I have a MAPECU that I just installed and I also have a Apexi SAFC (first version i believe), I am thinking of installing the SAFC, but now I am wondering if it is useless, does it do anything that the MAPECU doesnt do? Please give me some advice, the car is running rich and I need it fixed with the least amount of complication
MAP-ECU Tuning
- Thread starter kapkaniMD
- Start date
The SAFC won't be worth it if you have the map ecu. MAP ECU is much more powerful, whereas the SAFC will basically just change the AFM signal. Since you aren't using the AFM anymore and the MAP ECU will control all your fueling, no point in keeping the SAFC.
staticpat said:
I havent really done that much work on it yet, but for some reason the SAFC seems like it would be a lot easier to tune, does anyone have any experience with both that can give me pointers on correcting air/fuel ratio on either one
the safc is a lot more simple to use all you are doing is altering the afm signal and telling the computer to add or subtract fuel, the map ecu eliminates the afm by taking Manifold Absolute Pressure and converting it into an Afm voltage that the stock computer can recognize. you need a laptop to use the mapecu and IMO the safc is a better piggy back, the map ecu was frustrating to tune and does not have large enough parameters I.E. it only goes to -10 psi so you will tune some points for two different driving conditions. i can tune a car with an Safc in about 20-25 minutes street driving, the map ecu took a full day to get the car even drivable. If you want to safely and efficiently eliminate the AFM you should go standalone.
boostadikt said:
The AFC adjusts fuel at 8 RPM points and has high & low throttle adjustments. It isn't aware of boost or vacuum at all. It's a primitive tuning device.
The MAP-ECU adjusts fuel on a three dimensional 256 data point table that is dependent on both RPM and boost to determine the adjustment.
The S-AFC is a toy compared to the MAP-ECU. How you come to that conclusion you posted above is beyond me. It's ignorant.
An 4 stroke internal combustion engine at IDLE produces about 20 inches of mercury in vaccum. This is true in a 4 cylinder Civic, a Supra or a Viper V-10. When you convert that 20 inches of vac to psi you get -9.82 psi.
This is why the MAP-ECU goes to -10 PSI. Anything below that is 100% closed throttle and there's not tuning to be done. Your statements are not only false, they are, to be blunt, rather stupid.
I'm really baffled by what you posted. Yes, the S-AFC is easy. It's also primitive and crude. The MAP-ECU has a lot more tunability in it. The MAP-ECU can be tuned for every boost level from 1 psi to 30 psi. A S-AFC is tuned for a single boost level. If you change the boost you have to re tune the car.
Of course it takes longer to tune 256 data points instead of 8.
Telling someone to go standalone is once again, ignorant. Standalone has it's time and place, but with our cars that's generally north of 500 RWHP.
Supracentral said:
Alright, sweet, you sound like you know what you are talking about, is there anyway you can simplify the process of tuning with the MAPECU, or know where I can get some better instructions. I know that its not a toy and should be done professionaly, but anything can be simplified. If there is any pointers you can give that would be helpful. I have already uploaded the appropriate data file on my ecu (the preset 550cc file) however my car has a larger turbo and is still running rich. I can give you all the details you want just let me know, Thanks :wave:
kapkaniMD said:
The map is pretty easy to understand. It's correction, by RPM @ a specific boost level:
So for example, if you want to see the value used at a 4500 RPM @ 10 PSI, you'd look here:
If you watch a live pull, where it shows you which square it's using, you'll see a pattern like this, for example:
If those are the cells you are hitting at this specific boost level (10 psi in this case) you only worry about changing those cells to smooth out your A/F curve.
There are also areas of the map you will NEVER use. For example if your turbo can't make boost under 2000 rpm, the cells crossed out below would never be used:
Another way you can view the map is graphically. One thing that is important is that it is smooth looking. If there are large changes between cells, you've got the tune wrong an the TCCS will fight you on it. If you have "follow" turned on while you make a pull, you'll be able to see which cells it is using in this view as well:
Tuning with a MAP-ECU takes a lot more finesse than with other systems. You kind of have to have a knack for it. Some people have an easy time, others struggle. I will forewarn you though that tuning a karmann vortex car (ie. - MKIII Supra) on one if these is a real pain in the ass. Cars with AFM's (ie - MKIV Supra) are a lot easier.
One thing that will really mess you up is Vf. If you don't tune for Vf you are toast. The ECU will keep tuning out your changes. This goes for ANY piggyback, not just the map-ecu.
By using a system called LEARNED VALUE {Vf} or the FUEL TRIM correction system. The TCCS uses its best guess or BASIC FUEL CALCULATION plus a +/- 40% floating correction factor determined by the LEARNED VALUE Vf system to give the engine the correct required amount of fuel under all conditions.
This + or - correction amount is controlled by an active control system in the TCCS called the LEARNED VALUE SYSTEM, Vf fuel trim. Under this system the TCCS uses two types of fuel trims called the long and short fuel trims.
The LEARNED VALUE Vf system is used by the TCCS during both open and closed loop operation to fine tune the fuel control to the engine in relation to engine wear, sensor shift and other problems such as combustion leaks and intake air leaks.
