Occasional cranking issue on my NB8B. Some help?

[shuey]

Re CPS & hard starting, as opposed to motor cutting out:

Cam Position Sensor
My Miata was only hard to start when the engine was warm and on a warm or hot day. When the engine was cold it would start fine. But then when it was hot and on a hot day that took it a long time to cool down it would just crank and not fire up.

For a long time I was only receiving an EGR error code. PO402 EGR Flow Excessive Detected. It took a period of about two years and then it started throwing out a cam position sensor code. I replaced it and both of my errors went away. Prior to that I was replacing wires and plugs each summer. That seemed to get me through. This time I replaced the coils and that did nothing to help. So even if you are not getting the cam position sensor code on your miata You might think about changing it out.

http://mymiatarepairs.com/repairs/cam-position-sensor/

Wow, Paul.. you are definitely a wealth of knowledge
It does sound like what I'm experiencing right now..

I did call Allmaz up with regards to the EGI relay, but they wanted me to come in and show them the part itself cos they weren't sure what it was. I might just go in and get a spare one if they have one anyway for spare.

http://www.ebay.com.au/itm/Genuine-Mazda-MX5-Cam-Angle-Sensor-MX-5-NB-98-05-Camshaft-Position-Sensor-/140972597562?pt=AU_Car_Parts_Accessories&hash=item20d29f213a
Mania sells for $70, not that expensive.. guess I'll just get it and see how it goes (if I do get stranded in the coming week's MX5 meet-up, I do hope the others would not leave me stranded )

[93_Clubman]

Was just looking at the various options & that's a very good price by MX5 Mania for CPS. I've just PM'd you some buying links for EGI relay & fuel pump. Also meant to include mention of Dean @ Motorsport Essentials, 29E Glenvale Cres, Mulgrave, 9562 1005, if the problem persists.

[shuey]

Thanks, just bought the replacement CPS.
Will update you in a few days time to see if the problem is arrested
Not fun not being able to drive the car /shrugs

[93_Clubman]

Attached below is the MSM Engine Won’t Start Diagnostic Checklist based on the procedure developed by hobie237 – Moderator on Miata.net. Changes have been made to cover the Mazdaspeed Miata vehicle.

MX5 Engine Won't Start Checklist D.pdf

Link originally posted by:

This was posted on the mazda-speed.com forum and provides some very useful info that may help: https://docs.google.com/file/d/0B1P63nzyHOkYMjcyYzE4NjktM2FiZS00MTE3LWI2YmQtNmEwMmNjZGNkZGE0/edit?pli=1

posting.php?mode=quote&f=18&p=747008

Here's hobie237's posts that the above PDF is based on (see 30 Apr 09 & 11 Feb 10, as well as a few relevant comments in between on amendments): http://forum.miata.net/vb/archive/index ... 79746.html

Of course, where possible, ie not an intermittent fault, check for spark, fuel, & air first to narrow options:

Can check spark a couple of ways, by putting a new spark plug on one of the leads and making sure its metal (side or base) is Earthing, anywhere there is a good earth connection(usually an exposed bolt attached to the chassis or the inlet manifold).
If your unsure and have a multi-meter then check it, otherwise you could damage something.
The other way is if you have an old ignition lead with end exposed, that will work without a spark plug but you must keep a 1cm gap between it and earth
Then just turn the ignition and watch or listen for loud snapping noises
Just need to be certain there’s no fuel leaks or spilt fuel anywhere as it may ignite it, so if there a strong fuel smell then don’t do it.

or without checking for spark, you can just get a can of Starting Fluid, from any Autoshop, and spray a good amount in the throttle body, with it on full throttle, then try and kick it over.
If there is any kick or it starts briefly, it has spark and no fuel, no kick at all, will most likely mean no spark (so Electric or ignition issue)

viewtopic.php?f=29&t=35230&start=15

A basic check for fuel is to crank the engine prior to removal of a spark plug to check for spark & if the spark plug is wet then it's getting at least some fuel. Check for air is simply to ensure a cloth has not been sucked into the air cleaner pipe - this does happen - I found my old NA6 had a cloth in the airbox inlet pipe when I inspected just prior to purchase.