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ECMlink 2g High Idle Checked about everything, thoughts?

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PrimerPLus

10+ Year Contributor
1,158
20
Jul 28, 2011
Tokyo, Asia
1). Any boost, vac, or exhaust leaks?
Tested to 35psi no leaks other than at the ISC electrical pins. See video. Video is not new but it does the same thing now.
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2). Verified mechanical timing?
Yes all lines up.
3). Verified base timing?
2g
4). Ignition system
COP or Stock Coil: Stock
Wire brand and Age: NGK few months old.
Spark Plug brand, type and Gap: NKG BPR7ES gapped .025

5). Motor health (Compression Test)
Cylinder 1: 152
Cylinder 2: 150
Cylinder 3: 150
Cylinder 4: 153


6). Performed basic throttle body adjustments?
Idle Switch: Set via ECMlink
Throttle Cable: yes
TPS: .63 at idle
BISS: 2 full turns out from bottom

7). Compression ratio

8). Any known bad sensors or brittle wiring?
o2 sensor has same peeling of its heat shield but still seems to cycle fine via ECMLINK

9). Any DTC/CEL codes?
I do get a random missfire every now and then.
Otherwise known reasons.

10). Electrical system
Car off (not running):
Car running:

11). Base fuel pressure and injector values
Base Fuel Pressure:43psi
Injector Size (cc/min): FIC 1150cc

12). Properly calibrated and configured wideband sensor
Sensor Brand:AEM Uego
Calibration Date:

13). Type of fuel
Type: 90


14). Watched ECMlink how-to videos?
Yes

I can not get my ISC lower than 40.

When I ground timing to ecu, and ground diagnostic to ecu, the ISC will go to 9 and stay there.

I have done a BLT and don't think I have any but when I set the BISS to the IDLE I want which is 1100, and then unground those connectors the idle goes crazy. Up to 2k then cuts off and will just keep doing it.

If I screw the BISS all the way in I can get 1100 rpm idle no surge but I think the BISS is supposed to be about 2 full turns out from bottom.

I have no vac lines on the TB, they are capped off.
I just rebuilt the TB because it has shaft seals leak but now it is good.
I have a catch can so no stock PCV. Both of those ports, the one from intake manifold and the one on the valve cover are capped off.
My BoV is Tial, and I use an -4AN line and fitting from manifold to it.
my Hallman MBC also uses -4AN fittings, 1 to the boost source which is from intercooler piping, and the other is to the external wastegate.

Does it sound like I have a boost leak or something else?


Oh I use to have no problems but I recently had to do some changes including the TB rebuild, and also I changed my Catch Can from feeding back into turbo because I didn't like the residue going through intercooler and back into combustion. So it has a vented filter. So now my intercooler piping is clean no extra oil or vapors etc.
I took the TB off and checked it out. It seems to close fully.
I put everything back together and took a couple of logs.
I also tested the ISC coils and they all checked out. I also tested via the harness. I had a friend turn key on and I watched the ISC go in, turn key off and it goes back out.
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First is idle as it is warming up. All is good no surge nothing.
The second is idle as it is at operating temps. Also good.
Third is a cruise to the store. When I get to the store it starts to show sings of high idle.

Last is when I am leaving the store. I noticed that my TPS was fluctuating from .63 to .65 so I tried to adjust it. Still doing it. I unchecked use TPS adjust to set the TPS to .63 as it was idling. But then it would not go to 100% throttle. SO I used the TPS adjust to correct that.

I checked to make sure the throttle cable was not holding the plate open which I am sure it wasn't but I loosed it up some anyways.
After doing that the last log is the results.
 

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The BISS screw is not supposed to be a certain amount of turns....it just ends up where it ends up. That being said, it should not be 100% closed. I am pretty sure you still have a leak some where.

When you did the BLT did you test:
- the line running from the intake mani to the brake booster? I have had 1 of those leaking from a crack in the rubber before.
- the AFPR? I have had the vac lines leak before and also had the adjuster screw on the AFPR leak. To fix the leak on my AFPR adjuster I had to use about 6-10 wraps of teflon tape on it to get it to seal. Those threads are really really loose and leak readily.
- the vac lines going to the wastgate? I have had that leak once too.
- around the omni4bar map sesnor? I don't run one personally so I dunno how they mount but just throwing it out there.


I have had soooo many of those little vac line suddenly leak that I now zip tie each and every one....even the break booster vac lines.

Also noticed in the TB pic that you have the throttle plate adjuster....is it cracked open slightly so you have to close the BISS all the way?
 
Hey thanks for the reply.
Yah I known it's not exactly 2 turns out but it is a good position to start.
YEs I sprayed soap and water everywhere. Yah I know about the afpr. I have good amount of Teflon on it too. On my external wastegate I have 1 -4AN line running to my mbc. No leaks there either. Yah my omni bar map sensor is the Mitsubishi style and fits in same location as stock mdp. No leaks out of it either.
The boost pressure bleeds off slowly and I can pressure it to 35psi.

The isc is supposed to go in when key is turned to on correct. And stay there no other movement until key is turned off then it goes back out?
 
shiiiiit....I'm not sure then I'll keep looking and pondering.

