2G ECU/Idle Questions

[Twinturbo-w]

Hello i need some advice on my ecu the board has what seems to me to be corrosion of some sort on the side. The capacitors seem fine don't see any leaks on the top of them not too sure on the bottom but as far as i can see i dont see any puddles. Not entirely sure what to look for. Ive taken pictures tired to get good angles on it. Would i need to replace it is it fixable? I'm also wondering if this is what is causing my 1995 eagle talon tsi to idle surge. My check engine light also never comes on.

Ive checked for boost leaks using soapy water which lead me to a bov leak but i had "fixed" it for now with some silicone since it was missing its gasket. Also fixed throttle leaks by changing the throttle gaskets and the biss screw. Changed out the ics and tps. The car will idle fine when standing still but once i drive it around it goes into a wack. Going form 1,500-1,700 to 500 rpms at a constant rate as if i were taping the peddle. It will however stay at a constant idle (1,000 rpm) if i dont give it too much gas and put put around. Usually but then again once its warmed up the issue occurs. Another thing to note the previous owner took out the emissions stuff but plugged up the P.E.A on the throttle body.They looped p and a into one another with what was left of the vacuum tube and blocked off e with a cut tube and a screw blocking the end. I've changed it around to loop p to e and having a blocked off. Driving inspiration from other pictures of engine bays they seemed to do the same. But nothing seemed to change. Looked around for the egr too but cannot seem to find something that resembles it thought maybe a seal is causing the issue. Its most likely the previous owners didn't do the emission block off correctly. But i cannot tell if its correct or not.

Could also need a tuning but im not sure very new to all of this. So any suggestions would be greatly appreciated

 

[chrysler kid]

Alright

So your ECU looks new. The row of 5 black resistors are drivers for the idle air control system. Example:::

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The very first thing to do is to undo the throttle cable bolts that hold the cable above the throttle body on the intake manifold and then press the throttle body closed. See if that lowers your idle. This solves about 70 percent of high idle problems

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If that does not lower your idle you will follow the following settings if you did not mess with the throttle body before this, you need to verify multiple times you do not have a vacuum leak and boost leak, and do it 5 more times to be sure

You will need to set your biss screw base idle using the idle relearn procedure

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You will start the car and with the engine running use a paper clip to jump the blue 2 pin connector on the firewall by the injector driver box (which is on the same harness as the fuel pump primer connector) this will set the idle air control valve to position 30, position 30 is all the way closed warm idle for the idle air control valve. The computer uses position 30 to determine if it needs to trigger a code for idle air control fault. If your rpm is over 750 when the ECU commands position 30 it triggers a code for idle air control fault, because the computer is dumb and it blames a part

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Once the blue connector is jumped you will use the idle biss screw to set base idle on the throttle body. Screw in the top plastic biss screw on the throttle body till the car idles very low, and screw it slowly out until your idle is at 750rpms with the blue connector jumped with a paper clip

If you are unable to get an idle setting of 750 using the biss screw; the idle is over 750rpm with the screw all the way in and the connector jumped, you will reset the throttle set screw and manually push the throttle blade down to close the throttle blade after you slowly unscrew the throttle stop screw.

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If you've messed with the throttle body at all, rebuilt it etc this procedure is necessary. If you didn't mess with the throttle body at all and your car randomly just starts idling higher do not just jump to this procedure!!! . check for vaccum and boost leaks!!!

