Fuel Trims To High.. Need Help

[BaddAssGst]

I need some help getting my fuel trims down. I just put in 550s, a 190 fuel pump, and a S-AFC. My fuel trims are 139.8%, 125%, and 118.7% (low-medium-high). My throttle points are 30% and 80%. I have my AFC set to these

RPM Low High
1k -15 -10
2k -15 -10
3k -15 -11
4k -15 -11
4.5k -16 -12
5k -17 -13
6k -18 -14
7k -19 -15

I'm still learning how to tune and what not but I know my fuel trims should be down to 100% and I just don't know how to bring them down. I've been told to many different things... Help me out.

 

[spyderturbo007]

I will write this assuming that your 1g is a manual, not an automatic (automatics had smaller injectors than manuals). Anyway, with that said, a normal baseline correction for your SAFC would be -18 for the lo settings (450/550)-1 = -18.2.

A fuel trim of over 100% means that the ECU is adding fuel because the O2 sensor is showing a lean condition (in relation to the stoichometric point). If the FT is below 100% the ECU is removing fuel based on a rich condition. Well, actually it's just changing the IPW but thats for another day.

Wow, that was fun, wasn't it! Anyway, I am guessing you have a logger?

You need to take a look at the O2 voltages at idle and WOT. You will most likely find that your O2 sensor is dying and giving a "false low" value. The ECU then intreprets this as lean and adds fuel (thus the high FT's).

You want to see the O2 voltage (O2 sensor, bank 1 on the pocketlogger program) bouncing around constantly at idle. It should consistently bounce above and below 0.50, which is the stoichometric point.

 

[BaddAssGst]

It is a 1g and it is manual so are you saying on my low settings, I should set all my settings to -18 (from 1k-7k)? What about my high settings? I know they always vary from car to car, so is that something I have to do myself or is there a base point I can start out at? I do have a logger and off the top of my head, I don't know my exact o2s but I will check them out.
If my o2's don't jump around above and below .50, my o2 is bad?

 

[spyderturbo007]

I'm getting off work right now and don't normally get on here on the weekends, but I'll throw some stuff out at you quick before I go.

The -18% I gave you was the starting correction for the SAFC. This is because the 550'
s are 18% bigger than the 450's so you have to remove 18% of the airflow as seen by the ECU. You will have to adjust these at different rpm points (your Ne-points) based on your FT's. This will vary vehicle to vehicle, based on gas octane, barometric pressure, air temp, etc. I would suggest that you go out and set your low throttle Ne points to -18 and see if the FT's change. This will also give you a chance to look at your O2's at idle. If your O2 aren't changing at idle then there is something causeing a problem. If you log the O2, it should look similar to one of those heart monitors you see in the hospital. Up, down, up, down, etc. Sorry, I know that wasn't the most descriptive post but I really want to go home

Here is a really good link!! This will give you something to chew on over the weekend.

http://www.racingknowledge.org/topic.asp?TOPIC_ID=1011

Once again, sorry about the rushed post.

 

[BaddAssGst]

That website really helped alot. I will go out and check and change what the website says... Hopefully I'll be able to get my fuel trims down..

Anyone else have any suggestions, or anyone with the same set-up I have?