Hello All,

I purchased a GC8 a couple months ago with a few problems, the usual idle problems in neutral after short drive and cuts off the engine. Especially when the engine is hot and you switch off, turning it back on again right away fails.

I've taken the car to two reputable workshops in Perth and $3K later, the problem still persists however narrowed down to the following:

It seems the alternator is affecting the ECU when turning on the car and whilst driving causing intermittent idle issues in neutral or low rpm and stalls. If I disconnect the alternator and turn on the engine it works however once I connect the alternator after the engine is running it causes intermittent idle choking and stalls.

Do you guys have any thoughts on this?

Work on the two workshops have previously already tried:
-Power FC ECU Tune
-AFM/Idle Air Control Valve Replacement
-Water Temp Sensor Replacement
-Alternator switch
-Plus other maintenance

Many thanks in advance,

Bill

Wiring issue in the car

There old now..... sort of the the new RS liberty

Hi Seagull,

Thank you for your reply.

Do you have any suggestions to fix?

Cheers,

Bill

Replace the alternator.

Had a friends 99 do weird shit recently, like runinng on 3 and idling funny, unplug alt seemed fine.....so replaced alt, fixed.

__________________
MY99 WRX EJ2.35L 720whp 9.48@147mph
https://youtu.be/c_lYEG0_Dyo

Thank you for the reply.

The previous workshop I went to tried replacing the alternator with another spare and the problems still persists.

What are the chances of two faulty alternators, I’ll try seeking another one.

Cheers,

Bill

if it was just as old quite possibly also don't get the cheapest chinese alternator you can find off eBay either.

Hi Guys,

Bit of an update for those that are interested in the issue:

A workshop switched another working ECU and AFM over to run a few more tests and whilst doing so discovered a dodgy DIY wiring of the AFM > Power FC by the previous vehicle owner. The voltage on this wire didn't read right despite working ECU and AFM.

When the car reaches a certain temp and the fans switch on and/or while use of headlights/AC the vehicle draws more current and the faulty/loose AFM wire connected to the ECU doesn't quite handle hence the idle/stall issues.

The wire was temporarily fixed and the car was tested with 30% less fuel, running AC and headlights at heated temps and the car hasn't had any of the same idle/stall issues since however more variables will be tested to confirm 100%.

Hope this info helps other people as well, will post more updates as I receive.

Thanks

Bill