3000gt iac test. Bad ISC's have been known to damage the ECU.

3000gt iac test And having it die immediatly after starting if no gas in constant supply I used the muilmeter check on my iac but it tested fine but I still think its the issue anyone wanna let me barrow iac for few mins to make sure that's what it is befor I break down and replace it thanks again Nov 14, 2025 · The idle air control valve regulates idle speed in older vehicles by controlling the air bypassing the throttle plate. 5 months ago and was told the car needed this. But the one I have now has the problem every now and then but the main thing was the one day it was real hot and the car was running fine and had a small backfire & then died. When the new one was put in, the car was fixed. Sep 28, 2011 · i did test the resistance on the IAC and the wires leading to the ECU for both resistance and continuity. Now my car won't idle again so I did the voltage test on the pins of the IAC motor and got good resistance between them (around 30 ohms May 10, 2008 · My car (1994 Dodge Stealth R/T) kept stalling at idle so first thing I did was pull my IAC and test the resistance at each coil. How to clean an idle air control valve. I purchased the car about 1. First, the acronym identifications. Sometimes when I push the clutch pedal in the rpms will drop to nearly 0, then climb back up a little over 1k then idle lowly after that. Working on cars and trucks is my addiction and I would hope you enjoy May 20, 2024 · Issue: I have a 1991 Mitsubishi 3000GT SL that I have been having hesitation/sputtering when slowly accelerating mostly between 3000 rpm. I have yet to check the power going to the iac or do the simple test you have shown me just now. Here See full list on toolsweek. I really wouldn't have suspect that the idle would have gone up when you turned on the A/C because those symptoms are classic IAC problems. The pinouts for a 1991 Mitsubishi 3000GT VR4 and Dodge Stealth RT/TT Cali-spec ECU. I have a 1991 Dodge Stealth. Any help or links would be greatly appreciated. Mar 25, 2004 · How do you test your coolant temp sensor, TPS, and if there is one for your IAC. . Sep 23, 2025 · What is an Idle Air Control Valve? The Role of the IAC Valve in Engine Performance The IAC valve is a small yet crucial component in many fuel-injected vehicles, especially those with older throttle systems. This is a 3000GT IAC (Idle Air Control) tested with an Arduino nano and a bunch of transistors. Jul 7, 2014 · Care and feeding of IAC. Easily remove the intake manifold without having to deal with messy coolant lines. Aside from improper tuning, many people have minor idle problems that are easily fixed. I got a rebuilt TB from April, (with a different IAC), and fixed all of the SUPER small vacuum leaks that I though weren't a problem. Later service manuals call it the idle air control (IAC) motor (servo type How to Test an Idle Air Control Valve Hunter Automotive 6. Ill get a video to post tomorrow afternoon. Also when letting the ISC / IAC Servo Remove, Clean, and Install for the Mitsubishi 3000GT and Dodge Stealth by Jeff Lucius Introduction In the 1991 and 1992 service manuals, the servo motor that is used to control the amount of air that by-passes the throttle plate is referred to as the idle speed control (ISC) servo (stepper motor). Feb 8, 2013 · Faulty idle air control motor Poorly adjusted reference idle speed Service Manual diagnostic procedure: Engine: Troubleshoot Camshaft and Crankshaft Position Sensors Barometric Pressure Sensor Troubleshooting Hints Hint 1: If the barometric pressure sensor is faulty, poor driveability is caused at high altitude, in particular. When I tested it I had the same result as you, just slight movement. What do you all think? Jan 26, 2004 · -Remy Click to expand ok, I test my IAC and I get resistance between pins 1-2, 2-3, 4-5, 5-6 so as far as I can tell it's still good. Jul 28, 2002 · IAC Trouble I had trouble with my car stalling, so I removed the IAC to test it. 1-2,2-3,4-5 all read about 30. Jul 31, 2023 · Machined in 6061 billet aluminum, this is a complete replacement for the fiav/iac assembly below the throttle body. The IAC controlled by your ECU. You can test the idle air control valve with an OEM-level scan tool to determine if the engine part has failed It's Never Just a Tune! Diagnosing bad idle, test/replace Idle Air Control (IAC) on a 3000GT VR-4 • 7:28 Now playing Oct 1, 2013 · STANDARD MOTOR PRODUCTS Part # AC99 from Rock Auto 1992 DODGE STEALTH Idle Air Control (IAC) Valve I've heard though that either O'Riley's or Advance carries them now and might be a bit cheaper. When letting off the gas the idle dives to normal but instead will dive down