This long and short fuel trim is an automatic on the fly correction system that uses the engines sensors to add or subtract fuel from the BASIC FUEL CALCULATION to keep the fuel mixture going out the tail pipe on target under the fast and slow changing engine conditions, examples: Hot, Cold, idling, redline, wear in cylinders and head, or any number of engine operation conditions.
The current amount of fuel correction the long and short fuel trims systems are adding or decreasing from the BASIC FUEL CALCULATION can be read by reading the voltage coming out of the TCCS's Vf data output terminal in the diagnostics connector under the hood of the Supra. The Vf line feeds five stepped voltage values of 0,1.25, 2.5, 3.75, 5.0 volts. Each step in voltage is an indication of the amount of fuel trim to the BASIC FUEL CALCULATION that is taking place. The TCCS will always output one of the five voltages to the Vf terminal in the diagnostics connector under the hood. The voltage is measured at anytime between the E1 and Vf pins in the diagnostics connector when E1 and T1 are not shorted. Remember that the voltages are stepped in 5 levels as mentioned above! Depending on your car you may see 3.5 volts rather than 3.75 volts, this is normal and you can ignore the difference in the voltages.
The whole goal is to tune the system so that the Vf data is normal while getting the car to do what you want it to.
No mater what you set any piggyback to in closed loop mode the ECU will compensate back to 14.7 until you max out the ECU's capabilities. The best bet is to tune everything under 4000 rpm to Vf and then use the piggyback after 4000 RPM in open loop to get the right tune.
Since you are tuning over 4K and only at boost, you pretty much will wind up doing most of your tuning in the area indicated below:
It really is best left to someone with a lot of experience in it. That goes for the S-AFC as well. If the guy tuning your car isn't working with Vf, he doesn't know what he's doing and you should find someone else. Any idiot can get a car to run right with a S-AFC for a short time. Getting it running correctly in the long term is far more difficult.
Tread very lightly until you learn quite a bit about the way things work. Everything you need to know is on this site. And the people who wrote the FAQ's and tech-tips you find around the Internet for this car are (for the most part) on this site as well.
Start reading, and when you get stuck, start asking questions. If you really want to do this yourself, and to do it correctly and safely, you need to learn a LOT before touching a single setting.
Ok, I think I am starting to get this, say I am running rich for the whole rpm curve, then if you use the table adjust by % it will fix all of this correct?? Can you just insert an A/F ratio and it will adjust the curve automatically? Also to confirm, the higher the value in the table the more fuel?
For the purposes of my car, I am not trying to extract as much horsepower as possible, i am only trying to get the car running normally
I also have the HKS FCD, is this also useless and replaced by the MAPECU or should I hang on to it
For the purposes of my car, I am not trying to extract as much horsepower as possible, i am only trying to get the car running normally
I also have the HKS FCD, is this also useless and replaced by the MAPECU or should I hang on to it
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With the correct injectors and a map-ecu, you won't need that FCD.
I really dislike FCD's. That device is a signal clamp. I limits the peak output of your airflow signal.
Let's say you set your FCD to setting X. What that does is tell the FCD, pass the AFM (or map-ecu / s-afc) signal to the computer until it exceeds value X. If it's over value X, just keep telling the computer it's X.
Dangerous little toy. I NEVER use them.
I really dislike FCD's. That device is a signal clamp. I limits the peak output of your airflow signal.
Let's say you set your FCD to setting X. What that does is tell the FCD, pass the AFM (or map-ecu / s-afc) signal to the computer until it exceeds value X. If it's over value X, just keep telling the computer it's X.
Dangerous little toy. I NEVER use them.
kapkaniMD said:
Yes, and yes. But make VERY small changes at first until you get a feel for it. Make frequent backups of your map as well so you can drop back to them. Keep notes with each map as well (I usually keep a .txt file with the same name as the map to store notes in).
kapkaniMD said:
Ok, riddle me this:
Which turbo do you have?
What size injectors?
Which fuel pump?
What is your base fuel pressure?
Which fuel pressure regulator are you using?
What other fuel system mods do you have?
Intake and exhaust modified?
If we know all this upfront we can give you better answers.
ANSWERS ARE ABOVESupracentral said:
I just bought this car and I got it as it was and the car wouldnt start at all, I got all that fixed and now am ready to tune in as it was just rebuilt and the turbo has never been run on the car yet, it has been bypassed, it is a '91 targa if that matters, it also has a lot of other work done if you are interested let me know
i missed this, when tuning for vf: zero volts is rich, and the ecu is pulling fuel to achive 14.7? and 5 volts is lean?
yeah i was correct,
i couldn't belive how far i had to pull fuel on the ve table to get the vf to raise off zero, let alone start going lean, but once i got there i had a pretty consitant vf, hardly went lean at all, but would still drop down and be rich while driving aroudn a bit,
/sorry not trying to thread jack.,.
yeah i was correct,
i couldn't belive how far i had to pull fuel on the ve table to get the vf to raise off zero, let alone start going lean, but once i got there i had a pretty consitant vf, hardly went lean at all, but would still drop down and be rich while driving aroudn a bit,
/sorry not trying to thread jack.,.
