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... okay, so usually my car cranks over and start up pretty easily (although slightly laboured when the engine is cold as I only drive it over the weekend). However I've got a slight issue which occurred twice (once about a month ago when I was putting in a full tank of petrol, and once a couple hours ago when I was out and about). Scenario; start the car (cold, no issue) and did some errands. Got back into car, tried cranking and it wouldn't start. Started doing it a few times x5 at least, and it still wouldn't start, like an itch that never went away after constant scratching.

Waited a few more minutes while i pondered my options (tow truck, walking back home, crying etc?) and then tried cranking again, and the motor started as if nothing happened. Drove to Repco, got the battery tested and it was fine. Got back, cranked the car again and it fired at first go.

Any idea what went wrong.. i know it doesnt happen often, but not sure if its something more serious. Plus it's not fun to look like Wun trying to kick start a motor with his feeble legs.

I'd only recently changed my leads and plugs and checked that they are good. Clogged fuel lines? Etc?
Thanks!

Edit: just to note that my ride is stock standard with no mods to ECU etc

hey i have an NB8B also though 2000 build. the issue you speak of has happened to me before though not 5 times in a row. i remember it happening after running the car and never on the first start of the day.

i am also a weekender with this car though i recall reading other forums threads about this type of issue being attributed to the crank angel sensor slowly failing?

issue seems to be intermittent without any links to climate or situations other never doing it on first start, as its only done several times in 3+ years havent really done much other than regular servicing..........

... oh, actually what i meant by 5x in a row meant I kept on trying to crank it (key; off-standby-start/crank for about 10s x 5 times). And after 'waiting' for a bit, the next time i cranked it up..it just started like normal. looks like i'm not the one, gonna try to read up more about it and see if there is a way to arrest it. quite annoying/embarrassing too

Leads was my first thought but notice you mentioned changing those.

Fuel pump or filter?

Hate intermittent issues:evil:

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Hi.
To check if it is the fuel pump turn the ignition on for 10 seconds turn it off and immediately start. If it starts it usually means the pump is not supplying the correct pressure immediately and is on the way out.

ralt wrote:Hi.
To check if it is the fuel pump turn the ignition on for 10 seconds turn it off and immediately start. If it starts it usually means the pump is not supplying the correct pressure immediately and is on the way out.

normally that's what i do, turn on the ignition and wait till the beeping sounds go off and crank it..and it usually starts
so, let me recap what you meant to check on the fuel pump
.. turn on ignition, wait 10s and switch off..and start. if it starts up immediately, means the fuel pump is on its way out? (i thought if it starts immediately that's ok?).. prolly need a wee bit more explanation (sorry!) i'm a little confuse on what is a fully functional fuel pump and what's close to its deathbed

Hi.
Your car should start immediately you insert the key and start the car as the fuel pump delivers fuel at the correct pressure when you switch the ignition on. If your pump is not pumping as it should it takes time to pressurise the fuel rail and hence the test procedure of 10 seconds to get the fuel to the fuel rail mentioned previously.

ralt wrote:Hi.
Your car should start immediately you insert the key and start the car as the fuel pump delivers fuel at the correct pressure when you switch the ignition on. If your pump is not pumping as it should it takes time to pressurise the fuel rail and hence the test procedure of 10 seconds to get the fuel to the fuel rail mentioned previously.

Ah, thanks for the clarification..makes sense
Well.. I tried cranking immediately after inserting the key and it started up fine (well, cold morning so it took the regular 3 - 4 seconds to get going).. so I reckon fuel pump still ok so far?

It'll probably be the usually green (on NB8B) EGI relay in the fuse/relay box in the engine bay. If not, & if it does seem to be the fuel pump, then check the fuel pump wiring conections inside the top of tank before buying a new fuel pump. But before this, I'd be checking the CPS if the EGI relay checks out ok.

ah, crap. It happened again and now I'm stuck at a shopping complex car park. Dang it!

