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Hi guys,

My NB is turning off while im driving. It generally takes 5 mins to fire up again and only does it when its reached max running temp. I bet my balls its the cam or crank sensor but how do i tell which one?? Secondly, what are your thoughts about reading error codes from the diagnostics port? I read about gnd / ten but does this work when the car wont start?? Thirdly, if this doesnt work can i use my voltimetre to check the sensors?

any help would be appreciated

Try replacing the EGI relay first:
viewtopic.php?f=29&t=60268

93_Clubman wrote:Try replacing the EGI relay first:
viewtopic.php?f=29&t=60268

I will give it a try. Where do i buy the relay? I reset the ecu last night and hasn't turned off on my yet.

psi-mx5 wrote:

93_Clubman wrote:Try replacing the EGI relay first:
viewtopic.php?f=29&t=60268

I will give it a try. Where do i buy the relay? I reset the ecu last night and hasn't turned off on my yet.

.. are you saying that it shuts off while you are driving? (that's dangerous)
but what i'm reading that you mention it doesn't start when you're at max/optimum running temp (which is exactly my situation).
I changed the Cam Position Sensor (CPS), problem still persisted.. but after changing the EGI Main Relay (Green) so far so good, after about a week of testing over 30 - 45 mins driving distance.

I take it that you're in Melbourne, $30 (with pick-up from Viewbank 3084). Not too shabby considering what I paid for a good used one from the UK
http://www.ebay.com.au/itm/Genuine-Mazda-Parts-Main-ECU-Relay-Protege-Miata-MX5-B5B4-18-811-/221293355073?pt=AU_Car_Parts_Accessories&hash=item33861ca041

Good find & that's a bargain for a new one - think they're around $150 new.

shuey wrote:

psi-mx5 wrote:

93_Clubman wrote:Try replacing the EGI relay first:
viewtopic.php?f=29&t=60268

I will give it a try. Where do i buy the relay? I reset the ecu last night and hasn't turned off on my yet.

.. are you saying that it shuts off while you are driving? (that's dangerous)
but what i'm reading that you mention it doesn't start when you're at max/optimum running temp (which is exactly my situation).
I changed the Cam Position Sensor (CPS), problem still persisted.. but after changing the EGI Main Relay (Green) so far so good, after about a week of testing over 30 - 45 mins driving distance.

I take it that you're in Melbourne, $30 (with pick-up from Viewbank 3084). Not too shabby considering what I paid for a good used one from the UK
http://www.ebay.com.au/itm/Genuine-Mazda-Parts-Main-ECU-Relay-Protege-Miata-MX5-B5B4-18-811-/221293355073?pt=AU_Car_Parts_Accessories&hash=item33861ca041

sweet mate ill take it!! can i pick up this weekend??

Which model NB? VVT?

psi-mx5 wrote:sweet mate ill take it!! can i pick up this weekend??

lol.. i'm not the seller, mate (although I too am from Melbourne). after reading my post again, perhaps it was a tad vague..haha!
just stumbled on this on eBay a few days ago and rememberd that it is located in Melbourne. good luck with that, hope it fixes the problem.

shuey wrote:

psi-mx5 wrote:sweet mate ill take it!! can i pick up this weekend??

lol.. i'm not the seller, mate (although I too am from Melbourne). after reading my post again, perhaps it was a tad vague..haha!
just stumbled on this on eBay a few days ago and rememberd that it is located in Melbourne. good luck with that, hope it fixes the problem.

hahaha all good man. I just bought it and I'll let you's know how it goes.

Anyone had any experience with the GND / TEN trick to pull codes from the diagnostics port? Which side of the LED do I soldier the 1k resistor to?

Just guessing as you didn't respond to my question: https://www.google.com.au/webhp?hl=en&sa=N&tab=lw#hl=en&q=2001+mx-5+engine+cam+position+sensor
CPS failure is a common problem with VVT engines when they get hot.

JBT wrote:Just guessing as you didn't respond to my question: https://www.google.com.au/webhp?hl=en&sa=N&tab=lw#hl=en&q=2001+mx-5+engine+cam+position+sensor
CPS failure is a common problem with VVT engines when they get hot.

.. well, a quick search; 2001 NB8B w/ turbo. So CPS could come into play, but like myself.. I changed the CPS and the problem still persisted. $30 for a new EGI Main Relay is a bargain and worth trying. Better than the $70 I paid Mania for a new CPS (if you need a good used one, holler)

Edited, again.

On my previous car, the culprit was the Crank Angle Sensor.

When it got hot, the car turned into a paperweight.

Poured some water on it, let it sit for 5 minutes and then it was golden - until it happened again 100 metres down the road.

Rasputin wrote:On my previous car, the culprit was the Crank Angle Sensor.

Yep, that's the one.

ok guys just an update. Installed the relay and so far so good. Drove to and from work, then let the car sit and idle in the garage for another 15 minutes, then went for another 15 minute drive (car was heat soaked badly) and didnt shut down. Now, it's not exactly hot weather so i guess ill wait for summers 40'c days + aircon to really test it out.

Thanks for all the help. if It does shut down again, ill try swaping my cam sensor with a mates, then if its still shuts down ill buy a crank sensor. So far im $30 out of pocket and id rather try and test and get it right, then go a buy $150 worth of sensors.... money doesnt grow on trees.

I replaced 4 or so EGI main relays on my car over the years, cheapest I paid was $5 (for the one that's in there currently, and has lasted the longest!)

All NA and NB models have the same relay so they're not too hard to find at wreckers.