FIAV and ISC block off plate cold start idle fix.

[MrCup]

so i put a FIAV and ISC block off plate (Made my self) on my car (97 gst with 98 ecu). the idle works like a dream when it is at running temp but any temp below that it idles vary low. I know if i put the isc back on and just block off the FIAV it will most likely work right. i don't want that big hunk of junk on bottom of my TB. I live in Tempe, AZ it doesn't get ti freezing here so i should be just fine with out it. does anyone know how i can make it idle right at 850 with out the ISC when its below running temp? i have ceddy flashed.

my first idea is to trick the ecu into thinking that it is running at running temp all the time. i would do this by unplugging the coolant temp scencer and putting in a resister (300 ohm) sense thats the way the thing works. leave the coolant sending unit pluged in so it will still read on the dash. if it wont read on the dash i have a gauge that i can install to give me the temp of the car.

now with all that said the bad thing is that if the car does get hot then the fans wont kick on. so if i have to i can put in a two way switch and on one side have the resister for running temp and on the other side have a resister for little more then running to make the fans kick on.

really i would like to avoid all this by changing settings in ceddy to make it idle right. so if anyone has an idle on how to do that it would be great help!!!

PS i tryed to post this in the tunning part of the forms but it would't let me thinking because this is my first thead.

thanks for the help!!!

 

[motomattx]

If your injector size and deadtimes are right it should idle cold ok, unless you have those janky ford 1700cc injectors or some other huge injectors that run under 1.2ms of injector pulsewidth at idle. You can try turning your warm idle up to 1000 rpm to assist low pulsewidth on big injectors.

 

[MrCup]

If your injector size and deadtimes are right it should idle cold ok, unless you have those janky ford 1700cc injectors or some other huge injectors that run under 1.2ms of injector pulsewidth at idle. You can try turning your warm idle up to 1000 rpm to assist low pulsewidth on big injectors.

i have stock injectors. thinking i can adjust the timing and fuel to fix this. with out tricking the ecu.

 

[motomattx]

Well the isc and fiav are there to make the stock system idle when its cold, when you remove those then guess what happens? I would try getting the idle at 1000 rpm first, it will allow the injectors to flow better at idle.

 

[MrCup]

There is nothing wrong with the flow of the injectors. i have run evo scan on the car and all is working right. I truly think that the car is getting too much gas. when the isc is in the car it opens to allow more air to flow through and if the car is getting more air then it needs more fuel just like when you are pushing on the gas petal. but sense i removed the isc that air isn't getting into the intake but the ecu still thinks that it is still there and allowing air. so it is still adjusting the timing and adding fuel. so if i change the warmup fuel table and the warmup timing table to the same settings as the normal table then the car should run the same way as it does once it is warm.

 

[kchaazz]

Thats not really the way it happens, unfortunately, as any air entering the motor has already been measured by the maf and will be compensated for accordingly. In the end, all the ISC and FIAV valve do is allow more air to get into the intake manifold without you cracking the throttle plate. Most who have done away with the idle control system as you have experience the same issues youre having.

 

[MrCup]

Thats not really the way it happens, unfortunately, as any air entering the motor has already been measured by the maf and will be compensated for accordingly. In the end, all the ISC and FIAV valve do is allow more air to get into the intake manifold without you cracking the throttle plate. Most who have done away with the idle control system as you have experience the same issues youre having.

yes it has been measured by the maf but that has nothing to do with the air getting past the TB. and the fact the car is using a warm up table when the engine temp is below a specified temp in the ecu that says when engine is below that temp make the isc open and let this X amount of air through and add this much extra fuel (12.7 afr) according to my evo scan. and change the timing this much looks like -1 to -2. then when the engine gets to or above X running temp change to using just the normal fuel and timing map. i dont have a picture i can post right now (at work) but after i get home i will post one and maybe that will make it easier to understand.

 

[kchaazz]

I am familiar with the "warm up" maps and how they are used, and understand what you are referring to. You can try to lean them out to stoic, but it may make the car run even worse. The reason it adds extra fuel and the idle is high is to warm the motor up as quickly as possible. It takes more fuel to start and run a cold motor, but maybe if you lean it to, say, 13.7 in that area, maybe itll help. Ive ran the throttle body on my own cars in several configurations over the years, and I just prefer the seamless driveability of a properly functioning idle control system.

