17.0-18.0 Air/Fuel At idle

SFRacingGST · 10-30-2005, 07:31 PM

I just got my car tuned by Pruven in CT. However it seems to be runing rich at idle. was wondering if it was because of 550 injectors or becasue hks 264 cams??? Should i adjust the AFC to make it more around 14.5 at idle?? It runs so rick my air/fuel guage doesn't even lite up at idle. maby all the way to lean

Coup D E'Tat · 10-30-2005, 08:27 PM

The higher the number is lean, not rich. I.E. 17:1 is much leaner than 10:1.

What are you measuring these reading from?

SFRacingGST · 10-31-2005, 04:24 AM

Well the air/fuel read out on the turbo timer reads 17.0 to 18.0 at idle. The air/fuel guage does not go back and forth at idle, it stay on the lean side the whole time which is red ont my guage. Should i adjust this or is it ok seeing it runs fine as soon as i start driving it?

dnhieu · 10-31-2005, 05:35 AM

are you reading the narrow band a/f ratio reading on your autermeter guage and turbo timer? if so dont, thoes things are good for light shows and thats it. im sure pruven performance could get a good tune on the thing. if you dont think so tho you can always buy a lm1 and find out for yourself what kind of a/f ratio your running

hope that helps
david

howie3 · 10-31-2005, 05:45 AM

Quote:

Originally Posted by dnhieu

are you reading the narrow band a/f ratio reading on your autermeter guage and turbo timer? if so dont, thoes things are good for light shows and thats it. im sure pruven performance could get a good tune on the thing. if you dont think so tho you can always buy a lm1 and find out for yourself what kind of a/f ratio your running

hope that helps
david

I think a narrow band with a good o2 sensor can get you pretty close to your air/fuel ratio. I think he's pretty lean if you ask me.

TransAmConvert · 10-31-2005, 07:14 AM

Most likely your o2 sensor is just old and doesn't read at idle. Try swapping it with a known good one and see what it does.

SFRacingGST · 10-31-2005, 08:43 AM

I figured that pruven knew what they were doing, thats why i didn't touch it. I understant that the Air/fuel guage is basically junk also. but i am not sure why it is 18.0 on the apexi turb timer at idle. my o2's are fairly new and they read fine before they tuned it (flexing from lean to rich at idle). Now no lights show up at idle (maby just the one red lean ligh all the way to the left). Could it be giving me this reading because of the cams (hks 264) or the rc 550's? Is this bad running this lean at idle??? my only option is to adjust the fuel trim at like 1000 rpm on the SAFCII. please gimme some advice before i mess with the dyno tuned settings.

spyderturbo007 · 10-31-2005, 11:48 AM

I think there is some confusion here.

When your car was tuned, they should have only tuned the Hi-Throttle map. Using a dyno to tune Lo-Throttle on the SAFC is worthless and a waste of time. It is something that can be done at idle in your driveway.

Most likely, they only tuned your car for a WOT run, which would be the Hi-Throttle map on the AFC. You can change the Lo-Throttle settings until you're blue in the face and you won't effect the dyno settings, provided that the dyno shop knew what they were doing and used the correct map on the AFC. They would have also needed to set the TPS triggers correctly.

Sounds like your AFC Lo-Throttle map is extremely lean and should be corrected immediately.

Post up your settings and Ne Points for both the Lo-Throttle and Hi-Throttle maps and I'll help you along.

EDIT>

After rereading your post, it seems as though my response might need a little background to be understood correctly.

The SAFC-II has 2 different, independant maps that are based on throttle position. One is called the lo-throttle map and the other the hi-throttle map. At a user defined point, the SAFC-II switches from the lo to hi map and vice versa. You need to define this point within the SAFC-II. Most people set the low throttle point at 30% and the hi throttle point at 80%.

This means that when you are cruising around (TPS <30%) you are on the SAFC-II's lo throttle map. This map is set to maximize fuel efficiency by keeping the AFR around 14.7:1.

When you go WOT (or anything at a TPS >80%) the SAFC-II switches to the hi-thorttle map. The hi-throttle map was the one that was altered on the dyno. This map is designed for maximum power at a much richer AFR.....in my case 11.3:1.

So the company you took your car to should have set the proper throttle triggers and then tuned the hi-throttle map. They may have tuned the lo-throttle map for you, but it looks as though they didn't know what they were doing.

Do this, take a look at your logger and let me know what your FT's are at idle. Also, post up your settings on the SAFC-II.

SFRacingGST · 10-31-2005, 06:39 PM

Thanks for the help spyderturbo007... Makes alot of sense what you posted... The car runs great at full throttle (high throttle) but the only thing wronge is the air fuel at idle. I am not sure wether they tuned it, but weither way my settings are way off. My buddy has a data loger and i am gonna plug it in tommrow, i am also gonna get my low throtle setting and let you know...will keep this posted

diamondgst · 11-01-2005, 10:07 PM

Quote:

Originally Posted by spyderturbo007

I think there is some confusion here.
You need to define this point within the SAFC-II. Most people set the low throttle point at 30% and the hi throttle point at 80%.

This means that when you are cruising around (TPS <30%) you are on the SAFC-II's lo throttle map. This map is set to maximize fuel efficiency by keeping the AFR around 14.7:1.

When you go WOT (or anything at a TPS >80%) the SAFC-II switches to the hi-thorttle map. The hi-throttle map was the one that was altered on the dyno. This map is designed for maximum power at a much richer AFR.....in my case 11.3:1.

Ok i was wondering this also so lo-throttle setting is <30%, and hi-throttle setting is 80%>? so whats in between how do you adjust in between 30 and 80? i have wondered this?

Next no a narrow band with a good narow band sensor isnt going to help more or less give anywhere NEAR close to what accual AF ratio is. Wideband is the ONLY way. unless you get a narrow band conversion kit, but then its not worth it because widebands alsmost cheaper.

spyderturbo007 · 11-02-2005, 05:34 AM

Quote:

Originally Posted by diamondgst

so whats in between how do you adjust in between 30 and 80? i have wondered this?

There is no way for the user to adjust the AFR between the two throttle trigger points. The SAFC-II uses a linear extrapolation based on TPS and the Lo and Hi maps.

diamondgst · 11-02-2005, 07:36 AM

Quote:

Originally Posted by spyderturbo007

There is no way for the user to adjust the AFR between the two throttle trigger points. The SAFC-II uses a linear extrapolation based on TPS and the Lo and Hi maps.

so basically it takes the lo-t map and hi-t map and the amount of TPS signal and mixes the maps together to get a # of correction?

spyderturbo007 · 11-02-2005, 09:51 AM

Quote:

Originally Posted by diamondgst

so basically it takes the lo-t map and hi-t map and the amount of TPS signal and mixes the maps together to get a # of correction?

Correct!

It does the same thing between Ne points (such as between 1k and 2k).

SFRacingGST · 11-05-2005, 07:16 AM

ok, i finally got my car running again after finding 2 vacume leaks and replacing the fuel filter. I went into low throttle settings and i found that they were all set to -20. The throttle points were lo 69% and high 70%. I was told to set all of the low points to negitive 10 and the throttle % to 30 on low and 70 on high.. the car run better but still not perfect.. My air fuel idle is back to the 14's, but i think i may be running to rich at times now. Any suggestions?

spyderturbo007 · 11-07-2005, 05:54 AM

At -10% you are most likely still running rich, but the only way to know for sure is to take a look at your FT's.

What is your STFT & LTFT at idle?