Infamous AP2 06+ Hesitation Update
09-09-2018, 02:06 AM
#11
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I've come to the conclusion it's the tune. Not just the fueling, but more the throttle plate mapping.
I have completely discarded the stock throttle plate mapping, and created my own. Most of my changes are around eliminating most of the effect of vehicle speed from mapping. Now, at a given pedal position, the throttle plate position is largely unaffected by how fast the car is traveling. That, and making the rpm based table more linear. Push the pedal 10%, throttle opens 10% more.
The results have been fantastic. The car is so much more responsive. The throttle response now is unreal. Also, so far I haven't had any of the dbw hesitations.
If I have time, I may do some experimenting with taking the way the stock mapping does things, and go overboard farther in that direction, to see if it makes the hesitation more prevalent. That would give evidence that its the weird mapping that is the cause of the hesitation.
I have completely discarded the stock throttle plate mapping, and created my own. Most of my changes are around eliminating most of the effect of vehicle speed from mapping. Now, at a given pedal position, the throttle plate position is largely unaffected by how fast the car is traveling. That, and making the rpm based table more linear. Push the pedal 10%, throttle opens 10% more.
The results have been fantastic. The car is so much more responsive. The throttle response now is unreal. Also, so far I haven't had any of the dbw hesitations.
If I have time, I may do some experimenting with taking the way the stock mapping does things, and go overboard farther in that direction, to see if it makes the hesitation more prevalent. That would give evidence that its the weird mapping that is the cause of the hesitation.
09-09-2018, 04:49 AM
#13
The sensor should be available as a separate part (I believe it's a generic Honda part) but requires some surgery to replace on the throttle body. Google found several notes on this including how to grind off the offending part. Looked like too much grinding/chisel work to me.
-- Chuck
-- Chuck
09-09-2018, 07:40 AM
#14
You just described my S. I'm still working on the CR steering rack to get the quicker ratio. But so far I have:
Swaybars and springs from older model S, to give more rearward bias (for more dynamic fun on the street, not for lap times)
Flashpro with Gernby tune, hfc that allows tune to lower vtec, higher redline, and custom linear throttle map
Lightweight flywheel (11 lbs), cdv removed, heavy ss shift knob
Trying to combine the best attributes of ap1 and ap2 (my version of the best). I pretty happy with the results so far!
Swaybars and springs from older model S, to give more rearward bias (for more dynamic fun on the street, not for lap times)
Flashpro with Gernby tune, hfc that allows tune to lower vtec, higher redline, and custom linear throttle map
Lightweight flywheel (11 lbs), cdv removed, heavy ss shift knob
Trying to combine the best attributes of ap1 and ap2 (my version of the best). I pretty happy with the results so far!
Nice! Sounds like an awesome car to drive. I'm wondering how the throttle mapping would feel on an otherwise stock tune. I'm wondering if it is strictly a throttle mapping issue, a tuning issue, or a little bit of both. Also, is the throttle opening really dependent on vehicle speed? That is a bit unnerving to know actually and sounds really unnecessary.
09-09-2018, 08:45 AM
#15
09-09-2018, 09:35 AM
#16
The sensor should be available as a separate part (I believe it's a generic Honda part) but requires some surgery to replace on the throttle body. Google found several notes on this including how to grind off the offending part. Looked like too much grinding/chisel work to me.
-- Chuck
-- Chuck
I bought a Flash Pro also, but haven’t made any changes with it. I just sent my datalogs to Gernby. I’m eager to see that difference.
09-09-2018, 03:02 PM
#17
Nice! Sounds like an awesome car to drive. I'm wondering how the throttle mapping would feel on an otherwise stock tune. I'm wondering if it is strictly a throttle mapping issue, a tuning issue, or a little bit of both. Also, is the throttle opening really dependent on vehicle speed? That is a bit unnerving to know actually and sounds really unnecessary.
But its kinda moot. If you dropped $600 or so on FP, it would be silly not to spend a few bucks more on a Gernby etune.
09-09-2018, 11:28 PM
#18
I replaced my APP sensor earlier this year (selling the old used one if anyone wants to give cleaning it a go). Was getting bucking symptoms at low throttle and some hesitation. Swapping fixed everything. It's super easy to replace.
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steves (10-07-2018)
09-12-2018, 06:33 AM
#19
So glad I found this thread!
The hesitation I feel in my 07 is a lag in the pedal when trying to take off quickly in traffic at a light! The car falls on its face for a second and then picks up normal. I always thought it was heat soak and switched to a CAÍ but it still happens occasionally. My car is full bolt on with a gernby tune. I'm thinking the pedal sensor may be my issue!
I also swapped the throttle table from Gernby to OEM because I felt the car lag even more with gernby's table
The hesitation I feel in my 07 is a lag in the pedal when trying to take off quickly in traffic at a light! The car falls on its face for a second and then picks up normal. I always thought it was heat soak and switched to a CAÍ but it still happens occasionally. My car is full bolt on with a gernby tune. I'm thinking the pedal sensor may be my issue!
I also swapped the throttle table from Gernby to OEM because I felt the car lag even more with gernby's table
09-12-2018, 10:56 AM
#20
Here's what I've found... the APPS is held onto the spring assembly with two (2) 10-32 screws. I'm surprised they weren't metric. The screws have no slots for a screwdriver to bite into... the heads look similar to rivets. I grabbed and loosened them with vice grips, and was then able to unscrew them rest of the way with my fingers. Once the screws are out, the sensor pops off. It doesn't look like you can clean the sensor without damaging it. It's in a moulded plastic housing and looks to be sealed tight. Like the TPS sensor, the mounting holes are slotted so you can adjust the resting position to output a specific voltage. I don't know what that voltage should be. The only text on the sensor is "APS1" It appears to be a fairly generic Honda part. A quick search for "Honda APS1" reveals identical looking sensors available on eBay and Aliexpress with references to other Honda models. Hope this is helpful to someone.
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