Txdragon

The top line on my graph is my TPS. See how it dips? WTF? It ONLY does this on WOT, not idle of cruise. There are some tiny fluctuations in idle and cruise, like .2v or so, but not like this. I have a theory, but I can't seem to make sense of it because the rest just doesn't add up. The fuel stays pretty consistent, so it appears as if it is just a tps voltage drop. Why would it do this at WOT is my question? I can hook the laptop and test the tps with a slow sweep and it's beautiful. No blips in voltage. Slam on the throttle, the same. No variations. This occurs while the car is running, and at wot.
My theory is maybe a squishy motor mount causing an uneven twist while engine is torquing under load, relieving some tension on the throttle cable. This sound in any way logical? I need some ideas to kick around here. Thanks for looking and any input is appreciated!

Txdragon

Tuner says that this much of a drop from torque is fairly unlikely. Also says that it is weird because there are no other signs of a faulty tps. We've not logged any other issues than this.

ShinsenTuner

iTrader: (1)

Did you calibrate the TPS the old fashioned way or with the software? Hondata I assume?

Txdragon

I'm running Neptune. It's calibrated the good ol' fashioned way. This is the only instance we see a problem. WOT goes bonkers. Everything else is golden.

Relic1

the TPS is a potentiometer with 5V and ground end points, the wiper moves based on throttle butterfly position. The ECU reads this and uses it to know what your right foot is doing.
Asuming this log plot is a WOT pull and you never lifted.... it suggests that your ground is raising in potential at what ever RPM that is (seems to be around VTEC point) this is causing the voltage measured at the ECU to drop. Check your thermostat ground and ECU ground to it.

*edit* on thinking some more, it could be the TPS connections also, same reason, same end result.

*edit2* TPS signal should be pretty solid even while cruising (if your right foot is steady) there is a loose/bad connection somewhere in your setup.

Txdragon

Great observation and tips, thank you!
This is a pull that begins at 3k and goes til roughly redline; 6500. The TPS voltage drop begins about 3300-ish, right about when the turbo begins to spin, VTEC hits at about 5500. This is one of 2 pulls that it had been seen, and the only 2 things to have changed at this point are my wideband ground was moved to the t-stat housing, and I installed new injectors. Cut and solder pigtails. Slow sweep of the TPS shows no drop at all from closed to open and back. Only does this at WOT and when running. Well, it has only done this at that time. Never when the car is off. Maybe interference from the wideband ground? I'm pretty confident mechanically, but I go full potato on electrical

ShinsenTuner

iTrader: (1)

Checking in on this issue.

In your ECU, is there a parameter that shuts off the AC pump or the alternator under certain load/speed conditions?

Txdragon

There is an AC cutoff, but it is not enabled. I also removed my AC system, compressor, evap core, dryer, all of it, gone.

Relic1

if it were the wideband interfering then you would see it when you first switch on the car (ie wideband's heater is running and drawing a lot more power)

how much of a voltage drop are we looking at in the log? (without a scale it's impossible to tell)

What you describe points to something changing on the ground side. (fluctuations in battery voltage does not change 5v supplied sensors this much)

Txdragon

about 1.5v

Txdragon

I have been wracking my brain and troubleshooting chassis electrical for a good bit on this and after looking through log after log and scanning wiring schematics and probing every wire I touched; I FINALLY came across my problem.. Before I jump right into it, I want to thank those that may have done their own looking into the matter, regardless of input given. I would also like to say that I am both proud, and ashamed of my results..

My ******* floor mat.. It was JUST lodged under my gas pedal to cause enough "gap" to give a low voltage reading at WOT. This is why it was occurring at only wot and not replicable under other circumstances. It finally donned upon me when I happened to compare 2 recent logs with no issue and go through my day with a fine tooth comb, so to speak. Looking for ANY possible connection. The days I compared had 1 commonality; I cleaned my car and floorboards. Well, I pull my mats and wash them so they are reset and not inching their way forward.. I have been logging runs without my floor mats and have logged 0 instances in over 20 wot pulls.

/facepalm

Relic1

I've heard of floor mats holding the throttle down and holding it up, but never pushing it back up after allowing it all the way down.... unless you are stomping the throttle down hard and it pushes back hard enough to push your foot back after you relaxed your foot.
First rule of diagnostics, rule out nothing.

Txdragon

this. It's a rubber mat, kinda like a truck mat. It has some give to it, but any relax on the foot and it's all over.