1G Wire tuck, idle speed switch?

[DannyE]

Hi all my DSM friends. I have a few questions for you the first is the idle speed switch known as iss. My car is going to basically be a drag car but I will be driving it to the track, I have no emissions to worry about I also have a friend that helps me out on tech inspections I have deleted all of the emissions and so far depined everything I do not need. I no longer have FIAV or isc nor ac or ps. Can I just remove the idle speed switch?

It’s that brass colored single wire switch that adjusts the throttle plate. From what I have gathered the idle speed switch sends signals to the ecu and then the ecu adjusts the isc. If I removed the isc I would think I could also remove this as well and replace it with a adjustment screw with lock nut to adjust the throttle plate?

My second question is can I get rid of the A-56 noise condenser?

Thanks for all of the help fellas, I really appreciate all of it

 

[DannyE]

Sorry, just noticed I posted in the article forum , if the mods could please move this to where it belongs. Thanks again.

 

[steve]

On a 1G there is a Idle Position Switch used to tell the ECU when the throttle is closed. It's the connector by the TB pulley and doubles as the throttle stop.

The ECU does several things with the IPS, as you noted works with the ISC (Idle Speed Control Solenoid) to manage the idle speed when the throttle is closed but the ECU also uses the ISC as a dashpot to keep the engine from stalling when the throttle closes and to assist with starting by providing additional bypass air.

The ECU also cuts off fuel on deceleration when it sees the IPS close.

I don't remember which circuit the A-56 Capacitor is part of and a quick look at the schematics didn't refresh any dormant brain cells.

 

[DannyE]

Hmm, I get what your saying. I have noticed though that a lot of people run without the isc. I got a fiav block off plate not a bypass so I would assume I can run it without the isc? I really don’t want the isc to go bad and take out the ecu. Apparently this had happened to this particular car in the past because the prior owner told me and when I got it home I noticed the isc was bad so I went and bought a new one for one hundred plus dollars. I really do not want to do this anymore if you know what I mean, plus this is strictly a weekend car that will never see rain or snow.

If I have deleted the isc would there be any benefit to keeping the idle speed switch?

Also I will be running ecm link, don’t know if that changes anything or not but figured I’d throw it out there. I think with ecm link I could tune it to fuel cut on throttle closing?

Thanks for all the help bud, without it I am kind of lost on this subject.

 

[gsxeclipse102]

I deleted my idle switch with my wire tuck. Ecmlink can simulate an idle switch. I also have no isc or fiav. Cold starts you have to hold the throttle for about 30 secs. Then it idles fine at 900rpm with 276 cams.

 

[lasthope05]

You have to leave the switch there as it acts as a throttle stop, but you can leave it disconnected if you have ecmlink. Just be sure to enable stimulate idle switch .

 

[gsxeclipse102]

I want to add unless your running a large turbo and going for 600 plus hp And are very good with ecmlink/any standalone leave the isc. It takes a lot of tuning to get it to idle stready and not stall out when coming to a stop

 

[DannyE]

I was looking to run a pte 6152 and trying to make the most I can on pump 93-94 octane, I was hoping 400 to the wheels so that makes me a bit off the 600 mark. If I have to I could run a hx40 with bep housing and e85, but was hoping to try pump gas first.

I just want the engine bay as clean as I can get it with as little to go wrong as possible, I really can’t stand that blob under the throttle body. I’m just use to seeing lm7’s with clean 80mm throttle bodies I guess.

I suppose I could try and run the isc if it really makes life that much easier, as far as tuning ecm link, I will not be doing it and I will be getting a local tuner to set it up for me.

 

[Geeb]

You should be able to easily crank out 400 without breaking a sweat on that turbo. You coulda just got a 16 or 20g and made that with less lag... I've got a pte bb 6165 and I'm shooting for a quick spooling 550-600, wishful thinking on 600 since my turbine housing is tiny (.63ar)but we all can dream

As for my tucked harness. I'm going to be using a q45/jmf drag.. So aside from the TPS, and remote mounted IAC (nissan evap purge valve/dsm IAC I put together, hope it works.. Can't find many people that have done it) ..93rd 6r4 But besides those, don't have/need any other sensors/wires running up there..
Here's hoping I can get a decent idle..

 

[DannyE]

@Geeb actually it’s funny you just brought that up, I actually just got done reading that remote mount iac thread yesterday and I think I’m going that route, that way I can get rid of that blob of crap on the bottom of my throttle body. I really just want everything simple and clean, that way if I’m at the track and have a problem I don’t have to go through h e double L to fix an issue.

I’m actually on the fence about a turbo as of right now, I have two to choose from. One is the precision pte6152 new in box for $350 or a new hahn S20g for $420 but Im sure he will come way down on the price for that.

Thanks for the help bud, without you guys I would be lost in more ways then one.

 

[Geeb]

Ah get the PTE for 350

if it really is new. I got mine and opened it up and found this

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I bought it before I knew anything about turbine housing sizes and how much they affect power and all, and it has a .63ar t3 housing...

Which is small, great for spooling quick, but will probably PEAK at about 550whp..

So I'm trying to compensate with other parts for higher power like a jmf drag SMIM and 3" uicp, running e85, head work, etc.. 600 is my goal right now, but I just don't know if I'll get there

I'm ways away tho I gotta still finish shaving/painting my engine bay, redoing my brake lines, doing the cts v brembo upgrade, build the motor (I have alI I need), send my transmission gear sets out to get treated, finish all the fuel lines, run my new gauges, redo all my suspension bushings, weld in the toe eliminator, weld in my roll cage, throw in my 4 bolt rear, God Im getting sad typing all this hah let me stop..

 

[DannyE]

Dude if I bought a turbo that was said to be new and found that I would lose it. See that’s what I’m talking about, when it comes to buying things second hand it’s a real risk and for newbies it’s even more nail biting.