 

[Twinturbo-w]

Alright

So your ECU looks new. The row of 5 black resistors are drivers for the idle air control system

The very first thing to do is to undo the throttle cable bolts that hold the cable above the throttle body on the intake manifold and then press the throttle body closed. See if that lowers your idle

If that does not lower your idle you will follow the following settings

You will need to set your biss screw base idle using the idle relearn procedure

You will start the car and with the engine running use a paper clip to jump the blue 2 pin connector on the firewall by the injector driver box (which is on the same harness as the fuel pump primer connector) this will set the idle air control valve to position 30, position 30 is all the way closed warm idle for the idle air control valve. The computer uses position 30 to determine if it needs to trigger a code for idle air control fault. If your rpm is over 750 when the ECU commands position 30 it triggers a code for idle air control fault, because the computer is dumb and it blames a part

Once the blue connector is jumped you will use the idle biss screw to set base idle on the throttle body. Screw in the top plastic biss screw on the throttle body till the car idles very low, and screw it slowly out until your idle is at 750rpms with the blue connector jumped with a paper clip

If you are unable to get an idle setting of 750 using the biss screw; the idle is over 750rpm with the screw all the way in and the connector jumped, you will reset the throttle set screw and manually push the throttle blade down to close the throttle blade after you slowly unscrew the throttle stop screw.

If you've messed with the throttle body at all, rebuilt it etc this procedure is necessary. If you didn't mess with the throttle body at all and your car randomly just starts idling higher do not just jump to this procedure!!! . check for vaccum and boost leaks!!!

Would tampering with the biss screw mess with the base idle? All i did was take out the old replace with the new. Setting the screw to 2 full circles from being screwed all the way down. Read a post that is one way to set the biss screw but not the computer. It also isnt random but quite predictable the surge. When first starting the car it will start from 2,000 and somewhat slowly the rpms will go down to 1,000 and stay around there dropping to around 750 after running for a few minutes. When in first gear it will gerk when it has reached up to 1,500 rpms. It wont gerk if i give it enough gas. Which also reminds me when revving the engine to 1,500 at a stand still the idle shoots down when reaching that point falling to about 1,000. After going around the block it will start to stay around 1,500 and continuing driving will increase to 2,000. The idle will sometimes jump up and down without staying in one spot like i explained earlier. It just started to jump up and down again did that before i fixed the boost leak/ throttle leak. I thought that was due to having a gasket the wrong way which i fixed but didn't fix the jumping of the idle. One thing to note aswell when i replaced the sensors made sure to reset the ecu also when doing so by unplugging the negative on the battery. Ill look for leaks again later on today and get a video for a better understanding. Main problem is the idle increasing after being driven and gerking/falling at 1,500 rpms.

 

[chrysler kid]

Would tampering with the biss screw mess with the base idle? All i did was take out the old replace with the new. Setting the screw to 2 full circles from being screwed all the way down. Read a post that is one way to set the biss screw but not the computer. It also isnt random but quite predictable the surge. When first starting the car it will start from 2,000 and somewhat slowly the rpms will go down to 1,000 and stay around there dropping to around 750 after running for a few minutes. When in first gear it will gerk when it has reached up to 1,500 rpms. It wont gerk if i give it enough gas. Which also reminds me when revving the engine to 1,500 at a stand still the idle shoots down when reaching that point falling to about 1,000. After going around the block it will start to stay around 1,500 and continuing driving will increase to 2,000. The idle will sometimes jump up and down without staying in one spot like i explained earlier. It just started to jump up and down again did that before i fixed the boost leak/ throttle leak. I thought that was due to having a gasket the wrong way which i fixed but didn't fix the jumping of the idle. One thing to note aswell when i replaced the sensors made sure to reset the ecu also when doing so by unplugging the negative on the battery. Ill look for leaks again later on today and get a video for a better understanding. Main problem is the idle increasing after being driven and gerking/falling at 1,500 rpms.

Sorry I updated my post with fat finger sketches.

To set base idle, the biss screw is used with the blue connector jumped.

