RS Motorsport :: Classic Speed Restored

Watto,

Assuminng battery has not died, it's likely not the problem. If using lights results in a drained batery then check your alternator can deliver enough amps to run your electrical loads plus top up the battery.

Running the earth cable from the boot battery to the block is not the best way. Use a short earth cable from block to chassis and from battery to chassis adjacent. The chassis has a far greater cross sectional area than any cable your likely to run front to back.

Watto,
I've got my batt in boot and a EFI setup always had issues starting. I ran a 420 then 460CCA battery. Now upgraded to 750CCA and its very strong in cranking compared with before. Make sure your starter is up to the job, I had mine rebuilt only for it to be worse to start (took it back) so I put a spare in and it was fine.

I also run earth from batt to inside boot and have engine block earthed in engine bay.

What size wire are you running? 2gauge would be best but 4ga is ok if you don't run a big sound system or anything. Also if your running a battery isolator switch, I've been caught out here by using a cheaper one, they're known to drop current. So I've also binned that.

Rhys

Slightly of topic but went to a guys house last night whose Mk2 Escort we are crewing for in Targa West next month, it has one of those UK sourced Pinto fitment gear reduction starter motors, starts up really really well.

Apparantly they have about 40% less current draw while cranking

BTW, I had an Exide 550CCA bat in the boot for about 8 years and zero problems, just recently swapped to a 440CCA, still no problems with cranking. Mind you I have a battery lead the thickness of your thumb (not sure what guage) running from the bat to the starter.


Craig

ok, got this sorted. it was a bad earth problem.

thanks to jsa who tickled me in the right direction with the negative batt lead to chassis solution.

problem - 12volts at all the right places, but as soon as to apply a load, ignition, lights etc, the voltage dropped to 0v. metered out the earth circuit and it was around 4kohms...not good.

the neg lead was earthed to a plate that secured the battey box that was in contact with the boot floor. ok when I installed it, but moisture, etc caused a bad connection over time. I ran another lead from the plate to one of the chassis rails and now it is all good.

cheers
watto