Stall at idle?

COUNTRYRUNNER

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2003 MITSUBISHI ECLIPSE
6 CYL
2WD
AUTOMATIC
10,100 MILES

Ok I have been fighting this problem for 2 months now. When I start my car it runs fine cold, I start to drive around and works just fine. Then after a few miles of driving and the engine is warmed up it starts to die on me when I come to a stop or when im slowing down. It will start up just fine then die right when I start it up. Now when I let it cool down for a few it mins it will run just fine until its warm again. And I have to rev up the rpms to keep it from die on me. And when I get going down the road it runs just fine just. Took it to the shop and found no codes at all. I check the MAF and its good. Took it to the shop and they drove it around and would not die on them. So I did a experiment I drove it around town when it was cold and did slow stops and it would not die on me and when I did fast stops it would die on me. So checked the IAC with every test I could find to check it and came out fine. So I took it too the shop again. They read the data stream before it died on them and found that the crank shaft position sensor went out of spec when it died. But I think it was because it was about to die it caused the CPS to go out of spec. So they want to change out the CPS and I want to change the IAC. Can anybody help me with this strange problem?

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Sunday, September 26th, 2010 AT 11:32 AM

28 Replies

KHLOW2008

MECHANIC
41,814 POSTS

Hi countryrunner,

If no trouble codes are present and you have not cleaned the IAC yet, I would suggest getting it and the throttle body cleaned and retest.

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Sunday, September 26th, 2010 AT 12:52 PM

COUNTRYRUNNER

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I have cleaned the throttle body and I cleaned the IAC with carb cleaner and still no good. Im hoping the carb cleaner did not mess it up but I don't think it would

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Sunday, September 26th, 2010 AT 2:14 PM

KHLOW2008

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Carb clraner should not pose any problem and if any erractic running or difficult starting was encountered, it should go away after a short period of running.

Other items to check would be vacuum leakages, PCV, EGR solenoids, fuel pressure and purge control systems.

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Monday, September 27th, 2010 AT 1:02 PM

COUNTRYRUNNER

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Well I checked the pcv and it came out good. Im starting to lean towards the egr valve right now because the cars seems to warm up really quickly so it might be stuck shut but if it the egr its still not throwing codes would it not throw codes sometimes? And does my car have a DPFE sensor?

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Friday, October 8th, 2010 AT 4:56 PM

KHLOW2008

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Vehicle is not equipped with DPFE.

I would think it is an idle air control problem rather than the EGR or other systems.

If it is an EGR system fault, it would most likely trigger a code, given the time frame it has malfunctioned.

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Saturday, October 9th, 2010 AT 9:19 AM

COUNTRYRUNNER

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Well I can get a IAC from a friend that has a used one that is still good for $30 problem is coming up with it. And if it is the IAC I would have no problem building up some money for a new IAC but thank you so much for the help though

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Saturday, October 9th, 2010 AT 1:41 PM

KHLOW2008

MECHANIC
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Perform the following test and see if you come u with anything.

Idle Air Control Motor
1. Disconnect IAC motor connector. Check resistance between IAC motor connector terminal No. 2 and either terminal No. 1 or 3. Also check resistance between IAC motor connector terminal No. 5 and either terminals No. 4 or 6. Each resistance reading should be 28-33 ohms (Outlander: 26.5-32.5) at 68 °F (20 °C). If resistance readings are not as specified, replace IAC body assembly.
If resistance readings are as specified, go to next step.

2. If using lab scope, go to step 4. Engine coolant temperature must be 68 °F (20 °C) or less. If not, an Engine Coolant Temperature (ECT) sensor that is appropriate temperature can plugged into ECT sensor connector. Turn ignition on (engine off) and listen for IAC motor operation sound. Operational sound should be heard when ignition is turned on and off.

3. For testing IAC control circuit, perform diagnostic procedure for DTC P0506.

4. Using test harness, or backprobing, connect lab scope pick-up, in turn, to IAC motor connector terminals No. 1, 3, 4, and 6. With engine running, compare IAC motor waveform to normal waveform.

