / 10!!! Also a lot of ST fuel trim in my believe... But i'm not a pro here, so any input will be greatly appreciate! Again this is a MazdaManiac's tune v4.0.5

 

Did you just reflash the rebuilt engine with the old MM tune or did he tune it again starting from 0?

 

He's not responding to my mails, so no it is not a new or amended tune. And i can't tune it myself as there're no tools to do that on an EUDM version.

I've tried to uninstall the AP and the stock tune was even worse as the throttle response was **** and it felt weaker the MM's one.

 

MazdaManiac Custom Calibration Service Schedule

 

Thanks for the update. I wish i received this link from Jeff directly as a reply to my emails... I would call that a customer service...