NA6 MX5 suddenly won't start , Cranks but wont catch

ZL · Postby ZL » Sun Oct 26, 2014 1:16 pm

Hi, my MX5 suddenly wont start today, yesterday it was fine, i drove it back home and parked in my drive way. Today it will not start.
Once or twice it starts for like 0.5 of a second and die straight away.
The only thing i did during the time was clean the engine bay with a damp rag and also the fuel was running really low.
But i topped up the fuel another 7-8L since and still won't start.
Heres what i have checked so far.

- There is sufficient fuel
- All 4 leads give sparks.
- There should be fuel in the piston as after cranking the spark plug is really wet with petrol.
( but can't be 100% sure.)
- Remove oil cap and the crank spins.
- check all the fuses and none is blown.
- There is enough engine oil.

Please help, cant even get to work tomorrow and cant even get it to a mechanic.

Thanks

greenltd · Postby **greenltd** » Sun Oct 26, 2014 2:01 pm

Any chance you have knocked a wire or hose when wiping the engine?

ZL · Postby ZL » Sun Oct 26, 2014 2:26 pm

greenltd wrote:Any chance you have knocked a wire or hose when wiping the engine?

Hi there, i don't think so i went through most of the wires and hose nothing seems out of place.
What are the main wires and hoses i should be looking out for?

Im still suspecting fuel delivery system. I'm not sure how to jump the diagnoses relay for the fuel pump.
I found the GNP and FP relay in the diagnoses box but not sure what i'm doing.

ZL · Postby ZL » Sun Oct 26, 2014 4:12 pm

Hi, okay i just bought a bottle of starting fluid and the motor starts for a sec and than it stops.
Whats the problem i'm looking at right now?

Thanks

emily_mx5 · Postby **emily_mx5** » Sun Oct 26, 2014 4:19 pm

Possibly ran it so low that the gunk in the bottom of the tank has been sucked through and is now either blocking the fuel pump's filter bag, or the actual fuel filter or even an injector(s).

Washing engine bays is never a good idea.

Check the grounds (take off and sand) but also thoroughly thoroughly check the intake system. If the breather hose or iscv hose is off/leaking it will die straight away.
Check intake for cracks too.

ZL · Postby ZL » Sun Oct 26, 2014 4:25 pm

emily_mx5 wrote:Possibly ran it so low that the gunk in the bottom of the tank has been sucked through and is now either blocking the fuel pump's filter bag, or the actual fuel filter or even an injector(s).

Washing engine bays is never a good idea.

Check the grounds (take off and sand) but also thoroughly thoroughly check the intake system. If the breather hose or iscv hose is off/leaking it will die straight away.
Check intake for cracks too.

Hi, just wondering how much ground points are there on a NA?
And where are they located?

Thanks

gslender · Postby **gslender** » Sun Oct 26, 2014 7:39 pm

You could have flooded it if the spark plugs are wet. Hold down the accel pedal all the way to clear cranking for 15 seconds. Then ign off then start normal.

93_Clubman · Postby **93_Clubman** » Mon Oct 27, 2014 10:27 am

Hopefully it was just flooded, but if the problem persists or returns then also check for this: viewtopic.php?f=55&t=46425

myredmx5 · Postby **myredmx5** » Mon Oct 27, 2014 2:15 pm

Like 93_Clubman says.

I found it was in the fuel pump connections.

fran · Postby **fran** » Fri Nov 07, 2014 4:21 pm

Hi ZL. I've got car starting problems as well. Car cranks but won't start. The last changes made to the car were at a service with MX5 Mania: changed a couple of belts and the fuel filter.

The spark plugs were changed earlier in the year, the PCV valve & ignition coils were also recently changed and there don't seem to be any vacuum leaks. There haven't been any issues with the battery and I'll be changing the leads soon. I suspect an issue with either the fuel pump (yet to check), fuel injectors or camshaft position sensor.

Does anyone have any advice re the camshaft position sensor being an issue?

StillIC · Postby **StillIC** » Fri Jan 16, 2015 8:13 am

I had similar problems which were eventually diagnosed as faulty connections at the plug of the camshaft position sensor (the female sockets were a bit too big for the male pins) and repaired with some needle nosed pliers and a scribe.

It was sparking sometimes, but often not enough to get it running every time and stay running. But this was a problem that gradually became worse. Initially it would occasionally not start, which then became often, and eventually it wouldn't start at all, over a period of 2 year or so. It was not a sudden event, if you know what I mean.

aladdin96 · Postby **aladdin96** » Sat May 30, 2015 11:32 pm

Hi guys i had this problem. I changed everything and checked everything but nothing seem to wake it up. So there was one thing. What i did was disconnect the battery while holding on to the brakes for 10 SECS. After that i connected it and 10 mins later it struggled but started. I left it runing for about 20 mins. Then never had a problem. Please im not a mechanic. This might fix it or not. But thats my story. Cause i washed the engine as well. Good luck