GS - 2nd Gen (1998-2005) Discussion about the second generation GS300, GS400 and GS430 (1998 - 2005)

tuning issues

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Old 01-17-09, 07:09 PM
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fordsvtmfl
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ok..so i finally took my newly turbo'd car for a spin (untuned, the only thing was that i had added the 9% fuel to compensate for the 3" maf pipe, and i clamped the maf at 4.7v) it ran beautifully for about 20 min, (i only took it up to under 4psi, cuz the AFR seemed alright 12-13ish around 3000-3500k) well, then i blew a pipe that wasnt tight enough...so we checked it out, and then drove back home..and then it started to idle REALLY rough...so i connected the pipe back, and it still is really rough...any ideas? it seems like the maf is fighting my fuel increase...whats up?
also could someone explain the maf clamp idea better to me? i kinda understand it...but how do i know when my maf has stopped adjusting the AFR for me? and what is an unsafe AFR (rich and lean) cruising, flooring it, and at idle?
Thanks
Old 01-17-09, 07:24 PM
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fordsvtmfl
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also...could someone explain fuel trims?
Old 01-17-09, 08:52 PM
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fordsvtmfl
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well...i think i found out what might be the problem...i accidentally had bank 1 sensor 2 in the place of bank 2 sensor 1.... i think that would make sense...cuz it would run fine..and then randomly get to the point to where it was barely drivable, bucking all over the place..but my AFR stayed pretty much the same...anyways..i hope thats it..im gonna check it out tomorrow (another thing..if i let it cool down for like 10-15 min, and its like 20 out side, but the temp gauge in the car is still at nomal operating temp...anyways..it runs fine..and then after driving for 10 min it freaks out...if anyone has any other ideas...let me know..
Thanks
Old 01-17-09, 09:03 PM
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macd7919
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12-13 isn't really a safe afr, you should be tuning for about 11:5 under boost, anything higher then that is asking for trouble eventually.

As far as the car running funny, I can't comment on the swapped sensors or how it would effect the car. If you switch them and you still have trouble it sounds as though you are running in open loop and then switching to closed loop.

Closed loop is where the car while start to fight you. It's not just a couple minute thing however, the car will ALWAYS be fighting your tuning everytime you drive it and you will constantly be making small changes to the tuning. The only way to eliminate the computer altering your tuning us to totally take the factory fuel control out of the equation with a Haltech/Aem etc...

Welcome to the downside of na-t.

Last edited by macd7919; 01-17-09 at 09:08 PM.
Old 01-17-09, 09:10 PM
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fordsvtmfl
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Originally Posted by macd7919
12-13 isn't really a safe afr, you should be tuning for about 11:5 under boost, anything higher then that is asking for trouble eventually.

As far as the car running funny, I can't comment on the swapped sensors or how it would effect the car. If you switch them and you still have trouble it sounds as though you are running in open loop and then switching to closed loop.

Closed loop is where the car while start to fight you. It's not just a couple minute thing however, the car will ALWAYS be fighting your tuning everytime you drive it and you will constantly be making small changes to the tuning. The only way to eliminate the computer altering your tuning us to totally take the factory fuel control out of the equation with a Haltech/Aem etc...

Welcome to the downside of na-t.
i am using a aem fic, and i was told the point of the aem fic over the neo is that its supposed to be made so that your ecu does not fight you...

Last edited by fordsvtmfl; 01-17-09 at 09:14 PM.
Old 01-17-09, 09:33 PM
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I just read the quick description of the unit and it says that it works alongside your stock ecu, which would make it a piggy back. While it does offer more tuning options than the afc it's still using your factory MAF for a signal etc...The whole thing about it being able to adjust the maf signal is the same as what an afc does, it intercepts the maf signal and alters the voltage to trick the ecu into seeing increased/decreased air.


From what I can tell just from a quick scan is that the AEM FIC is basically just an Afc with the ability to run significantly larger injectors by cutting the pulse going to them. That's really not your problem though, no matter how much you modify the signal from the MAF the car is always going to be searching for a fuel ratio of say 14:1(just an arbitrary number here to make a point) You can tune the car to run at 11:5 but as long as the car reads 11.5 it's always going to be making adjustments in order to make the car hit 14. In order to get that the car will alter the long term fuel map over and over again in order to counteract any changes you have made.


