I'm experiencing a few new problems with my FD, so I'll start with this since I've searched a little bit and scanned the Power FC manual, but couldn't find anything.

Yesterday, as I was on some slow/stopped traffic on the freeway, the FD started hesitating once I started to go in 1st. It seemed to be in a "powered down" state, and I couldn't get it going fast enough to continue, so I pulled over, thinking to let my car cool down for a bit (outside air temp was about 90 degrees F). However, my water temps didn't register an abnormally high temperature according to my Defi temp gauge. IIRC, it was about 220F. My stock temp gauge (although we all know the stock gauge is pretty worthless) didn't register any abnormal increase either. But the temp reading on my Power FC read "---".

I tried starting the car, but it wouldn't turn over. I assumed the worst, thinking my FD had overheated, so I left the car off. After about 20 minutes or so, placed the keys in the ignition, and turned it just to get some readings. I noticed the Power FC temp reading climb from 0 to 99. At the same time, I saw my Defi gauge go from about 160 to 210. I let it cool down for another 20 minutes, then I started the car (it turned over fine), and made it back home pretty smoothly.

So my questions would be:

1.) Has anybody else experienced a "---" reading on their Power FC?
2.) Do you think the anomalies in temperature readings could have resulted from an air pocket in the system?
3.) Is there a "limp" mode to the Power FC when it thinks the engine is overheating?

Thanks in advance

 

try looking or posting here, its the engine management section of the forum. its already specified for pfc:

https://www.rx7club.com/forumdisplay.php?f=47

 

hi,

with the air temp being displayed as --- you should check out ETC, SENSOR SW CHECK it will highlight the broken or out of range sensor in black background.
typically if the air temp is --- then it will be AIRT the value is probably 0 or 5.00v

check your airtemp sensor and its physical connection, if the connection is OK replace the sensor with a known working one or new one to correct it.

The PFC wont go into a limp mode if the airtemp isnt working, it just wont retard timing when intake temp is over 60deg. by default the PFC will retard IGN timing when the airtemp exceeds 60deg (celcius). it wont "limp" or anything if the sensor isnt connected or not working, it will just run as normal.

 

however if you are seeing broken readings for water temp this will affect how the car runs. the PFC will correct the tune based on water temp. its likely the car may not start if water temp is toast (---) or reading broken numbers, say 99deg celcius etc.

althought 99deg ceclius is valid, its just very high, it will make the car sluggish as the PFC will retard timig, but it should still run and idle.

 

Sorry, and thanks to the mod who moved the thread.

Paul, thanks for the insight on the sensor check function of the Power FC. I'll make sure to check that if it happens again.

 

220F is very very hot for an engine. With the PFC, your fans should be setup to come on at 86F.

Most likely your temp sensor for the CEU has failed or it's wiring has failed.

 

True, I usually start to take measures to cool off the engine at about 210-215 degrees. However, I've seen some conflicting opinions, with some people waiting until about 230F until they start taking measures to cool off.

BTW, did you mean 86F, 186F, or 86C?

I'm starting to think that this episode was related to the 90F outside air temps. It's starting to warm up in SoCal, and I think that the open air intake that I installed 2 weeks ago is not helping (even though it has a heat shield). When I popped open the hood during the aforementioned episode, the underhood temps felt hotter than I've experienced before. This is going off topic, but I'm rethinking the air intake (could go back to the stock airbox), or invest in a vented hood or a vented headlight cover.

 

Sorry i MIXED F with C in my post.
86F should have been 86C which is 187F.

 

anything over 210 is too hot IMO, but 220-230 is where it starts to get dangerous.