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I've got some 'interesting' pcm issues. Here are some of the symptoms...
PCM reads lower than actual.
The pcm never sees the temperature as higher than 72c/161f.
This is after 2 new oem temperature sensors--with same result on all 3 temp sensors.
Currently using an aftermarket fan controller that turns the fans on at 180degs. So, if I let the car idle for several minutes after warming up, the aftermarket fan controller(with its' own built in temp sensor) will read 180 degs and kick on the fans as it should. Yet, the pcm reads as 161 or less.
Missing-
Compression is good. Tried new oem coils-same issue. Now running new BHR coils-same issue.
Specifically, i get the blinking cel only when letting off the gas while cruising--not while starting, idling or putting the engine under load.
From time to time, the idiot lights will all come on and stay on until I restart the car(while on, the car seems to run normally).
--this issue may be a bad ground-have not yet fully investigated that.
My main concern is the missing issue. I replaced the cat w/an oem when I bought the car last year and at $1500/per wld rather not ruin it.
I've got the car at a dealership now getting a diag and airbags replaced. The service manager basically said in order to diagnose would need to compression test, new coils, new injectors, yada, yada -- basically charge crazy $$$'s for stuff I've already done (- the injectors).
Tho, he did say it smelled *gassy*. So, I'm thinking possibly too much fuel causing the missing issue.
To fully diag the pcm at the dealership is gonna cost me at least a grand--that's b4 any fixes are done.
Assuming the injectors are good, wld an aftermarket fuel controller be a possibility?
Any other ideas to handle the missing/pcm issues?
For the weird temp sensor behavior... all these sensors are basically voltage meters, so if the wiring has been messed with you could be seeing funny behavior. Were there any edits to the wiring anywhere? Any chance the secondary temp sensor, the one that runs your aftermarket fan controller is creating a weird circuit configuration for the original temp sensor? Like maybe the 2 are wired in series?
For the weird temp sensor behavior... all these sensors are basically voltage meters, so if the wiring has been messed with you could be seeing funny behavior. Were there any edits to the wiring anywhere? Any chance the secondary temp sensor, the one that runs your aftermarket fan controller is creating a weird circuit configuration for the original temp sensor? Like maybe the 2 are wired in series?
Re the cel:sorry, i was juggling 3 things at a time and should've reread his msg a few times to get what he was trying to say. I'll pull the codes again and let u know.
Re the secondary sensor wiring: it's very simple. The probe is inline in one of the coolant hoses and there are 2 wires, a ground and a signal wire that connects to fan relays that are used to replace the stock fan relays.
I did. LOL
I guess I could have been more specific but I am operating on little sleep from this weekend. The new shop was framed and we have it 90% done already.
P0126-Insufficient Coolant Temperature for Stable Operation
In addition to being a douche who posts his opinions on the internet, I have a daytime job wherein I must meet the expectations of my customers so I apologize for the delay in my reply. My Mazda CD-ESI does not have the 126 code listed but I do have a 125 code in the menu, which mentions either PCM failure, ECT sensor failure, or MAF sensor failure. I am not sure if it is relevant, but have you tried cleaning or replacing the MAF sensor yet?
Hey man, any reply-delayed or otherwise-is appreciated. I know you guys have more important things to do than diagnose my rx8 issues.
I have had the MAF sensor cleaned. I may try tracing pcm wiring and connections to see if any issues there. I guess a bad connection betw the pcm and ect could possibly cause the same misreading regardless of the ect.
BTW-in attempting to solve misfire issues, I purchased a set of coils from you last month. The car really hums now. EZ install too.
04-18-2016, 09:14 AM