93_Clubman wrote:It'll probably be the usually green (on NB8B) EGI relay in the fuse/relay box in the engine bay. If not, & if it does seem to be the fuel pump, then check the fuel pump wiring conections inside the top of tank before buying a new fuel pump. But before this, I'd be checking the CPS if the EGI relay checks out ok.

okay, after almost calling a tow truck.. i decided to crank it again, and it came alive.. like a scorned mistress
how do i check the CPS to see if the EGI relay checks are okay?
good thing this isn't my daily, but looks like it's gonna be sitting in the garage till i rectify this problem

Shuey, EGI relay & CP sensor are two different possible causes of the issue.

See Manga Blue re the EGI issue:
viewtopic.php?f=29&t=38526&p=535770&hilit=relay#p535770

viewtopic.php?f=29&t=49188&p=617511&hilit=relay#p617511

search.php?keywords=relay&terms=all&author=manga*&sc=1&sf=all&sk=t&sd=d&sr=posts&st=0&ch=300&t=0&submit=Search

See de B re CP sensor issue:
viewtopic.php?f=29&t=38526

viewtopic.php?f=29&t=45592

search.php?keywords=nb8b+sensor&terms=all&author=*bounce&sc=1&sf=all&sk=t&sd=d&sr=posts&st=0&ch=300&t=0&submit=Search

Could also be fuel pump wiring or even the fuel pump causing the issue, but above two are more common: viewtopic.php?f=55&t=46425

Thanks, Paul.
Have gone through the threads you mentioned and also those on miata.net
Well, so far since the car's been at home I've been cranking it up (over time) and it's a-okay.
I guess from reading the thread on the "NB8B engine cut out" and also a PM from Kev05, seems like the issue was the engine cutting out while driving, but for me it's fine when I'm driving (as in doesn't cut-off), just intermittently doesn't want to start after I'd dríven it awhile.

Got a couple more questions though. Is the buzzing/humming sound of the fuel pump audible when I put the key into the ignition and turn it to standby/ready (i.e. when that beeping lights come on and the check engine, battery lights come on)? I know I can hear a clicking sound from the engine bay...and what seems like a faint hum (not 100% certain) from somewhere in the car. Not sure if that would suggest that the fuel pump is working?

I did pull out (wiggle it out with much effort) the EGI relay and put it back, just for good measure.. since I don't have a ODB reader, won't be able to look up for fault codes..

Anyhow, I'm still gonna pop it down to MX5 Factory one of these days to have this checked out since I don't have the expertise to assess/change the fuel pump and its wiring (don't know how to access it tbh). Do hope it's not the fuel pump since that's gonna cost a pretty penny

Thanks all!

Shuey, appreciate that it's not cutting out at the moment, & that it's sometimes a problem with starting, but don't completely rule out the CPS. However, if it was an NB8A then I'd say coilpack.

Can't hear the fuel pump kick in on my NA8 when key turned, but others reckon they can hear theirs on other model MX5s. You should hear the click in the engine bay, as you are doing, which should be the EGI relay. The hum sounds like your fuel pump is working, but the point is though that when it won't start do you still hear the click & hum?

Generally the EGI relay (Fuel Inj relay on the NA) is difficult to remove the first time, which given you suggest yours was not easy to remove, seems to indicate yours has not been removed in the past. Simplest thing to do is buy another relay (2nd hand) - if it turns out you don't need it then you've at least got a spare.

No need for OBD reader as I don't believe your NB8B has an OBDII port - from memory OBDII port was introduced in Aust in 2002. So to check for error codes on an NB8B, see both of Caff's posts in:
viewtopic.php?f=18&t=16872

Bit more reading on fault codes for NA:
http://www.miata.net/garage/Engine_Diagnostics.html
http://www.miata.net/garage/faultcodes.html

On the NA at least there's also a fuel pump relay under the dash on the driver side (RHD), but these seem quite stable, particularly compared to the EGI relay in the engine bay. If it's the fuel pump then a replacement can be had for under $100 posted to you. If it's the fuel pump wiring then it's just a few $ to fix, but both involve removing the fuel pump & fuel gauge sensor assembly from the top to the tank just under the rear parcel shelf. This isn't difficult but it's critical you do it in an extremely well ventilated area where there is no chance of a spark or flame (pilot light) being near by!

A cheap multimeter can be very handy in diagnosing the fuel pump or fuel pump wiring issue. If a call had to be made on order of likelihood, then it would be: EGI relay, CPS, fuel pump/ wiring.

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/