Idle Out of Control (IOC)!

[jeffcoslacker]

Take the ECM to a parts store with a tester, see if they can spot something corrupted in it's operation. You said it seemed OK after the idle relearn, then went back to incorrect operation after restarting, as if something is corrupting the open loop run strategy after one cycle?

[starla3366]

Jeff, That sounds like a great idea.

Is there any problems i would have. Is it really easy to bend the pins on the ECM? I noticed the ECM is a little tough to get to because the radiator overfill is mounted right there.

I am a little sketchy about messing with something that is so expensive, but, If I can troubleshoot down to the ECM Replacement, then, I will just sell the car and notify the buyer of the ECM problem.

Does anyone have any problems with messing with the ECM at this point. I am just to affraid to mess with it right now.

[tblake]

are you sure you have found the ecm? I havn't heard of one being anywhere near the radiator overfill. I'm not sure exactly, but isnt the ecm in the drivers side kick panel inside the car? Um, it should just be a few plugs and screws to take out. Pretty straight forward.

[kevinb70]

take a look at that black plastic housing that sits on the passenger wheel well, you will see two metal clips that hold the top on. it also looks like there is a vent going from the headlights to the ecm in order to cool it? once you remove the cover, you'll see a silver metal module about 5"x5" by about 1.5" thick. I'm supposing this generates heat is why they put it there instead of the passenger compartment, where it could be better protected from teh elements...

[jeffcoslacker]

No problems, really, just unplugs. Lotsa pins but the connectors are made in a way that they have to slide straight apart so it won't damage them.

The parts store I used to work at just got a tester that will do ECM's, so I haven't seen it in action, but they say it works real well, and has cut their incedence of customers trying to return them because that wasn't their trouble.

I don't know if you still have to change the chip on the new ones over to the replacement, you used to. You just have to take care to be static free and very careful to push it in dead on so nothing gets bent up.

[kevinb70]

Powertrain Control Module (PCM) Replacement/Programming

PCM REPLACEMENT/PROGRAMMING

CAUTIONS:


In order to prevent possible Electrostatic Discharge damage to the PCM, Do Not touch the connector pins or the soldered components on the circuit board.
Turn the ignition OFF when installing or removing the PCM connectors and disconnecting or reconnecting the power to the PCM (battery cable, PCM pigtail, PCM fuse, jumper cables, etc.) in order to prevent internal PCM damage.
NOTES:


Service of the PCM should normally consist of either replacement of the PCM or EEPROM programming. If the diagnostic procedures call for the PCM to be replaced, PCM should be checked first to see if it is the correct part. If it is, remove the faulty PCM and install the new service PCM.
The Crankshaft Position System Variation Learn Procedure should be performed if:
The PCM has been replaced.
The PCM has been reprogrammed. See: Crankshaft Position System Variation Learn Procedure
IMPORTANT: When replacing the production PCM with a service PCM, it is important to transfer the broadcast code and production PCM number to the service PCM label. Do not record on PCM cover. This will allow positive identification of PCM parts throughout the service life of the vehicle. THE SERVICE PCM EEPROM WILL NOT BE PROGRAMMED. DTC P0602 indicates the EEPROM is not programmed or has malfunctioned.

REMOVAL PROCEDURE


Disconnect the negative battery cable.
Remove the left strut brace.
Remove the air cleaner housing cover and the PCM from the housing assembly.
Disconnect the harness connectors from PCM.
Remove the PCM from the engine compartment.
INSTALLATION PROCEDURE


Install the connectors to the PCM.
Install the PCM into the air cleaner housing cover.
Install the air cleaner housing cover.
Connect the negative battery cable.
If a new PCM is being Installed, program the EEPROM.
The PCM will need to learn the crankshaft variation. Refer to CKP System Variation Learn Procedure.
EEPROM PROGRAMMING


Set-up - Ensure that the following conditions have been met:
The battery is fully charged and a battery charger is not connected.
The ignition is ON.
The Techline equipment cable connection at the DLC is secure.
If the BCM has been replaced the PCM must relearn the Theft Deterrent password. Refer to BCM Replacement/Programming procedure.
Program the PCM using the latest software matching the vehicle. Refer to up-to-date Techline equipment users instructions.
If the PCM fails to program, proceed as follows:
Ensure that all PCM connections are secure.
Check the Techline equipment for the latest software version.
Attempt to program the PCM. If the PCM still cannot be programmed properly, replace the PCM. You must also program the replacement PCM.
FUNCTIONAL CHECK


Clear DTCs.
Perform Powertrain On Board Diagnostic (OBD) System Check. Refer to Powertrain OBD System Check.
Start the engine and run for one minute.
Scan for DTC(s) using the scan tool.

[kevinb70]

Crankshaft Position System Variation Learn Procedure

The crankshaft position system variation compensating values are stored in the PCM non-volatile memory after a learn procedure has been performed. If the actual crankshaft position system variation is not within the crankshaft position system variation compensating values stored in the PCM, DTC P0300 may set (refer to Diagnostic Aids for DTC P0300).

The Crankshaft Position System Variation Learn Procedure should be performed if any of the following conditions are true:



DTC P1336 is set.
The PCM has been replaced.
The PCM has been reprogrammed.
The engine has been replaced.
The crankshaft has been replaced.
The crankshaft harmonic balancer has been replaced.
The crankshaft position sensor has been replaced.
IMPORTANT : The scan tool crankshaft position system variation learn function will be inhibited if engine coolant temperature is less than 70°C (158°F). Allow the engine to warm to at least 70°C (158°F) before attempting the crankshaft position system variation learn procedure.

