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-   -   The FC build challenge (https://www.rx7club.com/build-threads-294/fc-build-challenge-1020591/)

beefhole 09-21-13 09:13 PM

^ i agree with "cutting corners". ;) My car years ago made it through emissions with a corvette electric airpump, and some cat I bought off a forum member. My car was far from stock and actually had passing numbers. OK fine, it took 5 tries...

I really can't understand though how some states still have the "resources" for this. How the hell does a mechanic know to check the "lower left doohickey" on the 27 year old mazda? For fucks sake... Brakes good? Seat belts good? All lights functioning? No smoke spewing out the tail pipes? Fantastic.. NEXT!

RotaryEvolution 09-21-13 09:35 PM


Originally Posted by beefhole (Post 11579103)
^ i agree with "cutting corners". ;) My car years ago made it through emissions with a corvette electric airpump, and some cat I bought off a forum member. My car was far from stock and actually had passing numbers. OK fine, it took 5 tries...

I really can't understand though how some states still have the "resources" for this. How the hell does a mechanic know to check the "lower left doohickey" on the 27 year old mazda? For fucks sake... Brakes good? Seat belts good? All lights functioning? No smoke spewing out the tail pipes? Fantastic.. NEXT!

they don't, hence why california is just about as close to their debt as the US government(slightly exaggerated, but not much).

the real question is how the smog stations can keep up without upselling $500 worth of repairs in addition to the $40 smog check. most miss things, then the CARB jumps their ass, threatens fines, retrain employees, etc.

j9fd3s 09-22-13 10:41 AM


Originally Posted by RotaryEvolution (Post 11579029)
nice job so far.

so, next time when someone challenges you to re-build a delapidated FC in a month.... tell them it will be a 1 year and a month. challenge on! :D

now you know how i feel when i walk into the shop everyday. ;)


i say put a powerFC in it, slap some duct tape over the Apexi logo and say it's a stock ECU. result! not like the refs are actually going to get their knees dirty checking it anyways. for the CEL just wire it in as a "follow me" light to pass visual. it was always sort of a challenge passing CA emissions but in the end the cars usually burned cleaner than brand new. if that doesn't fly, cut a new ECU top plate to eliminate any aftermarket logos, remove the serial numbers, any defining labels and then they will just scratch their heads and move on.

worrying about emissions is a waste of time until you have some direction from the testers. the techs always are different, some may let some things fly while others won't.

lmao totally! i've actually had the car for like 3 years, it just sat for two of em, cause i didn't even want it!

its funny one of my ECU's is a JDM, and i was just going to swap to the US ecu cover, but the stickers are on different sides! i do agree the PFC would be easy, i just need to make sure i'm not going to fry it first!

RotaryEvolution 09-22-13 11:35 AM

not likely the techs are going to understand the ECU part numbers anyways. they mainly just look to see if all the original smog equipment is there and functional.

j9fd3s 09-22-13 01:34 PM


Originally Posted by RotaryEvolution (Post 11579459)
not likely the techs are going to understand the ECU part numbers anyways. they mainly just look to see if all the original smog equipment is there and functional.

all the emissions are there, they aren't working though, hence ECU test board...

i think i've actually wired something wrong, either i've crossed the 5v power with the ground somewhere, or the MAP sensor is backwards or maybe i DO have 3 bad FD ecus?

RotaryEvolution 09-22-13 02:00 PM

doubtful, but are these USDM or Jspec ECUs?

j9fd3s 09-22-13 02:50 PM

i've got 1 JDM, N3A7, a us N3A1, and an N3C1 and they all work the same. i do have an N3E1 too, but if i fried 3 ecu's, i'd rather not fry the 4th!

j9fd3s 09-23-13 03:35 PM

well good news!

1. ECUs are good, they spit out codes, i didn't check all of em, but 3/4.
2. the test board takes HOURS to setup.
3. something is wrong with the car, and i have no clue what!

