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Hacking up Honda's ECU
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 Post subject: Re: COMPETITION
PostPosted: Tue Jan 27, 2004 2:01 pm 
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Location: Cincinnati, Ohio
THE POINT ISN'T TO FUCKING DISABLE IT!!!
Doc told me how to disable it MONTHS before this competition was started.
The point of this competition is to enable the engine simulator project to be finished. If you just disable the IACV in code, how are you ever going to be able to monitor the duty cycle of the IACV properly?

Competition remains open. Someone please solve it. I know how to disable the IACV in code and I'm not interested.

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 Post subject: Re: COMPETITION
PostPosted: Tue Jan 27, 2004 10:23 pm 
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has anyone disassembled an iacv yet? i'd like to know how they are constructed.

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 Post subject: Re: COMPETITION
PostPosted: Wed Jan 28, 2004 5:29 pm 
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RadioShack.. 10w 10ohm.. Part Number #271-0132

http://www.homemadeturbo.com/forum/inde ... adid=15444

This may only be for obd0. I will try it tonight.

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 Post subject: Re: COMPETITION
PostPosted: Wed Jan 28, 2004 8:33 pm 
only for OBD0 ... OBD1 has issues with it when driving.


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 Post subject: Re: COMPETITION
PostPosted: Fri Apr 02, 2004 1:35 am 
What even became of this???


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 Post subject: Re: COMPETITION
PostPosted: Wed Apr 07, 2004 3:07 pm 
yeah ive been soaking up information about the iacv and how it works and how we could fool the ecu .. i dont think its gonna be hard in the end its just a matter of research.... heres what i got so far if it helps anyone.

IACV RESEARCH
http://www.globaldenso.com/TECHNOLOGY/c ... index.html
General Information 1 (248) 350-7500
DENSO Aftermarket 1-888-96-DENSO

Idle Speed Control (ISC) Inductor with 58mH inductance and ~ 15 ohm DCR
Uses PWM Pulse Width Modulation to open and close.

Idling is the state during which the accelerator pedal is released with the engine running. With conventional engines, the idle speed was adjusted slightly on the high side so that the engine will not knock. However, the engine's condition changes over the years, therefore the idle speed becomes unstable. If the idle speed is unstable, unpleasant vibrations or engine breakdown when started may occur, or fuel economy may drop. To eliminate such problems, ISC has been introduced to optimize the idle speed. In this method, an air bypass passage is provided in parallel with the throttle valve, and opening degree of the ISCV (idle speed control valve) attached to this passage is adjusted by the ECU. This causes the quantity of bypass air to change, thereby controlling the idle speed.

Idle speed control valve (ISCV) (Linear solenoid valve)
A solenoid valve attached to the throttle body. Quantity of intake air is adjusted as the opening degree of this valve is controlled.

Various Sensors used to maintain (ISC)
--------------------------------------------------------------------------------
List of sensors provided to detect running condition of engine

> Coolant temperature sensor
> Throttle position sensor
> Crank position sensor
> Speed sensor
> Starter signal
> Air conditioner signal
> Neutral signal
> Electrical load signal


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 Post subject: Re: COMPETITION
PostPosted: Sat Apr 17, 2004 3:31 am 
UPDATE:
(Opposite of conductor look it up on internet)
The IACV is just an inductor^ that the ECU sends PWM pulses to in order to make it open more so air can bypass the throttle body and make your car idle properly. On the return leg of the plug comming from the IACV back to the ECU there will be a variable voltage that depends on how many pulses are being sent to the IACV and on what frequency they are being sent. The ECU will throw a trouble code if the "Range" of voltage its expecting is superceeded or under a certain voltage. I can probably guess that these values are in the code. Teachers at my school say as long as you replace it with a inductor of the same resistance that I measure at 11.5 DCR and try to match the inductance of 58mH (milihenry) that the ECU shouldnt know the difference.

I will try to test this theroy this weekend when I get a chance.

By the way Mark can you measure the resistance of your Greenie and tell me what the DCR is?


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 Post subject: Re: COMPETITION
PostPosted: Mon Apr 19, 2004 10:25 am 
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OutkastN8 - you're totally right. Now find a 58mH inductor with 11 ohm DCR that doesn't cost $50 :)

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 Post subject: Re: COMPETITION
PostPosted: Mon Apr 19, 2004 12:44 pm 
Is it 58 millihenry or .58 Point 58? with a decimal..