The scan tool crankshaft position system variation learn function will be inhibited if any powertrain DTCs other than DTC P1336 are set before or during the crankshaft position system variation learn procedure. Diagnose and repair any DTCs if set.

The crankshaft position system variation learn tunction will be inhibited if the PCM detects a malfunction involving the camshaft position signal circuit, the 3X reference circuit, or the 24X reference circuit.



If the scan tool indicates a problem with the Cam signal, refer to DTC P0341 CMP Sensor Circuit Performance.
If the scan tool indicates a problem with the 3X crank signal, refer to DTC P1374 3X Reference Circuit.
If the scan tool indicates a problem with the 24X crank signal, refer to DTC P0336 24X Reference Signal Circuit.
Set the parking brake.
Start the engine and allow engine coolant temperature to reach at least 70°C (158°F).
Turn OFF the ignition switch.
Select the crankshaft position variation learn procedure with the scan tool.
Proceed as instructed by the scan tool. If the procedure is terminated, refer to Important above for instructions.
Observe DTC status for DTC P1336.
If the scan tool indicates that DTC P1336 ran and passed, the crankshaft position system variation learn procedure is complete. If the scan tool indicates DTC P1336 failed or not run, check for other DTCs. If no DTCs other than P1336 are set, repeat the crankshaft position system variation learn procedure as necessary.

[kevinb70]

Testing and Inspection

POWERTRAIN CONTROL MODULE DIAGNOSIS
To read and clear diagnostic trouble codes, use a scan tool. Use a scan tool to clear diagnostic trouble codes from the PCM memory.

The Vehicle Identification Number (VIN) is programmed into the PCM. Do not exchange a PCM from another vehicle for testing or replacement. When replacing the PCM, the VIN must also be programmed into the new PCM.

Because the PCM can have a failure which may affect only one circuit, follow the diagnostic procedures in this section to determine which circuit has a problem and where it is.

TROUBLESHOOTING
If a diagnostic chart indicates that the PCM connections or PCM is the cause of a problem and the PCM is replaced, but does not correct the problem, one of the following may be the reason:



There is a problem with the PCM terminal connections. The diagnostic chart will say PCM connections or PCM. The terminals may have to be removed from the connector in order to check them properly.
EEPROM program is not correct for the application. Incorrect components may cause a malfunction and may or may not set a DTC.
The problem is intermittent. This means that the problem is not present at the time the system is being checked. In this case, refer to Symptoms and make a careful physical inspection of all components and wiring associated with the affected system.
There is a shorted solenoid, relay coil, or harness. Solenoids and relays are turned on and off by the PCM using internal electronic switches called drivers. Each driver is part of a group of seven called Output Driver Modules. A shorted solenoid, relay coil, or harness will not damage the PCM but will cause the solenoid or relay to be inoperative. The J 34636 tester, or equivalent, provides a fast, accurate means of checking for a shorted coil or a short to battery voltage.

[tblake]

[quote=starla3366][quote=Marlamar]What about a low grade electrical short which drains your battery ? and when you start up, your computer compensates for the drain by speeding engine up to recharge low battery. I had a short in my 95-3.1 that did the same thing, really idled fast on startup and stayed fast for a long period until battery charge caught up.

I checked for bad grounds and shorts in electrical wires last weekend with no joy unfortunatley. But, I did check again last night, with no joy. Also read out the battery at 12.08 volts w/out engine on and 14.06 w/engine running. Now as for letting the vehicle sit for long periods of time, I did not start it up last weekened. So I think if it is elecritcical problems causing this, then it would be a strong enough short to drain the battery with in 24 hours. Great idea though.

Only 12.08 volts? This seems kind of low to me. Shouldnt it be around 12.6 area when not running? Um, was it just cehcked with a voltmeter, or did you actually load test it with a VAT-40 or something? I maybe on a hunch would take the battery out and bring it to a shop to have them load test it. That seems low to me for a healthy car with a good alternator. How often is this car driven?

[tblake]

hey kevin, are you sure he has to go through all of this? Its a 1993 Lumina with OBD1, not OBD2.

[kevinb70]

oh eeek... i got this confused with the 97 lumina thread!!! sorry

and how do you have a 2001 lumina?????

[tblake]

its the last year they made them, they phased them out to start the impala in 2001. Why does that seem odd?

[starla3366]

Originally Posted by tblake

Only 12.08 volts? This seems kind of low to me. Shouldnt it be around 12.6 area when not running? Um, was it just cehcked with a voltmeter, or did you actually load test it with a VAT-40 or something? I maybe on a hunch would take the battery out and bring it to a shop to have them load test it. That seems low to me for a healthy car with a good alternator. How often is this car driven?

Load Test Checked Good at Advance Auto Parts. Tested the alternator also. That checked good also.

I drive the car every single day, minus a day or two on the weekends, back and forth to work. The baby runs great except for this idleing problem.

Oh, and by the way it is an OBD I if anyone has any doubts.

I really appriciate all the feed back I've been getting here. Should I just sell the car, or what, hah hah.

I'M NOT GIVING UP ON THIS SMALL PROBLEM SHE IS HAVING.

[kevinb70]

I thought 1999 was the last year for the Lumina, and that the 1999's were mainly fleet vehicles... I honestly didn't know there were 2000 and 2001 models... just checked autozone and see now there were vin J's... 3.1L only...

[tblake]

yes sir, Its basically a 1998 lumina or 97 or 95, all are the same in my book. They all have the same motor and same body style, hardly no changes that I can see.