only starts by jump start
 

Hi.. So my bros 85 Supra 5sp recently will only start by jump starting it.. the battery is fine. Im pretty sure he can turn on the lights it just wont crank.. the battery i belive is 592 CC and 12.9volts was read i belive.

thinking starter but not sure..

Thanks

starting
 

hey there,

Does engine start every time with jump?, if so starter should be fine.
Any funky nosies?
Try borrowing a batt from a friends motor you know is good/new and see if the car starts fine after that, if so looks like batt.

I had a prob with a few cars over the years were the batt alone just couldnt turn over the engine fast enough due to sticking start but with the jump it gave it the extra boost required to fire up.

also had prob with dirty dis. cap and rotor and batt just didnt have enough on its own, although ran lumpy on idle.

Also check growned to body from batt negative, engine to body with multimeter as seen that before, extra batt means more load can be pulled and allow power to Jump around a bad earth.

get back to us, there is a few things to go through, out off my workshop at present but back tomorrow.

Dont relay on voltage as it could be fine but its the amps that are require to crank motor over, load testing batt is better but need equiptment.

Hope above is of use
Stewie
Scotland

hey thanks.. Ill tell my brother to get his battery tested and check those grounds.. Do Supras normaly need high CCA to get started anyways??? is 595CCA pretty low for a big 2.8 engine..

Batt.
 

Hey,

595 CCA, (cold crank Amps) this is more than enough if in fact thats what your getting from your batt, i'm running a 3.0 turbo on 400 cca batt which is a little lower than what it should be.
You may have a short in your batt caused by buckled plates in a cell reducing your load capacity.

check your grounding and borrowed batt. to try

ta stewie

after talking to my brother I also found out he didnt tie down his battery .. SO im guessing from it sloshing back and forth has ruined it,, if that can ruin a battery..

Batt.
 

Sorry for the delay,

this will not help the batt, but is not a normal problem unless some on the cells are low (you can see the top of the plates dry in some of the cells).
good luck with the motor, let me know how you get on.

Ta stu

I'm almost 99.9% positive it's your starter. same thing happened to my buddy's 96 talon. it'll stop starting via jump here pretty soon and then you REALLY need to get a starter.