Failsafe activating after shift.

[Iworktofish]

Greetings,

My setup:
*97 BMW M3
*Technique Tuning Stage 2 turbo
*8psi wastegate, 13psi normal, 15psi with 50/50 meth
*HFS-6 with single 1mm jet and 0.7mm HSV restrictor
*Eboost2 wired to only allow HFS-6 to see IDC >13psi using auxiliary output to relay
*Coolingmist 1.5gal U shaped tank in trunk

During a single gear pull, system is spraying above 13psi as intended, indicated by 5-7 bars (best I can tell, hard to see & drive simultaneously). However, after I shift to the next gear, failsafe is activated dropping me to 8psi wastegate, and either stays active, or sometimes comes back after short delay.

I have tried adjusting the SC to ensure I'm getting ~5-7bars of lit LED's.
I adjusted WL 2 clicks CCW, WH 2 clicks CW to open up the window.
I have turned down the failsafe RST to minimum recover time.
Meth tank is not the greatest design and prone to sloshing (per Howerton) but it is full, and sensor is near bottom.

I am still getting intermittent failsafe activations after shifting to the next gear. Any ideas what would cause this and how to fix?

Thanks!

[Richard L]

This is interesting, the failsafe window is wide enough to cope.

Try two things:
1. increase the "FLSF SENS" trimmer by advancing it a few degress "clockwise". I gathered the naming of this trimmer is quite mis-leading. Clockwire to slow down the repsonse time. (range 0.2-0.7 seconds)

2. Unplug the tank level sensor so that it doesn't cause visual confusion to the fialsafe trip.

The amount of liquid you are injection is relately small compared to what the system is capable of. By inceasing the sensitiveity of the system with SC trimmer, you will be loosing some sampling resolutions. It causes more "over-shoot" and "under-shoot" of the flow senssing circuitry. By incrasing the "FLSF SEN" (clockwise), you are averaging the incoming signal so minimising the false trigger of the failsafe threshold.

[Iworktofish]

Thanks Richard,
So to make sure I understand, return the SC trimmer to normal 12 o'clock position, and instead use the FLSF SENS to slow down response time?

While driving the car again last night, I did notice that when the relay opens at 13psi and sends IDC to the HFS-6, I immediately get 5-7 red bars, but as RPM's climb it scales back down to 2-3 bars. I'm wondering if this is an unexpected result of using the relay to limit IDC signal. Perhaps this is what is triggering failsafe? Is this normal and if not, what setting do I have to adjust to increase flow in upper RPM range?

Thanks for tip on unplugging tank sensor...will try that first to see if that's the issue.

Lastly, by widening the failsafe windows to avoid false triggers, will they still come on to protect my engine in the event of a legitimate failure?

[Richard L]

Not quite, set the SC to display 5-6 bars under WOT. Set the WL and WH as normal. Just increase the SLSF SENS on the controller to 4 o'clock and let me know if this works.

[Iworktofish]

SC set to 12o'clock, WL at 11a, WH at 1p, and FLSF SENS set to 4pm as suggested and it appears the problem is gone. No more failsafe after shifts and no more tapering of spray, at least for the 2-3 passes I made. Should I start narrowing WL/WH or are the current settings ok and will provide failsafe protection?

2nd question. It takes ~1-2 seconds for the system to start spraying again after shifting and applying WOT, as indicated by the return of 5-6 LED's. My concern is that for this brief moment I'm boosting past the recommended 13psi without meth. Is this safe?

[Richard L]

We hav establish the caused of failsafe trip. I would set the FLSF SENS to 3pm and start narrowing of the WL and WH.

The HFS-6 is triggered by IDC% only. Boost and IDC is not always in unison. At low gear the boost tend to build at higher RPM. Vice vesa at high gear the boost builds up at lower RPM. the higher the load, the quicker the turbo builds up.

There are no delays on the system. What is the THRES ADJ trimmer set to? Reduce it a little bit and tell me if makes the system response to boost ramp sooner.

[Iworktofish]

ok will do.

THRES ADJ was left at 12o'clock. Since I've got the IDC masked until 13psi anyways, I will reduce the threshold lower and see if it quickens the delay after shifts.

Thanks much for your assistance.

[Richard L]

Since you have masked the iDC signal, you can set the "THRES ADJ" to 9 'clock. Let me know.

I think the reason for the delay was due to the IDC% (set to 12 o'clock or ~42%) was not low enough under certain conditions when the boost reaches 13psi. Loweing the iDC threshold should overcome this.

[Iworktofish]

Richard,
I set the THRES ADJ to minimum CCW (7 o'clock?) before I read your above post and the delay is still there. I guess that is how long it takes for the turbo to spool back past 13psi after shifts?

[Iworktofish]

Hi Richard,
up until now I've been testing on local roads in 2nd and part of 3rd gear. Just the past 2 days I've driven the car on the highway testing in 3rd and 4th gear and discovered the original problem is still there. Once I shift, failsafe is activated and the duration of the next gear is on wastegate at 8psi down from 15psi.

Here's what I've done recently:
1. set FLSF SENS back to 4o'clock (max) from 3o'clock
2. disconnected tank level sensor
3. set Eboost to trigger relay to 12psi, 11psi, 10psi and then anything greater than 100rpm so HFS-6 always sees IDC

After all of the above, failsafe is still activating after I shift. I am out of ideas...please advise.