Initial S-AFC settings for High/Low- 2g

[kmoore]

Tom, thanks a lot.

I'm not TOO concerned about the oil issue. The only reason why I thought it was weird is because I put in 4 quarts of oil and it's not even half full. I bought two more quarts today, just for good measure.

And I will log Coolant temp, wait til it reaches 180*. When that happens, I will look at the STFT on the logger and if it says +5%, I will adjust -5 on the S-AFC? Correct? I am REALLY sorry, I'm not getting this yet. Will the Fuel Trim number cycle or will it go up and stay there?

EDIT: And I'm assuming it's alright to let the car idle in an exremely rich condition, until the STFT starts to cycle?

 

[2gGSX]

To be honest, I'm not sure how you do it with an SAFC so Nathan or Steve will have to step in to explain it correctly.

Kris' guide seems to cover it in a pretty foolproof way as well: http://www.dsmtuners.com/forums/articles-tuning-ecu/58403-definitive-piggyback-tuning-guide.html

You should be fine idling rich for a while.

 

[kmoore]

Now, look at the low fuel trim (2g's only have the LTFT). If it is positive, add a few percent on the SAFC at the 1000 rpm point.

See, this is what I don't get. If STFT is positive according to the logger, you change S-AFC setting in the negative don't you? He doesn't say, that's why I'm asking.

Try to get the fuel trims close to 100%, plus or minus 10% Keep in mind that in a 1g, a perfect fuel trim is 100%, but in a 2g it's 0%.. That means that in a 2g, if the fuel trim is negative, you have to lean it out a bit, and if it's positive, you have to richen it up.

And also, if the fuel trim was negative (according to the logger), wouldn't you have to richen it up on the S-AFC by + ing, to get to that 0% that we're aiming for? And vice versa for the positive fuel trim and making the S-AFC - ing.

 

[2gGSX]

If your LTFT is positive, then the ECU is trying to add fuel. Thus, to compensate, you add fuel. Vice-versa for negative LTFTs.

 

[kmoore]

If your LTFT is positive, then the ECU is trying to add fuel. Thus, to compensate, you add fuel. Vice-versa for negative LTFTs.

So the logger is just showing me what the ECU is TRYING to do? So if the LTFT is positive, like you said, I would + (positive) on the S-AFC right?

 

[2gGSX]

Yes. The LTFT is essentially the ECU compensating for a rich/lean condition, based on front O2 sensor data from running closed loop.

 

[kmoore]

Yes. The LTFT is essentially the ECU compensating for a rich/lean condition, based on front O2 sensor data from running closed loop.

So then the tech guide is wrong? About the whole negative and positive thing?

 

[2gGSX]

On the contrary, the tech guide is saying the exact same thing you are.

Now, look at the low fuel trim (2g's only have the LTFT). If it is positive, add a few percent on the SAFC at the 1000 rpm point.

So the logger is just showing me what the ECU is TRYING to do? So if the LTFT is positive, like you said, I would + (positive) on the S-AFC right?

A positive adjustment on the SAFC means you are inflating the airflow seen by the ECU at that RPM by that %, meaning the ECU will inject more fuel at that RPM, and thus richen the combustion charge.

 

[kmoore]

I see, so really the logger is just telling me what to do on the S-AFC? I'm just trying to take this one step at a time. Get the short term fuel trims down than work on the long term fuel trims.

 

[spyderturbo007]

Correct. You are trying to do what the ECU is doing with the logger. So if the ECU is trying to add fuel (Positive trim), you'll want to add fuel, by adding airflow, with the SAFC. Vice versa if the ECU is pulling fuel (Negative trim)

 

[kmoore]

Correct. You are trying to do what the ECU is doing with the logger. So if the ECU is trying to add fuel (Positive trim), you'll want to add fuel, by adding airflow, with the SAFC. Vice versa if the ECU is pulling fuel (Negative trim)

Got it! Alright great. Now one more quick question. When reving up the car and holding at a certain RPM. How long should I hold it at that certain RPM point? When the fuel trim starts to change should I let off?

 

[spyderturbo007]

No, you are going to have to hold it there while the FT changes. You'll see the STFT change within about 5 seconds of making an adjustment on the SAFC. The LTFT takes much longer to change, maybe about 60 seconds or so. I just adjust the SAFC until I see the STFT stop moving and is equal to zero when added to the LTFT. At that point, you know sooner or later, things will even out.

For example, you rev to the 1k Ne Point and see the LTFT at +9% and the STFT is at +4%. You start making adjustments on the SAFC until the STFT stops moving around -9%. So, now you have a STFT of -9% and a LTFT of +9%. Sooner or later, they will both be zero.

