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Listen to my hands...
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Discussion Starter #1 (Edited)
Do you guys know anyone running a G-force on an OBD2(98 in particular) car wihout any tuning problems?

I had my AFC rewired and dynoed again. I can sit at idle and take fuel out and the car will eventually stall from lack of fuel. But I cannot put any fuel in under boost. It's like the ECU overrides my AFC. The car wont run richer than 13.2 A/F under boost. It's better than the last time I dynoed, but I still cannot control it. Fuel pressure is at 70 psi at WOT. It will have the same A/Fs with the AFC zeroed out as it will with over 10% fuel added.

I have faxed both sheets to Dusty...hopefully he can get them up soon.

I'm almost positive the AFC is wired correctly with the VPC. I have ordered a GCC just to see if that will help...next swapping ECUs to see if that will help.

Scott

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What do you have your high throttle % set at...I am guessing you are trying to use the high throttle map.

Tony
95TT6SPD
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I have mine set to come on at 85% high throttle and I make sure to tune on the high throttle map. Are you sure you are using the high throttle map when trying to tune...there are 2 maps that can be used.
If you turn the 3rd dial from the left on the VPC does the air flow % change on the AFC?...you can try doing this at idle. Mine idles at about .5% and I can take it up over 1% and drop it down to like .3%...the main thing is this test is telling me everything is working properly.

Tony
95TT6SPD
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Listen to my hands...
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323 Posts
Discussion Starter #5
I play with the VPC idle control all the ime when the climate changes. I was just testing the AFC inputs at idle to see if it would change anything. That's when I removed % until it starved the car at idle.

I don't even mess with the Lo-Thr settings when tuning.

Thanks for the responses.


Scott

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Scott:

How are you doing with your fuel tuning???

Did the GCC solve the problem...or was the AFC rewired or other???

I would like the features of the AFC but not the possible problems...so hope to hear how you solved this one.

I spoke to XS Engineering and they claim that the VPC by nature is rich on bottom and lean on top. Maybe you need to richen the VPC GAIN knob a bit to compensate for it leaning out too far on the top end. Then, you can use the AFC to make fine adjustments where needed.

Another way of putting it: As I understand, right now you are running too lean and the AFC cannot richen enough...so if you richen the VPC GAIN course setting, this would make it run richer on top and you can use the AFC to richen more as necessary.

I hope you get it tuned soon!!!!

Let us know.
 

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Listen to my hands...
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323 Posts
Discussion Starter #7
Hboostn97TT said:
Scott:

How are you doing with your fuel tuning???

Did the GCC solve the problem...or was the AFC rewired or other???

I would like the features of the AFC but not the possible problems...so hope to hear how you solved this one.

I spoke to XS Engineering and they claim that the VPC by nature is rich on bottom and lean on top. Maybe you need to richen the VPC GAIN knob a bit to compensate for it leaning out too far on the top end. Then, you can use the AFC to make fine adjustments where needed.

Another way of putting it: As I understand, right now you are running too lean and the AFC cannot richen enough...so if you richen the VPC GAIN course setting, this would make it run richer on top and you can use the AFC to richen more as necessary.

I hope you get it tuned soon!!!!

Let us know.
I'll have the GCC on Monday. The AFC has more tuning abilities...but hopefully since the GCC is an HKS product, it will work better with the VPC. I still might have to swap ECUs when all is said and done.

Scott

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