NightHawkR

since s5 dosen't have a variable resistor as i read from couple other threads, how do i adjust the idle mixture for a s5 engine?

RotaryRocket88

iTrader: (7)

You can't.

Chuck

iTrader: (2)

You can always get squirrelly and adjust the butterfly valve set screw. Make changes in very small steps though. Messing with the butterfly openings can have some major effects on engine idle. Standard opening is the width of a very small wire.

NightHawkR

My problem is after i readjust the tps (which is replaced only couple months ago, and the readings i got from the connector wasn't off by that much before i adjusted.) the idle is getting very rough, jumping up and down between 700-1500. Had wideband and safc neo installed and noticed the afr at idle is very lean, and somehow the throttle reading is completely worng as well (it shows 100% no matter what). Had the wiring checked according to the manual, everything was connected properly.


Is there any way to adjust the fuel mixture at idle through safc?...

btw I have a s5 swap but the ecu is still from the s4(un-modded), and i current have the safc setup for s5. Will that affect all these as well?

edit: had all the groundings and wires checked, no problem, no vaccum leak anywhere either.

arghx

iTrader: (3)

Do you have your airpump installed? it will read very lean with the airpump and ACV running. You may have your AFC Neo set up incorrectly. Try adjusting the throttle position sensor setting.

You can lean out the idle with the AFC by changing the low throttle airflow correction. But first get your TPS set up correctly in there. I'm also not convinced that you really need to lean your idle out more. With no airpump installed it shouldn't be any leaner than 13:1, maybe 13.5:1

RotaryRocket88

iTrader: (7)

You say you're using an S4 ECU, does this mean you also have an S4 TPS, MAP sensor & AFM? Because you should.

Also Hailers posted the following in another thread. It caught my attention because you mention that your TPS reading is stuck at 100%, which is what he just had happen. The TPS can be a sensitive pain in the *** sometimes.

HAILERS2

It's 4:24am and I need to sleep, but something caught my eye. You have a series four ECU but have it set up for series five. That's your main problem. You need it set up for a series four because that is what the ECU is. Engine matters NOT.

Can't help with the TPS much. If you have a digital meter, then key to ON, engine HOT, and backprobe pin 2G of the ECU. Green/Red wire. Should show approx 1vdc if the engine is HOT. If not, then adjust the TPS screw til 2G reads one volt dc. But again, if you have a series five engine and series five TPS......how did you rig the wiring to fit a series four EM wiring harness...............eh, need sleep. Must have mis read or not read enough of your post. Gone.

HAILERS2

Well it's six forty two and what I wrote above still applies.

The TPS is either rigged wrong............is kaput itself..........or you wired it to the SAFC wrong. It should read one volt dc when the engine is HOT. If memory serves there is a place on the SAFC where you can read the VOLTAGE output of the TPS. I'd do that and adjust it to one volt dc.

Then if not before the above, I'd read the SAFC instructions and set it up for a series four car, because that is what the ECU is.

Just in case, this is how thing work with the TPS: When driving along at road speed, and you let off the pedal, the ECU sees you've done so because its monitoring the TPS value. When it sees the TPS has returned to a low value, and the engine rpm is over approx 1300 rpm, the ECU cuts fuel from the injectors. After the rpms get below approx 1300 rpm the ECU kicks the injectors back on.

I had an anomaly where the TPS was, for unknown reasons, outputting *** backwards values. At idle it was outputing at 100%. As the pedal was depressed the value was going downward i.e. 100,99,98,97,96,95,94,93 etc. So. When I tried to drive the car by putting it in gear and pressing the pedal, the TPS value almost instantly goes down to the 20% range, telling the ECU I've let off the pedal and at the same time as I press the pedal the rpms go up to over 1300 rpm. All the conditions for the ECU to cut the fuel from the injectors.

MY problem corrected itself somehow. F.O.D inside the TPS? Got me. Wires are/were not loose on the TPS. Plunger had spring tension on it so it wasn't stuck in the fully depressed postion (also proven by the value on the RTEK going up down as the pedal was depressed/let go).

Also a seires four ECU also NEEDS to have a series four boost/pressure sensor and afm to go with it. Mix in a series five boost/pressure sensor and or afm and you get crummy results. The series five outputs to the ECU won't match what the series FOUR ECU is looking for.

While your at it make sure the water thermo sensor is inputting 0.40 to .5 vdc to the ECU input wire when the engine is HOT.

NightHawkR

Thanks for the info, about the swap... you got me too... i bought the car with the swap done already. According to the previous owner the car was supposed to be completely rewired with s5 harness and COMPLETE s5 swap... but ends up to be a mess when i send the car to a shop to get couple seals changed on the rear end and tranny and checking some other stuff on the wires what i noticed is the following...

s5 engine
unknown tranny... (due to the fact that we ordered every possible version of seal for s4 and s5 but nothing fits, ended having to custom made a metal sleeve to go with the seal)
s4 ecu
s5 turbo
nothing execpt the tacho and speedo works on the cluster (confirmed nothing to do with the sensors)
and alot of mix and match between the two series....

btw the reason i installed the safc + wideband is because of the FD fuel pump and 720 injector if that will affect anything.


Anyways gonna play with the safc again tomorrow see if things will get fix, and also will it make a huge difference (in terms of reliability) switching to a s5 ecu?

HAILERS2

What's the number on the ECU? N332? N333? or N????

The TPS. How many plungers does it have? One or two?

Do you have a digital meter where you can read the input voltage on the pin 2G of the middle ECU plug? A green/red wire coming from the narrow range TPS if it's a series four ECU. If so, you could monitor the voltage as you move the gas pedal. Voltage should move around as you do so. Somewhere b/t 1-5 vdc and no more. IF more, then the wires going to something it should not go to.

Part of the problem is where you say the guy said it was completley rewired with S5 harnesses..........but it's got a series four ECU. The elect plugs are not compatible. Not saying it couldn't be done, but there'd be a lot of rewiring of the EM harness and front harness plugs for that to happen.

Attached is a jpg of what the wires colors in a series four ECU plug(s) should look like. One is the middle plug and the other the largest plug on the far right of the ECU. Comparing these wire colors with the ones on the plugs on Your car should say something.

RotaryRocket88

iTrader: (7)

Additionally, what does the AFM look like, and what model number does the boost sensor have? S4 AFMs are metal & rectangular, while S5s are black, plastic & round. The S4 TII boost sensor model number is N318.

S4 TII ECUs are N33x, while S5 TII ECUs are N37x.