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-   -   mx5 starting probs (http://www.haynes.co.uk/forums/showthread.php?t=13804)

garyt 9th January 2016 01:32 PM

mx5 starting probs
hi folks I need some help with this one, its an mx5 1.8 2003 motor etc, it was starting but hadn't started it for a few months went to start it after charging the battery and its not turning over
battery is giving a healthy 12.8 v static and still reads 12.6 when key is in the cranking position
12.8 v at the hot solenoid terminal
9 - 10 v at the thin solenoid wire when key in cranking position
all other electrics working as far as I can work out
when I bridge the hot 12v terminal on the solenoid to the starter one , starter motor spins but doesn't turn engine, swapped over starter motors for another "new" second hand one and all exactly the same........
haven't tried bumping it yet need some extra bods for that one.
any ideas or something obvious I'm missing

any help welcomed :)

metal matt 9th January 2016 03:21 PM

I had this problem when I tried to start mine for the first time. Turn out it had a clutch switch (push the clutch peddle in to start). I then done away with the switch by joining the wires together. Just a thought for you to check.


garyt 9th January 2016 03:38 PM

thanks but I had it starting earlier with no issues and now it wont turn over if I bridge the contacts the starter spins but doesn't engage the flywheel, tried a replacement starter and its the same, ..... unlucky I don't think so so I guess I will try bumping it and see if it will start that way :)

metal matt 9th January 2016 03:43 PM

When I was trying to get mine started I did everything you have done like crossed the solenoid and it would spin but not engage then done a little reading to find out about the clutch switch. It might of got by passed on your doner and with your work maybe the wires came loss

garyt 9th January 2016 03:53 PM

thanks, that's a good point I'll try and dig under the dash tomorrow, means taking the dash out again , oh well its got to start. I will go back over my wiring diagrams and see if I can identify the wires so I know roughly what im looking for.... needle and haystack come to mind ...lol

garyt 9th January 2016 03:58 PM

when I hold the key in start I get power to the solenoid switch though, this is what is confusing me ...
power from battery to solenoid and power from key to solenoid and a good earth, should equal turning as there is no other connection
any way I will have a hunt for any sign of the clutch switch wiring

garyt 9th January 2016 04:33 PM

found this ont internet
"you should have battery voltage at the starter lead wires (12) and with the key in the crank position you should get battery voltage to the small wire. make sure in neutral if a standard tranny. the 12 volts applies current to windings in the solenoid called pull in they move the metal center to engage the hold in windings another set of wires in the solenoid and at this time the starter motor gets power and starts turning. when it is pulled in the starter drive is engaged"

so IF I use a length of wire , ignition on and take the 12v to the wee wire it should engage and turn... right ... if it does then I need to find out why I have a voltage drop between the key and the solenoid wee wire, if it don't then its the solenoid
starting to think a handle in the front was a good idea back in the day :)

garyt 10th January 2016 03:31 PM

Sorted, I checked the ignition switch voltage and it was fine on start so after running a gash line from there to the solenoid she started straight away. After some investigating I found that I had picked up an ignition feed for the switches from ig1 wire which stays live on start this caused enough of a voltage drop to prevent the solenoid working.
so a wee bit of rewiring and all is ok.

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