Overvoltage when throttle

[Lacostas]

Hey all!

Everytime i press the gas pedal from idle in my 986 2.7 M96.23 , i see that the voltage spikes and sometimes goes over 14.8 even 14.96V.

Throttle body is new, VR is new and i just changed the battery ground cable in case that was the issue. Alternator's output seems fine at all times (load/no load).

When the system gets increased electrical load on idle (e.g AC on, radiator fans) it struggles (falling to 500 rpms) and then recovers. Seems like electrical issue but still trying to figure it out.


Any input would be appreciated!

[JFP in PA]

Voltage regulator.

[Lacostas]

Originally Posted by JFP in PA

Voltage regulator.

Bosch Voltage Regulator is brand new. Any chance this is being caused by the alternator somehow ? Or by a bad ground somewhere ? Im running out of options

[997_986]

I would also be inclined to see the regulator as the cause of this symptom

[JFP in PA]

Originally Posted by Lacostas

Bosch Voltage Regulator is brand new. Any chance this is being caused by the alternator somehow ? Or by a bad ground somewhere ? Im running out of options

The regulator controls what the out put voltage of the alternator is, I seriously doubt it is the alternator, but you can have it tested by any decent alternator shop.

[Lacostas]

Originally Posted by JFP in PA

The regulator controls what the out put voltage of the alternator is, I seriously doubt it is the alternator, but you can have it tested by any decent alternator shop.

true.. What's the next thing to check ? Maybe the Regulator cant "see" the correct voltage of the system due to a bad ground ?

1. Bad starter ground, even though car starts perfectly fine
2. Bad alternator mounting ground (where it bolts) ?
3. Other ECU/electronics ground im missing ?

Any other electrical side worth to check ?

[JFP in PA]

Originally Posted by Lacostas

true.. What's the next thing to check ? Maybe the Regulator cant "see" the correct voltage of the system due to a bad ground ?

1. Bad starter ground, even though car starts perfectly fine
2. Bad alternator mounting ground (where it bolts) ?
3. Other ECU/electronics ground im missing ?

Any other electrical side worth to check ?

If you suspect that you have grounding issues, run voltage drop tests across all the grounds.