S4 NA into REPU HELP!
05-09-13, 12:40 PM
#27
Originally Posted by RotaryEvolution
for the wiring i would focus mainly on the main engine harness, the ampillary harnesses can be custom made, like CAS wiring with a shielded 4 wire audio cable. all the emissions stuff can be amputated but the main sensors should remain: CAS, AFM, ignition, pressure sensor, ECT, injectors and TPS. even the IAT isn't all that important, nor are the closed loop function sensors like O2. the stock maps are very close to maximized already, assuming there is no vacuum leaks in the system. closed loop only engages in a very narrow window and you likely won't be seeing it for even 1% of your run time. i almost never spend much time on closed loop function components on these engines because they rarely do much if anything at all.
05-09-13, 12:43 PM
#28
IAT on the FC i believe was only for startup purposes as well as maybe closed loop function but don't quote me.
i've run many FCs without an O2 sensor and never noticed much of a difference either way. as far as i'm concerned it is nearly a worthless closed loop system which can be bypassed with no ill effects. it will throw a code when it wants to actually use the O2 sensor but that's about it, it will not go into any form of limp mode but simply remain focused on using open loop fuel tables which are already very close to where they need to be without any outside assistance, assuming all vacuum leaks are accounted for and the AFM is in good working order.
i've run many FCs without an O2 sensor and never noticed much of a difference either way. as far as i'm concerned it is nearly a worthless closed loop system which can be bypassed with no ill effects. it will throw a code when it wants to actually use the O2 sensor but that's about it, it will not go into any form of limp mode but simply remain focused on using open loop fuel tables which are already very close to where they need to be without any outside assistance, assuming all vacuum leaks are accounted for and the AFM is in good working order.
05-09-13, 12:43 PM
#29
Originally Posted by RotaryEvolution
i would forget the walbro as i said, they already have a tendency to raise fuel pressure more than any other pump available due to their design.
Just one quick question about the walbro. If I ran an EFI FPR to bring it down to 40psi BEFORE it enters the FC rail, would that keep the injectors happy?
05-09-13, 12:53 PM
#31
Originally Posted by RotaryEvolution
IAT on the FC i believe was only for startup purposes as well as maybe closed loop function but don't quote me.
i've run many FCs without an O2 sensor and never noticed much of a difference either way. as far as i'm concerned it is nearly a worthless closed loop system which can be bypassed with no ill effects. it will throw a code when it wants to actually use the O2 sensor but that's about it, it will not go into any form of limp mode but simply remain focused on using open loop fuel tables which are already very close to where they need to be without any outside assistance, assuming all vacuum leaks are accounted for and the AFM is in good working order.
i've run many FCs without an O2 sensor and never noticed much of a difference either way. as far as i'm concerned it is nearly a worthless closed loop system which can be bypassed with no ill effects. it will throw a code when it wants to actually use the O2 sensor but that's about it, it will not go into any form of limp mode but simply remain focused on using open loop fuel tables which are already very close to where they need to be without any outside assistance, assuming all vacuum leaks are accounted for and the AFM is in good working order.
Ok, I'll think about adding an O2 bung, but if I never get around to it, no big deal.
As for everything else, I can only assume the AFM is still good at this point. The previous owner couldn't get it to run right and blamed the throttle cable and/or dashpot? Upon teardown and removal, I noticed they blocked off the BAC hose nipples, ended up crushing a piece of old gasket between the upper and lower manifolds (vacuum leak!), blocked off the aux port sensing tube (that threw me for a loop right there!) and kept the emissions solenoids+rats nest even though the EGR, air pump and ACV were already removed/blocked off. It was a head scratcher that they got it to run as well (poorly lol) as they did. But it DID infact run!
So I'm feeling pretty confident that I can make it run grafted into another chassis. But again never done anything remotely like this before. Hence all the questions.
05-09-13, 12:55 PM
#33
Originally Posted by RotaryEvolution
that's fine, more fuel is obviously better than less. the turbo cars normally run around 40psi static anyways. the drop down to 32psi at low loads are mainly for emissions purposes.
Is there a write up for how to swap to a banjo bolt?
05-09-13, 02:42 PM
#35
THANKYOU!! I have to do an order there anyway.
