car cranks really slow..

[Rotary#10]

well one problem after another on my daily driven 7...
its a 91 n/a FC... it cranks really slow...
battery is over 12.4 volts
starter is good had it tested at autozone
plugs are good, I have spark
I have fuel and air of course..

any ideas ? ign switch?

[My5ABaby]

What's the voltage while cranking?

[Max777]

Do you have a "DVOM" (Digital Voltage/Ohm Meter) available to diagnose your problem?

Get a Haynes Manual for the RX-7, as well as take a look at buying a Factory Service manual, if this is your daily driver, the book will SAVE you money in the long run, so it's a heck on an investment. I think Racing Beat might still have a paper version in stock, or if you could just go here:

http://www.rx7city.com/techconnect.htm


PS: Even with quite a few knowledgeable people on here, it's still better to look at the factory service manual first to avoid wasting time on simple problems. :D

[vex]

Voltage Drop test. It could be anything from a weak battery, to a bad voltage drop across the starter (and everything in between). Break out your Voltmeter and start testing.

[Whizbang]

what kind of battery. hold old is said battery. what is the CCA rating?

[rx4ur7]

Get the book and DVOM.
Check battery connections and all grounds. If good test battery.

[TehMonkay]

yeah check the resistance on the wires going to the starter, perhaps try to clean them where they attatch to the starter as well.

[Rx-7fetish]

what kind of battery. hold old is said battery. what is the CCA rating?

I believe GravityFed meant how old, and ditto on asking the age and cold cranking amperage.....

[Rotary#10]

hey ya'll i pulled the plug on my car for a while... i figured if its going to be down I'll get the injectors cleaned.. so i'll post an update bout when i put things back together...

[Rotary#10]

Hey ya'll this is something that i figured out last night.... its highly possible that the plugs i put in a san jose. Fouled up on the trailing side, the plugs i pulled on the trail side of both rotors had oil and ash or (carbon?) on them when i pulled them... i tested all the plugs and the trailing had weak spark. compared to the leading which had stronger spark.. speaking from visually seeing the spark itself.
Do you think that what happened? I redid some grounds and added some too..

[Rotary#10]

What's the voltage while cranking?

Cold cranking amp 640. Do you think I need something higher?

[My5ABaby]

Cold cranking amp 640. Do you think I need something higher?
Volts != amps.

[Rotary#10]

Volts != amps.

thanks but everytime i crank the car over and over it sounds like it getting slower, i rechanged that same battery over 2 hrs ago and it still cranks really slow... its not my grounds, I cleaned them and checked them too, even added a few. any recommondations on a new battery ? brand ? cranking amps? price ? etc

[mazda master tech]

[QUOTE=Rotary#10;82910]well one problem after another on my daily driven 7...
its a 91 n/a FC... it cranks really slow...
battery is over 12.4 volts
starter is good had it tested at autozone
plugs are good, I have spark
I have fuel and air of course..

any ideas ? ign switch?[/QUOtE

[mazda master tech]

Look at your cables or manual trans could be your throw out bearing

[Rotary#10]

mmm I am begining to believe the battery has a bad cell, it doesn't hold a charge for too long.

[Rotary#10]

i got another battery and it cranks faster but doesn't start.. I got spark but is it strong enough though. im going to pull my starter and check the connections and clean it up.