HELP! Intermittent Startup Problem with my 2002 LW300 Saturn Wagon

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HELP! Intermittent Startup Problem with my 2002 LW300 Saturn Wagon...

For a year (April 2011 to April 2012), my wagon has started up erratically. Although I narrowed the art of starting it up to placing the key in ignition and turning it into 'ON' position (without starting the engine), and leaving it sit for 4-6 minutes - it would 9/10 times startup (after that wait of time). After being rear ended, it became near to impossible to get it to start - so it would rarely ever startup - even after using the same technique i described above.

A diagnostic specialist performed many a test and narrowed it down to suspect the "ECM for Saturn (Engine Control Module, aka Powertrain Control Module?)" to be performing erratically. One of the consistent indicators he observed is that, although the fuel pump sends gasoline to the front of the vehicle (he tested pressure, besides you can smell the fuel after repeated-unsuccessful attempts to try and start the car) - he said that something was causing the injectors to NOT actually inject fuel into the engine. Almost as though some security feature was keeping the car from being stolen.

After, all these tests, I purchased a brand new ECM from GM (one that matches the VIN of my car). Upon installing it, the diagnostic specialist re-programmed it. We tested it, and it appeared to have worked. By this time, though, my battery (an old one that had come with my saturn), had become so damaged that it did not have enough juice in it to even turn the radio, much less the engine. The amount of power left in the battery seemed to be hovering around the threshold of where i can hear clicks clicks clicks underneath the hood, and definitely not enough power to turn the engine. So i've replaced the battery with a brand new one. And it seems to have gone back to the original pattern, where I have to leave the key in the 'ON-position' for 4-5 minutes before it will startup again.

I've read many of challenges posted up on the forums. I've begun to wonder if there is something else that is ill-informing information to the ECM that is, in turn, causing this anomaly.

1) Some have brought up the possibility of the crankshaft position sensor (CPS): Would the crank shaft position sensor interfere, interact with or affect the ECM (engine control module)?

2) Are there other things that could be sending a mixed message to the ECM?

3) Is there a relay or a cable that we can test for this weird/erratic/inconsistent startup problem?

Any thought to this situation that may help is much appreciated.

My car, once running, it never turns off on its own until i turn the key off. It's good that way. But scary cause when I go somewhere far from home, i've become scared to even turn it off. So at times, I leave it running with a friend in the car while i go get groceries or visit the doctor so that I can drive it home. This has become a very difficult, discouraging, serious and impeding concern.

I had the water pump and time belt replaced in january 2012, and change the oil every 5000 km's.

Would spark plugs be the issue?

I appreciate any feedback or recommendation that may help solve this nuisance of a problem.

[fdryer]

1-How many km's/miles?

2-Is the security indicator ON or flashing during START? If flashing during starting then Passlock (GM's theft deterrent system) disables the injectors to prevent driving the car away. It must be OFF during starting.

3-Search for the sounds to listen for at ignition ON time before STARTing. You should hear the faint sound of the fuel pump for 2-seconds.

3-Depending on mileage, the fuel filter may need replacing (100k miles/km's?).

4-Same for spark plugs.

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1 - My LW300 has ~223,000 km (~138,566 miles?)

2 - After reading your feedback, i did notice the 'Security' light flash 3-4 times after each unsuccessful start attempt (engine would turn but not start). I pointed that out to the diagnostic guy who was helping me isolate the problem. At the time he had previously checked it, it did NOT show up as a problem. This appears to have possibly been due an intermittent/erratic problem that was not always constantly noticeable.

3 - The fuel always made its way to the front of the vehicle. It just was being kept from being injected (and it appears it was a security feature - what a nuisance)! Computerized systems should have a keypad security bypass so the owner of the vehicle can request computers bypass systems while they malfunction. Just like a power window feature should have a manual-crank option in case the driver is left with a non-operating powerwindow while driving in the arctic with an oncoming storm. Intelligent add-ons are no longer that intelligent when dealing with the unforeseeable malfunctions.

4 - I'm not sure how to tell what condition these spark plugs are in. Apparently, its not that visibly accessible without first removing some thingy that's covering them. What kind of indicators would lead me to suspect spark plugs need to be replaced. I'm the 3rd owner of this vehicle and don't have reference to its maintenance history.

Conclusion:
Thank you so much for your input. Soon after reading it, I had a diagnostic specialist show up (one last time) to help continue to pinpoint the problem and apply solutions.

Brief background: the diagnostic specialist (Final Exam Diagnostics in Vancouver, BC), during several previous visits, would show up and the car would start working fine. He explained he could not track down the problem unless it was acting up. Finally, during one of his visits, the car was acting up. At that point, he was able to pinpoint that the ECM (engine control module, aka powertrain control module) appeared damaged. After waiting one week for the ECM which matches my exact VIN# to arrive, he installed it, and again, it appeared to start normal. But that normal startup quickly disappeared by the next day. Based on his last visit (after reading your feedback), he believes the ECM was ill-informing the body security computer (that sits out of site, attached to the upper/outer shell of the glove compartment) that all was fine. But this body security computer was not acknowledging that I had the authentic key to startup this car. This would cause injectors not to inject fuel into engine - a theft protection feature (how stupid while its the owner using an authentic key). This is a prime example where a bypass mechanisms would not be a bad idea.