to 400 and bounce back up Feb 1, 2001 · $1000, a tune up and an IAC motor later and my idling problems are fixed! I know some of you guys were having the same problem as I was having (rpm's diving down to 500 at stop lights) and the new IAC motor solved the problem! It took about 2 days for the computer to recognize the new configuration and finally correct the problem but my baby's purring like kitten and sitting pretty at stop Oct 29, 2014 · My car (1994 Dodge Stealth R/T) kept stalling at idle so first thing I did was pull my IAC and test the resistance at each coil. Tested agian and pins 2 & 3 were dead. 5-6 did not register at all. Iac & maf 3000GT/Stealth Car ForumsVery nice info thanks guys. so i just hold it at like 2,000rpm for 10 seconds every morning and let it warm Short vid showing location Sep 13, 2011 · It keeps throwing p0505 code even after i replaced the IAC twice! Its idling erratically, up and down. My symptom is when I first start the car, I have to let it warm up for about 5 min before I attempt to drive it. The resistence values ended up being 38 (1,2), 37 (2,3), 39 (4,5), 38 (5,6) ohms. The weird thing about the servo though was I am thinking it was replaced before. Nov 20, 2004 · From the posts I've read, they say when you turn the wheel and your idle goes up, the IAC is working. Is this noise normal? I feel like the change in noise levels is excessive for only moving 1-2 steps considering the IAC has something like 80 steps in May 10, 2008 · My car (1994 Dodge Stealth R/T) kept stalling at idle so first thing I did was pull my IAC and test the resistance at each coil. The idle speed, also known simply as “idle,” is the amount of revolutions that the engine keeps when our foot is not pressing the accelerator. The symptoms of a bad idle air control valve are an illuminated check engine light, stalling, wrong idle speed, and the rare instance of the engine failing to start. I used an ohmeter to test the connections. Bad ISC's have been known to damage the ECU. Mitsubishi 1992-I 996 Volume 2. Jun 3, 2011 · 1992 :mitsu: 3000gt Vr4 Daily Driver-MODS 13g turbos, ID 1050x Injectors, Walbro 450 (3SX hotwire), Fuel Lab AFPR, Chrome ECU, Jester's maf, 2 piece drive shaft, Lat 42 Performance 2800lb pressure plate with stock disc, Full turboback exhaust, drilled cats and test pipe. 91 stealth twin turbo. You should try to replace it sooner rather than later. P0505 diagnosis and repair. I took a gamble and bought a new on for nearly $350 from the dealer. The purpose of the IAC is to control the idle speed of your 6G72 motor. But if I punch the gas it goes away, but if I hold the gas at a steady around 1/4 down, it just sputters and doesn't really go anywhere. Jun 5, 2002 · The IAC, Idle Air Control (you will also see it called ISC) is a DC controlled stepper motor. Dec 5, 2012 · Hi there. Perhaps the motor can be rebuilt. If you are having problems with your idle too high or low, try adjusting the idle adjustment screw to see if you can get it to idle properly. The rps will also bounce on occasion. It was all black. Now how much should the idle go up, mine goes up about 100 rpm, not much, is that enough or is my IAC on the way out? Here, we’re covering an idle speed issue on a Grand Marquis. However, I've read that to have your idle set to the proper RPM (about 700-750), you have to May 10, 2008 · To do the IAC test? You're going to unplug the IAC and ohm test the coils with it disconnected. If I try and drive it right away, it stalls/dies Step by step process on replacing the ignition coils, PTU, idle air control valve, spark plugs, and spark plug wires on a Twin Turbo (DOHC NA owners can follow along for the most part) Mitsubishi I decided to test the IAC one morning after starting the car and it was idling high. Oct 15, 2013 · Was the IAC new? You should test your replacement with a multimeter and compare the specs per the service manual. I let it sit for a Sep 14, 2003 · A forum community dedicated to all Mitsubishi 3000GT and Dodge Stealth owners and enthusiasts. Jun 4, 2022 · When you hotwire pump test connector what pressure do you get with engine off? Should be 43-45 psi. Now I'm asking: Will this help my cruddy 12-16mpg I've been getting? Stop my timing Jun 7, 2024 · But regarding testing the IAC, the old one did not show continuity from 1-2 and 4-5, while the new one did perfect on the continuity test, but 1-3 and 4-6 would show continuity, not sure if that's normal. Plugged it all in and started the car. AC, electrical load, power steering etc will cause the ECM to change the step count. I am not real sure, but I don't think "cleaning" it can repair it. My IAC motor went out a while back so I replaced it with a used