MX 5 Mrk 1 1.6 1990 jap import cranks, starts, dies then just cranks.

[Robbie260]

Is there a water temp sensor, have you tried disconnecting or grounding its lead?

Yes there is, the wire too it is broken. Just grounded it out there now when you turn on the ignition the fan comes on still cutting out when returning to run though.

 

[dave h 2]

Should also set the mixture.

 

[dobbslc]

still cutting out when returning to run though.

What do you mean by that?
Is it dying when you let go of the key?

 

[Robbie260]

Right car runs on brake clean,

What do you mean by that?
Is it dying when you let go of the key?

yes

 

[Robbie260]

Should also set the mixture.

It’s injected is that necessary?

 

[dave h 2]

Yes, it's cold it needs more gas it's hot then it doesn't. All for the loss of the handbag hook still needs choke.
Like wise the revs should go up.

 

[DickyDoDah]

You say it dies after catching when cranking. If you try to rev it when starting does it keep going? If yes then you may need to adjust the base idle as if that is too low the idle will droop and probably stall. Plenty of how to's available with a quick Google. I sometimes just put a bit of card under the throttle stop screw to temporarily increase the idle to warm up the engine etc.

 

[m_c]

It was found the fuel lines were on the wrong way round this has now been sorted and fuel flows as it should.

This could be a problem, and combined with your written question about whether the fuel pump should run continually, is probably where your issue is.

Anything that age will most likely use a vacuum controlled pressure regulator, with the fuel pump running continually.
If the pipes have been connected the wrong way around, it could have damaged/jammed something.
Most things of that era would have a test port on the fuel rail (usually a Schrader valve), and a quick first check in the absence of a proper test gauge, would be push the valve in with the pump running (being very aware of the risks of petrol spraying out under 5-6bar of pressure!).

 

[dobbslc]

Right car runs on brake clean,

yes

Will it run if you keep the starter motor running?

 

[Cal]

I had a similar ****uation on a couple of golfs that blew the injector fuse.

 

[jsf55]

Does this car have a factory installed alarm/anti theft system ?

 

[dave h 2]

It’s injected is that necessary?

I take it you have searched on here

 

[Alucard7002]

Yes there is, the wire too it is broken. Just grounded it out there now when you turn on the ignition the fan comes on still cutting out when returning to run though.

That's just the fan switch.

The NA 1.6s have the CTS on the back of the cylinder head where the thermostat used to be before Mazda made it longitudinal Vs transverse.

Lots of misinformation/generalisations here some of which flatly do not apply to the little 5.

You have fuel pump, you have fuel pressure, you have spark, you have air.

As this seems to have started since the timing belt was changed, have you confirmed 110% the belt is installed correctly? These are non interference engines and will quite "happily" run 4 teeth out on the cams and/or 2 on the crank, little cockroaches really.

You can't install the CAS the wrong way around but I see no mention of setting base timing.

If I were you I'd start with the real basics, check the belt is installed correctly, set base timing with a timing light, it should just run from there.

If it DOESN'T then I'd personally be checking the ignitor is not dead (you can get spark in open air but under cylinder combustion/pressure it'll blow out its so weak) PPF and chassis grounds (dipstick to chassis leg) as well as coil pack/HT leads installed correctly. You might be 180 out on the crank but also 180 out on the coilpacks for example.

In very rare cases the CAS does actually die but that's in 1 of every 2/300 non running MX5s on the original ECU.


If you get REALLY stuck I can send a man with a trailer and fetch it over and get it going

 

[Robbie260]

That's just the fan switch.

The NA 1.6s have the CTS on the back of the cylinder head where the thermostat used to be before Mazda made it longitudinal Vs transverse.

Lots of misinformation/generalisations here some of which flatly do not apply to the little 5.

You have fuel pump, you have fuel pressure, you have spark, you have air.

As this seems to have started since the timing belt was changed, have you confirmed 110% the belt is installed correctly? These are non interference engines and will quite "happily" run 4 teeth out on the cams and/or 2 on the crank, little cockroaches really.

Right so the timing belt came off as there was a leak from the thermostat housing but apart from it being 1 tooth out on the crank I bout it back the way it came off though, this is the only the second timing belt I have ever done so I may have cocked up. Though I’m fairly certain that’s not the problem as how would the car be starting and then running on brake clean if I was 180 degrees out I suppose compression may be doing it but don’t think it be that effective.

Right I’ll order a timing light and see what happens with the base timing