Fitting Crankshaft Sensor To A Mk1 1997 Uk spec
 

Hello i have a 1997 mk1



i want to install a crankshaft sensor, due to having issues with starter kickback when cold.



from what i understand i need a mk2 crankshaft pulley boss and crank sensor installed on the oil pump i will be using a 36-1 or 36-2 wheel



i understand that i wire the crank sensor into my factory wiring for the cas, what i want to know is what do i do with the cas, can i unplug and let the megasquirt ms2 just run off of the crank signal, and not utilise the cas



Thanks

Why do you think a separate crankshaft sensor is going to fix this?

Can you attach your tune and a log of the starter kickback happening?

I was under the impression that the cas isnt very accurate during start up

tune and log attached attached

the battery voltage drops quite low, i have just changed the battery out but haven't logged since

Thanks

Try negative numbers on your cranking advance

MS2/MS3 firmware. This is a known issue on wheels that have few teeth, the timing is sometimes wrong and results in starter kickback. Installing a 36-2 crank wheel completely solves the issue.

i originally had it set to 6 then lowered to 0. would you have an idea of how much to lower it at a time?

Helps in that the kickback is usually less severe and allows the engine to somewhat continue turning so that you don't have to pull the key out and crank again, but doesn't solve the core issue, which requires a firmware fix.

If i run the 36-2 wheel what do i do with the cas, can i just unplug it (just use the crank side for the crankshaft signal coming from the cas plug)

on tunerstudio do i run as sparkmode 36-2 , any other changes

Thanks

Cut off the inner two teeth, cut off 3 out of the 4 outer teeth,then you can run sequential injection and ignition again.

Edit: 36-2 is reserved for the 99-05 with the factory cam sensor. You will need to run Toothed Wheel mode, set Dual Wheel with missing tooth, then set number of teeth to 36, missing teeth to 2. Main wheel set to crank speed.

are the inner teeth crank signal.

does it matter which three teeth i remove.

what settings do i need to change once i have modified the cas

Thanks

The inner teeth (two) are the "Cam" signal but this doesn't matter, you will be cutting wires anyway to do this mod. So you will use one of the four outer teetth (which are normally the "Crank" teeth) and use the crank trigger as the actual crank teeth. I've given you a basic guideline above, you'll need to figure out the rest.

Ok will give it a go

how do i know which teeth to remove out of the four which one will i leave alone.

would it be possible to use a nb valve cover with cam sensor on the cam wheel

Yes, that would be easy to do. You will need to get a valve cover, sensor, connector and a NB intake cam gear (has the teeth the sensor reads). You will get 12V and ground for both sensors (crank/cam) from the CAS, and route the signal from each back to the CAS connector wiring. Then use the Miata 36-2 mode and you're golden. One thing to note - you really do need to get the FM 36-2 wheel, not ANY other 36-1 or 36-2 wheel. Using any other wheel may not work.

Will try the nb method i think,

thanks for the advice/help

Have you tried increasing the skip pulses with the CAS (in conjunction with reduced crank timing)?

tried to upload SS of the TS field, but the uploader keeps stalling at 90%.

its currently set to 3 as default will increase it and let you know. Cranking advance is set to 0

Reduced the cranking advance to - figures made an improvement but still noticeable.

changing the skip pulses didn't improve anything.

Have decided to go down the nb cam sensor route