one and it fixed all my problems at the time. Pulled it apart and pins 2-3 read fine. Try the discount dealers I list on the Garage Page at my web site for better pricing (I use Tallahassee Mitsu a lot May 6, 2024 · I have a long thread troubleshooting some issues, but I figure this might be worth its own thread if someone comes here looking for IAC issues. sometimes at 700 and sometimes at 1500 or higher. It idled perfect after that. It ran fine. Apr 10, 2010 · So I took the time today to pull, test, and clean the ISC/IAC. Sure enough, each read about 30 ohms. So yesterday i went ahead and ordered a new knock sensor from Capital Mitsu. GT-Pro ARC/2. Come join the discussion about performance, modifications, VR4 turbo upgrades, troubleshooting, maintenance, and more! Aug 7, 2013 · Does anyone know how to properly adjust the idle? I understand that if your IAC is working properly, then your ECU will control the idle via your IAC and make any adjustments necessary if it is off. To use the stock IAC, I snipped the middle 2 wires in the connector that normally power the two coils of the IAC stepper motor. The test was conducted after I repaired the IAC coil but the s Jun 14, 2011 · Okay so its finally starting but the idle is very unsteady and rougher than I remember. The throttle body is inside the red square in this picture, and the IAC is mounted on the bottom of it, as indicated by the yellow arrow. If your IAC shorts out or the servo becomes worn, your idle may fluctuate either too high or too low. Later service manuals call it the idle air control (IAC) motor (servo type We would like to show you a description here but the site won’t allow us. You might want to check for vacuum leaks because they can really screw up the idling. Before adjusting This is on the throttle body, at the very top of the engine on the passenger side, right near the battery. The Megasquirt stepper motor driver powers the coils on the other 4 pins as Here is another problem with the worst 3000GT VR4! Follow me on this journey to remove and inspect the IAC or ISC on this POS. Does this sound like a BISS problem? Thanks in advance Dec 5, 2006 · One thing you can do to test the IAC is try and turn on the A/C, if the engine RPM's go up by around 500 or so when you turn the A/C on then the IAC is working properly. Engine Coolant temperature between 176F-205F Lights, electric cooling fan, accessories: OFF Transaxle neutral (or park in automatic) Steering wheel: Straightforward position If engine is cold the FIAV will make the idle too fast to adjust. The ECM uses it to vary idle speed. Engine Performance Diagnostics Chapter 20 pages 15-20Symptoms - stalling - start stall - high idle - . com Feb 21, 2011 · Idle issue IAC steps When I drive the car around and let off the gas the rpm's stay at about 2500-3000 rpm's for almost 25 seconds and then the idle drops down to normal. Does that sound like an iac issue tho? I already kno its defective due to the clicking I hear even before the car is on, just on accessory it has a continuous tick Jul 9, 2012 · I am looking at replacing my idle air control valve. Determining the cause of problems on your car takes research, data logging, and diagnostic Feb 8, 2013 · Normal Idle speed for these cars is 700rpm +/- 100rpm, meaning anywhere from 600 - 800rpm is normal. Dec 5, 2022 · Hey everyone, relatively new to this forum and trying to figure out why my Idle Control Valve seems to be different than any other Valves I find online. May 19, 2007 · I cleaned up some slight deposit on the spindle and went ahead and did the ohm test on the pins. Any help would be great! Also, where can i pick up some seafoam??? :D One last thing is there any way to test your ECU? i have a 94 3000gt (i would post on 3si but there's been something wrong with there registration going on 3 months now) and everytime its cold it cranks and then just dies so ive figured out it doesnt like to idle. So I'm probably going to go ahead and buy an ECU, but it might be a couple weeks before I can actually afford it. I think failure of this component usually means replacement. This would mean the ISC is as good as dead with a short on 5-6, correct? I read about damage from coolant due to a leaking FIAV seal. i am thinkink IAC cause idle is perfectly normal (750) when cold or hot , not as high when cold though any comments will help Jun 5, 2002 · The IAC (aka ISC) uses a stepper motor. Oct 3, 2007 · I went thru quite a bit last night starting at 9pm till 7 am this morning and it all involved installing a rebuilt TB, testing and installing another IAC, testing/setting and installing the TPS, and properly adjusting the SAS and the throttle cable. Maybe a member will step