NB8B Wont Start

[ducktape69]

hey guys,

need some advice again please.
i parked the car for 5min then went to start it again, it started then stalled straight away.
Now it isnt starting at all.
it is ticking over but not starting.
does this sound like a fuel pump or coil pack? or something else? any tests i can do myself to test?

there were no symptoms leading up to this, so just happened suddenly.

Cheers,
Sam

[wun911]

You have coil over plugs...

I have had the same issue my fuel pump died (NB8B) came out of a movie and it simply didn't start.

[ducktape69]

thanks wun!!
yeah i thought it was but damn so sudden without warning

any recommnedations on fuel pumps? go OEM or aftermarket?

[wun911]

I got OEM pump it was really really expensive, in hindsight I should have got an aftermarket one. (I killed the oem one because I like to run the car with mininum amount of fuel all the time)

There are Walbro fuel pumps they are suposed to be good but maybe a little noizy and they are like 1/3 the price of oem ones...

[Hammer]

I was having similar problem last year, but it happened when the weather was warm. The car would just stall with no warning (or would not start). It ended up being an SVT sensor (located at the rear of the engine, near the firewall).

Not sure if this is the same as your problem.

[Mr Morlock]

I suggest do not jump to conclusions- you may not have spark to the plugs. Not sure what you meant by ticking over- cranking or actually running??

[ducktape69]

it is cranking, but not starting.
definately sounds like fuel pump...it has never stalled on me before.

so whats the GO with types of fuel pumps? walbro? OEM?
i dont get about noise(how loud can it possibly be?).
preferably the best bang for buck i guess.

by the way, im guessing you need to strip the boot lining etc to get to the fuel pump in the fuel tank??

[Garry]

It could be the fuel injection relay in the engine compartment fuse box or a mirriad of other things. Have you tried shorting out the fuel pump pins in the diagnostic box to see if you can hear the fuel pump? I'd be doing some diagnostic work before I shelled out the big bucks for a new fuel pump.

If you're looking for the fuel pump it's under 2 covers on the parcel shelf. You will need to take out the carpet on the parcel shelf and probably the wind blocker to get to it. If it does turn out to be the fuel pump and you decide to go for a Walbro pump make sure you get the correct fitting kit for the MX5 because it comes with a rubber sleeve to fit over the pump to keep the noise to an acceptable level. Mine was extremely loud and drove me insane before I managed to source a sleeve for it. I couldn't hear the exhaust at idle over the fuel pump, and the SP exhaust is pretty loud. My friends sitting in the next lane and 1 car behind me could hear the pump over all the other traffic noise when stopped at the traffic lights. And it wasn't much quieter inside. Now it's not much louder than the stock pump.

[Okibi]

Yup gotta agree with Gary,

Check you have spark and check you have fuel.

A dead fuel pump could simply be a fuse or a relay.

Perhaps the immobiliser has popped out? Mine did that once on a remote bit of road, I had been playing under the dash and luckily looked there first before trying to get a lift to somewhere with mobile reception to call a tow truck.

Also we had an ignition switch die many moons ago, slightly different issue (it kept trying to spin the starter motor) , i think they're another weak point that could cause a potential problem.

[ducktape69]

ive checked all fuses and relays and they r look OK(not burned/snapped).
where is the immobiliser located?

anyone got a pic of which pins to short?

[trader]

Looks like you need to google miata garage and then search "fuel pump relay". The headings "tips for fuel delivery problems and "changing the fuel filter" should give you most of the info you need. Mine turned out to be the earth to the pump. The fuel guage earth is the same connection so if your fuel guage is not working then there is your problem. The earth can be spotted or found with your fingers by removing the panel in the boot (of an NA anyway) that covers the fuel intake pipe. Shine a torch up the space and you will see the connection - it is screwed to the body and if you can wiggle it then you wont have a good connection. You may then have to go in behind the seats to tighten it. (thanks to RussleB for pointing this out to me).

[ducktape69]

thanks for all the advice guys!
after all the reading, i determined it was the fuel pump just by process of elimination.
ANyway, apparently mazda said they dont sell just the fuel pump itself anymore, and wanted $1800 for the whole assembly. SO after i almost spit on the phone, went down to blacktown auto spares and picked up and aftermarket unit for $80(tradies price).
Got my mechanic to fit it and hey presto! all ok now...

the weird thing is that the engine sounds and feels smoother and a little torquier after this...
guess the pump was on its way out for a while?

Anyway, ive put this failed pump down to the fact that i ran the tank down REALLY low for the past few tanks...kinda tryin to do a kramer/seinfeld test

Cheers,
Sam