Hi all, 

 

I'm having strange problems with my VRS. Sometimes (especially when driving fast) the battery refuses to start the car

 

I have relocated the battery into the boot and I'm using a racing battery for a Ferrari challenge car so it's definitely powerful enough 

 

When it does die and I bump start it, I can switch it off straight away and it'll start up no problem. So I don't think the battery is to blame 

 

Thanks in advance 

 

Dan

Does it turn over but not start, or not turn over at all?

It tries to but it's as if the battery is completely dead. But it doesn't make the usual clicking noise if you get what I mean

Do all the lights on the dash go out as well?

 

If not you could just have a bad connection or bad earth or even a dodgy starter maybe.

 

Either that or the battery is on its way out.

Edited 22 August, 20178 yr by SuperbTWM

Battery is brand new, the lights stay on. What earth points should I have a look for, where are they? 

Could be the solenoid connection if there's no action at all. Common issue and can be intermittent until it snaps off completely. 

Just replaced the cable for the solenoid. It does try to star but is as if the battery is flat but it's definitely not

What size is the cable from battery positive to starter?

What size is the battery?

 

Tell us Ah and CCA rating please, you're trying to start a diesel not a Fezzer, it's much harder on the battery.

Two 120 amp cables from front to back 400cca and 36ah

 

It's a dry cell battery and has cracked the car over for over 30 seconds continuously before without fail

Just now, Deejaywh said:

Two 120 amp cables from front to back 400cca and 36ah

 

It's a dry cell battery and has cracked the car over for over 30 seconds continuously before without fail

 

It's tiny, are you kidding me, that won't cope with a PD engine.

6 minutes ago, Deejaywh said:

Two 120 amp cables from front to back 400cca and 36ah

 

It's a dry cell battery and has cracked the car over for over 30 seconds continuously before without fail

What's that in millimeters squared or AWG?

One positive and one earth cable, or two positive?

Got to agree with Sepulchrave the CCA on that battery is tiny compared to what it should be. My battery is in the boot and I run a 780CCA. 

 

If you have a hot start issue it could be down to the ECU as I've heard of a problem, which can be corrected by mapping, when it won't start when hot. 

 

Obviously check the standard all the connections, earth especially, are tight of course.

My guess is that the 90 Amp alternator is heating up the cables trying to recharge the battery and hot cables won't pass as much current as when cold, I'm amazed that the cables haven't started melting because a PD starter motor pulls much more than 120 Amps when cranking so it's probably emptying that tiny battery just starting the car.

On 8/22/2017 at 18:29, Skoda_Saint said:

Got to agree with Sepulchrave the CCA on that battery is tiny compared to what it should be. My battery is in the boot and I run a 780CCA. 

 

If you have a hot start issue it could be down to the ECU as I've heard of a problem, which can be corrected by mapping, when it won't start when hot. 

 

Obviously check the standard all the connections, earth especially, are tight of course.

From memory, even my 3 pot derv has a larger capacity battery than that. But check the connections. Best check without a meter is to look for hot spots as this will indicate bad connections.

Depending on age of the car, it might be worth checking the voltage drop across the solenoid at crank over, as bad contact here will reduce the voltage to the starter.

With lights staying on, I'd suggest it's not a battery or loss of voltage to the rest of car. My guess would be solenoid bad contact . But check voltage on crank -across the contacts. Last I heard 0.5v or lower  was recommended.