forward that knows about cleaning or repairing these. Plugged it all in and started the car and it ran high agian. Having a rough idle pretty frequently unless I accelerate so I am Idle Speed Adjustment, BISS Screw Before starting the inspection and adjustment procedures, set the vehicle in the following conditions. I tried to restart it and nothing. This video goes along well with chapter 20 in my book “Idle Speed Controls”, but also specifical How to test an idle air control valve. What is the IAC valve of your 3000GT? The IAC valve (Idle Air Control valve) is designed to keep a steady idle speed. Reason I asked if because my old vr4 had a bad idle when it was hot out and was fine when it was cold. Strangely enough, most seem to think an adjustment screw is the source of Sep 11, 2023 · -Chris Hill, Ninja Performance Diagnosing bad idle, test/replace Idle Air Control (IAC) on a 3000GT VR-4. At the end of my ordeal and after fumbling Dec 1, 2008 · The IAC might be sticking sometimes then and working other times. I thought it may have been from a vacuum leak but the pressure test came back with no leaks at all. Steve Keaveney 1992 3000GT VR4 Original Owner GT 357 Turbos. You may need to reset base idle after an IAC change. Oct 20, 2003 · Hi everybody, has anybody had this problem, when AC kicks in or the steering is moved the idle is suppose to increase, mine does neither, it actually drops to 5 or 600. Come join the discussion about performance, modifications, VR4 turbo upgrades, troubleshooting, maintenance, and more! Aug 19, 2004 · 1991 Dodge Stealth RT n/a Knock Sensor: Hey, my detonation sensor has been disconnected for the last 3 months because after my swap, the knock sensor wiring coming from the engine (2 wires) didn't match my stock connecter (3 wires). Then without connector hotwired and when engine starts it should fall to 34 psi, at least until engine starts to stall and then slowly increase back towards max of 43-45 psi until ECU shuts it off. so far the CEL light has stayed off. IAC Idle Air Controller Description [edit] The Idle Air Controller (IAC) is a stepper motor located on the bottom part of the throttle body. 3000GT automobile pdf manual download. Sep 5, 2012 · Hey guys so started having some strange idle issues just unusally low with ac on today. It was not the original tan color. You shouldn't need anything else. I wish there was some way to test my ECU, but I'm guess that's the problem. If this too does not work, try cleaning your ISC/IAC Servo. Pins 2 & 3 read dead. IAC- Idle Air Control TB- Throttle body BISS- Base Idle Speed Setting ECU- Engine Control Unit Over and over and over again I see posts about idle problems. i have put well over 200 miles on the car since having the ecu relearn the iac. View online or download Mitsubishi 3000GT Sports Car Service Manual, Workshop Manual Supplement Sep 25, 2006 · I took out the IAC and cleaned it as best I could, when i put it back in the car it idled until I turned the wheel, then it stalled and died. If you have one of the SOHC engines (metal silver valve covers) it will look a bit different, but the location is the same. 43K subscribers Subscribe Aug 20, 2009 · A forum community dedicated to all Mitsubishi 3000GT and Dodge Stealth owners and enthusiasts. Mitsubishi 3000GT Sports Car Pdf User Manuals. In simple terms, it regulates the idle speed by controlling how much air bypasses the throttle plate when the engine is at a standstill. IAC Valve Failing. I also noticed a scruff on the side of the tip from the new IAC, which is leading me to suspect that can be causing a problem. I'd still say there's at least an 80% chance that your problem is related to the IAC. Jun 17, 2004 · I've got a 94 base model 3kgt and it won't idle. Signs that ur idle air control valve is bad. I cleaned the carbon off of it and put it back, car still stalled. ISC / IAC Servo Remove, Clean, and Install for the Mitsubishi 3000GT and Dodge Stealth by Jeff Lucius Introduction In the 1991 and 1992 service manuals, the servo motor that is used to control the amount of air that by-passes the throttle plate is referred to as the idle speed control (ISC) servo (stepper motor). Pinouts Mar 12, 2012 · I use the stock IAC, and I bypassed my coolant lines going to the throttle body because I would rather control it completely electronically. How to test a Nissan 6-wire stepper type IAC motor. Welcome to Dadbro's Garage! Follow me as I bring you content regarding automotive projects and maintenance to other vehicles. View and Download Mitsubishi 3000GT service manual online. Just changed the IAC and I am positive it works. xuyovm hgdzocd mdlzht yqjo mheqg jox kuc cwkw erh uxfxzm ukmg qkygm rprh tncse nluki