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 Post subject: Re: COMPETITION
PostPosted: Mon Apr 19, 2004 1:31 pm 
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58 millihenry I believe ... rather large inductor, rather low DCR. hard to find.

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 Post subject: Re: COMPETITION
PostPosted: Mon Apr 19, 2004 1:55 pm 
Blundar - What if we took them out of OLD IACV's?????

I'm sure everyone could get one or 2 from their local JY's or speed shops that have old SOHC parts laying around.

Are they not the same from 92-00 in the Civic and 94-01 in the Integra???


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 Post subject: Re: COMPETITION
PostPosted: Mon Apr 19, 2004 2:49 pm 
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Location: Scotland, UK
How about just fitting a 2 pin PCB mount screw terminal, then the user can connect a standard IACV from the boneyard for a few $?

(waits for abuse, lol)


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 Post subject: Re: COMPETITION
PostPosted: Wed Jul 14, 2004 11:27 pm 
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Location: Tampa bay, Florida
The IACV compensates for the inaccuracy of the Speed-Density system in determining airflow at low RPM. In order to bypass the IACV and not trip an engine code, you need to create a lookup table that compares the PWM of the input to the IACV and relates that to a change in another sensor that could create the desired affect: RPM alteration of the engine. If the idle is too high or too low, the ECU recoils with an IACV fault.

The fact that the little green inductor didn't trip an IACV code is a result of the setup of that specific engine: where the air bypass screw was set very close to what was needed for that particular atmospheric pressure and air temperature. If the pressure or temperature were vastly different than the day he tested, it probably would not work so well.

My best guess is someone should tap a MAP sensor AFTER the IACV and compare that to the difference of the factory MAP sensor. The difference should be logged with the IACV PWM reading, and air temperature and set to a lookup table. Having a PIC or similar micro-controller compare all of the values and performing a lookup might do exactly what you want.

Case point: An idiot friend adjusted his throttle stop screw to adjust the idle of his Honda. I tried unsuccessfully to get that screw close to what it should have been. Can't find an exact setting that works. He has to tune the IACV for hot/cold weather now. Can adjust it perfect for one, but when the temperature changes 10 degrees or pressure drops, idle suffers greatly and a temporary IACV fault comes up.

Hope that points you in the right direction.

Daniel


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 Post subject: Re: COMPETITION
PostPosted: Sat Jul 24, 2004 3:03 am 
Case point: An idiot friend adjusted his throttle stop screw to adjust the idle of his Honda. I tried unsuccessfully to get that screw close to what it should have been. Can't find an exact setting that works. He has to tune the IACV for hot/cold weather now. Can adjust it perfect for one, but when the temperature changes 10 degrees or pressure drops, idle suffers greatly and a temporary IACV fault comes up.


If TPS needs to be calibrated do that first. Refer to Honda manual for procedure involving this.

Adjust the IACV

1. The idle adjustment screw has a procedure to adjust it properly... it is meant to be adjusted with the IACVunplugged and the engine warm.

2. Warm up your engine to operating temperatures (Wait for fan to come on) then unplug the 2 pin connector from the IACV.

3. Idle should drop or engine may die. Have somone keep it alive or keep it alive yourself by manually opening the throttle plate and slowly decrease idle until the motor will idle itself. (may need to adjust screw out to get it to idle)

4. Make sure throttle plate is closed and not stuck open at all.

5. Adjust the idle screw in or out to make the motor idle at 500 RPM +- 200 RPM
Note: 500 RPM is the first line right above 0 on the Tachometer not halfway to 1000. It seems really low but that is how the gauge works.

6. Plug the IACV back in and perform the ECU reset procedure to get rid of the CEL for IACV.

Assuming that your TPS is already calibrated correctly there should be no further adjustment.

Drive your car to test it out I usually adjust it during the day or in the afternoon when its not so hot to allow for change in Atmospheric pressure.
I used to have the same problem as you before I did this procedure so I hope it works for you.

-NATE

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Post Edited (07-24-04 03:05)


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PostPosted: Fri Jul 30, 2004 3:30 pm 
I have a problem with my damn EACV right now....throwing a code 14 and wont go away. I have tried 3 different valves and the same shit eveyrtime. I checked the voltage and resistance per factory shop manual and it all checks out. I even adjusted the RPM the proper way, but as soon as i plug the valve in, it idles to around 2.5K. I cant wait to find out wtf the problem is......i have it disconnected as of right now and asjusted the idle to 900, but id like to get rid of code and plug it back in.


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