I’m in the exact position friend. Everything needs to be done still for me too. Engine bay, wiring, engine, you name it and that’s about where I’m at. Will we ever get done? Oh yeah that’s right, we’re never done because as soon as we think it’s done we find something else that we need to upgrade and then even that gets blown out of proportion .

Thanks again bud.

 

[serviceguy]

I would upgrade to a 2G TPS and use its built in ISS.

 

[DannyE]

Would this require any additional wiring? I might have to look into this because I had no clue the 2g’s had the iss built into the tps.

Although I know I can just simulate the iss through link, but not for sure if it will idle worth a crap or not.

Thanks for letting me know this bud.

 

[serviceguy]

You need to extend the wire that originally goes to the ISS to the 4th, unused pin of the TPS connector (it's pin #3, you will need to install an addition connector pin or source a 2G TPS connector). I would run the wire inside the harness since you're working with the harness anyway. I can't remember if the signal polarity is the same between 1G and 2G but I do believe it is. Pin out is the same, with #1= 5V, #2= TPS, #3 = ISS (2G) / NC (1G), #4 = GND.

 

[DannyE]

Got ya, I think I know what your saying. That will leave me that additional option if I do decide to eliminate the iss.

This has been a lot of help to me, thanks again man.

 

[Vegas Smith]

I would just leave it on. It's not in the way of anything and it helps driveability.

 

[DannyE]

@Vegas smith See that’s the thing, when I originally purchased the car the previous owner said that the ecu had been replaced then repaired within a four year time frame. He said it happened because of the isc motor going out, he also said it left him stranded both times. When I got the car I also tracked the high idle issue to a bad isc thanks to this site so I replaced it with a new one and it solved the issue, but now looking at it, it really is a major issue with these cars. Even a good friend of mine had the same issue. He did a complete delete and he hasn’t had any problems since.

When I rode in his car the only noticeable downside was having to keep it idled for about twenty seconds on cold starts, other then that I have seen no issues. He has a big 16g and link, I know for sure he is no where near 600hp, I’d say maybe 350 and he has no issues after letting off the throttle after a pull? It doesn’t dip low or anything, He did say he had to tune for the fiav delete but that it wasn’t too bad.

I will most likely keep the isc and iss plugs tucked away just in case I decide I want to keep them, but I will try and run without them and see if I can get it tuned well enough to idle good and not dip after letting off the throttle and stalling out, but then again fingers crossed.

Thanks again for all of the help, it’s much appreciated.

 

[gsxeclipse102]

You can play with your timing at idle and under it to help stabilize the rpms. Like i previously said i have no isc or fiav. I also delted the idle switch and simulated it through ecmlink. After the initial 30 second hold of the throttle it will idle 900rpms pretty steady. It only stalls coming to a stop if i put it in neutral at high rpms. I usually engine break until around 2k rpms before putting clutch in. No problems

 

[DannyE]

Unfortunately I have an auto so engine braking may not be an option. Do you think it will be fine with an auto?

 

[Vegas Smith]

@Vegas smith See that’s the thing, when I originally purchased the car the previous owner said that the ecu had been replaced then repaired within a four year time frame. He said it happened because of the isc motor going out, he also said it left him stranded both times. When I got the car I also tracked the high idle issue to a bad isc thanks to this site so I replaced it with a new one and it solved the issue, but now looking at it, it really is a major issue with these cars. Even a good friend of mine had the same issue. He did a complete delete and he hasn’t had any problems since.

When I rode in his car the only noticeable downside was having to keep it idled for about twenty seconds on cold starts, other then that I have seen no issues. He has a big 16g and link, I know for sure he is no where near 600hp, I’d say maybe 350 and he has no issues after letting off the throttle after a pull? It doesn’t dip low or anything, He did say he had to tune for the fiav delete but that it wasn’t too bad.

I will most likely keep the isc and iss plugs tucked away just in case I decide I want to keep them, but I will try and run without them and see if I can get it tuned well enough to idle good and not dip after letting off the throttle and stalling out, but then again fingers crossed.

Thanks again for all of the help, it’s much appreciated.

I believe the problem with isc is people don't set them correctly and they wind up burning out trying to over adjust for airleaks or improper settings and then it takes out the ecu. Set the isc/biss screw correctly and you'll be aight.

 

[DannyE]

@Vegas smith To be honest I agree with that assumption, I have always been one of those guys that follow the service manual to a T. Then again I have also read where people have followed the guidelines and still had issues but then again you never know.

There is also a guy I work with that has a 2g gst that’s all original and it has somewhere north of 280k on it, and it has the original isc motor and he said he has never had issues with isc nor crank walk.

I think some Mitsubishi employees felt good the day they assembled his car.

Maybe the 2g’s have a higher quality isc motor then 1g’s? Although the design seems to to be the same, maybe just better quality.

Thanks again for all the info.

 

[serviceguy]

There's two types of ISC, the brown one (lower quality but rebuildable) or the black one (better quality but non rebuildable). Pick your poison. When I say rebuildable I mean that it can be taken apart and if you have a spare unbroken coil from another broken ISC you may be ale to fix it and wait for the next coil to go bad. That said, the black ones go out too. As far as I remember, if the coils short then the driver in the ECU goes bad, but I may be wrong.

 

[DannyE]

That’s what I have read as well, I would rather avoid the driver meltdown in my fresh eprom ecu then worry about a simple idle issue you know, plus this car is primarily just a track slash sometimes street car. Now of course if this was a daily then yes I would try everything to keep the isc, but then again if it was a daily I wouldn’t be installing any performance parts. I just could not see anyone daily driving a 1g but that’s just me and I know that there are people that do it.