DTC P0506: IDLE CONTROL SYSTEM RPM LOWER THAN EXPECTED

Circuit Operation

"� The idle air control motor power is supplied from the MFI relay (terminal No. 4).
"� The ECM (terminals 4, 5, 17 and 18 - M/T) or PCM (terminals 14, 15, 28 and 29 - A/T) drives the stepper motor by sequentially turning "ON" the power transistors in the ECM (M/T) or PCM (A/T) and providing ground to the idle air control motor (terminals 1, 3, 4 and 6).

Technical Description

"� The amount of air taken in during idling is regulated by the opening and closing of the servo valve located in the air passage that bypasses the throttle body.
"� If there is a malfunction of the IAC system, the actual engine speed will not be identical to the target engine speed.
"� The ECM (M/T) or PCM (A/T) checks the difference between the actual engine speed and the target engine speed.

DTC Set Conditions

"� Check Conditions - Under the closed loop idle speed control. Engine coolant temperature is more than 171 °F (77 °C). Battery positive voltage is higher than 10 volts. Power steering pressure switch: "OFF". Volumetric efficiency is lower than 40%. Barometric pressure is higher than 11 psi (76 kPa). Intake air temperature is higher than 14 °F (-10 °C). 25 seconds have elapsed from the start of the previous monitoring. Target idle air control motor position is more than 100 steps.

"� Judgement Criteria - The actual idle speed is more than 100 RPM lower than the target idle speed for 12 seconds.

Probable Causes

"� Idle air control motor failed.
"� Open or shorted idle air control motor circuit, or loose connector.
"� ECM failed (M/T).
"� PCM failed (A/T).

Diagnostic Procedure
CAUTION:To prevent damage to scan tool (MB991502), always turn the ignition off before connecting or disconnecting it.

1. Connect scan tool (MB991502) to the data link connector. Turn the ignition on. Set the scan tool to read DTCs. Turn the ignition off. If a diagnostic trouble code other than P0506 is output, refer to the appropriate diagnostic procedure. Go to the next step.

2. Check the throttle body (throttle valve area). If the throttle valve area is dirty, clean it and proceed to step
14. If the throttle valve area is clean, go to the next step.

3. Check connector B-34 at idle air control motor for damage. If the connector is in good condition, go to the next step. If the connector is damaged, repair or replace it and proceed to step 14.

4. Check the idle air control motor coil resistance. Disconnect the idle air control motor connector B-34. Measure the resistance between idle air control motor connector terminal No. 2 and either terminals No. 1 or 3. Standard value: 28-33 ohm at 68 °F (20 °C). Measure the resistance between idle air control motor connector terminal No. 5 and either terminal No. 4 or terminal No. 6. Standard value: 28-33 ohm at 68 °F (20 °C). If the resistance is normal, go to the next step. If the resistance is abnormal, replace the idle air control motor
and proceed to step 14.

5. Check the power supply voltage at idle air control motor harness side connector B-34. Disconnect the connector B-34 and measure at the harness side. Turn the ignition on. Measure the voltage between terminals No 2, 5 and ground. Voltage should be battery positive voltage. Turn the ignition off. If the voltage is normal, proceed to step 7, otherwise, go to the next step.

6. Check connector A-18X at MFI relay for damage. If the connector is in good condition, repair harness wire between MFI relay connector A-18X terminal No. 4 and idle air control motor connector B-34 terminals No. 2, 5 (because of open circuit or short circuit to ground). If the connector is damaged, repair or replace it. Proceed to step 14.

7. Check the power supply voltage at ECM connector C-49 (M/T) or PCM connector C-50 (A/T) by backprobing. Do not disconnect the connector C-49 (M/T) or C-50 (A/T). Measure the voltage between terminals No. (4, 5, 17 and 18 - M/T) or (14, 15, 28 and 29 - A/T) and ground by backprobing. The voltage is 1 volts or lower for approximately 3 seconds, then changes to the battery positive voltage when the ignition switch is turned on. Turn the ignition off. If the voltage is normal, proceed to step 10, otherwise, go to the next step.

