Symptoms of MY dying PowerFC
01-31-23, 11:24 AM
#1
Symptoms of MY dying PowerFC
The death of my PFC:
Thought I'd share my personal symptoms when my S4 PFC failed. My car had sat for around 2 weeks but before had been driving fine on the street after a long series of track days.
On start up, had the following symptoms:
-Extremely rough idle, essentially seemed like my car was running on 1 rotor
-After the car warms up with me holding the throttle slightly to keep it from dying, idle would seem to even out. It would retain idle for a minute or so but then idle would come down from my set 1000 RPM slowly until the car bogs and dies.
-During a test drive, the car would hit a HARD fuel cut at 4000 RPM, its the initial symptom that made me suspect electrical due to how hard the fuel cut was
-Revving during idle, the car would start breaking up around 4k RPM though it wasn't a hard cutoff, just more and more break up scaling with RPM.
-The commander sensor check showed correct voltages for MAP and TPS
-Most of the feature sets on the commander worked (though I was mostly just blindly scrolling through the tables)
-With the car off, and key to ACC on, I would hear a faint clicking noise from under the UIM. Some solenoid was toggling with ACC on.
-With the MAP disconnected, this clicking would become significantly louder, so probably one of the turbo control solenoids (wastegate/pre-control).
Final death:
-I wasn't sure what the issue was at the time, either fuel, the smart coils I regretted installing or what, so I troubleshot the first weird thing to me, which was the clicking solenoid with ACC on.
-I hit my circuit breaker for the car, took off the UIM, hooked the battery back up and then keyed on, but now the PFC seemed completely dead. Commander would not come on, no fuel pump priming. I disconnected it, checked the 3 power wires on the 1 connector and all three were the correct voltages.
-Grabbed a test PFC from sakebomb, it worked. The car idles fine on the other PFC and revs freely.
Take aways:
While this is unfortunate, the main thing I am concerned about is how I could have troubleshot this if the PFC hadn't completely died. The only reason I had to suspect the ECU was when the commander went out and the fuel pump no longer primed. If the PFC had stayed in the semi-working state and started up but caused the rough idle and driving issues, I would have been chasing my tail checking fuel, spark, solenoids till times end. Given how old PFCs are now, it's sure to be more and more common for them to fail...
Thought I'd share my personal symptoms when my S4 PFC failed. My car had sat for around 2 weeks but before had been driving fine on the street after a long series of track days.
On start up, had the following symptoms:
-Extremely rough idle, essentially seemed like my car was running on 1 rotor
-After the car warms up with me holding the throttle slightly to keep it from dying, idle would seem to even out. It would retain idle for a minute or so but then idle would come down from my set 1000 RPM slowly until the car bogs and dies.
-During a test drive, the car would hit a HARD fuel cut at 4000 RPM, its the initial symptom that made me suspect electrical due to how hard the fuel cut was
-Revving during idle, the car would start breaking up around 4k RPM though it wasn't a hard cutoff, just more and more break up scaling with RPM.
-The commander sensor check showed correct voltages for MAP and TPS
-Most of the feature sets on the commander worked (though I was mostly just blindly scrolling through the tables)
-With the car off, and key to ACC on, I would hear a faint clicking noise from under the UIM. Some solenoid was toggling with ACC on.
-With the MAP disconnected, this clicking would become significantly louder, so probably one of the turbo control solenoids (wastegate/pre-control).
Final death:
-I wasn't sure what the issue was at the time, either fuel, the smart coils I regretted installing or what, so I troubleshot the first weird thing to me, which was the clicking solenoid with ACC on.
-I hit my circuit breaker for the car, took off the UIM, hooked the battery back up and then keyed on, but now the PFC seemed completely dead. Commander would not come on, no fuel pump priming. I disconnected it, checked the 3 power wires on the 1 connector and all three were the correct voltages.
-Grabbed a test PFC from sakebomb, it worked. The car idles fine on the other PFC and revs freely.
Take aways:
While this is unfortunate, the main thing I am concerned about is how I could have troubleshot this if the PFC hadn't completely died. The only reason I had to suspect the ECU was when the commander went out and the fuel pump no longer primed. If the PFC had stayed in the semi-working state and started up but caused the rough idle and driving issues, I would have been chasing my tail checking fuel, spark, solenoids till times end. Given how old PFCs are now, it's sure to be more and more common for them to fail...
01-31-23, 07:13 PM
#2
Had the ecu remained in its pre death stage, you absolutely would have been chasing your tail going through the troubleshooting process. Had you came to the forum with your issue many suggestions would have been made to include the power fc itself being the problem. Unfortunately, an FD with sudden issues on a power fc will always have the ecu itself as a possible culprit. Some of them have been in circulation for quite some time with varying time between use, storage, handling..... all sorts of things. They don't age like wine.
In the universe where you would have troubleshot, all the individual components would have checked out and the only thing left would have been the ecu. The end result would have been the same but the time spent reaching the conclusion would have been extensive.
