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Old 11-10-2017, 05:56 PM
MiztahSparklez MiztahSparklez is offline
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Join Date: Jan 2017
Location: San Francisco
Posts: 16
Default Re: Hfs-4 wiring for Audi B8 s4 3.0 (2009-2013)?

Hey Richard, I'm attempting to tune the HFS4 and my logging is less than optimal for when meth is activating. I am getting timing pull on the 91 octane tune I have. I also had some strange activation issues where the system would light up both lights (even with failsafes set to fully counterclockwise/clockwise respectively) and not spray. Perhaps my ratio of P/I-R and thres was not set low enough to engage.

Is it better to use the MPS or IDC jumper for triggering in my case? My boost level is around 19-20PSI. Likewise, should I have the p/i-r knob kept at half, above or below? I am trying to get a better understanding of how these settings change the system. Edit: I think the order of tuning goes P/I-R, Thres, then Gain, this is something I just realized now. All the settings relate to one another.

From what I understand so far:

Trigger jumper/POT: this is how much load/boost you wish to trigger the system. I have it set to 30-45% and jumper set to IDC. This engages about the time where I start loading the engine and sprays during mid-range and higher RPM.

P/I-R - flow ratio in terms of boost and fuel. Counterclockwise will adjust flow rate more in line with boost, while clockwise will adjust it based on fuel/injector load. (This one I'm not sure is working the way I think. At one point I attempted to go fully counter clockwise, but got no spray with two yellow lights). I almost think boost isn't being read correctly or I have something set wrong (edit, likely Threshold set too high). I did get the B to light every time I hit boost, however.

Gain: this is how fast you reach max flow of your system, in relation to what is set in the POT above.

I did not reach the 95% IDC light at all while I was tuning

I measured all the tank connections, power and the floater seem to be working the way it should.

Last edited by MiztahSparklez; 12-10-2017 at 09:35 AM.
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