If you use the biss screw without the idle air control valve at position 30 it will not set your ECU controlled base idle. You need to trigger the idle air control valve first and then use the biss to set your idle at 750 rpms

So the ECU acts all wonky after it senses a base idle of 750 can't be accomplished using it's set ECU procedure. Sometimes it will get close, but then it sets a diagnostic procedure testing the iac and measuring O2 and map readings which causes an irradic bouncing idle. Usually unhooking the battery the car will almost act normal, after a day or so the idle will start bouncing and the check engine light comes on. I've had it go a week between triggers because the ECU only sets that idle air control setting at a certain engine coolant temp after a certain mileage or 02 reading

CHECK YOUE THROTTLE CABLE TENSION FIRST! UNHOOK THE 2 BOLTS ONTOP OF THE INTAKE MANIFOLD

 

[chrysler kid]

Honestly if you haven't gotten a check engine light for p0505 it's usually your throttle cable is too tight. The ECU sees the tps as open and it reacts to that understanding the iac does not control the tps to read open

Also biss screw depth is not a set number of turns. The Mitsubishi manual states 1.5 turns or whatever outwards after bottoming out. This was for brand new cars, brand new seals, stronger compression and vacuum on a brand new motor. It also states this needs to be done by technicians differently at different elevations above sea level and is only a starting point for tuning the idle

 

[Twinturbo-w]

Honestly if you haven't gotten a check engine light for p0505 it's usually your throttle cable is too tight. The ECU sees the tps as open and it reacts to that understanding the iac does not control the tps to read open

Also biss screw depth is not a set number of turns. The Mitsubishi manual states 1.5 turns or whatever outwards after bottoming out. This was for brand new cars, brand new seals, stronger compression and vacuum on a brand new motor. It also states this needs to be done by technicians differently at different elevations above sea level and is only a starting point for tuning the idle

Alright an update, i did some fiddling with the throttle line moved the bracket back that is mounted to the intake manifold resulting in the line loosing some of its tension it had and it stopped the idle from staying at 1,500 to around 1,000 after being driven around. However after a round a round the block it started to stay around 1,500 until i revved which resulted in it going down to 1,100 and staying relatively there. Also re created to a degree of when the idle would climb and tested out closing the throttle all the way with the cable un attached from the manifold and it brought it from 1,100 to about 2 ticks below 1,000. But still when starting the car the idle will climb and slowly fall down, gerk when in first gear at about 1,700 rpms or fall downward to 1,000 when keeping my rmps at a steady pace with the pedal to 1,700 rpms when idling. Those i have a strong feeling are from a leak but haven't yet found it. Don't have access to a smoke machine so instead i use a spray bottle with some soapy water. Just need to do a little more adjustments i feel.

 

[chrysler kid]

I've had them stick before, but usually only after a rebuild and I over tighten the blade.

You can try to clean out the throttle body, don't use brake cleaner, try something less damaging to seals or just use a damp cloth to clean up the area where the blade and the throttle body housing meet. Sometimes the dirt can cause the blade to stick open

You didn't mess with the throttle position sensor at all, correct?

 

[Twinturbo-w]

I've had them stick before, but usually only after a rebuild and I over tighten the blade.

You can try to clean out the throttle body, don't use brake cleaner, try something less damaging to seals or just use a damp cloth to clean up the area where the blade and the throttle body housing meet. Sometimes the dirt can cause the blade to stick open

You didn't mess with the throttle position sensor at all, correct?

Oh dam im sorry Ive been busy and i didnt notice that you responded once more. The only thing i did with the TPS is replace it with a new one. However i do have a slight update I made myself a boost leak tester and tested the lines out. Found that the bov was leaking by the screw. The bov has been in bad array since i got it no surprise. Another leak from the j pipe were it meets the turbo which was missing its gasket with a shitty rvt job and one more leak were from the vacuum line from the intake manifold to the fuel rail someone had tried to do a boost gauge there. I did go out and buy some throttle cleaner and wiped down the butterfly value wasn't really dirty but did it anyway just in case. Anyway we'll see if fixing these leaks will help its been running really rich too with black smoke puffing out when on the gas. Hoping its not the seals in the turbo spewing oil into the exhaust.

 

[Gordon King]

What was the solution to the problem?