8. Check connector C-49 at ECM (M/T) or connector C-50 at PCM (A/T) for damage. If the connector is in good condition, go to the next step. If the connector is damaged, repair or replace it and proceed to step 14.

9. Check for open circuit and short circuit to ground between idle air control motor connector B-34 and ECM connector C-49 (M/T) or PCM connector C-50 (A/T).

A. Idle air control motor connector B-34 terminal No. 1 and ECM connector C-49 terminal No. 4 (M/T) or PCM connector C-50 terminal No. 14 (A/T).

B. Idle air control motor connector B-34 terminal No. 3 and ECM connector C-49 terminal No. 17 (M/T) or PCM connector C-50 terminal No. 28 (A/T).

C. Idle air control motor connector B-34 terminal No. 4 and ECM connector C-49 terminal No. 5 (M/T) or PCM connector C-50 terminal No. 15 (A/T).

D. Idle air control motor connector B-34 terminal No. 6 and ECM connector C-49 terminal No. 18 (M/T) or PCM connector C-50 terminal No. 29 (A/T).

If the harness wire is in good condition, replace the ECM or PCM, otherwise, repair it. Proceed to step 14.

10. Check connector C-49 at ECM (M/T) or connector C-50 at PCM (A/T) for damage. If the connector is in good condition, go to the next step. If the connector is damaged, repair or replace it and proceed to step 14.

11. Check the idle air control motor operation using special tool (MB991709). Remove the idle air control motor. Connect special tool (MB991709) to the idle air control motor. (All terminals should be connected.) Use the jumper wires to connect terminal No. 2 of the idle air control motor connector to the positive battery terminal. Check to ensure that the motor operates when the terminals 1 and 3 of the idle air control motor connector are respectively connected to the negative battery terminal using a jumper wire. Vibration should be present at each application of voltage to test clip combination. Use jumper wires to connect terminal No. 5 of the idle air control motor connector to the positive battery terminal. Check to ensure that the motor operates when terminals No. 4 and 6 of the idle air control motor connector are respectively connected to the negative battery terminal using a jumper wire. Vibration should be present at each application of voltage to test clip combination. Install the idle air control motor. If the idle air control motor is operating properly, go to the next step. If the idle air control motor is malfunctioning, replace the idle air control motor and proceed to step 14.

12. Check for harness damage between MFI relay connector A-18X (terminal No. 4) and idle air control motor connector B-34 (terminals No. 2 and 5). If the harness wire is in good condition, go to the next step. If the harness wire is damaged, repair it and proceed to step 14.

13. Check for harness damage between idle air control motor connector B-34 and ECM connector C-49 (M/T) or PCM connector C-50 (A/T).

A. Idle air control motor connector B-34 terminal No. 1 and ECM connector C-49 terminal No. 4 (M/T) or PCM connector C-50 terminal No. 14 (A/T).

B. Idle air control motor connector B-34 terminal No. 3 and ECM connector C-49 terminal No. 17 (M/T) or PCM connector C-50 terminal No. 28 (A/T).

C. Idle air control motor connector B-34 terminal No. 4 and ECM connector C-49 terminal No. 5 (M/T) or PCM connector C-50 terminal No. 15 (A/T).

D. Idle air control motor connector B-34 terminal No. 6 and ECM connector C-49 terminal No. 18 (M/T) or PCM connector C-50 terminal No. 29 (A/T).

If the harness wire is in good condition, replace the ECM or PCM, otherwise, repair it. Go to the next step.

14. Carry out a test drive with the drive cycle pattern. Check the diagnostic trouble codes. If DTC P0506 is output, retry the troubleshooting. If the DTC is
absent, the inspection is complete.

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Saturday, October 9th, 2010 AT 4:06 PM

COUNTRYRUNNER

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WOW that is a lot of info im just a regular guy with a service manual I don't have a scan tool but I will print this off and take it to my mechanic and have then look at it and thanks for the info

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Saturday, October 9th, 2010 AT 4:49 PM

KHLOW2008

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You're welcome. Hope it is helpful.

