Strangest Thing Just Happened!

[Go Go]

Hey guys,

Strangest thing just happened to me on the way home from work! Was cruising about 60-70kph on a straight road (had music on quite loud).

Anyways the car just dies, and slowly comes to a stop.....

Tried to start it back up, and the starter motor turns, but it wont start!! All the electrics are working, air con still on so I figured the battery was fine.Got my mechanic mate to come help me out, he checks everything in the engine bay everything seems fine. Fuel is pumping. This is where things get interesting.

Attempt to start the car again - nothing!

Pulled out the ecu harness, waited then reconnected. Then attempt to start the car again - nothing!

A couple mins later, as a last ditch effor, we get our jumper cables out. Connect it up and bam !!! It starts!!

Having said that...

1) if it was a battery issue, why on earth would my car just die like that while cruising?

2) why would all the electrics be working, starter motor turning etc etc?

Not that i think it matters, but my battery is pretty small, I had the music up real loud with the bass crankin. So even if my alternator was fudged, doesnt explain why it would die mid-drive. What do you guys reckon?

EDIT: Car is an R34 GTT

Edited December 12, 2008 by Go Go

[GTR-N1]

I think that you did everything you could and in the correct sequence.

I wonder about a fault in your alternator though.

[(B1) MR_fanny]

you might be onto something there. could well be your alternator...must have been some fat beats hey to suck all the juice out of your car mid drive.

[Go Go]

Hi guys thanks for the responses so far!

So how would a drained battery and stuffed alternator cause my car to shut down mid drive?

[eeiko321]

Hey guys,

Strangest thing just happened to me on the way home from work! Was cruising about 60-70kph on a straight road (had music on quite loud).

Anyways the car just dies, and slowly comes to a stop.....

Tried to start it back up, and the starter motor turns, but it wont start!! All the electrics are working, air con still on so I figured the battery was fine.Got my mechanic mate to come help me out, he checks everything in the engine bay everything seems fine. Fuel is pumping. This is where things get interesting.

Attempt to start the car again - nothing!

Pulled out the ecu harness, waited then reconnected. Then attempt to start the car again - nothing!

A couple mins later, as a last ditch effor, we get our jumper cables out. Connect it up and bam !!! It starts!!

Having said that...

1) if it was a battery issue, why on earth would my car just die like that while cruising?

2) why would all the electrics be working, starter motor turning etc etc?

Not that i think it matters, but my battery is pretty small, I had the music up real loud with the bass crankin. So even if my alternator was fudged, doesnt explain why it would die mid-drive. What do you guys reckon?

EDIT: Car is an R34 GTT

i would say its electrical.......im not a professional auto electrician..........

but generally what happens is.....

when your car is off....whatever you turn on.....fan, radio lights etc.........it uses the battery......

but when the car motor is running...it should transfer to the Altenator...which produces electricity via magnetic fields..(thats why you see copper coils through the fins in altenator) so all devices your using including the motor running is supplied by the altenator. and the altenator should also charge the battery.

unless you were running on your battery only and the altenator stuffed.......

look just take it to an auto electrician.....NOt just any dodgy mechanic.....

and with a few tests with the multi-meter.....they should tell you whats not working

[some_cs_student]

Hi guys thanks for the responses so far!

So how would a drained battery and stuffed alternator cause my car to shut down mid drive?

My R31 did this, brilliant Nissan engineers decided to put the "ALT" globe in the dash into the circuit. The solder joints just broke again so now my alternator does not work unless it "self-excites" ie. car hits 3500 or 4K RPM.

Until then my volt meter sits around 8-10volts. EDIT: in car volt meter, its not perfectly accurate but it tells me if the alternator is running or not

On the above, yes, my R31 starting running rough and stalled after been jump started (got about 5-6mins up the road) and driving it with the alternator effectively turned off (I didn't know about the self exciting thing back then ).

[MBS206]

Our cars are prone to changes in voltages.

If you have a loose connection say on the alternator, when it's dropped out, the battery is running the show. Add to that the big "fat beats" you were "pumping" when the sub kicks, it draws a lot of amps, and as such, the batteries dynamic voltage will drop. It could have dropped down to around 9 or 10 Volts dynamically, which is not enough to keep the ECU happy, and it shuts off.

When you're stopped and measuring the volts, it may read 12 or 13 volts, then when you crank it, it will drop to around 8 or 9 volts. Hence, again it's not enough to keep the ECU happy enough to start the car, but JUST enough to get the motor cranking.

Check your alternator out, and all connections.

[Go Go]

Our cars are prone to changes in voltages.

If you have a loose connection say on the alternator, when it's dropped out, the battery is running the show. Add to that the big "fat beats" you were "pumping" when the sub kicks, it draws a lot of amps, and as such, the batteries dynamic voltage will drop. It could have dropped down to around 9 or 10 Volts dynamically, which is not enough to keep the ECU happy, and it shuts off.

When you're stopped and measuring the volts, it may read 12 or 13 volts, then when you crank it, it will drop to around 8 or 9 volts. Hence, again it's not enough to keep the ECU happy enough to start the car, but JUST enough to get the motor cranking.

Check your alternator out, and all connections.

I've checked my alternator, seems fine. All connections and wiring seem O.K.

Is it possible there is faulty wiring in my stereo and is draining too much power for the alternator?

[madbung]

How many volts is the alt outputting?

[GTR-32U]

what size Amplifiers are you running to power the whole sound system ? I mean if its one really huge MoFo

of a sound system then you could be using more power than the alternator is capable of putting out. When

you drive the car at Nightime does the Bass dimm the headlights and inst cluster lights to the Beat ?

[Go Go]

How many volts is the alt outputting?

The in-car factory gauge reads just over 14v.

[madbung]

If you have a multi meter, check across the battery terminals at idle and with revs, should be 13-14volts for both.

Also check the field (f tab-wire on alt) should be @ 12 constant.

If you get those readings at the battery and field you're alt is a ok.

Just clear up some mis-imformation

but when the car motor is running...it should transfer to the Altenator...which produces electricity via magnetic fields..(thats why you see copper coils through the fins in altenator) so all devices your using including the motor running is supplied by the altenator. and the altenator should also charge the battery.

The alt charges the battery, the car-engine-acc ect draw power from the battery...very simple