Thought I was out of the woods with my 207k mile Gen1 Prius purchase. Today I encountered drive train stuttering. Here is a summary Recorded this drive session on my MVCI+Techstream so have full data. Just need to know what I'm looking for. - No codes on Techstream. No warnings on dash - Seems to occur after driving about 5+ miles. Can't get it happen all the time. Did a 30min drive cycle tonight and only got it once early on (car already warmed up from prior drive cycle). Parked briefly and fiddling with Techstream, couldn't get it to occur again. - Seems to occur on low acceleration. Feels like the electric motor is bucking if that makes sense - Goes away on faster acceleration. ICE RPM goes up - Car is drivable. Just bucking drive train at low acceleration. Starts fine. - Seems to not happen if in pure electric mode. Only when blending ICE+MG2. Temperature looks good. ICE (180F) > MG1 motor (~80-100F) > MG2 Motor (generally 10F below MG1). MG1 Inverter Temps goes up to 100F under load. 64F when not much demand. I did remove the cowl and spray water to clean out all the gunk the night before. Got the engine bay a little wet. Not sure that has anything to do with this. This occurred in a morning drive cycle and again this evening. Evening drive cycle is where I recored the data in TechStream. For those with Techstream, here is the TSE file with 2 drive cycles. https://app.box.com/s/vhjef6mzo7rxno67m58vfdwftwzxx43d
New one on me. Was engine running? If the engine was off and the accelerator had electrical noise, the transaxle might respond to the noise and if low enough to not trigger the engine . . . The inverter coolant pump is working? I look forward to the file. Put it upon on a Google drive, open folder? Bob Wilson
Yes, engine was running and only occur when ICE is on and low acceleration input. No stuttering in pure electric mode or stump on the accelerator. Maybe I'm mistaken a misfire for MG issues. Inverter pump is running (see flowing coolant in inverter reservoir) Just put up the TSE file.
UPDATE - SOLVED. Looks like misdiagnose. Also pressure washed the engine yesterday and drove fine for 50miles afterwards. But I pulled the coils just now and one chamber was filled with water. So had a misfire which occurred after water got hot and expanded. Symptoms occurred often on hills. So top of the expanded water probably reached the coil/plug contact. This is the 2nd car I've encountered in the last 2 months where an obvious misfire was not reported by the ECU. On the other car, I left 1 coil off and ECU didn't report a misfire!
Caution when washing the engine. There is a junction box between the engine and firewall that has an inverted vent tube. In theory, washing a hot engine might cool that junction box enough to suck in some water and cause a ground-fault code. Being in the back with limited venting, drying it out could be . . . a pain in the a**. Bob Wilson