RotaryEvolution 09-23-13 03:39 PM

what is it doing again? from the initial start it sounded like everything was ok. what changed between then and now?

j9fd3s 09-24-13 02:14 PM


Originally Posted by RotaryEvolution (Post 11580418)
what is it doing again? from the initial start it sounded like everything was ok. what changed between then and now?

it idles rich, and it'll drive but when you give it gas it cuts out before you hit boost.

next logical step was to check for codes, because the smog guy WILL look for that, and the FD triggers the light differently than the FC, plus it might tell me i have a bad sensor/part.

but it wouldn't spit out codes in the car, so after trying a bunch of stuff i put it on the board to make sure its not the ECU, which it isn't.

so next step is to start checking wiring, i think i've either got the MAP sensor backwards, or i've crossed the 5v power and ground somewhere. i do know the MAP sensor is good (its actually new), the ECT is good, TPS adjusted good before...

RotaryEvolution 09-24-13 02:25 PM

check the ECT signal to the ECU as well as the 5v signals from the map. those are the 2 largest contributors to the way the ECU delivers fuel amounts.

also make sure somehow a check valve didn't wind up making it's way onto the MAP sensor line instead of the filter, and that it is connected to the correct port. there is still a few non metered ports on the FD UIM, but not nearly as many as the FC has.

j9fd3s 09-24-13 02:44 PM

10-4! as usual i'm up the river with no shovel...

j9fd3s 09-27-13 06:57 PM

one small step forward!

i unplugged the 2 ECU connectors that don't have power or ground, #2,3, and CEL worked.

so i unplugged all the sensors/solenoids/etc on plug 3, and CEL didn't work. looking at the other things on connector 3, one of them is the 5v sensor power.

so i unplugged the MAP sensor, which is the only 5v sensor NOT on connector 3, and checked it, and sure enough power and ground were backwards, reversed those, and now

i have a working CEL.

stupidly i then tried to read the codes, and there are a lot of them!

RotaryEvolution 09-27-13 07:09 PM

lol, i'm rather surprised it even ran if that was the case. running with virtually no map sensor will do that on a map based car since it will default to atmospheric pressure(sound like a bridged engine and smoke black smoke like a train).

j9fd3s 09-27-13 10:13 PM


Originally Posted by RotaryEvolution (Post 11584381)
lol, i'm rather surprised it even ran if that was the case. running with virtually no map sensor will do that on a map based car since it will default to atmospheric pressure(sound like a bridged engine and smoke black smoke like a train).

lol, it did idle worse than the P port!

j9fd3s 10-05-13 04:53 PM

so an update, i have it running, the check engine light stays off, although if you check codes it has some for some of the emissions solenoids that aren't plugged in yet.

so it still idles rich and then falls on its face when you give it gas.

while i was putting a turbo fuel pump in it, i looked at the wiring diagrams for the FD and S5 and the FD uses an NC relay, and the FC uses an NO relay, so predictably they use the same ecu pin, but are in reverse.

so i have 12V at the fuel pump at idle, and when i step on it, 9v.

kind of funny!

diabolical1 10-07-13 11:46 PM

i applaud your focus, dedication and SKILL! these ECU issues have been persisted and to be honest, i would have probably cried and quit already. i know MY limitations. :) i do see YOU figuring it all out though. so good luck and i hope it gets sorted soon.

j9fd3s 10-08-13 07:09 PM


Originally Posted by diabolical1 (Post 11592508)
i applaud your focus, dedication and SKILL! these ECU issues have been persisted and to be honest, i would have probably cried and quit already. i know MY limitations. :) i do see YOU figuring it all out though. so good luck and i hope it gets sorted soon.

i do feel like i haven't done anything except wiring, and its like one step back, two steps back, but someday i'll be able to work on something else, right?

and it does seem like the smart move would have been to sell the FD engine, and just buy a J spec S5, and rebuild that, would have bolted in, and i could have been done months ago!

clokker 10-08-13 07:40 PM


Originally Posted by j9fd3s (Post 11593145)
... it does seem like the smart move would have been to sell the FD engine, and just buy a J spec S5

Maybe, maybe not.

I totally get the seductive lure of the similar though.
I mean, it's basically the same engine from a later (and presumably, better) version of your car. how hard could it be?