In the universe where you would have troubleshot, all the individual components would have checked out and the only thing left would have been the ecu. The end result would have been the same but the time spent reaching the conclusion would have been extensive.
02-01-23, 09:02 AM
#3
RX-7 Bad Ass
iTrader: (55)
I would maybe get up with someone like Michael Gagne and send the PFC in for analysis. This is likely something that can be repaired, it's just electronics and the PFC is a standard circuit board and quite repairable.
I bought my PFC new in 2004 and have had zero problems with it.
Things may change as the electronics age, a lot of the issues can be related to things like something shorting out an input to the ECU, hooking up a battery backwards, other environmental factors. I also think some aftermarket IGN-1a setups can be problematic as they have to be wired correctly and many times they are not which can cause issues with all kinds of things.
Dale
I bought my PFC new in 2004 and have had zero problems with it.
Things may change as the electronics age, a lot of the issues can be related to things like something shorting out an input to the ECU, hooking up a battery backwards, other environmental factors. I also think some aftermarket IGN-1a setups can be problematic as they have to be wired correctly and many times they are not which can cause issues with all kinds of things.
Dale
The following users liked this post:
Akagis_white_comet (02-02-23)
02-01-23, 02:39 PM
#4
At the risk of sounding like a vocal few that call the PFC 'trash' (I don't like them, but I understand their appeal and their place), this is exactly the type of situation that lends itself to more modern ECUs with more comprehensive and open interfaces with proper tools for diagnostics as well as functional support networks.
Glad you were able to find the culprit.
Glad you were able to find the culprit.
02-01-23, 04:14 PM
#5
Modern ECUs die as well although much less common. Not exactly a fair comparison either way given the age of most power fcs in circulation.
You're absolutely correct about their appeal though. Cost, availability, use, ease of install.... they are for sure what they are lol. Until they all die of old age and apexi stops making them, all we can do is become more familiar with it and its quarks. Not that there's much more to figure out after all this time.
For most street cars we advise people use a power fc. From what we see, most don't need or can even use half of the capabilities of an adaptronic, link or haltech. For the additional cost there just isn't much value. It's not being used outside the capabilities of the power fc so why spend more?
For our other customers that are in the pursuit of power we advise not using a power fc. The safety strategies and control of a modern ecu are incomparable. Under performance/competition conditions we don't see the power fc as being a good option. Japan knows what they're doing and FEEDs demo car is running a damn f-con lapping Tsukuba lol.
You're absolutely correct about their appeal though. Cost, availability, use, ease of install.... they are for sure what they are lol. Until they all die of old age and apexi stops making them, all we can do is become more familiar with it and its quarks. Not that there's much more to figure out after all this time.
For most street cars we advise people use a power fc. From what we see, most don't need or can even use half of the capabilities of an adaptronic, link or haltech. For the additional cost there just isn't much value. It's not being used outside the capabilities of the power fc so why spend more?
For our other customers that are in the pursuit of power we advise not using a power fc. The safety strategies and control of a modern ecu are incomparable. Under performance/competition conditions we don't see the power fc as being a good option. Japan knows what they're doing and FEEDs demo car is running a damn f-con lapping Tsukuba lol.
The following 2 users liked this post by FDAUTO:
gracer7-rx7 (02-01-23),
Jesturr (02-02-23)
02-02-23, 10:24 AM
#6
Modern ECUs die as well although much less common. Not exactly a fair comparison either way given the age of most power fcs in circulation.
You're absolutely correct about their appeal though. Cost, availability, use, ease of install.... they are for sure what they are lol. Until they all die of old age and apexi stops making them, all we can do is become more familiar with it and its quarks. Not that there's much more to figure out after all this time.
For most street cars we advise people use a power fc. From what we see, most don't need or can even use half of the capabilities of an adaptronic, link or haltech. For the additional cost there just isn't much value. It's not being used outside the capabilities of the power fc so why spend more?
For our other customers that are in the pursuit of power we advise not using a power fc. The safety strategies and control of a modern ecu are incomparable. Under performance/competition conditions we don't see the power fc as being a good option. Japan knows what they're doing and FEEDs demo car is running a damn f-con lapping Tsukuba lol.
You're absolutely correct about their appeal though. Cost, availability, use, ease of install.... they are for sure what they are lol. Until they all die of old age and apexi stops making them, all we can do is become more familiar with it and its quarks. Not that there's much more to figure out after all this time.
For most street cars we advise people use a power fc. From what we see, most don't need or can even use half of the capabilities of an adaptronic, link or haltech. For the additional cost there just isn't much value. It's not being used outside the capabilities of the power fc so why spend more?
For our other customers that are in the pursuit of power we advise not using a power fc. The safety strategies and control of a modern ecu are incomparable. Under performance/competition conditions we don't see the power fc as being a good option. Japan knows what they're doing and FEEDs demo car is running a damn f-con lapping Tsukuba lol.
And out come the apologists.
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