New AFM blowing black smoke?
Posted: Mon May 21, 2012 10:47 pmHi Guys,
I recently noticed that my car was hunting when idle after the sensors had heated up. Speaking to my mechanic and also reading on this forum, it seems the AFM was at fault. This made sense as unfortunately the VF38 turbo recently failed; I have an MY06 BL Liberty GT Tuned by STi. At the time of the failure, allot of white smoke (oil) was blown back through the turbo and forward onto the AFM.
I am not the original owner, and whilst the service history seemed sound, I have been told that a lack of servicing can cause premature turbo failure. I service my car every 5000km's so I am sure I didn't add to the premature failure of the turbo.
So after sending the VF38 housing to GCG Turbo and having it machined out to install a VF34 ball bearing core into the VF38 housing, retaining the twin scroll setup etc, I had the new turbo fitted and made preparations to have it tuned at Chip Torque on the Gold Coast. As I suspected the AFM was on its way out and I wanted the best tune possible, I ordered a new AFM geuniune DENSO OEM Part Number: 22680-AA310 / 197400-2090. In the meantime I drove around with the new turbo, on stock boost, the car drive very nicely, I noticed that even with the stock ECU tune and failing AFM the car felt very responsive and new that the new turbo was doing its job.
Wanting to fix the hunting problem before it got tuned etc, I decided to fit the new AFM myself tonight, a simple matter of unscrewing two screws, disconnecting the harness plug and installing the new AFM part. HOWEVER as soon as I installed the new AFM, the car choked and spluttered, wouldn't rev and continuously belched out black smoke! Now I know black smoke means its running very rich, so much so that the car was undrivable.
Could I have a failed AFM on my hands or could the new very sensitive new AFM be reading heap of new Air Flow from the bigger, turbo over fueling to compensate??? Keeping in mind this is a stock ECU which has never been tuned?? Is there anything I should be doing when I install a fresh AFM??? I have sine refitted the old broken AFM and the car is back to 'normal'.
The car will be tuned by Chip Torque on the 30th of May with a bigger Walbro Fuel pump and a new Unifilter and MRT Performance Cross Flow TMIC.
Any advice would be greatly appreciated, as I have to figure out if I need another AFM ASAP before the tune next week. BTW the AFM was bought new from a seller on eBAy who sells genuine OEM Subaru parts, it came new in the Fuji Heavy Industries/ Subaru / Denso box, so I am hoping it unlikely a failed AFM.
I recently noticed that my car was hunting when idle after the sensors had heated up. Speaking to my mechanic and also reading on this forum, it seems the AFM was at fault. This made sense as unfortunately the VF38 turbo recently failed; I have an MY06 BL Liberty GT Tuned by STi. At the time of the failure, allot of white smoke (oil) was blown back through the turbo and forward onto the AFM.
I am not the original owner, and whilst the service history seemed sound, I have been told that a lack of servicing can cause premature turbo failure. I service my car every 5000km's so I am sure I didn't add to the premature failure of the turbo.
So after sending the VF38 housing to GCG Turbo and having it machined out to install a VF34 ball bearing core into the VF38 housing, retaining the twin scroll setup etc, I had the new turbo fitted and made preparations to have it tuned at Chip Torque on the Gold Coast. As I suspected the AFM was on its way out and I wanted the best tune possible, I ordered a new AFM geuniune DENSO OEM Part Number: 22680-AA310 / 197400-2090. In the meantime I drove around with the new turbo, on stock boost, the car drive very nicely, I noticed that even with the stock ECU tune and failing AFM the car felt very responsive and new that the new turbo was doing its job.
Wanting to fix the hunting problem before it got tuned etc, I decided to fit the new AFM myself tonight, a simple matter of unscrewing two screws, disconnecting the harness plug and installing the new AFM part. HOWEVER as soon as I installed the new AFM, the car choked and spluttered, wouldn't rev and continuously belched out black smoke! Now I know black smoke means its running very rich, so much so that the car was undrivable.
Could I have a failed AFM on my hands or could the new very sensitive new AFM be reading heap of new Air Flow from the bigger, turbo over fueling to compensate??? Keeping in mind this is a stock ECU which has never been tuned?? Is there anything I should be doing when I install a fresh AFM??? I have sine refitted the old broken AFM and the car is back to 'normal'.
The car will be tuned by Chip Torque on the 30th of May with a bigger Walbro Fuel pump and a new Unifilter and MRT Performance Cross Flow TMIC.
Any advice would be greatly appreciated, as I have to figure out if I need another AFM ASAP before the tune next week. BTW the AFM was bought new from a seller on eBAy who sells genuine OEM Subaru parts, it came new in the Fuji Heavy Industries/ Subaru / Denso box, so I am hoping it unlikely a failed AFM.