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Vf is not something monitored by the map-ecu, or other piggyback computers. This is done usually with a voltmeter connected to a wire on the ECU.
If you look under your hood in the diagnostic block, you'll find a Vf1 pin.
The Vf1 output has three different types of Vf output.
1. Oxygen Sensor Feedback Mode.
* T1 and E1 Connected (In the diagnostic block.)
* Engine Running at 2500 rpm
Result of Ox sensor signal processing:
5v=Rich
or
0v=Lean or Open loop condition
_______________
2. Diagnostic Mode
*T and E1 connected
*Engine off
Results of Diagnosis:
5v=Normal, No trouble codes stored.
or
0v=TCCS Trouble code stored. View the 'Check Engine' Light, It will blink codes.
________________
3. Learned Value Mode
*T and E1 not connected
*Any operating conditions, RPM's, or speed.
The Vf line feeds five stepped voltage values of 0,1.25, 2.5, 3.75, 5.0 volts
Meaning: Result of Air-Fuel ratio voltage feedback
Learned Value: It is a fuel injection correction coefficient which tailors the standard fuel injection duration to minor differences between engines due to manufacturing tolerances, wear, and minor mixtures disturbances like small vacuum leaks.
This coefficient is capable of altering the calculated injection {before Ox correction} by as much as 20% to prevent Ox sensor correction from being excessive.
If you encounter a driveability problem that sets number codes, this Vf voltage feedback can be of some help, especially code 25/26. (engine condition rich or lean)
_______________
Note:
If you look under your hood in the diagnostic block, you'll find a Vf1 pin.
The Vf1 output has three different types of Vf output.
- o2 Sensor Feedback Mode
- Diagnostic Mode
- Learned Value Mode (<-- this is the one we are talking about for tuning)
1. Oxygen Sensor Feedback Mode.
* T1 and E1 Connected (In the diagnostic block.)
* Engine Running at 2500 rpm
Result of Ox sensor signal processing:
5v=Rich
or
0v=Lean or Open loop condition
_______________
2. Diagnostic Mode
*T and E1 connected
*Engine off
Results of Diagnosis:
5v=Normal, No trouble codes stored.
or
0v=TCCS Trouble code stored. View the 'Check Engine' Light, It will blink codes.
________________
3. Learned Value Mode
*T and E1 not connected
*Any operating conditions, RPM's, or speed.
The Vf line feeds five stepped voltage values of 0,1.25, 2.5, 3.75, 5.0 volts
Meaning: Result of Air-Fuel ratio voltage feedback
Learned Value: It is a fuel injection correction coefficient which tailors the standard fuel injection duration to minor differences between engines due to manufacturing tolerances, wear, and minor mixtures disturbances like small vacuum leaks.
This coefficient is capable of altering the calculated injection {before Ox correction} by as much as 20% to prevent Ox sensor correction from being excessive.
If you encounter a driveability problem that sets number codes, this Vf voltage feedback can be of some help, especially code 25/26. (engine condition rich or lean)
_______________
Note:
- Discard Vf reading when engine is cold- It will be fixed on 'Rich'.
- The Vf learned value tells you how hard the ECU is working to keep the engine running properly.
- After loss of power to ECU, it will take a certain amount of time to relearn, depending on the engine model and vehicle driving conditions.
- The ECU will learn faster if the input signals are stable- Water Temp, Air Temp, Throttle position sensor, Air, O2, etc..
- At high altitude operation, Vf can be 0v 'Lean' but it is considered to be normal. {lack of oxygen}
- Vf voltage can be "border line" also, flipping back and forth between 2 ranges.
Ok so when my MAPECU reads rich when I first start the car, do I ignore that and wait till it warms up or can I assume that it is running rich? Also I am using the powerhouse racing premade haness, there are also a bunch of extra wires, do any of these need to be hooked up at all??
Supracentral: Can you please comment on the info I gave you early about my car's mods and what I need to do
Supracentral: Can you please comment on the info I gave you early about my car's mods and what I need to do
great post supracentral.
any way you can add this info to dr.j's post here ? http://www.supramania.com/forums/showthread.php?t=39170
i think people would find it easier to find!
any way you can add this info to dr.j's post here ? http://www.supramania.com/forums/showthread.php?t=39170
i think people would find it easier to find!
kapkaniMD said:
You have to let the car warm up. Cold start is not a tunable condition.
kapkaniMD said:
If I recall correctly, Jarrett's harnesses have extra wires for other items. It's pretty much plug and play for a map-ecu.
kapkaniMD said:
I'm assuming that's the bosch inline pump? Do you know if the in-tank pump is stock? Has the J-tube been bypassed or bored out?
kapkaniMD said:
OK, I doubt it's stock, but anything is possible.
Take a look at this:
Take a look at your fuel rail. One of the above is attached to it, or connected to it via a hose. Which one?
kapkaniMD said:
If the FPR is aftermarket, it either has a gauge, or a port for a gauge. You've got substantial fuel system mods, you need a fuel pressure gauge.
pimptrizkit said:
Done.