 

[motomattx]

This guy wants to reinvent the wheel I guess . O/P do you think that the factories add all of those parts to the throttle body just to waste money? they are there for a reason. If you do as I said and raise the idle to 1000 rpm it might just not stall on you, I run the same setup. When I talk about getting your injectors to flow better I am talking about getting the injectors up above 1.2 ms of pulse width with the higher idle speed, most injectors work better in that area.

 

[MrCup]

This guy wants to reinvent the wheel I guess . O/P do you think that the factories add all of those parts to the throttle body just to waste money? they are there for a reason. If you do as I said and raise the idle to 1000 rpm it might just not stall on you, I run the same setup. When I talk about getting your injectors to flow better I am talking about getting the injectors up above 1.2 ms of pulse width with the higher idle speed, most injectors work better in that area.

most of that stuff was put there to meet the standards of emissions or to help the car to stay running because emissions. I don't have to deal with that stuff were i live most of this stuff is no longer needed. i am not trying to reinvent the wheel trying to improve it. all the people i read about doing this mod just seem to deal with the fact that there car wont run right tell it gets all the way warm. i am just looking to see if someone has tried this and i have not seen that anyone has. i see what you are trying to say now about the injectors. i did not understand what you were trying to say before wasn't vary clear to me.

 

[TAMA_player]

Im in the same boat as you.
I tried several things, adding fuel not help to idle at all, and timing not too much. It needs extra air.

I just started raising idle rpm to 950 to make this issue "less worst" as Motomattx said.
I'm still looking for ideas on this and I just don't already tried to eliminate cold enrichment in ECMlink. Let me try this today and post my results.

Subscribed.

 

[MrCup]

i know there is a way to get around using it as dsmlink has a isc simulator that you set so its not needed. just trying to find out what it changes exactly so i can a much of the same thing in my car with ceddy. there is no reason this can't be done. even if i have to write code to do it. with help of course.

 

[TAMA_player]

This:

I am familiar with the "warm up" maps and how they are used, and understand what you are referring to. You can try to lean them out to stoic, but it may make the car run even worse. The reason it adds extra fuel and the idle is high is to warm the motor up as quickly as possible. It takes more fuel to start and run a cold motor, but maybe if you lean it to, say, 13.7 in that area, maybe itll help. Ive ran the throttle body on my own cars in several configurations over the years, and I just prefer the seamless driveability of a properly functioning idle control system.

There is no way to simulate an ISC (ECMlink idle air clamp is to help with over-rich throttle off situations). Without a proper way to let more air in with throttle body closed, seems that the best we can do is try parameters to avoid engine stalling and try to warm the engine faster as kchaazz suggests.

 

[Phantom DSM]

This:


There is no way to simulate an ISC (ECMlink idle air clamp is to help with over-rich throttle off situations). Without a proper way to let more air in with throttle body closed, seems that the best we can do is try parameters to avoid engine stalling and try to warm the engine faster as kchaazz suggests.

I have ecmlink v3 on 1g and it allowes simulation of idle through TPS wih a click of a button. Not sure of 2g version.
O.p. I guess there might be a limitaton with ceddy not allowing simulation, but there are other measures you can take to improve idle, but it wont be perfect.
You can use a FIAV bypass plate and loop the coolant lines and install the ISC back on

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[MrCup]

I have ecmlink v3 on 1g and it allowes simulation of idle through TPS wih a click of a button. Not sure of 2g version.
O.p. I guess there might be a limitaton with ceddy not allowing simulation, but there are other measures you can take to improve idle, but it wont be perfect.
You can use a FIAV bypass plate and loop the coolant lines and install the ISC back on

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do you know what the simulation does (how it works), what it changes?

 

[mjdarg]

There is no way to simulate what a stepper motor can do with a computer. Link can simulate the FIAV using the ISC, but thats it .

 

[Phantom DSM]

There is no way to simulate what a stepper motor can do with a computer. Link can simulate the FIAV using the ISC, but thats it .

Are you being sarcastic?? Do you have link? The idle switch is separate and in Link it can be simulated through the TPS. In occurrence that the ISC is not present, this can help. The Fiav can also have a leak causing strange behavior as well.
To the o.p., If you decide to get a bypass plate or eliminate isc all together, this can be an option of help, otherwise you will need the isc at the moment to help you idle better.
I added a few links , first has an issue and idle switch and simulation are discuussed and other 2 has tutorial of how Link simulates with pics.

http://www.dsmtuners.com/forums/ecm...e/395568-dsmlink-idle-surge-tuning-issue.html
idlesurge [ECMTuning - wiki]
v3tpsadj [ECMTuning - wiki]

 

[b00st3d]

Way old, but here's a garage block off plate.

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