S-AFC Throttle Position errors?

2-0turbo · 08-28-2002, 08:58 PM

I just got my SAFC installed tonight. Viewing a logger, with your foot OFF the gas, the standard throttle position is 10%, right. The SAFC registers 0% without touching the gas. No problem.

The problem is the SAFC hits 100% thottle when the logger only shows 60%. So, subtracting off the 10% normal, the throttle only moves 50% but the SAFC shows that it moves 100%. If you view the voltages on the "ETC" screen, the voltage is scaled correctly and changes the entire time I am moving the gas pedal.

It shows 100% with the throttle pedal still off the floor a good bit and then continues to read 100% as I push it all the way to the floor. What gives? Do anyone elses SAFC do this? Has anyone ever checked? Have I done something wrong, or have some setting funny? Ideas? Thanks.

2-0turbo · 08-29-2002, 01:44 PM

No one has ideas on this or seen it happen before? The only thing I could find reference to was mis-adjusted throttle cables, but I am off by a lot for throttle cables to be the problem! And, I would see the problem on my logger too if I was off that much.

I called the distributor, they were no help and suggested that SAFC's are not very useful and perhaps I should buy a Greddy e-manage or Power FC. (????? Yeah, whatever--that solves my problem). So, I called Apexi and the dude had never heard of this problem and told me to call back later when their R&D dudes were back. ... ....

Rodman · 08-29-2002, 07:37 PM

Yes that is normal. Don't worry so much about your throttle position readings. Use the logger to look at knock and timing values, as well as 02 trims, 02 voltage and fuel trims. Remember, the logger isn't tuning the car, the AFC is.

2-0turbo · 08-29-2002, 09:28 PM

Quote:

Originally posted by Rodman
Yes that is normal. Don't worry so much about your throttle position readings. Use the logger to look at knock and timing values, as well as 02 trims, 02 voltage and fuel trims. Remember, the logger isn't tuning the car, the AFC is.

Well, I don't know if I agree with you that it is normal, but it "seems" to be correcting itself. 100% on the SAFC now shows 77% on the datalogger, so they are getting closer. I went and drove it probably 60 miles today. I am not doing much tuning since I am still on stock injectors--most of my settings are zero. I did richen it up at idle a bit (I know, can you believe it?) to get my fuel trims down from 119%. I hope to get my 2G MAS in soon and crank my fuel pressure up to 43--that will give me a little room to play. Thanks for the response. Nice looking 1G, BTW. I really like the black/black and the wheels too. Very nice.

candela · 08-29-2002, 11:56 PM

In truth you can move the pedal more but the throttle plate will still be open all the way. If the voltage is working for the tps sensor than your good. When the voltage hits 5 (i think) then thats 100% wot.

2-0turbo · 08-30-2002, 04:34 AM

Quote:

Originally posted by candela
In truth you can move the pedal more but the throttle plate will still be open all the way. If the voltage is working for the tps sensor than your good. When the voltage hits 5 (i think) then thats 100% wot.

Right, and this was/is the problem. My TPS voltage shows .49 - 4.985 volts full range. My SAFC hits 100% on the display at roughly 3 volts. The funny thing, I played around with and changed the throttle type to regressive (instead of progressive) and it correctly displayed 100% with my foot off and 0% with it on the floor. Hummmm...if this doesn't clear up soon, I'm going to say this thing is flakey.

candela · 09-08-2002, 12:18 PM

I was talking to a guy whos having the same problem...and I remembered this posts. Sorry I cant help you, he has no idea whats up either. My afc's rpm readings are constantly about 500-700rpm lower than what the needle says. Im gonna try and hook up a nice timing light and see what it says compared to the afc...These things just very well may be flaky!

2-0turbo · 09-08-2002, 06:25 PM

I still haven't gotten to the bottom of this. The company is sending me another one (honestly, I think by accident). I am going to try the other one. My buddy just got his car back on the road and I sat in his car and it works fine. Mine just doesn't want to believe that there is any throttle left beyond 3.1 volts.

candela · 09-08-2002, 09:37 PM

What I posted before isnt exactly true. I thought it was just a few hundred low, but I wasnt really watching it before. The afc reads exactly half of what my tach reads (which is perfectly nsync'(lol) with my pocketlogger....). No matter what I do to adjust the car type or sensor or anything it still reads half. I dont know

is up. Did you call apexi and ask for a new one. The rest of the functions work fine, and its really tuned pretty good right now, although it shows the wrong rpm, the setting inputs are still dead on. Maybe Ill call them tomorrow. Later,

Austin

2-0turbo · 09-09-2002, 04:54 AM

Austin, your problem is documented. On your car setup, change to either a 2 cylinder or an 8 cylinder to fix your problem. This is detailed on the RRE site. I have heard of this a good bit. I never really found out if it was something actually wrong with the SAFC or the wrong wire was tapped at the ECU. I have heard both theories. Anyway, the easy way to fix it (and perfectly acceptable way) is through the software on the car setup screen.

BatmanGSX · 09-09-2002, 05:53 AM

Quote:

Originally posted by candela
The afc reads exactly half of what my tach reads

You tapped the wrong wire. There is a wire that has a signal that is exactly half of what the actual tac signal is. I forget why. I also forget which wire is the correct wire. Switching to 2cyl is a band-aid. Tap the correct wire.

2-0turbo · 09-09-2002, 07:25 AM

RRE's tech site. See at the bottom under common problems.

BatmanGSX · 09-09-2002, 08:37 AM

Mine is set to 4cyl and displays the correct rpm.

candela · 09-09-2002, 10:12 AM

I appreciate both your posts, I set it to 2 a while ago, I was just curious/saying that mine does that (flaky). I really don't think its wired wrong, but maybe...thanks

BatmanGSX · 09-09-2002, 10:33 AM

Quote:

Originally posted by candela
I appreciate both your posts, I set it to 2 a while ago, I was just curious/saying that mine does that (flaky). I really don't think its wired wrong, but maybe...thanks

Well the wiring that DSMers have typically been using changed at some point, one is the new way, one is the old way. I was under the impression that the 2cyl way was an output wire from the ECU going to the coil packs and the 4cyl way was a signal coming back into the ECU. I'm not sure but there is def. an "old wiring" and a "new wiring". The diagram I used was updated for that change. Don't get me wrong, the 2cyl way works, I'd just rather have it right because I am anal like that.