One quick question. Is there a stock steel banjo bolt like that? Like say a T2 turbo oil banjo bolt that fits in the front iron? I know FD/Cosmo is a bigger bolt. Just curious. Thanks!
One quick question. Is there a stock steel banjo bolt like that? Like say a T2 turbo oil banjo bolt that fits in the front iron? I know FD/Cosmo is a bigger bolt. Just curious. Thanks!
05-09-13, 03:37 PM
#37
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Have you done a setup that didn't have an IAT and O2 before? Just curious since I'll be into the wiring harness anyway, might as well keep them, but it means I gotta add an O2 bung to the exhaust. I was gonna add an aux port sensing tube anyway, so might as well right? Mazdatrix style.]
edit: if you don't run the IAT put a resistor in there to simulate some middle temp. the FC computer in theory has a default value, but in practice its too dumb to figure out that it needs to use it.
for instance, if the coolant is 85C and the intake air temp is -120C, the S4 ecu will just output according to those numbers
05-12-13, 06:05 PM
#38
Some updates! Ordered the banjo bolt. Started to de-pin harness #1. Removed all the useless crap and left these:
H radiator switch (because j9fd3s said to connect it. To where? Ground? Switched 12V?)
M trailing
N CAS
P CAS
Q CAS
T CAS
U trailing
V leading
X trailing
Everything else is ignition related and self-explanitory on this harness. Please let me know whether I need to keep the radiator switch wire. Thanks!
H radiator switch (because j9fd3s said to connect it. To where? Ground? Switched 12V?)
M trailing
N CAS
P CAS
Q CAS
T CAS
U trailing
V leading
X trailing
Everything else is ignition related and self-explanitory on this harness. Please let me know whether I need to keep the radiator switch wire. Thanks!
05-12-13, 06:41 PM
#40
Cool! It's easy enough to remember which wire it is, to remove later if not needed.
Gonna de-pin the other two harnesses next! Do you have a quick list of the letters I can remove? I see a few obvious ones already like:
remove? \/
2N EGR solenoid valve
2O switching solenoid valve
2P relief solenoid valve
2Q Bypass air control valve (these three are just the rat's nest solenoids right?)
3D Inhibitor switch
Does 2K split air solenoid also get chopped?
Let me know if I'm on the right track. Thanks!
Gonna de-pin the other two harnesses next! Do you have a quick list of the letters I can remove? I see a few obvious ones already like:
remove? \/
2N EGR solenoid valve
2O switching solenoid valve
2P relief solenoid valve
2Q Bypass air control valve (these three are just the rat's nest solenoids right?)
3D Inhibitor switch
Does 2K split air solenoid also get chopped?
Let me know if I'm on the right track. Thanks!
05-13-13, 03:19 PM
#42
I left these wires in place:
Harness 2
A V ref
B Boost sensor [MAP]
C Ground
D O² sensor
E Air flow meter (Vs) [AFM]
F Variable resistor
G Throttle sensor [TPS]
H Atmospheric pressure sensor [BARO]
I Water thermo sensor
J Air flow meter (Intake air temperature sensor) [AFM]
L Intake air temperature sensor (dynamic chamber) [IAT]
Q Bypass air control valve [BAC]
R Ground
Harness 3
A Ground
B Starter switch
C Injector (Rear primary)
E Injector (Front primary)
F Injector (Rear secondary)
G Ground
H Injector (Front primary)
I Main relay
J Battery
Wires removed: 2KMNOP, 3D
Harness 2
A V ref
B Boost sensor [MAP]
C Ground
D O² sensor
E Air flow meter (Vs) [AFM]
F Variable resistor
G Throttle sensor [TPS]
H Atmospheric pressure sensor [BARO]
I Water thermo sensor
J Air flow meter (Intake air temperature sensor) [AFM]
L Intake air temperature sensor (dynamic chamber) [IAT]
Q Bypass air control valve [BAC]
R Ground
Harness 3
A Ground
B Starter switch
C Injector (Rear primary)
E Injector (Front primary)
F Injector (Rear secondary)
G Ground
H Injector (Front primary)
I Main relay
J Battery
Wires removed: 2KMNOP, 3D
05-13-13, 03:50 PM
#44
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05-13-13, 03:53 PM
#45
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ah! AWS = Amazingly Worthless System!