Then, after I get everything where I want it, I go for a nice cruise. You know, put the top down and go for a Sunday drive. Oh, wait, sorry.......You can't do that because you don't' have a Spyder and it's freakin' 10 degrees here and snowing so neither can I. I guess I was just daydreaming for a couple seconds there.....

Anyway, go for a drive and when you get home, just verify that your trims are back to ~0 by reving to each of your Ne Points up to 4k. Then you are all done and get to start with the fun stuff.

 

[kmoore]

No, you are going to have to hold it there while the FT changes. You'll see the STFT change within about 5 seconds of making an adjustment on the SAFC. The LTFT takes much longer to change, maybe about 60 seconds or so. I just adjust the SAFC until I see the STFT stop moving and is equal to zero when added to the LTFT. At that point, you know sooner or later, things will even out.

For example, you rev to the 1k Ne Point and see the LTFT at +9% and the STFT is at +4%. You start making adjustments on the SAFC until the STFT stops moving around -9%. So, now you have a STFT of -9% and a LTFT of +9%. Sooner or later, they will both be zero.

Then, after I get everything where I want it, I go for a nice cruise. You know, put the top down and go for a Sunday drive. Oh, wait, sorry.......You can't do that because you don't' have a Spyder and it's freakin' 10 degrees here and snowing so neither can I. I guess I was just daydreaming for a couple seconds there.....

Anyway, go for a drive and when you get home, just verify that your trims are back to ~0 by reving to each of your Ne Points up to 4k. Then you are all done and get to start with the fun stuff.

Excellent. When I get the 1k, 2k, and 3k, NE points would you suggest me to go rev up to the 4k NE point and carry that 4k setting across to 5k, 6k, and 7k? Or should I just stick to carry the 3k NE point setting across to 4k, 5k, 6k, and 7k?

Man so, basically I'm going to be holding a 3k rpm rev for a minute?! The neighbors will be really happy with me.

 

[kmoore]

Alrighty, so I filled the car up with some more oil today, and some more coolant. Went to start it and it won't turn over. It won't start. It's like I'm flooding it with fuel or something. Any suggestions?

 

[kmoore]

Alright. Well I definately flooded it. Pulled the plugs and they smelled like fuel like no other. I also could see some condensation (fuel) inside the cylinder. I picked up some new plugs (BPR7ES- WOO HOO) and I am waiting for the fuel in the cylinder to evaporate.

Now my question is, what can I do to prevent this from happening again? Or what caused this in the first place? Should I negative the S-AFC before I even start the car or what?


Also, found out I got a leaky radiator. Atleast it gives me an excuse to buy a "blingin" one.

 

[2gGSX]

Now my question is, what can I do to prevent this from happening again? Or what caused this in the first place? Should I negative the S-AFC before I even start the car or what?

Yes.

 

[kmoore]

Yes.

To what do you think?

 

[spyderturbo007]

I thought you had it started the other day? Tom is correct, you'll want the SAFC negative before you start the car. I thought we talked about this earlier, but maybe I'm mistaken. Go ahead and start about -10% at the 1k Ne Point, but like I said, you'll have to adjust by the seat of your pants until the ECU starts to adjust the trims.

 

[kmoore]

I did. Thats why its really weird. I will negative the AFC out and try again.

 

[kmoore]

Well, put the new plugs back in, turned the S-AFC to -30 on the low setting.... and still nothing. It just won't fire. I am absolutely dumb founded. All I did differently from the time that it started and now is that I added more oil and more coolant. That's it. I have no clue

 

[2gGSX]

If it's a no start situation, then start checking the usual stuff--air/fuel/compression, and all sensors. It's most likely something stupid.

 

[kmoore]

I know what you mean. I am more than likely going to kick myself when I do figure this out.

What I have done so far.

Spark- Check
Fuel- Check (I guess just because of the simple fact that the plugs smell like gas and I can see some condensation inside of the cylinder)
Compression- haven't checked it yet

I went out and tested my battery to see if that was the issue. The test said the battery was bad, so I bought a new one hoping that that would solve my issue. Well it didn't. I did however seem to help. It sounded like it wanted to turn over a little bit more. Is there a chance that the new battery was bad from the get go?

I'm almost thinking about retrasing my steps and draining a little oil out just to see if that would do anything. Probably not I know, but I really have no clue.

This is really a dumb question but since my radiator is now leaking, would that effect how the cooling system is pressurized, thus effecting my start situation?

 

[tominatortwo]

Check for fuel and spark, if you have both in the proper order, somethings going to happen!

 

[kmoore]

I have both fuel and spark. I just don't know. Like I said, it does turn over, it just won't fire up. I hear like a "put put" every few seconds when cranking it just won't turn over.

 

[tominatortwo]

I have both fuel and spark. I just don't know. Like I said, it does turn over, it just won't fire up. I hear like a "put put" every few seconds when cranking it just won't turn over.

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