Unfortunately the only way to get around this is by taking the factory ecu COMPLETELY out of the fuel loop and running an AEM EMS/Haltech as I mentioned before. Either of those options uses a dedicated pressure meter (map sensor) to determine fuel response. Since it uses a dedicated system of it's own the factory ecu isn't even connected to the injectors and has zero control over changing the way the car is tuned even if it wanted to.


If you would like more info try searching the IS forums, they have tried and tried and tried to bypass to tune with the factory computer but nothing has worked. In the end everyone will tell you that Haltech is the way to go. That's one of the major issues with NA-T, tuning is a nightmare without a standalone, I'm surprised you didn't come across that in your research before taking on the project. A Haltech can be had for around $1200 with the sensors and harness and is user programmable if you are familiar with EMS tuning, if not you will be looking at about another $500 for a good tune from a reputable shop. That will have your car up and running the right way and get rid of the tuning headaches that come with NA-T.

Btw- I can't recall what you were planning to run boost wise but have you replaced your pump and done a return line yet? What size injectors are you running as well?

Last edited by macd7919; 01-17-09 at 09:36 PM.
Old 01-17-09, 09:39 PM
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i researched a ton before i bought the fic, and was told by a few different ppl that have the fic, that it was the way to go for 8psi, and that it would not fight my tune like the neo. and i have also read fic tuning instructions from the IS forums, and there seem to be plenty of ppl that have made it work fine...i know its a piggyback..but have you ever used the fic? no offense..but if not..i dont think you should jump to conclusions saying it will not work..IMO
ive read tons of post of ppl who have made it work...so unless they all lied...
Old 01-17-09, 10:51 PM
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Originally Posted by fordsvtmfl
i researched a ton before i bought the fic, and was told by a few different ppl that have the fic, that it was the way to go for 8psi, and that it would not fight my tune like the neo. and i have also read fic tuning instructions from the IS forums, and there seem to be plenty of ppl that have made it work fine...i know its a piggyback..but have you ever used the fic? no offense..but if not..i dont think you should jump to conclusions saying it will not work..IMO
ive read tons of post of ppl who have made it work...so unless they all lied...
No, I haven't used the FIC but I have built over 20 Turbo Gs/Is's and I know what works and what doesn't.

As I said, I did a quick read over it. Since you have researched it then I would be interested to hear how it's different than a Neo as far as working better for the Gs application.

Also, before you dismiss me as jumping to conclusions remember that you are the one who is having trouble, not me. My car has been done and on the road for the last three year along with all the other's that I worked on, without issue. You asked for help and I'm answering your question, I understand it may not be what you want to hear but that doesn't make it the wrong answer. I've been there with AFC's, Custom piggybacks, Greddy E-Manage, Map Ecu, Haltech and AEM. I have a good understanding of how each works.

As I said before, I haven't personally used the FIC so if you have researched it as you said please educate me on what makes it different than the way an afc works.

Last edited by macd7919; 01-17-09 at 11:11 PM.
Old 01-17-09, 10:53 PM
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currently my car boost fine. i hav not plugged in the fic yet...what i did was i had to relocate the o2 sensors. weld 2 on the turbo manifold and 1 on the turbo exhaust and 1 near the cat..i.ve been running this for the past 3-4 months and it still runs like stock til i hit boost...i'll put in the fic when i switch out the injectors and tune
Old 01-18-09, 04:29 PM
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gs30062-1
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your target afr under boost should be 11.5 and that all should be done with the fact ecu in open loop. the "fighting back" issue is when people are trying to adjust afr when the fact ecu is in closed loop the fact ecu will just trim fuel to its target AFR. Are you running bigger injectors?
Old 01-18-09, 05:16 PM
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Originally Posted by gs30062-1
your target afr under boost should be 11.5 and that all should be done with the fact ecu in open loop. the "fighting back" issue is when people are trying to adjust afr when the fact ecu is in closed loop the fact ecu will just trim fuel to its target AFR. Are you running bigger injectors?
That's correct but the factory ecu is only in open loop when the car is still cold etc...once it's up to operating temperature etc...then it goes to closed loop where it runs of pre-based maps. I'm sure that's what you were getting at but I just wanted to make it clearer to other readers.

