Chrysler Repair/intermittent shutdown problem: 3.3L '99
QUESTION: I checked tps, the voltage varies between 1-4V between signal and ground. So I guess, it is ok.
I cleaned Idle Air Control Valve; it is still doing this engine stall.
Next I checked EGR again (I have cleaned it previously with no good) as I read on MSN Autos that EGR solenoid is a problem on this model. Now here is what I found:
With the electrical connector disconnected from the EGR solenoid:
I checked the continuity between solenoid contacts and the multimeter gave me zero ohms, so I guess it is ok.
Then I checked for 12 volts on the connector, I got:
between the two wires on connector: 3-5 volts
between the positive wire on the connector and negative terminal on the battery (or body): 12 volts
between the negative wire on the connector and positive terminal on the battery: 3-5 volts
This is true whether the key is just in on position or engine is running. My conclusion is that the solenoid is not getting 12 volts due to the negative wire. I am not sure if the negative is fed through the ground and is coming independently from any junction box. I am not even sure if there should be 12 volts on solenoid connector pin. Please guide on how to investigate/correct further.
ANSWER: Hi Shafique,
The white/black wire on the egr solenoid is a 12v supply wire and is present when the engine is running.
The gray/yellow wire at the solenoid is coming from pin 40 of the pcm and it I would expect would read some voltage other than ground (so 3-5V is OK) except when the pcm wants to open the egr at which point it would ground pin 40 which then puts the full 12v across the solenoid to open the valve. It should typically do that when the engine is operating at a steady rpm while the vehicle is moving (not accelerating or decelerating which is when it seeks to let the egr close under internal spring-action) and which is the condition during which allowing recirculation to occur reduces pollution.
So I conclude that there is nothing wrong with the egr electrical circuit.
I don't know what to suggest to solve the stall. Other than to monitor that the voltage outputs of the ignition switch's various sections themselves are steady while you are driving, since you have no codes and the egr is not slightly ajar which would be the only other items to verify and you have done those.
---------- FOLLOW-UP ----------
QUESTION: First of all, I appreciate your patience with me and my van. You have helped me a lot in ruling out many factors for this stalling issue.
Today, something happened which has not happened before. The engine was at operating temperatures and I was waiting with transmission in P and engine idling. Then suddenly the rpm dipped to 300-400 rpm as if the engine was dying, both Alarm Set and Service Engine Soon lights came on momentarily but then the rpm jumped to normal idling rpm and the engine restarted without cranking. Previously, the engine used to always die if idling and used to restart if I was going at 40-50mph. I suspect this from idle air control valve, which I cleaned along with its housing on Saturday. I cleaned it due to the following symptom: Starting the engine, rpm will go to 1500, then dip to 500 and then rise to normal idle 700-800; the van is still doing it even after cleaning.
Could the cause of stall is this idle control valve? Is there a way I can further check the operation of the valve and its motor? or should I change it. I heard that the pcm needs to relearn, once the idle control valve is disconnected; I am not sure how long.
I would believe that the iac valve would set a code were it not functioning as requested by the pcm, particularly since you cleaned it. I do suspect the problem may be in the ignition switch circuits not being solidly 'on' when they should be. Have you tried spraying some electrical contact cleaner inside the switch proper? Again, try monitoring the fuses I listed to see if the voltage shown on any one of those appears to 'dip' at the same time that the malfunction occurs.
I don't believe there is a significant learning cycle for the iac valve after replacement.