What about the throttle being cracked open a bit from that throttle stop?

In that vid you are leaking a bit from the ISC maybe its that?

I also noticed your fuel trim is in the 12% range at idle which is very high....tryna thing why that is as well. Your air flow per rev is in the right range.
 
@PrimerPLus this might be a dumb question, but did you set your fuel pressure with the vaccum line disconnected from the AFPR?

That high fuel trim shouldn't be that high with your airflowperrev where it should be had me thinking.
 
No I will check the fuel pressure though.
Yah it is deff A mystery right now LOL.

Also I'm thinking could it be a fiav issue?

You have to disconnect the vac line from the AFPR while the engine is running to set the fuel pressure...set it to 43 psi like before. When the motor is idling its pulling a lot of vacuum which lowers the fuel pressure (and fuel delivery) so that's why your fuel trims are so high...you have to set the AFPR with no vacuum at all....it needs to be at atmospheric pressure when you set it.

Then hook the vac line up, reset your fuel trims (its in the "ECU" menu at the top) and then start the motor. That should (will) get the fuel trims back to where they need to be.

Try that and post a new log....see if you can get it to do that high idle thing again.

Ya it could be the FIAV....there is some threads on here for testing it with a multimeter.
 
I drove home and it was doing the high idle thing every time I stopped. Not really surgeing just idleing aroun 1900-2k.

Got home and parked on a slant because only available space currently. Shut off car checked fuel pressure using ecmlink. It is correct at 43psi no adjustment made. Reset fuel trims. and then started up car and took a log. It idled fine after initial startup. Looking at the log for some reason when the AirflowPerRev is .25 it idles high then when it went to .35 it idled perfect. Timing is also higher in the .25 range.
 

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Check injector seals on cylinder head side. If you have an external waste gate check the vac lines by this too as well as the vacuum line by the BOV. Brake booster vacuum line. the check valve in mines was defective.These were spots where I had leaks when I had a boost leak test performed.
 
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I had the exact same issue. Everything was fine until I drove it then it would surge and idle around the same range you're seeing. I adjusted my cruise control cables and got it to run normal but I do believe I also have a boost leak but I haven't been able to get any help on it. I hooked up a boost leak tester and found air coming from the intake manifold through the nipple where the BOV vacuum line connects to. I'm not sure if I'm supposed to get air there I thought it should be a vacuum so I think I have a boost leak there. Not sure how to go about fixing it though, just thought I'd try to give some input.
 
Do you still have coolant lines going to the tb? The FIAV needs hot coolant to shut.

When I rebuilt my throttle body, I tightened the FIAV down snug with a pair of pliers, which essentially disables it. I think it's under a freeze plug or something (don't exactly remember).
 
Mine is idle at 2 also did you find the reason?
Did you look into your cruise control module? The cables can cause a high idle if they are too tight. That's what my problem was. Took a while to figure it out but was easy to fix. Try adjusting the stop screw on the throttle also.
 
Do you still have coolant lines going to the tb? The FIAV needs hot coolant to shut.

When I rebuilt my throttle body, I tightened the FIAV down snug with a pair of pliers, which essentially disables it. I think it's under a freeze plug or something (don't exactly remember).

This is correct. Pop the plug off the bottom of the throttle body and spin the FIAV clockwise into it's bore. This will block off the passage. For some reason I'm seeing an influx of people with this problem lately, if there's no coolant, the valve doesn't shut like it's supposed to. Someone else on here had this issue yesterday as well.
 
Hi, no I have not resolved it yet.
I do not have cruise control it has been deleted since I owned the car and I use a Non cruise control throttle cable that I got from JNZ.
I do not have coolant lines running to the throttle body, it is looped back.
I have a FIAV Bypass that allows for just the ISC to work.

I unplugged the ISC today to see if it made any difference, it just started surgeing like crazy so I plugged it back in.
I screwed the BISS all the way in and it idled at 1800rpms.

I have been busy and haven't ran any Seafoam yet but I will tomorrow.

I checked the throttle cable to make sure it was loose even after it is warmed up, it is, I tried shutting the throttle plate by hand to see if any movement, there is none.

I can put it in first gear and give no gas and it will go and drive at about 1500rpms.

Not sure what is going on.
 
I have a FIAV Bypass that allows for just the ISC to work.

What kind of bypass? Is it a blockoff plate or what? Can you convince yourself that it is actually working?

I checked the throttle cable to make sure it was loose even after it is warmed up, it is, I tried shutting the throttle plate by hand to see if any movement, there is none.

The throttle stop screw could be out of adjustment. You want to unscrew it so that the throttle plate just starts to stick when it fully closes, and then unscrew it so that it is just past the point of sticking. The idea is that the throttle isn't truly closing all the way. TPS volts are meaningless here, since you probably adjusted the tps under the assumption that the throttle is fully closing.
 
@A Sharp it is a bypass plate. meaning it will only allow the ISC to function. I used black epoxy to seal it, it is pretty strong seal I think. I tried to blow air into the coolant nipple with an air compressor none seemed to escape except out the nipple I was testing due to pressure.

