F/IC MAF Volt Clamp?
#24
That about where I had everything set at. But I think I was running the MAF clamp at 4.5. I also had MAF table at 14%.
I had tons of bucking at 2800 RPM and 4500 RPM. I was logging AFR data and INJ duty cycle. At those 2 RPM points AFR and INJ duty went nuts.
I just pulled all of it out and put the FM voodoo back in.
The car just was totaled so I wont have a chance to find out why this was happening.
Chris L
I had tons of bucking at 2800 RPM and 4500 RPM. I was logging AFR data and INJ duty cycle. At those 2 RPM points AFR and INJ duty went nuts.
I just pulled all of it out and put the FM voodoo back in.
The car just was totaled so I wont have a chance to find out why this was happening.
Chris L
Why does the FIC need a voltage clamp? My xede works fine and it doesnt clam the MAF at all.
For now I returned to the xede until I can figure out what is going on.
#25
http://forum.aempower.com/forum/inde....0;attach=3700
- it explains the purpose of the MAF voltage clamp with the FIC.
http://www.xede.com.au/files/XEDE%20...20Version).pdf
Comparing these piggybacks is like comparing apples to oranges.
Personally since I was going to be the one tuning my car, I much preferred the more straight forward manner the AEMFIC handles fueling - by intercepting injector signal AFTER the ECU versus the Xede spoofing the MAF signal going INTO the ECU. See page 11 in the Xede tuning guide in regards to how timing is affected by changing the loads that the ECU sees. From FIC tuning tips: "Modern ECU’s can detect even the smallest changes in calibration of these signals." i.e. causing CELs and even having the ECU "fight back" your tuning. My thought was: why try to force or trick the ECU into doing something it's not programmed to do (Xede), when the ECU doesn't even need to know what is going on "behind it's back" (AEMFIC).
Many issues like bucking are ECU "fight backs".
The one thing the FIC itself does not do is advance timing, but you can use the FIC to spoof input signals to the ECU to get the ECU to advance timing....
You really need to know how different these two are and understand "how they work" before you start tuning...
Read everything you can get your hand on, digest, and really understand how this stuff works, and you WILL be successful at tuning & troubleshooting - that's how my dumb *** did it - of course with my education to all things turbo via miataturbo.net!
Good Luck...
Last edited by secretsquirrel; 04-13-2009 at 02:26 PM. Reason: Clarification...and props to the forum.
#26
I understand the difference in the units, it one of the reasons I wanted to change to the FIC.
Bad part is that I dont have a stock car to take original logs from. So Im having to start out tuning with 550cc injectors and a turboed engine.
Whats really getting me is Im having the bucking problems out of the boost area. Im just taking the car line by line on the fuel map and trying to tune it before going to the next level.
Do you thing that if i log the MAF voltage at high rpms and no boost, it would give me a pretty good place to set the Voltage clamp? I speaking of an equivalent clamp voltage of a non boosted car.
Bad part is that I dont have a stock car to take original logs from. So Im having to start out tuning with 550cc injectors and a turboed engine.
Whats really getting me is Im having the bucking problems out of the boost area. Im just taking the car line by line on the fuel map and trying to tune it before going to the next level.
Do you thing that if i log the MAF voltage at high rpms and no boost, it would give me a pretty good place to set the Voltage clamp? I speaking of an equivalent clamp voltage of a non boosted car.
#27
The MAF clamp voltage would be the highest voltage the ECU would see when normally aspirated (high rpm/high load). Tough to get that right with the turbo on the car even with wastegate trickery - the turbo will still be a factor, larger injectors are not. One thing though...how are you reading the MAF voltage? Through the ECU with scan tool, FIC live display, or FIC logger? It is the ECU that you want to keep happy...
#29
Just so you guys have a larger feedback pool to work with. I didn't even hook my F/IC upto the MAF as most of the other Miata tuning solutions don't either. Other cars need a clamp but the Miata doesn't, unless you are running more boost with the F/IC then you probably should be. The buck you are seeing upon entering boost is related to the o2 clamp. I had the exact same problem with my setup and to took a bit to work out. I don't have the files on this computer but, I'll try and post some images soon.
