DaleClark

iTrader: (55)

Hey guys -

Over time, I figured something out that's been bugging me about the PFC. The PFC uses the exhaust overheat warning light for its warning light - fine and dandy, but I probably won't be consulting a warning lamp that's under my right elbow when I'm at full throttle .

Always thought that was weird. Then, I discovered the Japanese cars apparently have the exhaust overheat light up in the instrument cluster, where the defrost, check engine, high beam, etc. warning lights are. That makes WAY more sense.

The reason it lights that light is the ECU has direct control over it. The check engine light is actually lit by the ELD (electrical load) computer, based on feedback from the stock ECU's self-test program. The PFC doesn't have the self-test circuitry the stock ECU does - ie, the diag connector under the hood is pretty much useless, you can't jumper TEN and GND to get the lights to flash, etc. That's fine, since the sensor check screen on the commander takes care of that stuff for ya.

Anyhow, I wanted to make that feature useful. I figured if I could tap the check engine light into the overheat warning light circuit, the check engine light would light up if the PFC experienced high knock/high injector duty cycle. Took some digging to find the proper wires and to make SURE I was hooking it up right.

The wire to get the signal to the check engine light is at the ELD computer. Attached is a fun pic I took of the ELD computer - took me a while to find it. It's behind the ECU, up a bit, has a Mitsubishi sticker and a yellow tape wrapped harness going to it. Find the ORANGE/BLACK STRIPE wire - this is the wire to trigger the check engine light.

Now, find a midget with tiny hands, shove him up under the dash, and have him strip the wire back a bit, wrap the end of a 2-foot or so wire around the stripped area, then solder the connection and wrap with tape. Since I didn't have a midget (with tiny hands) I did it my damn self. It's tricky, and there's no way you're getting more working room with that wire unless you pull the dash. Take your time and don't burn a hole in the carpet with the soldering iron.

Next, find the exhaust overheat wire going to the ECU. It's on connector 2, the small connector without a lot of wires going to it (pin 2I). This wire is ORANGE/BLUE STRIPE. Connect the other end of the wire to this one. I hooked a quick disconnect coupler in between the two in case I wanted to put a stock ECU in the car for some reason, or I needed to unplug it for more working room.

So far, it seems to work. With the key On, the check engine light comes on. I didn't feel like beating the snot out of my car to see if I could make the light come on, but I'll keep an eye on it.

Thoughts/comments/ideas?

Dale

rotarypower101

iTrader: (1)

Very clever and a great idea.

Glad to hear that this was not just a complete DUH move by apexi, but rather a issue with hardware.

DaleClark

iTrader: (55)

There's a few compromises that are made with the PFC due to JDM/USDM differences (like cutting the 4 wires). At least it's better than the Supra guys - they can't use the JDM PFC since the JDM Supra TT's use a MAP sensor instead of an AFM.

Dale

DaleClark

iTrader: (55)

Duh - realized I forgot to attach the ELD computer picture .

Dale

books

iTrader: (8)

Dale,

Don't know if you have a Datalogit or not, however if you do you may want to lower the injector warning per centage in the Settings 1 menu in order to verify the light comes on
when the threshold is exceeded.

btw, nice work

DaleClark

iTrader: (55)

No Datalogit yet - I'm waiting for Fasthatch's box . I've seen in the Datalogit menus that the variable can be changed, which is way cool.

Dale

Bob_760

I did it today, worked perfect! I used scotchlok connectors, little easier than soldering. Tomarrow im gonna adjust my injector warn settings and make sure it comes on when it's supposed to.

mjw

iTrader: (1)

This is great work Dale, and would solve this problem for Calif. people with emissions testing. First thing they check for is that your check engine light comes on with the key turned to the 'on' position before starting the car, it was an automatic fail otherwise. Now for the sniffer part..hmmm.

Matt

Bob_760

Definately intersting to see the CEL again after all these years...
So I tried to change my injector warning and I found out I dont know what those settings do.... So I couldnt get either the CEL or Overheat Exhaust to light under the warning conditions... HOWEVER if anyone knows how to make these values work in the first place I will try it.
-Kurt

fritts

iTrader: (5)

Sorry, I got mixed up on the first post to this so this is my edit

The Threshold is the value you want the CEL to light at. The Setting is the length of time for the flash of the CEL light. 30 is slow 9 is fast flashing. I would set the injector warning threshold to 30 and see if it goes off. Then turn it back to 95 or whatever and test knock at like a threshold of 20 or so and do some runs and see if it goes off. The speed of the flashing tells you which warning is going off. In the stock pfc case slow for injector warning and fast for knock.