I never have adjusted the Throttle stop screw it has been the way it is since I got it from the rebuild place.
I did check it though and followed the instructions to set it properly. I believe it is correct.

I tested the ISC coils all pass.
I tested the TPS sensor itself and I believe this might be the problem.

Following these instructions, and an old video I made before I got a new throttle body.
Unplug the TPS and measure the sensor itself with an ohmmeter. Should read between 3.5k-6.5k ohms between pin 1 (where the green/yellow wire connects) and pin 4 (black wire connects) - measure the sensor pins, not the wires.

Then between pin 2 (brown/red) and pin 4 (black), and also between pin 2 (brown/red) and pin 1 (green/yellow) - it should change smoothly as the throttle valve is opened/closed (one way increases resistance, the other decreases - you really need an analog meter [one with a needle] to check for smoothness). If this is not smooth (it jumps somewhere), the TPS is faulty and needs replacement.

Then between pin 4 (black) and pin 3 (yellow/red) it should be infinite with throttle open, and under 150 ohms when fully closed (if not under 150 when fully closed it also may be due to mis-adjustment). The manual says 0 ohms but you'll rarely get this in the real world.

Adjusting when the IPS opens (Idle Position Switch - which is pins 3 and 4) is critical (or can lead to high idle or idle surge) and is described per Mitsu manual here: http://www.dsmtuners.com/forums/newbie-forum/255885-bad-tps-again.html#post151940336.

This video is not my current throttle body it is an old one I did when I was trying to figure out if my TPS was dead, it was. I think this is my issue now.
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So testing using a BOSCH FIX 7665 Digital Multimeter set to 2000 Ohms
Pins 1 and 4 I get 1 i think this means open loop. It will flash to 1600k for a milasec. then go to 1.
Pins 2 and 4 closed it says 649 and opening it will raise in numbers and less than half it will go to 1
Pins 2 and 1 says 1 while closed and little less than half it starts showing numbers and fully opened it goes to 200
Pins 4 and 3 closed it says 033 and just barely opening throttle it will go to 1 all the way to fully opened.
 
Update:
Ok so I got a new TPS and it seems to have better values. I installed it and good news and confusing news?

Good news: It will idle at what I want now no more is it stuck at 2k rpms it is around 1100 now.

Confusing news: The ISC stays at 54 at idle no matter if I screw in the biss or screw it out. The idle changes but not the ISC. The ISC moves while driving though.
I tested the coils on the ISC they are all good.

The idle will dip below 1k sometimes though when coming to a stop so I think that it is due to the ISC but I am not sure why the ISC wont go to 30 like it should. I will see if I can test the harness side of the ISC as I know the coils are good on the ISC.

Logs attached.
 

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Update:
Ok so I got a new TPS and it seems to have better values. I installed it and good news and confusing news?

Good news: It will idle at what I want now no more is it stuck at 2k rpms it is around 1100 now.

Confusing news: The ISC stays at 54 at idle no matter if I screw in the biss or screw it out. The idle changes but not the ISC. The ISC moves while driving though.
I tested the coils on the ISC they are all good.

The idle will dip below 1k sometimes though when coming to a stop so I think that it is due to the ISC but I am not sure why the ISC wont go to 30 like it should. I will see if I can test the harness side of the ISC as I know the coils are good on the ISC.

Logs attached.
I ignored the f*ng isc value for weeks.
When i came back i noticed it was no longer stuck at 0.
It's 15-30. Depending on what ignition timing i use at idle .

0° places me at 30 isc value .
But 15° at idle makes my car easy more stable when i engage the AC compressor.
So I'll see a lower isc value.

Just sharing
 
I had the exact same issue. Everything was fine until I drove it then it would surge and idle around the same range you're seeing. I adjusted my cruise control cables and got it to run normal but I do believe I also have a boost leak but I haven't been able to get any help on it. I hooked up a boost leak tester and found air coming from the intake manifold through the nipple where the BOV vacuum line connects to. I'm not sure if I'm supposed to get air there I thought it should be a vacuum so I think I have a boost leak there. Not sure how to go about fixing it though, just thought I'd try to give some input.


I installed an aftermarket intake manifold and deleted EGR and emissions and now it idles up and down from 3k to under 500 could it be same issue with fuel?
 
Just my .02

The isc, or idle air control valve is used only to make a more stable idle depending on the draw of accessories against the motor.

The biss screw determines the amount of air let in by the iac.

Trouble shooting a high idle should be done in the following order, loosen throttle cable on intake manifold, verify continuity of tps sensor pins 3 and 4 with tb closed, verify and clean isc or iac sensor and housing, verify fiav adjustment, reset throttle set screw while adjusting biss



For example the idle air control valve should be at its max open position when the a.c. is engaged, the headlights are on and the car is at operating termperature with the fans running.

It is little more than a stepper switch to release air past the throttle body to stabilize the idle.

A typical malfunction of the isc, or iac, would be the car idles too low or dies when the a.c. or alternator are at high output, or that the car has a random that goes up and down.
 
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