New to SAFC need some help

[TotalEclipse112]

Ok heres whats going on, my car is a 91 Talon AWD AUTOMATIC (just putting that out there so I don't get 5 speed type responses.). Got the car real cheap because the previous owner, had it at 3 shops and they couldn't figure out why the car was running so rich. Also since its an auto I have no big plans for it just to use it as a winter beater. Now when I began trying to figure out the original problem as to why it was running rich, I was looking through a stack of repair receipts the guy I bout it from gave me and discovered the ECU took a dump and he had it replaced. Unfortunatly when it was replaced some dummy put a manual ECU in it so there was the source of the problem. Unfortunatly with that ecu in it the stock 390cc injectors were working at max duty cycle since the ECU thought they were 450cc injectors fryed them. So I found an automatic ECU and replaced that, and since autos are harder to find parts for I picked up a set of 450cc injectors and a SAFC from a kid at school for $170.

Now with everything installed and the car idiling correctly now the car feels like a slug, I suspect its still running rich and I want to tune it out with the AFC but am a bit confused. I read the tech articles and they just confused me more. Here is how I have the AFC set up: Low throttle 25% High throttle 45%, RPM points set at 1000 RPM, 2000 RPM, 3000 RPM, 4000 RPM, 5000 RPM, 6000 RPM, 7000 RPM, and 8000 RPM, and the correction is set at -4% accross the board for both high and low throttle. Everything on the car is stock except the above mentioned modifications, a hacked air can, and the lower honeycomb is removed from the MAF (I didn't do it that how it was when I got the car).

Now in a span of 60 miles, mostly highway, I used about a quarter of a tank of gas which isn't much better than my mustang or my wifes Durango for that matter, so I belive it is still dumping a ton of gas in the cylinders. Now my question is does anybody out there have any experince with an AFC on an auto that could tell me how they have theirs set up or give me some information that would help me tune this thing better? Thanks in advance.

Also sorry for such a long post just wanted to make sure I got all the pertinent facts out there.

 

[spyderturbo007]

Couple of things before we get started:

Do you have a logger? If not, you really need to pick one up. Tuning with the "butt dyno" doesn't work very well.

Change your Lo throttle trigger point to 30% and the Hi Throttle trigger point to 80%. You really don't want the SAFC to jump on the Hi Throttle map at 45% on the TPS.

I am hesistant to give you any more information than that, as without a logger, we could actually do some harm to the car. And I can't stand to see an injured DSM.

 

[TotalEclipse112]

Thanks for the info its a start but I really need to tune the car. I'll change the map and take it from there. But as for the logger, its kind of out of the question moment, due to a couple of facts, first off it needs both rear pads an rotors replaced desperatly, and secondly I just purchased $5000 woth of tools last month so I'm a bit short on cash, at least till I get my firs paycheck. So at the moment I am stuck tuning with the 'ol butto-o-meter till I can get a logger. As for hurting the car I'm not really too worried about that because it was a $1000 and when I bought it didn't even run right, had a donut on the front and the drivers side door was ripped off of it. So pertty much what I am saying is I need a rough ballpark place to set my correction for the time being for driveablity sake and I and when I get a logger, maybe after christmas, I'll fine tune it then. Thanks.

 

[calcifer]

You can get a cable and a compatible palm on ebay for about $50, there's no reason not to get one even if you did only spend $1000 on the car.

 

[TotalEclipse112]

OK I don't want to get off topic here and start discussing my financial situation, and why I don't have $50 to get a logger. Once again I spent Five Thousand dollars on tools last month and barely have enough to pay this months bills, let alone get a logger for my winter car.

I'll probally get a logger after the first of the year, after I replace the breaks on the car, and get a new set of tires to replace my poor man's slicks.

Now where do I need to set the AFC, ball park area, to get it to stop runnig so rich? I'll fine tune it after I get a logger.

 

[5150DSM]

If I understand you correctly... You are running 450cc injectors and an automatic ECU with a SAFC, your only mods being a hacked aircan and lower honeycomb removed? If this correct then a little simple math should put you in the ball-park. The stock injectors for your car are roughly 14% smaller(in flow) then your current injectors and though it does not translate exactly, a -14% on the AFC should put you near stock flow. Also, further compensation is needed to off-set the hacked air-can, generally speaking this is an additional 5-8%.
I would start by adjusting the SAFC to -15%, then go for a test drive, from there just adjust it in 1-2% increments until you find a spot that "feels" good to you. You won't have it exact until you can log your results and work from there, however, this should get you in the area.
Aloha

 

[kraka]

whoa whoa whoa...Just to get things straight...Have you checked the 02 sensor?? I know that you need tuning from the larger injectors, but still, if you are that incredibly rich than a lot of times the 02 sensor is the culprit

 

[TotalEclipse112]

whoa whoa whoa...Just to get things straight...Have you checked the 02 sensor?? I know that you need tuning from the larger injectors, but still, if you are that incredibly rich than a lot of times the 02 sensor is the culprit

No need to, the last of the three shops they previous owner took the car to thought the same thing and replaced it, and I belive him since I drink with the mechanic that did the work on the weekends. I have the receipt to prove it. Thanks anyways.

If I understand you correctly... You are running 450cc injectors and an automatic ECU with a SAFC, your only mods being a hacked aircan and lower honeycomb removed? If this correct then a little simple math should put you in the ball-park. The stock injectors for your car are roughly 14% smaller(in flow) then your current injectors and though it does not translate exactly, a -14% on the AFC should put you near stock flow. Also, further compensation is needed to off-set the hacked air-can, generally speaking this is an additional 5-8%.

I would start by adjusting the SAFC to -15%, then go for a test drive, from there just adjust it in 1-2% increments until you find a spot that "feels" good to you. You won't have it exact until you can log your results and work from there, however, this should get you in the area.

Thanks I'll try that tommorow. That was exactly what I was looking for. I was trying to figure out precentage wise how smaller the stock injectors were but math was never my strong suit, after all I'm a mechanic/welder, not an math wiz. Thanks again.

 

[spyderturbo007]

Thanks I'll try that tommorow. That was exactly what I was looking for. I was trying to figure out precentage wise how smaller the stock injectors were but math was never my strong suit, after all I'm a mechanic/welder, not an math wiz. Thanks again.

Equation:

[(Old injector size / new injector size) - 1] * 100 = Baseline SAFC-II correction factor

So in your case:

[(390 / 450) - 1] * 100 = -13.3%

I would go with, like 5150dsm, about - 15%. I would like to see you leave it there until you get a logger. You will still be running rich, but not pig rich like you are now. This allows for the "every car is different" fudge factor.

 

[5150DSM]

Glad to be of help.
Post some data when you do pick up a logger and we can help you to fine-tune the vehicle.
Aloha

 

[TotalEclipse112]

Thanks for the help once again, once I get a logger for the thing I'll let you know how it works out. Thanks again.