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ironmike
ironmike, ASE Master tech
Category: Chevy
Satisfied Customers: 3304
Experience:  30 years ASE Master L1 GM certified
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2007 Uplander: 3.9L..It is stalling..intermittantly..immediatly

Customer Question

I am working on a 2007 Uplander with 89K miles and the 3.9L engine. It is stalling intermittantly, immediatly re-starts. I have checked connector 305 for moisture/corrosion, replaced the CKP sensor and ignition module/coil pack, checked fuel pressure and scanned all modules, no codes. No misfires in datastream, all paramaters appear within specification. Checked variable camshaft timing actuator, oil control rod rebounds properly. Any ideas?
Submitted: 5 years ago.
Category: Chevy
Expert:  goodwrench9124 replied 5 years ago.
Hello, and welcome, does the engine stall on decell? or at low speeds?
Customer: replied 5 years ago.
It stalls at any speed, accell or decel.
Expert:  GM Master Tech 01 replied 5 years ago.

Can you watch engine data with the scan tool you are using

Customer: replied 5 years ago.
I have a Genisys scan tool with 2008 Domestic/Asian software, A Solus with 2007 Domestic and Asian software, and a Launch CRdata recorder I have been running on the vehicle. Whan datastream parameters are you interested in?
Expert:  GM Master Tech 01 replied 5 years ago.
cam possiton sensors, Do they drop out when the vehicle stalls?
Customer: replied 5 years ago.
No, the CMP and CKP are counting revolutions until the motor actually quits. I replaced the CKP to correct a misfire condition prior to the stalling situation. I bought the CKP from GM and warrantied it out when the stalling started. I also removed tha variable cam timing actuator to make sure the oil control rod was rebounding as it should.
Expert:  GM Master Tech 01 replied 5 years ago.
Did you check for history codes?
Customer: replied 5 years ago.
Yes, initially there was a U1000 Serial Data Communication Interruption code in the ECM and TCM and an Ignition Starter Circuit code in the BCM (I forget the number) but they have not recurred since replacing the ignition switch. Currently there are no codes in any of the several modules accessable to the Genisys. I wish I had a Tech 2, but I am not in a position to afford one now.
Customer: replied 5 years ago.
I have a question for you. I replaced the CKP to correct a misfire condition. I BELIEVE that the stalling condition started AFTER this, however the car lot that I am doing the work for is trying to tell me that the vehicle had a stalling condition all along. I feel that they are trying to get something over on me (as car salesmen will), but I could be mistaken. My question is that when I replaced the sensor, I was unable to do a crank variation relearn with any of my scan tools on this particular engine. I took it to someone who has a Tech 2 with current software but he was unable to find anywhere in his scan tool to do a crank relearn either. There is no code in any module as I have stated, including PCM for relearn needed. I assumed that because it had a variable cam timing system that it does not need to do a crank relearn. Am I mistaken? If it does need to do a relearn, how do I go about it? Did the man with the Tech 2 overlook it, and if so where is it at in the software? Thank you very much for your input, but this thing is kicking my butt right now.
Expert:  ironmike replied 5 years ago.

Greetings,

Acording to si there is a relearn procedure needed to be done if the cmp or ckp is replaced.

Important: The Crankshaft Position (CKP) system variation learn procedure is also required when the following service procedures have been performed, regardless of whether DTC P0315 is set:

An engine replacement
A engine control module (ECM) replacement
A crankshaft balancer replacement
A crankshaft replacement
A CKP sensor replacement
Any engine repairs which disturb the crankshaft to CKP sensor relationship.

 

Important: The ECM monitors certain component signals to determine if all the conditions are met to continue with the CKP System Variation Learn Procedure. The scan tool only displays the condition that inhibits the procedure. The scan tool displays the signals of the following components:

CKP sensors activity--If there is a CKP sensor condition, refer to the applicable DTC that set.
Camshaft position (CMP) signal activity--If there is a CMP signal condition, refer to the applicable DTC that set.
Engine coolant temperature (ECT)--If the engine coolant temperature is not warm enough, idle the engine until the engine coolant temperature reaches the correct temperature.

 

  1. Install a scan tool.
  2. Monitor the ECM for DTCs with a scan tool. If other DTCs are set, except DTC P0315, refer to Diagnostic Trouble Code (DTC) List - Vehicle for the applicable DTC that set.
  3. With a scan tool, select the CKP System Variation Learn Procedure and perform the following:
  4. 3.1. Block drive wheels.
    3.2. Set parking brake.
    3.3. DO NOT apply brake pedal.
    3.4. Cycle ignition from OFF to ON.
    3.5. Apply and hold brake pedal for the duration of the procedure.
    3.6. Start and idle engine.
    3.7. Turn the air conditioning (A/C) OFF.
    3.8. The vehicle must remain in Park or Neutral.

    Important: While the learn procedure is in progress, release the throttle immediately when the engine starts to decelerate. The engine control is returned to the operator and the engine responds to throttle position after the learn procedure is complete.

