bad misfire

[GlennyGills]

With the help of Percy Verance it managed swap the old coil pack off. So after changing coil pack,plug leads and spark plugs I still get some misfire around 1500 rpm when under load.
Not quite back to square one, but nearly.

BTW. If you use the aftermarket coil pack from Autolink, be aware that you can’t use a ring spanner on the driver side upper bolt

[GlennyGills]

Well after much knuckle bashing I finally managed to get the oil coil pack off and replaced it with a new one and still some misfire. Does not last as long - but that was only one trip. so new coil pack, plugs and leads and still a misfire.

Keep looking.

Two points though
1. The under bonnet lights are a great bonus - definitely worth fitting I worked in the dark with the lights and forgot it was dark.
2. The Aftermarket 3 pin Mk1 1.8 Coil pack from Autolink has a minor niggle. The upper driver's side bolt needs an open end spanner as a ring won't fit.

[Mazda Mender]

A misfire is miss spent fuel, so check the wires to the packs, connections, plugs and injectors, just an after thought but is your timing ok?
I know those lights are great, owners without them will never understand the ease and benefit they give, more should fit them..
as for the coil pack frame ,you should of swapped the new packs onto the old frame, thats what i would of done .
M-m

[GlennyGills]

I will see how it goes over the next few days. But yesterday after say 2 mins of struggling, it came alive and was perfect for the drive.
I will check the wires and see if there is a dirty contact.
I will check timing.

Thanks

[GlennyGills]

I put mthe MX5 Tech diagnostic tool on the car and tested the base revs and found they were around 425rpm, with the engine struggling. I corrected the base revs back to 850rpm and today I tested and got no misfire. I can’t check too much as the car has failed mot on emissions.
Currently awaiting parts to correct lambda issue.

[blackyb]

That MX Tech diagnostic is a must have for all early 5s with OBD1. Saves so much messing about and good to do a test once in a while to make sure alls ok.

[GlennyGills]

Car passed the annual Cat convertor replacement test (MOT). I had to fit new Oxygen sensor and new cat convertor on and it is purring like a kitchen now. No misfire anymore.

[blackyb]

Alls good then for another year of miles with smiles

[Mazda Mender]

Get the decat back on.
M-m

[GlennyGills]

I am taking the car for a run today and then will test the oxygen sensor again. I want some confidence in the sensor. Definitely will be using it for those smiles.

[GlennyGills]

Well took the car for a long drive,got the engine up to temp. I then tried th MX5Tech oxygen test and got nothing even after running at more than 3000 rpm for3minutes and still nothing. I guess next thing is testn the wiring.

[GlennyGills]

So I have cured the misfire - I now believe that the issue was that the Base Idle was somehow set ridiculously low and the car would not idle under testing mode. Strangely once warm the idle was fine. I guess there is some kind of switch over that uses one idle for cold and perhaps the ECU then takes over.
Anyway setting the Base idle mode to around 850, the misfire has gone.