05-13-13, 04:23 PM
#46
it does help with flooding though, but a properly running setup doesn't need it.
i've had a few people over the years who couldn't be bothered by warming up their cars, as if they were brand new off the truck still and wanted everything functional to jump in and drive off year round. luckily there's always the good old thermowax as backup, the system you love to hate.
i've had a few people over the years who couldn't be bothered by warming up their cars, as if they were brand new off the truck still and wanted everything functional to jump in and drive off year round. luckily there's always the good old thermowax as backup, the system you love to hate.
Last edited by RotaryEvolution; 05-13-13 at 04:26 PM.
05-13-13, 04:34 PM
#47
Thanks guys! 2K went bye bye!
I just have a few questions.
The 20k mile switch. Leave it alone? It's a fresh rebuild. Worry about it in 20k miles? lol
Harness 3, pin B Starter switch. What do I connect it to? Does it only receive 12V in ignition "start" position? Must be a cranking only thing.
Harness 3, pin I Main relay. I didn't grab this from the car. Can I hook up a common 30 or 40 amp automotive relay? Is it triggered by the ignition switch? Does it get 12V in "Start" as well as "On" key positions? Does it need a fuse? How big?
Harness 3, pin J Battery. Does this go to a full time B+ source? Does it require a fuse? 30 Amp or so ok?
I just have a few questions.
The 20k mile switch. Leave it alone? It's a fresh rebuild. Worry about it in 20k miles? lol
Harness 3, pin B Starter switch. What do I connect it to? Does it only receive 12V in ignition "start" position? Must be a cranking only thing.
Harness 3, pin I Main relay. I didn't grab this from the car. Can I hook up a common 30 or 40 amp automotive relay? Is it triggered by the ignition switch? Does it get 12V in "Start" as well as "On" key positions? Does it need a fuse? How big?
Harness 3, pin J Battery. Does this go to a full time B+ source? Does it require a fuse? 30 Amp or so ok?
05-13-13, 04:56 PM
#49
Thanks guys! 2K went bye bye!
I just have a few questions.
The 20k mile switch. Leave it alone? It's a fresh rebuild. Worry about it in 20k miles? lol
Harness 3, pin B Starter switch. What do I connect it to? Does it only receive 12V in ignition "start" position? Must be a cranking only thing.
Harness 3, pin I Main relay. I didn't grab this from the car. Can I hook up a common 30 or 40 amp automotive relay? Is it triggered by the ignition switch? Does it get 12V in "Start" as well as "On" key positions? Does it need a fuse? How big?
Harness 3, pin J Battery. Does this go to a full time B+ source? Does it require a fuse? 30 Amp or so ok?
I just have a few questions.
The 20k mile switch. Leave it alone? It's a fresh rebuild. Worry about it in 20k miles? lol
Harness 3, pin B Starter switch. What do I connect it to? Does it only receive 12V in ignition "start" position? Must be a cranking only thing.
Harness 3, pin I Main relay. I didn't grab this from the car. Can I hook up a common 30 or 40 amp automotive relay? Is it triggered by the ignition switch? Does it get 12V in "Start" as well as "On" key positions? Does it need a fuse? How big?
Harness 3, pin J Battery. Does this go to a full time B+ source? Does it require a fuse? 30 Amp or so ok?
disregard the 20k mile wire, i don't even know its purpose
pin B, wire up to the ignition to supply 12v when cranking only
pin I is your main relay, which can be a 40A relay wired to turn on and feed power to this wire whenever the key is in the run or crank position(this is basically your ignition on signal wire versus crank signal wire above). the main relay is also used to power the ignition system and injectors as well as all the solenoids, which you don't have now.
pin J, i believe is constant 12V to power the whole ECU
every power fed wire should have a fuse in the circuit somewhere, normally where it feeds that circuit. redundant fuses are not really necessary. the REPU has the main fuse block on the driver side near the windshield, this can be expanded to add more fuses, it is also fed by the power distribution block located behind the passenger seat fed by the band type fuses.
Last edited by RotaryEvolution; 05-13-13 at 05:06 PM.
05-13-13, 05:03 PM
#50
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