Hey guys, so I noticed something odd on my datalog from today and not sure if I should be concerned or just ignore it. Transmission in question is a 4l80e built with a Jakes performance lvl 3 kit and recalibration with a 10" FTI converter. Transmission shifts perfect, locks up, line temp is right around 160-170, no issues that I feel when driving. The pressure spikes that almost look like oscillation, happened during WOT. It's the first time I'm seeing this happen. I'll post a pic of the log and if anybody wants to look at the tune and log I can also post those up as well. Thanks guys have fun!!

Purple line at the bottom. Pressure spiked to 260+ psi

 

The 80e like the 60e has no return to see actual. So what you are seeing is generated by the PCM and what it is commanding. Not what the trans is doing. though it may indeed affect pressure . But that is not what you are seeing..You would need a gauge to see actual pressures

 

Okay makes sense. That pressure reading is from my sensor in the pressure port that's being fed into my Dominator. Sensor is a 500 psi low dollar Motorsports sensor

 

Ok didn't realize the holley accommodated an actual sensor . In that case if you are seeing them on the command side and the actual line then it is a tuning/sensor/ command issue . Could even be a mass air issue if the holley uses that for load like the stock PCM. To check that look at MAF signal fuel mixture spikes. If only on the trans side I would think could be sucking air or cavating. causing drop jumps ?
In either case it is probably not an issue for concern for the trans anyway.

 

I would like to see two additional logs overlayed with your spikes. One would be what the trans controller thinks it's sending the solenoid and another would be the actual voltage at the pressure solenoid.

As you may know, the solenoid controls the pressure, but it's not intuitive. The pressure generated is higher when the solenoid is off(open) and lower when it is on(grounded). The trans controller pulses a ground and an open in a certain ratio to set the desired line pressure. This happens many times a second. If you disconnect the solenoid, you get maximum pressure.

Three of the possible scenarios that might cause your spikes could be:
a) you have a loose connection that shows up with the vibration at WOT, momentarily causing the solenoid to lose the PWM to ground supplied by the trans controller. This could be caused by a bad connector or even a loss of ground to the trans controller or loss of 12V supplying the solenoid. Anything that momentarily causes the solenoid to be turned off could create a spike.
b) the trans management is commanding the pressure spikes because it sees some other input spike from other sensors. If you see the trans controller commanding the spikes, then look upstream for other inputs
c) vibration is causing your line pressure sensor to give an erroneous reading.

The log of the the trans controller is commanding and the actual voltage to the solenoid will tell you more information.

Edit: I looked at your chart again and the trans pressure graph is off the page when your spikes are happening. Can you fix that and show the graph again?

I had wires short at WOT because the torque of the motor at WOT moved things around and caused and instant power drop, then as the power dropped, it would no longer short and power came back, and this would repeat and repeat. This wasn't a trans issue, but you get the idea.