#31
Sorry about the delay I've been traveling ALOT! I created a thread with my cal file in it.
https://www.miataturbo.net/forum/t34968/#post407021
https://www.miataturbo.net/forum/t34968/#post407021
#33
So I have been playing with the car, if I set the MAF clamp to 3.38 I have problems with lean out under 3K rpm in low gear acceleration
If I set the MAF clamp to 4-4.5 I get the bucking at 3k
I really need a stock 2003 to take some reading from so i can set my base map up.
Is there a way to make to 02 map to not touch the 02 signal until in boost and then send a fake 14.1.
I see that I can set a fake voltage, where 0 is no change and a number is a voltage out.
Or I can set a pulse out, but I dont want to fake the 14.1 out of boost.
For now I think that I will set the fake 14.1 02 in all cells just to eliminate it from the tuning equation.
If I set the MAF clamp to 4-4.5 I get the bucking at 3k
I really need a stock 2003 to take some reading from so i can set my base map up.
Is there a way to make to 02 map to not touch the 02 signal until in boost and then send a fake 14.1.
I see that I can set a fake voltage, where 0 is no change and a number is a voltage out.
Or I can set a pulse out, but I dont want to fake the 14.1 out of boost.
For now I think that I will set the fake 14.1 02 in all cells just to eliminate it from the tuning equation.
#38
I think that I am going to pull the MAF connection off the FIC. I have tried all values between 13-16% and I run into the same problem every time. At idle I can get a perfect fuel trim, but around 5000 rpm the car is rich.
I noticed that as i pass 3K rpm the car will start to jump to rich - it appears that this is when the car is moving out of closed loop. The AFR will slowly drop until Im at 10.1 at 7K rpms. To fix this i had to make my fuel map remove more fuel as the RPMs more up.. I only talking about in vacuum at the moment.
Looking at my logs my MAF signal has increased over half a volt in the upper range do to the added 13%, I have a feeling that this is not right and the correct way to do this is to start at idle with 13% and reduce down towards 0% as you start to reach 5volts from the MAF.
I agree with another user on the forums that left his MAF disconnected from the FIC.... if it is not doing anything why added to the pool of variables. Later if I decided to simulate the MAF I will rewire it back in, but at least I can then know if it is a MAF table that needs to be fixed vs a fuel and/or MAF table combined.
Being an Xede user I can tell you that the ECU doesn't require a voltage clamp, the xede would some times add 5% to the MAF to get the correct fuel, So I'm sure that there is plenty of MAP on the Factory ECU to handle the MAF under boost.
I will post my cal once I have something worth presenting.
I noticed that as i pass 3K rpm the car will start to jump to rich - it appears that this is when the car is moving out of closed loop. The AFR will slowly drop until Im at 10.1 at 7K rpms. To fix this i had to make my fuel map remove more fuel as the RPMs more up.. I only talking about in vacuum at the moment.
Looking at my logs my MAF signal has increased over half a volt in the upper range do to the added 13%, I have a feeling that this is not right and the correct way to do this is to start at idle with 13% and reduce down towards 0% as you start to reach 5volts from the MAF.
I agree with another user on the forums that left his MAF disconnected from the FIC.... if it is not doing anything why added to the pool of variables. Later if I decided to simulate the MAF I will rewire it back in, but at least I can then know if it is a MAF table that needs to be fixed vs a fuel and/or MAF table combined.
Being an Xede user I can tell you that the ECU doesn't require a voltage clamp, the xede would some times add 5% to the MAF to get the correct fuel, So I'm sure that there is plenty of MAP on the Factory ECU to handle the MAF under boost.
I will post my cal once I have something worth presenting.
#39
So pulling the MAF connection made it a little easier to tune, but my car still has the rich spike right at 3K RPM and its perfectly fine after 3500
Dont know whats going on, but with out the MAF connected the spikes are much smaller that I cant feel them while driving.
Did notice some RPM spikes in the logs, dont know what that it all about, but it may be my problem.
Dont know whats going on, but with out the MAF connected the spikes are much smaller that I cant feel them while driving.
Did notice some RPM spikes in the logs, dont know what that it all about, but it may be my problem.
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