MX5Ireland

Iv attached a video to show you what the problem is, as you can see the car will start and tick over but when I try to rev it seems to be backfiring or miss firing or something, at first I thought it was a problem with the ecu as the floor in passenger side was very wet due to the window being left down and rain got in. Picked up a replacement ecu today fitted it and thought the problem was solved as I started the car and it seemed ok but after driving a few hundred meters it started acting up again and lost power and began backfiring again.

I then thought if its not the ecu and all electrical connections seem to be fine then it must be the crank position sensor. I adjusted this and then the car wouldnt start at all just turned over. After messing around with it for a while I couldnt seem to get the car started so I removed the sensor and noticed some scoring on the face meaning the teeth must have been hitting the sensor.

Is it possible that the car would have run fine for a certain length of time before the teeth hitting the sensor did enough damage to cause the fault? Id say the car was out only 4 or 5 times since fitting the new engine so mayb it took that long to wear down the sensor enough?

Next step is to fit another sensor and see if that fixes it but thought before I drive all the way out to Robert again id see what you guys think...

Any help much appreciated




https://www.youtube.com/watch?v=kdm3WGVCETA

sounds like the CAS alright... but if you want to try some stuff before you go, check the voltage on the wires to the CAS, check your timing (belt may have jumped a tooth), your grounds, your sparkplug wells for water and check each spark plug for spark (might be a coil).

There has to be slight gap betwen the crank sensor and the 4 points that are on the crank pulley plate.Approx 2mm or similar.If its too far away it wont pick up the pointers and too near well it damages sensor as you see.

@steve: Thanks will check those things this evening

Was the sensor alright replaced it this evening and the car is spot on now. Thanks again to Robert for sorting us out with parts!