I'm still looking forward to hearing about how the FIC is different than the AFC for this application. It would be nice to have an alternative to standalone fuel setups, but I guess we will have to wait until Ford responds to find the differentiating features.

Last edited by macd7919; 01-18-09 at 05:21 PM.
Old 01-18-09, 05:35 PM
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i dont know the technical reasons why it is different (i dont know how the other one's work...so even if i knew everything about the fic i still couldn't answer your question) but now that i switched the o2's its running perfect, now i just have to tune the AFR at WOT
Old 01-18-09, 05:52 PM
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gs30062-1
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MACD7919 you are way off!! yes when the car is under a set coolant temp it will be in open loop this is when it runs on a set map. Once warmed up it will go into closed loop where it will now use base map+fuel trims. Now under high load the car will go into open loop this is where in your map you will tune.
Old 01-18-09, 06:19 PM
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Originally Posted by gs30062-1
MACD7919 you are way off!! yes when the car is under a set coolant temp it will be in open loop this is when it runs on a set map. Once warmed up it will go into closed loop where it will now use base map+fuel trims. Now under high load the car will go into open loop this is where in your map you will tune.

I don't know what you mean by "way off" as your are just repeating the same thing I said in my previous post, though I didn't mention full throttle so I guess we agree?

Anyways, your issue isn't going to be with full throttle as you only spend a fraction of your time driving at this position. The long term map for everything but full throttle is whats going to be a constant battle, that is, everything that affects driveability is where the true issue is. For instance, anytime you want to merge into traffic/accelerate etc....under boost but not mashing the gas will be an issue as the car is always going to be fighting you for a lean condition. As the long term maps are altered you will continue adding fuel to the map just to stay under A/F curve. Either way, it's been a much discussed topic for years on the Is boards.

As far as your target A/F's. You should be looking for about 11.5 under WOT, at idle you can run around high 16's-17:1 and cruising generally high 15's-16:1 as there is hardly any load on the engine. Once you get your idle and light cruising down you basically just street tune incrementally for load/throttle position and work your way up. For example, once you get the car running fine under light throttle/vacuum just do some light pulls (15% throttle for instance) under boost until the car starts running lean (anything above low 12's). The just increase the fuel a little bit and repeat until you can make a clean run etc....working your way up to full throttle. Under partial throttle you will be safe running a little leaner than WOT so you could safely aim for low-mid 12's.

Also, as mentioned before, whats your fuel setup? Injector size? Pump? etc....

Last edited by macd7919; 01-18-09 at 06:22 PM.
Old 01-18-09, 06:53 PM
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Nope closed loop is map plus trims, open is map only. It seems you dont comprehend how a factory ecu works or the point of a piggyback. in closed loop the ecu's target will be 14.7 so when doing what Ford is you only set up for the injector change then you dont mess with any areas of the map that will be in closed loop thus keeping drivability of the factory ecu. and only tune in open loop areas. if AFR needs to be changed in a closed loop area you have to alter o2 signal
Originally Posted by macd7919
I don't know what you mean by "way off" as your are just repeating the same thing I said in my previous post, though I didn't mention full throttle so I guess we agree?

Anyways, your issue isn't going to be with full throttle as you only spend a fraction of your time driving at this position. The long term map for everything but full throttle is whats going to be a constant battle, that is, everything that affects driveability is where the true issue is. For instance, anytime you want to merge into traffic/accelerate etc....under boost but not mashing the gas will be an issue as the car is always going to be fighting you for a lean condition. As the long term maps are altered you will continue adding fuel to the map just to stay under A/F curve. Either way, it's been a much discussed topic for years on the Is boards.

As far as your target A/F's. You should be looking for about 11.5 under WOT, at idle you can run around high 16's-17:1 and cruising generally high 15's-16:1 as there is hardly any load on the engine. Once you get your idle and light cruising down you basically just street tune incrementally for load/throttle position and work your way up. For example, once you get the car running fine under light throttle/vacuum just do some light pulls (15% throttle for instance) under boost until the car starts running lean (anything above low 12's). The just increase the fuel a little bit and repeat until you can make a clean run etc....working your way up to full throttle. Under partial throttle you will be safe running a little leaner than WOT so you could safely aim for low-mid 12's.

Also, as mentioned before, whats your fuel setup? Injector size? Pump? etc....


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