Power FC New Power FC install - no start - water temperature sensor
12-12-17, 08:06 PM
#1
sold--no longer in debt
Thread Starter
New Power FC install - no start - water temperature sensor
I spent most of my day searching/reading power fc and plain old fd no start threads and never came across my exact issue, so I'm posting this thread in hopes someone else needs it one day and also finds it. If you don't want to read the story (tl;dr) just scroll down.
Just installed a new (to me) power FC in my 93 FD. Also did a few other things as usual to add confusion to the mix. While pulling the rats nest out I managed to break (or finish breaking) the ECU's coolant temperature sensor (top one on the back side of the feed neck w/ a green plug). Also tore the wire out of the thermoswitch below it.
Get the car all wrapped up (ignoring these two broken things figuring it wont matter) and go to start it. First off I'm getting a constant buzzer yelling at me. I ignore that. Try to start the car and it will turn over all day but never even tries to fire. Power FC sensor screen has water temp highlighted and it's reading 4.99V. Ok so what, deal with it car. Back to the engine bay - I dig around and find the broken thermoswitch wire. I somehow unplug it, manage to sort of repair it (the single wire broke off right at the connector. I dug the insulator out and got enough wire to solder to, then spliced it back in to the harness). After that, time to try again: Constant buzzing is gone yay. Car still wont start. I check spark - looks ok, garage stinks like gas and when I prime the pump it does kick on so going to assume it has fuel.. great.
I try to unplug the green clip on the water temp sensor and the plug side of the sensor just breaks off the sensor itself. I ground a 19mm down to nothing and was able to remove the broken piece and install a new sensor. Plugged it in, reset power fc for the hell of it, go to crank it - 2-3 revolutions and it fires right up. Yayyyyyyyyyyyyyyyyyyyyyyyy.
tl;dr: A dead ECU coolant temp sensor (top sensor w/ green plug on back of thermostat housing) can apparently cause a no-start situation. Swapping in a new duralast one solved my problem.
Just installed a new (to me) power FC in my 93 FD. Also did a few other things as usual to add confusion to the mix. While pulling the rats nest out I managed to break (or finish breaking) the ECU's coolant temperature sensor (top one on the back side of the feed neck w/ a green plug). Also tore the wire out of the thermoswitch below it.
Get the car all wrapped up (ignoring these two broken things figuring it wont matter) and go to start it. First off I'm getting a constant buzzer yelling at me. I ignore that. Try to start the car and it will turn over all day but never even tries to fire. Power FC sensor screen has water temp highlighted and it's reading 4.99V. Ok so what, deal with it car. Back to the engine bay - I dig around and find the broken thermoswitch wire. I somehow unplug it, manage to sort of repair it (the single wire broke off right at the connector. I dug the insulator out and got enough wire to solder to, then spliced it back in to the harness). After that, time to try again: Constant buzzing is gone yay. Car still wont start. I check spark - looks ok, garage stinks like gas and when I prime the pump it does kick on so going to assume it has fuel.. great.
I try to unplug the green clip on the water temp sensor and the plug side of the sensor just breaks off the sensor itself. I ground a 19mm down to nothing and was able to remove the broken piece and install a new sensor. Plugged it in, reset power fc for the hell of it, go to crank it - 2-3 revolutions and it fires right up. Yayyyyyyyyyyyyyyyyyyyyyyyy.
tl;dr: A dead ECU coolant temp sensor (top sensor w/ green plug on back of thermostat housing) can apparently cause a no-start situation. Swapping in a new duralast one solved my problem.
12-15-17, 10:25 PM
#2
Eye In The Sky
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A broken water temp sensor or it's wire that causes a 4.99 v reading, is telling the ecu that it is so cold, to max out fuel enrichment.
Go to section F of the RX-7 manual and read.
Go to section F of the RX-7 manual and read.
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