Sigh... MX5 won't start

omega36 · Postby **omega36** » Fri Mar 07, 2014 7:52 pm

Hi all,

Not having the best run with my MX5 in the past few months :/

Finished work, tried to start my 1998 NB MX5, it cranks over, but doesn't start. I have fuel, and battery/voltage seems fine. Plug leads, spark plugs and coil pack have been changed in the last 5-6 months.

The car's never shown any signs of difficulty when trying to start. There's potentially oil on the spark plugs, but I don't have the necessary tools to check. I've called out RACV which will be here in the next 2 hours (sigh).

Does anyone else have any suggestions as to what I should be looking out for ? My primary suspect is the fuel pump, but have no way of proving this (I don't hear it priming when the engine is cranking).

If it is potentially the fuel pump, does anyone know where I can pick up a new one on the weekend? Your help is appreciated as always

Magpie · Postby **Magpie** » Fri Mar 07, 2014 8:14 pm

Immobiliser?

omega36 · Postby **omega36** » Fri Mar 07, 2014 8:30 pm

Magpie wrote:Immobiliser?

Are they all fitted with immobilisers? Would that still allow it to crank? I don't have any extra key :S

omega36 · Postby **omega36** » Fri Mar 07, 2014 8:58 pm

Soo, RACV came around, tested for spark with a spark plug and lead for cylinder #1 and there was no spark. I suppose that this means it's any part of the ignition system then ?

I have a spare coil pack which I'll replace tomorrow, otherwise does anyone else have any pointers for me? Luckily it's in a secure parking spot for work, so I do not need to stress about leaving it behind.

aviper4u · Postby **aviper4u** » Fri Mar 07, 2014 9:34 pm

omega36 wrote:Soo, RACV came around, tested for spark with a spark plug and lead for cylinder #1 and there was no spark. I suppose that this means it's any part of the ignition system then ?

I have a spare coil pack which I'll replace tomorrow, otherwise does anyone else have any pointers for me? Luckily it's in a secure parking spot for work, so I do not need to stress about leaving it behind.

well atleast you have something to go off......

to answer question about immoboliser, i have a NB8B and tried starting without transponder key (after lockie said i didnt need one) and the engine fired and ran but only for 5-10 seconds.

good luck!

omega36 · Postby **omega36** » Fri Mar 07, 2014 11:53 pm

aviper4u wrote:
omega36 wrote:Soo, RACV came around, tested for spark with a spark plug and lead for cylinder #1 and there was no spark. I suppose that this means it's any part of the ignition system then ?

I have a spare coil pack which I'll replace tomorrow, otherwise does anyone else have any pointers for me? Luckily it's in a secure parking spot for work, so I do not need to stress about leaving it behind.

well atleast you have something to go off......

to answer question about immoboliser, i have a NB8B and tried starting without transponder key (after lockie said i didnt need one) and the engine fired and ran but only for 5-10 seconds.

good luck!

Thanks dude.

The more I read in to it, the more it seems that it is potentially the key/immobiliser system. Now that I think about it, when the car wasn't starting, the red car/key icon was flashing on the dash... the few results I can find suggest that this is the immobiliser in effect. Hmm...

omega36 · Postby **omega36** » Sat Mar 08, 2014 1:09 pm

Ok, so got back to my MX5, and it is indeed an immobiliser fault. I received immobiliser diagnostic code (DTC) 24, which is 2 long and 4 short flashes (which is a general open circuit issue).

I've popped open the fuse box, and have found that one of the EGI relay pins isn't looking so fresh:

I accidentally broke one of the clips trying to open it up to see inside, but I'm quite certain it's due this relay. Does anyone know where I can find one today? I've tried all the wreckers in Melb, they all seem closed or don't have this relay.

Cheers!

speed freak · Postby **speed freak** » Sat Mar 08, 2014 5:41 pm

Not that this helps you for today but usually you will find them on ebay, most of the mx5ers on here get them from ebay.

Otherwise keep trying wreckers, you would think one would have one somewhere.

93_Clubman · Postby **93_Clubman** » Sun Mar 09, 2014 10:06 am

Not sure if you're aware, but the NB8 EGI relay is used across a number of makes & models, which broadens the number of potentially helpful wreckers, but on a long weekend in Vic (now Sunday), it will be a struggle. As SF mentioned above, a number of forumites tend to buy them off ebay.

omega36 · Postby **omega36** » Wed Mar 12, 2014 4:50 pm

Hi all,

For posterity, turns out that it was the bastard EGI relay. Thanks again all for your suggestions & help.

hks_kansei · Postby **hks_kansei** » Wed Mar 12, 2014 4:57 pm

Just wanting to confirm, is finding the NB8A fault codes the same process as an NA?

I've tried the NA method on my NB8A and couldn't get any codes, just the single long flash.
I had no way of telling if there simply weren't any fault codes to read, or if the method was wrong for the NB....

(I knew there was a fault however, the o2 sensor was poisoned but the ECU didn't know that)

omega36 · Postby **omega36** » Wed Mar 12, 2014 5:02 pm

hks_kansei wrote:Just wanting to confirm, is finding the NB8A fault codes the same process as an NA?

I've tried the NA method on my NB8A and couldn't get any codes, just the single long flash.
I had no way of telling if there simply weren't any fault codes to read, or if the method was wrong for the NB....

(I knew there was a fault however, the o2 sensor was poisoned but the ECU didn't know that)

I'm not certain how to check on an NA. The process for finding the DTC for the immobiliser on my car was:

1) Attempt to start car [car doesn't start]
2) Leave key in ON position, wait 60 or so seconds
3) A red icon with car and key lights up on the dash
4) After a few moments it then starts to flash the error code

Hope this helps!

hks_kansei · Postby **hks_kansei** » Wed Mar 12, 2014 5:05 pm

Ah, that's completely different to the NA method.

The NA method involves getting an LED light, opening the bonnet and shorting a few pins on the Diagnostic connector, then watching the LED blink.

I couldn;t find ANY answers on how to do it on an NB when I looked, everything was either NA only, or was from the US and just said "plug in a code reader to the ODB2 port"

Thank you for the info.

omega36 · Postby **omega36** » Wed Mar 12, 2014 5:17 pm

hks_kansei wrote:Ah, that's completely different to the NA method.

The NA method involves getting an LED light, opening the bonnet and shorting a few pins on the Diagnostic connector, then watching the LED blink.

I couldn;t find ANY answers on how to do it on an NB when I looked, everything was either NA only, or was from the US and just said "plug in a code reader to the ODB2 port"

Thank you for the info.

Ahh right. I think I still check general ECU fault codes on my NB8A (ODB1) the same way. It seems that the immobiliser has it's own fault code readout (yay)

Rolley · Postby **Rolley** » Tue Aug 09, 2016 11:10 am

Morning mate,
I have a couple of LA10 relays, I think that's the one in the engine bay fuse box, correct me if I'm wrong.
I also have a spare black and yellow main relay on the accelerator pedal bracket.
Drop me a message I'd be happy to sell one of each or we can sort out a time to test first if you're happy to head to the northside.

I also came across the ADM/JDM ECU problem after swapping out my MX-5 big nose B6 for a Eunos short nose B6. It didn't cause starting problems though, just a loss of power at points through the rev range. It's in my garage thread.