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View Full Version : Slow Cranking, full power to everythiong else


need RX7
01-01-2009, 09:19 PM
I went out and tried to start my car last night, it cranked very slow. I put it on a charger for about 4 hours, let it sit overnight and tried starting again today. It still cranked slowly today, but I tested the headlights and they pop right up and shine bright. As soon as I try starting it, all the lights dim and the voltmeter needle plunges.

Any ideas what could be wrong. The starter was replaced in February. I'm thinking about the wires running from the battery to the starter, what should I look for when I'm looking at them? Any other ideas?

RotaryProphet
01-01-2009, 09:44 PM
Sounds like the engine ground, or possibly corrosion or loose battery terminals or the starter positive line.

rx7 FC TII
01-01-2009, 10:48 PM
im having this problem along with the 3rd gen that i hang out with. i havent started to work on it and figure it out yet but if i figure it out ill report back.

EDIT: ive done a bit more research on this and its sounding like its most likely the starter.check all the connections and grounds for it and if not then you can try to replace the brushes on the starter if you go to napa and order them. ill be doing it this weekend so ill let you know.


http://www.napaonline.com/MasterPages/NOLMaster.aspx?PageId=470&LineCode=ECH&PartNumber=E512&Description=Starter+Brush

RETed
01-02-2009, 12:09 AM
Sounds like a bad battery...

What is the voltage with everything off?
Ideally it should be over 13.0VDC.
What is the voltage while cranking?
Ideally it should be over 10.0VDC.

The engine can crank down to 9.x VDC, but if it gets any lower than that, the battery is no good.


-Ted

need RX7
01-02-2009, 03:06 AM
It sits right at 12v with the key turned to on and the parking/dash lights on (I couldn't see anything without them ha) I walked away for a couple minutes (with the parking lights on) and it had dropped to about 11v. So I guess I'm off to get a new battery...

http://i222.photobucket.com/albums/dd320/noob5000000/fuuusingle.jpg


I'll still check out the grounds and stuff just in case... Thanks for the help guys.

RotaryProphet
01-02-2009, 09:33 AM
12 volts is normal for a battery on a non-running engine. 13.5 is about where you want the voltage in a running car with the alternator working.

djmtsu
01-02-2009, 11:44 AM
Forget about voltage when the battery is idle (no high amp draw).

Check the voltage with a GOOD METER (no dashboard gauge) when you are cranking the car.

The battery might have a 'dead cell'. They can show a normal voltage when idle, but when load is applied the voltage drops significantly.

I used to be a DC power technician, so I have a clue.

need RX7
01-02-2009, 02:46 PM
Alright, the battery's at Murray's right now getting tested. Whether or not the battery is the problem, I think it's about time for a new one anyway. It's not even the right one for the car, it's effing huge. :rofl: Hopefully I can get an Optima.

Whizbang
01-02-2009, 02:51 PM
dont be so sure about the too huge. The rx7s (FB and FCs) usually speced D28 batteries

need RX7
01-02-2009, 03:00 PM
dont be so sure about the too huge. The rx7s (FB and FCs) usually speced D28 batteries

Yeah, I know the battery's supposed to be pretty big, but this one doesn't even fit right in the battery tray (and the PO told me it came from a truck :rofl:)

Fidelity101
01-02-2009, 03:59 PM
optima red/yellow top are good batteries but pretty damn heavy and since their solid state if you leave your lights on or something overnight and you drain your battery, tough luck you need another one.

djmtsu
01-02-2009, 04:27 PM
optima red/yellow top are good batteries but pretty damn heavy and since their solid state if you leave your lights on or something overnight and you drain your battery, tough luck you need another one.

Not solid state, Absorbed Glass Mat.

And yes, once they are toast, they don't come back. I recently had my Red Top go down, form lack of driving. It charged back up, but only lasted another 2 months before it died all together. Now I have the 1000 CCA Red Top in it.

need RX7
01-02-2009, 04:33 PM
Alright, the battery I had turned out to be toast, so I picked up a DieHard from Sears. I don't want to drop $150 for an Optima on a car that I probably won't keep for much longer. I haven't hooked it up yet (need to put my trailing coil back on) But I'm pretty confident that the battery will fix the problem.

Fidelity101
01-03-2009, 02:03 AM
Alright, the battery I had turned out to be toast, so I picked up a DieHard from Sears. I don't want to drop $150 for an Optima on a car that I probably won't keep for much longer. I haven't hooked it up yet (need to put my trailing coil back on) But I'm pretty confident that the battery will fix the problem.

Thats the spirit!

rx7 FC TII
01-03-2009, 02:22 AM
i wish that was my problem. my starter is fucked. itll barely start so thats my project tomorrow.

congrats on fixin yours.

need RX7
01-03-2009, 04:02 AM
Yay, Battery solved everything!! Starts up quite easily. Good luck with yours rx7 FC TII, I had to do the starter on mine, it wasn't too bad. The hardest part is the tight space you're working in (giggity).

Fidelity101
01-04-2009, 04:47 AM
Now are you sure the battery fixed it or not having the battery clamp on tight enough before...


:P

Spooln2
01-08-2009, 05:58 PM
I just bought an Interstate Mega Tron $99 It's a beast!

Kelton
01-09-2009, 12:03 AM
Starters seem to be the norm these days.