whats the black thin cable that runs off solenoid?

[omodos]

Hello, I am checking the connections on my starter as been having some slow statrup issues (loooooooong story)please can someone let me know the purpose of the black cable shown in the pic?it has play in it maximum 5mm up and down as in pic when i try by hand,what could the consequences be? could I just crimp or apply some pressure with small pliers to make it a tighter fit to what I guess is a spade connector type connection under the black sheath? it seems loose but wont come off and I dont want to force it off......thanks

PS Just looked on some bmw m3 site , could it be the solenoid trigger wire?

[upallnight]

whats the black thin cable that runs off solenoid? That's the trigger wire to energize the solenoid so that the current from the wire from the alternator/battery is transferred over to the lead to the starter motor.

[omodos]

Originally Posted by upallnight

whats the black thin cable that runs off solenoid? That's the trigger wire to energize the solenoid so that the current from the wire from the alternator/battery is transferred over to the lead to the starter motor.

ok thanks to al,l alas tightening up all the points I could see still hear it made no difference, still sluggish start

12.94 v reading with car off (and after battery charging and letting it rest in car all night)

drops down to 9.44 V on crank

(low figure i know but bearing in mind had battery tested 4 times and all said was ok it cant be the battery)

Can I conclude that my starter motor amp draw is causing sluggishness in firing up as it exceeds 400amps on both amp clamps tests I did)

14.33v on idling (and also in ok range when driving and accessories on0

the fellas on a uk forum are pretty confident my Denso 2.0kw rated starter is the issue .....mechanics out here are looking at me funny when i menton this to them-they go on about glow plugs etc hmmmmmm

ps anyone got pics of the location of the engine grounding cable?