Optimism goggles blind one to the minefield of rabbit holes that awaits.

j9fd3s 10-09-13 10:55 AM

3 Attachment(s)

Originally Posted by clokker (Post 11593181)
Maybe, maybe not.

I totally get the seductive lure of the similar though.
I mean, it's basically the same engine from a later (and presumably, better) version of your car. how hard could it be?

Optimism goggles blind one to the minefield of rabbit holes that awaits.

its even dumber! pics are of the K2rd shop car, from 2003, these pics are actually right before the engine/turbo died, and we cut the car up, but i'm literally using leftovers from this car in mine.

the difference is that the yellow car had an E6K, so wiring is much simpler.

as a point of historical fact, that yellow car was running 12's in the mid 90's, had an REW in it in 96/97 it had some history. it also had been in some big wreck at some point and had bondo on the frame rails(!), and some rust problems

hmm that may be ReTed in the background in fact

j9fd3s 10-10-13 01:32 PM

so for a change of pace i decided to install the turbo fuel pump, incorrectly and then leave the key on, so i was able to make it not run AND have a dead battery in one easy step.

or

it gave me something to do today, install the fuel pump correctly (stupid O ring), and charge the battery.

the FD switches the fuel pump speed in reverse of the FC, so i get 12V at idle, and 9v @wot, i don't think this is why its rich at idle, but it can't help, turbo fuel pump seems to have made this worse...

driftxsequence 10-10-13 01:47 PM

You should mark down what pins you are moving around. If you made a plug and play harness to drop an FD engine in I'm sure there would be buyers considering how many more FD engines are available (93-02 rather than 86-91) and the increased output.

j9fd3s 10-10-13 02:03 PM


Originally Posted by driftxsequence (Post 11594734)
You should mark down what pins you are moving around. If you made a plug and play harness to drop an FD engine in I'm sure there would be buyers considering how many more FD engines are available (93-02 rather than 86-91) and the increased output.

i do have a list, its not even that complicated, i'm just making mine run with no CEL, which means i need to wire up everything, and there is a lot of stuff.

scrapp 10-10-13 03:18 PM

The knowledge that's being thrown around so carelessly in this thread... I only hope future generations realize what kind of REAL problems we are going to be dealing with one day, and start to plan... I wish I had all this technical amassed.... I just want to learn. shoulda spent more time in the past getting involved than lurking... I digress.


Anyway... What year is the car? What are your laws where you live? I REALLLLLYYYY hope they are not going back on something I've dreamed about since I was a kid... Down here, after 25 years, a car is a classic and all you need to pass is like you say: "Tires, lights, and beepy thing"

I last year I finally got my coveted milestone and was given a "Classic car" inspection tag. AFAIK, I have no more need to worry about standalones, engine swaps, premix, fuel type... emissions junk attached around my keg....


Anyway... I never knew about this thread... I want a REW FC, and I really dont know why....

j9fd3s 10-10-13 03:48 PM


Originally Posted by scrapp (Post 11594826)
The knowledge that's being thrown around so carelessly in this thread... I only hope future generations realize what kind of REAL problems we are going to be dealing with one day, and start to plan... I wish I had all this technical amassed.... I just want to learn. shoulda spent more time in the past getting involved than lurking... I digress.


Anyway... What year is the car? What are your laws where you live? I REALLLLLYYYY hope they are not going back on something I've dreamed about since I was a kid... Down here, after 25 years, a car is a classic and all you need to pass is like you say: "Tires, lights, and beepy thing"

I last year I finally got my coveted milestone and was given a "Classic car" inspection tag. AFAIK, I have no more need to worry about standalones, engine swaps, premix, fuel type... emissions junk attached around my keg....


Anyway... I never knew about this thread... I want a REW FC, and I really dont know why....

i'm in California. the car is a 1991, which gets a dyno smog, plus a visual, where they are check to make sure that all the emissions control devices are present.

since i'm putting a later engine in the car, technically i need to go get the swap certified with the BAR, but since the FD and FC have the same emissions control parts (air pump, cat, etc) i'm just going to hope nobody knows what a turbo FC looks like...

if you have no smog, this gets WAY easier, like the yellow car, its just an E6K, so the engine harness is like 12 wires or something, piece of cake


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