I hope this works as this function would be incredibly useful as a warning. If it works I plan on putting a bright red LED on top of my cluster so that when it goes off it gets my attention. A buzzer might be nice too.

87GTR

iTrader: (61)

I had been thinking about something like this. My plan was to use the output to turn on a relay that I could tie into a large warning light using LED's

Problem is my power fc is not a FD its for FC. does anyone have a pin out of the AP engr PFC?

Dale what wire and connector on the FD's ecu is the output on?



my ultimate goal is to tie into the GReddy Profec B Spec 2 and have trigger the over boost limiter in the profec and have it open up the wastegate more and lower the boost if the warning light comes on as safty

fritts

iTrader: (5)

Anyone get this to work yet?

fritts

iTrader: (5)

Any updates??

DaleClark

iTrader: (55)

Tony - the exhaust overheat light is pin 2I on the FD. Everything I've seen is the AP Engineering PFC is just an FD PFC adapted for use on the FC. The 2nd connector is the smallest connector, and has very few features that are needed on a non-auto car.

BTW, if you looked at Banzai Racing's how-to install an FD PFC in an FC, the #2 connector is the one with only like 2 wires that are needed.

I still haven't had my check engine light come on, which is good - my car is running nice and safe, thanks . I can't change my warning point as I don't yet have a datalogit or the like - I'm hoping to get Fasthatch's box when it becomes available.

But, the Check Engine light does light with the key on/engine off and goes out when I start the engine, which is good .

Dale

TailHappy

Well that's a very slick idea for getting the CEL to come on when the key is first turned on. Very nice work.

Unfortunately, a while back I had already tested whether even the exhaust warning light came on, and at least on my car it doesn't. I set the injector and knock warnings to be really low, exceeded those limits, and nothing. Maybe that's just my car, but I just wouldn't rely too much on using that as a warning.

Bob_760

Your exhaust overheat light bulb could be burned out, mine was. I dono if the datalogit dosent really affect the values when the bulb comes on or what but when i changed the duty cycle CEL values neither the dash or exhaust overheat light ever came on... however i'm sure if the exhaust overheat light ever DID come on, the CEL would too.

TailHappy

Nah, I verified that by seeing that it comes on when the switch is first turned on.

dhcernese

Couldn't you just wire the CEL lamp to the power on the add-coolant lamp, then you'd always pass the visual inspection?

Ledfoot

iTrader: (1)

...The weekend after the first 500 miles breakin in my new FD....my brother once asked me..."what this red light for?"

...when we pulled over and looked at the front cat..it was red hot...thought the car was gonna catch on fire...got back in and cruised for a bit.

Noxlupus

Not just your car, mine does the same thing. I changed the Knock warning value to 3 and never saw any lights come on. And I know i exceeded that based on logs.

fritts

iTrader: (5)

I was thinking about this yesterday and was wondering if anyone has checked for any signals coming from the PFC. Seems to me that the PFC has to send some sort of signal to the ELD to tell it to light the check engine/exhaust heat light. If someone tapped all the wires going from the PFC to the ELD they might be able to find the one that sends the threshold warning by setting it low and either reving the engine with a low duty cycle threshold or knock value.

fritts

iTrader: (5)

Actually taking another look at the circuit diagrams I don't think it will come from the EL unit. I wonder it its one of the unused pines in the ECU. I am still trying to find an Australian diagram to find out where that damn light gets its signal.

fritts

iTrader: (5)

Looking at the PFC and the US harness there are a total 4 pins that look to be active at the PFC but do not have wires on the US harness. Since I currently have the harness out I believe I will try and add some wires to those pin places from pins that I am not currently using in the harness (single and no ac). It might be a bit dangerous to spice them into the datalogit so I may have to monitor them with a voltmeter for a signal. Still working on a series 6 JDM electrical harness diagram though.

Noxlupus

I'm sure you've found this already but just in case it might prove to be helpful. This is for the US harness btw.

DaleClark

iTrader: (55)

I have the JDM wiring schematic, and here's the deal.

4F (split air bypass) and 4P (AWS) don't exist on the JDM harness. 3J JDM is input from the rear defroster relay, and 4O is input from the TNS relay.

I've thought about rewiring a US car to be like a JDM car - it might help idle quality a bit.

Dale