car dies at high rpm

[AudiCoupeParts]

Hi Guys,

My 1994 S4 with AAN engine is acting weird.

Under high RPMs at standstill, or while underway the car will spudder for a instant and then DIE. No power. No lights, NOTHING. Dead as a door nail.

I check the battery and it is very warm. The cables on the battery are warm.

I test the battery it is DEAD. I remove the battery and put in another one that is freshly charged and when I try to put on the cables I get a serious spark! Like dead short welding spark! I can't put the second cable on!!!!


I wait a few hours and then try it again and I can NOW put on the cables with no problems. The car come to life and starts fine. I rev the engine past 4000 rpms again it dies! Battery is still normal temperature but the cables are getting warm again and when I take them off they spark.


I suspect it is the Alternator. Something inside it that is bad going to dead ground short at high revs??? Any thoughts from anyone?

Thanks
joe

[Pirvu Eugen]

At high rpm...voltmeter..in the dash..how much is showing?
As...the voltage rises too much...dont know the exact figure...will shut down for protection.

[AudiCoupeParts]

At high rpm...voltmeter..in the dash..how much is showing?
As...the voltage rises too much...dont know the exact figure...will shut down for protection.

Hi. Thanks for your reply.

My S4 does not have a volt meter in the dash. It has a stupid clock instead!

[rynaqui]

Normal should be 14 Volts.

Could not be regulating the voltage correctly which could cause the car to go crazy..could be bad cables, alternator etc..

[Pirvu Eugen]

Ahh...i forgot that the S4 dosint have that...sry...
Put an multimeter at the engine bay...you have an + connection and an ground..and measure the voltage....Should be in 14V region....iff you raise the engine rpm and voltage goes up....passing 15V..then you have an alternator problem...
Goodluck!

[AudiCoupeParts]

Normal should be 14 Volts.

Could not be regulating the voltage correctly which could cause the car to go crazy..could be bad cables, alternator etc..

Yes, the car does go crazy right before it shuts off. Tach jumps wildly, lights flicker on the dash. ABS Off light comes on and then NOTHING. total darkness on the dash. zero power. engine dies.

It only does this when the engine is reved up. At idle it is fine.

[AudiCoupeParts]

Ahh...i forgot that the S4 dosint have that...sry...
Put an multimeter at the engine bay...you have an + connection and an ground..and measure the voltage....Should be in 14V region....iff you raise the engine rpm and voltage goes up....passing 15V..then you have an alternator problem...
Goodluck!

Thanks! I will give it a go and report back!

[Pirvu Eugen]

Check Voltage....I am pretty sure that you will read close to 16V when the engine will shut down...
Let us know please!

[AudiCoupeParts]

I tried it. Now it kills the engine the second I raise the throttle a tiny bit! Car started fine. Idled. Added a touch of throttle an it died. The volt meter went 14.89 volts then it died.

[rynaqui]

Sounds like alternator..it's not regulating the voltage correctly.

[prj]

Yep, too high voltage, it's shutting down to prevent damage.

Fix it ASAP, because if the shutdown does not happen, stuff will start burning out all over the car.

[rynaqui]

Fix it ASAP, because if the shutdown does not happen, stuff will start burning out all over the car.

Don't want that to happen