On a cold start everyday my car does this, when its warm it starts fine. Any ideas where to look? Ive got a new battery, battery is relocated in boot earthed to the rear seatbelt. The battery seems to be chargeing the battery ok, need to test if there is something draining the battery over night or do we think this could be a weak startor motor?

How thick is the cable from battery positive to starter?

50mm 345amps

Should be enough, probably;  decent crimp connections both ends?

Edited 10 March, 20215 yr by Wino

Can you measure voltage at starter motor when cold cranking, with an assistant on either the meter or in driver's seat? Probably awkward to get probes in there though.

 

Does the positive cable from battery go directly to starter?

Earth problems seem more likely, join positive and negative battery terminals together then measure total resistance across the starter.

That is what I was thinking  as well ! 

 

We experienced a problem with a Group A Civic where it cranked slow - We had her earther to the middle belt anchor as well - we ended up boring an M14 hole in the shell and stripping the paint around the crimp and earthing to there ! 

 

 

1 hour ago, Wino said:

Can you measure voltage at starter motor when cold cranking, with an assistant on either the meter or in driver's seat? Probably awkward to get probes in there though.

 

Does the positive cable from battery go directly to starter?

I could get someone to give me a hand, and yes goes streight from starter to the battery in the boot