Slow cranking
 

Hi all,

I've just been through a bit of work on my FD doing a V-mount install, new injectors, rails, FPR, vacuum replacement, etc. more info on the wider build here:
https://www.rx7club.com/build-thread.../#post12452607

I've finally gotten the car back together however it's really struggling to start, per below video:


My first thought was a dodgy battery (having sat for 4 months) so swapped this out right away, exact same result. Battery at 12.7V with car off, 12.5V with accessories on, 10.1V under starter.

I'll be checking the engine (which I doubt to be the problem as all was well when it went on stands) tonight by just pulling the plugs and rotating this by hand.

Assuming this is not the issue I'm looking for any thoughts or guidance on what else I may need to look at here? I am not the most electrically minded so might take a little time to work out but I assume I've either missed something leading to a short or there some amperage leakage somewhere along the lines. The only thing that has been deleted and not plugged back into anything are:

• Air pump
• Fuel temp sensor

One more item of note is that during cranking the alternator pulley gets extremely hot extremely fast. After perhaps 10s of cranking it's nearly too hot to touch on the pulley itself so unclear if this is a separate issue? The belts seem to be appropriately tight.

Keen to get some views on what else I might be able to chase down here as a possible cause. Thank you in advance for any assistance and I'll be sure to update this thread when I find an answer to help future searchers :)

From the short video, it looks like an OE starter. Mine started the same way, and I had to also give it a little throttle. Hot starting was a joke. I recently got an upgraded starter Banzai, and it's much better. I still have to give it some throttle when starting, but it spins much better, and hot starts improved (still not great).
I got the Banzai because I didn't want to get an RX8 starter, core it, and put the new internals in the FD nose. Probably cheaper to go the Banzai route, too.

Just closing this one off as a fortunately easy fix once I spent some time on it.

Ultimately the issue was just not the right grounds in the right places. I followed a diagrams, sanded and cleaned up all my grounds and got things back together and it fired right up!

For anybody experiencing similar in future, make sure you've checked your grounds :)

Do you have a relocated battery? That contributes big time to cranking problems, many times the wire gauge isn't big enough, grounds aren't good, etc.

But, glad you sorted it out!

Dale