Quote:
Originally Posted by firstmk1
I tried an early shaped ECU (don't know what code) that ran my '89 model fine for a short run up the road. Maybe it was a change over year ECU.
Yup, Both of my mk1s are 1989 with 89661-17140 ECUs.
I have run the mk1a (89661-17030) and early mk1b (89661-17070) ECUs in my mk1b (and also the 1985/6 AE86 ECUs) without problems.
However. the mixture screw wiring is different so with a mk1a ECU (or a 89661-17070 ECU) in your 89661-17140 mk1b the mixture screw ceases to have any effect.
Also, the MAP sensor (and injectors?) are different types apparently.
For these reasons you should stick to the correct ECU for your car.
What about the differences in the engine mk1a vs mk1b? The ribs on the engine are different and so are some of the internals. Also my red mk1b was one of the last made and it has a slightly different cam cover to my blue 1989 mk1b. (different as in colours of the cam lettering)
The mk1a ECU (89661-17030) has a bigger 3D ignition map. It is mapped up to 7200rpm. :)
The mk1b (89661-17070) is only mapped to 5200rpm for the ignition. :cry:
The later mk1b (89661-17140) is only mapped to 5600rpm for the ignition. :(