Anyhow, it was only after installing a new ECM that the body security computer was able to then indicate to the diagnostic equipment that it did not yet have the latest software update provided by GM. So we downloaded this update and after installed, made sure the system re-learned the 'authentic key'. After all this, the car did it start like a car should.

Now I have a normal 'starting' saturn - in the sense that it starts when I want and I can get groceries and meet appointments.

I thank this forum and the member who replied to my request for help! It's a combination of your expertise, this forum and my perseverance that helped pinpoint the problem and get my wheels to be wheels again.

MY NEXT GOAL:
To try and solve the 'Service Engine Soon' light to turn off (ERROR PO431 - which I think read Catalyst Warm Up Efficiency Below Threshold).

In March 2012, I replaced that catalytic converter (apparently, the one we removed had no ceramic content in it). The diagnostic specialist asked that I confirm with suppliers (NAPA) that the catalytic converter i bought was actually OBDII certified.

Also, through some online (generic, not make or model specific) research, I found the following...

"A code P0431 may mean that one or more of the following has happened:
* The catalytic converter is no longer functioning properly (which I just replaced in March 2012)
* An oxygen sensor is not reading (functioning) properly
* There is an exhaust leak

To solve it inspect for exhaust leaks. Next step is to measure the voltage at the oxygen sensor on Bank 2. In fact, it would be a good idea to test each oxygen O2 sensor while you're at it. ...."

Questions:
a - How do I inspect for exhaust leaks?
b - Where is Bank 2, and how do I test the O2 sensor - what should the voltage reading be and what exactly am i touching to give me a reading (what tools do i use, and what settings if with an ohm meter or whatever tool i'm supposed to use)?

note: i've heard from GM that bank 2 suggests the passenger side. This is not very clear when i look beneath the vehicle. Is there some diagram to show bank 2 and which 02 sensors I should be testing?

[fdryer]

Its good that this worked out but there may be some confusion about roles between the ecm and bcm

The bcm contains the security program that mainly remains reliable insofar as members here posting issues. The ecm requires coordinating with the bcm as part of GM's Passlock security system for theft prevention. Your ignition key is actually a plain key and does not have any resistor, chip, rfid inserted. A plain ignition key. The security circuitry physically surrounds the ignition switch/lock cylinder assembly and simply requires turning the ignition switch for the security check. The separate physical Passlock sensors are sensing proximity magnets as well as sending a resistance (voltage) for security to match the bcm pre-programmed value. Once this matches, the bcm sends a fuel password to the ecm to allow the ecm to operate injectors. If the Passlock sensors do not turn in sequence with the ignition switch then the security signals won't arrive to signal the bcm at the correct time. The failure to see correct security signals then forces the bcm to send a fuel disable signal to the ecm that disables fuel injection. Its a well proven system and is used throughout many other vehicles besides GM products. So reliable that improvements have now incorporated the rfid chip in the plastic head of ignition keys to use transponders similar to Mobil's SpeedPass, new swipe (smart) cards, EZ Pass for toll roads, etc.. Security seems to be in two steps; identification first (turning the ignition key) and then sending either a valid or invalid security password within the electronics to either enable or disable fuel injection. While sophisticated, its largely reliable.

Something wasn't done to relearn or re-marry the bcm to ecm. There is a procedure to do this if electronics falters. It has never been posted here that Passlock sensors failed or needed replacement. Most issues were power related where security was interrupted and either a 10-minute reset or 30-minute relearn procedure was done to reset security. Ecm's rarely fail while bcm's have failed. Most early failures with bcm's, reported here, were related to less than reliable bcm's. More often than not the bcm's failed with some disabling injectors that required a tow to Saturn to replace it.

As far as spark plugs, they're buried under the solid state ignition coil packs. The intake manifold runners must be removed before the icp's can be removed to reveal any spark plug. Replacement is needed every 100k miles. There's no telling what can go wrong if they remain beyond their useful life.

P0431 catalyst efficiency can be as you listed so with mileage well up there an exhaust system inspection is needed to check for pin holes leaks before the catcon. Next would be suspecting one of two post-catcon O2 sensors. The front two by the radiator are for bank 2 while the rear firewall side are for bank 1. The pre-cat O2 sensors are in front of each coffee can sized pre-converters. The post cat O2 sensors would be after the two pre-cats and before the main catcon. If a pre-cat is worn or damaged from long term use then it would have to be replaced. Inspection would require separating the exhaust system to look into each pre-cat for crumbling or separation damage within the normally solid ceramic honeycomb substrate.

As an aside, I just recovered from a second O2 sensor error code and researched what to do before acting on it. Running through the steps over the week end and asking around, I finally decided to pull one or two fuses to check on blown ones. One of three ecm fuses will reset the error code (not what I wanted) but did so before starting up this morning. As expected, the SES light turned off and stayed off during this morning's drive. I won't know if the error will come back until later when going home. Another O2 sensor error occurred a few years ago in the winter and after the same research I tried a reset - also went away and never came back. My car now has about 72k miles. I don't expect these O2 sensors to fail with little mileage on them.