     

    3.9. Accelerate to wide open throttle (WOT) and release when the fuel cut-off occurs.
  5. The scan tool displays Learn Status: Learned this Ignition. If the scan tool indicates that DTC P0315 ran and passed, the CKP variation learn procedure is complete. If the scan tool indicates DTC P0315 failed or did not run, or another DTC is present, refer to Diagnostic Trouble Code (DTC) List - Vehicle and perform the appropriate diagnostic procedure.
  6. Turn OFF the ignition for 30 seconds after the learn procedure is completed successfully in order to store the CKP system variation values in the ECM memory

Good luck

 

Customer: replied 5 years ago.

Perhaps I was not clear. I have access to Alldata and Mitchell On Demand and am capable of reading the procedure myself. I am looking for someone who has actually had experience with this particular variable cam timing system and can give me a step by step outline where to find the crank relearn procedure in the Tech 2 machine. It is not listed where it normally would be or is with any other engine other than the 1 VIN code engine. I can not find a relearn procedure in my Solus or Genisys for this particlular engine and if I try to do it under another engine option it is unsuccessful. Apparently there is something unusual about the software for this engine.

I am trying to be as specific as I can get. I am an ASE Certified Master Technician with 25 years experience, also L1 Advanced Engine certified as well as certified in Florida as an Electronics Technician. I am not a parts changer. This vehicle has something very unusual going on with it, and I do not wish to be treated as an idiot who needs basic instruction. Thank you.

Expert:  ironmike replied 5 years ago.

Greetings,

I got this from the GM si . I am sorry if you are offended, I did not mean to do that.I don't like to be treated that way, so I would never do that to others. If I were doing this procedure this is what I woud see. I would hook up the tech 2 and look under engine and search through the options.

Customer: replied 5 years ago.

OK, I am probably a little testy because I have not had something elude me like this van in a long time. Guess I need a little humble pie occasionally.

I sent it back over to the tech I know with the Tech 2. If he can't find the operation on his tool, I guess I will bite the bullet and take it to GM, although I do not have much confidence in the rip-off Chevy dealer and the Pontiac/GMC dealer is down to one driveability tech (the service manager offered me a job, in fact). Hopefully a relearn will fix my problem. I will let you know. Thanks.

Expert:  ironmike replied 5 years ago.
Greetings,
            Most of my experience has been in the independent shops. I am factory trained in ford(2005-2006)Chrysler service contracts 2006-2008 and just recently GM(working for a Chevrolet dealer for 7 months) and I have been doing tons of training. Lots of stuff you can do on the tech2. I will be glad to help and learn at the same time as you.
Customer: replied 5 years ago.
One of the techs found the CKP relearn under Module Setup, did the relearn, but the vehicle stalled within 2 miles after I picked it up. So I still have the same problem. I am about to give up and send it to GM. I really have no other idea except maybe ECM, but I am loath to comdemn it without some other symptoms. And I have never had an ECM cause this sort of issue.
Expert:  ironmike replied 5 years ago.
Let me check for bulletins again.
Expert:  ironmike replied 5 years ago.
Greetings,
             we just had an uplander with an intermittant misfire, rough running with no misfire codes. I checked the cam variable actuator like you, checked injector flow and run some cleaner through the system. I saw the throttle assembly (tac) was off when started after warmed up(19% instead of 12. It turned out to be a spark plug that was cracked(#1 , the hardest plug to get. I didn't see any bulletins that close other than one for leaking valves and the common injector problems from bad fuel.The GM upper engine cleaner really works, not expensive either.
Expert:  ironmike replied 5 years ago.
<p>Greetings,</p><p>                  I have a colorado with misfire on idle, no codes. I was leaning toward an injector but found a bulletin on the vaves leaking causing a misfire at idle. They have a bulletin for misfire and idle issues on the uplander for the same , leaking valves. I have to replace the cylinder head, not looking forward to this warranty job.</p>
Customer: replied 5 years ago.

Mike,

The engine is not misfiring anymore, not since I replaced the CKP sensor. It only stalls now, then immediatly re-starts. I did see the TSB you spoke of earlier, and did an upper cylinder clean because I thought the valves were leaking due to carbon build up. But at that time it was misfiring intermittantly. Everything is intermittant with this thing. Anyway, good luck with your valve job. These vehicles seem to be problematic, and I will never own one. Bring back the good old Astro with the 4.3.

 

Brian

Expert:  ironmike replied 5 years ago.
Greetings,
            When you did the upper engine cleaning did you clean the throttle body? I remember now an uplander that had a misfire issue, I also checked the magnet and the varible cam actuator(stupid design)and found nothing. I saw the tac out on start up and changed the throttle assembly and that was the last I saw of that vehicle. I have seen trucks with the tac set up, cleaning usually doesn't work. They stall and give reduced power on the information center. I had one truck after doing the throttle body gave me a hard time relearning idle. GM lacking in Computer programing and eating up batteries from all the ecm's.
Good luck
Customer: replied 5 years ago.

Mike, I honestly don't remember if I cleaned the throttle body. I did use a Snappy decarbonizer machine and cleaner, but I do not remember checking the throttle. I will look at it tomorrow, but I have never had a dirty throttle cause an engine to stall. However, I also have not had a lot of time with GM drive by wire either. What did you have to do on the trucks that did not clean up, replace the throttle body?

Expert:  ironmike replied 5 years ago.
<p>Greetings,</p><p>                  It happens time to time on the trucks, I would try that and see what happpens.</p>

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