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Saturday, October 9th, 2010 AT 4:58 PM

COUNTRYRUNNER

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Here is another hint that might help out I had to drive the car today to get to work and when I was coasting down a hill at 40mph the engine was idling at around I think 1000rpm then it would drop about I say 100-200rpm then go back up to 1000rpm now I don't know if that is normal or what. And same thing happens when I accel then let off the gas the rpms will drop to a normal rpm range for that speed but then it will drop some more for a split second then go back up to normal rpm. Just thought I would at this in. Im taking it to a new shop on friday so hopefully they can find something out.

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Wednesday, October 20th, 2010 AT 3:35 PM

KHLOW2008

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Electrical load would affect idling rpm but the IAC should compensate for the difference therefore there should not be a noticeable difference in rpm.

Recheck/clean the IAC again and it might help to reduce or eliminate the problem.

It is good to get a second opinion when one does not work.

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Wednesday, October 20th, 2010 AT 8:53 PM

COUNTRYRUNNER

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Well here are two videos that I made of showing the idle down hill thing. And the only thing is that I does this idle problem only when the car gets warmed up but not when its cold.

Images (Click to make bigger)

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Friday, October 29th, 2010 AT 2:52 PM

KHLOW2008

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When coolant has not reached operating temperature, the cold start system would be in effect and the idling rpm would be higher.

At operating temperature the idling speed would be lower and susceptible to stalling if it is too low.

You need to start replacing something to check if the problem is caused by it and I would recommend starting with the IAC.

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Saturday, October 30th, 2010 AT 10:06 AM

COUNTRYRUNNER

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Well I replaced the IAC and still did not fix the problem. This is a very weird problem it only happens when the engine gets warm. Like when the thermostat opens up to let hot fluids flow and its messing up something or some component is getting hot from the engine and messing up.

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Tuesday, November 9th, 2010 AT 5:05 PM

KHLOW2008

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You mentioned checkig the MAF, did you clean it?

If you can get a scan tool to be plugged in and test drive, you might be able to get freeze frame data to understand what happened when engine stalled.

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Wednesday, November 10th, 2010 AT 7:41 AM

COUNTRYRUNNER

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Well I checked the MAF buy having the engine running and unplugged it. The engine bogged down really bad and almost stalled. And as far as using a scan tool the shop that I take it to ran a scan tool on it while it was die all the time and they said it was the crank shaft position sensor was going out of spec when the engine stalled.

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Wednesday, November 10th, 2010 AT 8:57 AM

KHLOW2008

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In this case you would have to check the CPS. It could be due to dirt accumulation around the sensor.

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Wednesday, November 10th, 2010 AT 9:01 AM

COUNTRYRUNNER

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The what gets me is that the main symptoms of a bad CPS is the car won't start. But I was doing some research on the CPS and the one reasons why it can fail is that hot fluid can get on it and short out the sensor. Maybe when the fluids get warmed up its hitting the CPS and shorting it out but won't do it when its cold. But I will have the shop take a look at it again to be sure.

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Friday, November 12th, 2010 AT 7:38 PM

COUNTRYRUNNER

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Oh and just to add one person said it could be the FIAV that could be not working right here is a quote from him:

"Well, Son you have witnessed the old FIAV failure. What happens air leaks in the FIAV after warm up. During cold start the flows though with no problem, but as soon the Bi-metal spring warms up it is doesn't shut down this part of the idle circuit. The ECM doesn't see this air till it's to late then the ECM is trying to correct this problem, with erratic problems. Time to rebuild the throttle body, or have yours rebuilt. Or do what I have done is by-pass the FIAV altogether."

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Saturday, November 13th, 2010 AT 9:40 PM

COUNTRYRUNNER

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This is just a update I replaced the o-ring on the FIAV and that did not fix the problem. But I have learned something else all winter long that I have been driving it I have had no problems with the car. But as soon as it starts to warm up it died on me again so I am now for sure that something in the car is warming up and when it gets hot it is messing up. Now some one was telling me that moisture could get into the crank shaft position sensor when it is warmed up but works fine when it is cold, is this true?

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Saturday, March 5th, 2011 AT 1:17 AM