QuestionDear Roland:
In an effort to feel somewhat proactive as my mechanic keeps me on pins and needles, perhaps you can shed some light here. I purchased this car in October of 2005 and it ran fairly well. Replaced the tie rods, did a front-end alignment and a rear brake job. Last week Monday, the car cranked but wouldn't turn over. AAA couldn't jump it, I had it towed to my mechanic, it was too cold to do anything and he had to heat the engine up. After doing so, the analyzer told him that the ECM needed replacing, because it was opening the fuel injectors wide open upon ignition, which flooded the plugs and prevented the ignition. He replaced the ECM with a rebuilt from a dealer (under 1-year warranty) and the car worked just fine.
That night and the next day, the "Check Engine" light came and stayed on. Took the car back, had the left-side O2 sensor replaced, no more check engine light.
Believe it or not, a week later, this past Monday of this week, the exact same thing happened (in weather that was much warmer) and I recognized the sound of the car cranking and not turning over. Called AAA again, told them not to bother jumping and to tow the car right away to the mechanic. Mechanic states that he has tested all of the sensors and nothing seems amiss, leading him to think that the ECM is again at fault. Now I'm no mechanic, but obviously, something has to be telling the ECM to open the injectors wide at the wrong time. What are the odds that two ECM's in a row have the same defect?
I'm not sure how to politely suggest to him what he might want to look at, but what is your opinion on the matter? I'm getting rather disgusted at this point.
Joe
AnswerHi Joe,
I doubt it is the ecm being defective. I would of course want to be sure that you have spark for a full 5 seconds of cranking, and if not do you have it for 1-2 seconds or not at all.
If that is resolved, then my next approach would be to look for Fault codes stored in the ecm. Ask if he has looked for faults it may have observed and stored as two digit code numbers. If not, he can try using the ignition key: turn it "on-off-on-off-on" and leave it "on" (doing this quickly, no longer than 5 seconds). Then watch the 'check engine' light to begin flashing, then pause, flashing, pause, etc. Count the number of flashes before each pause and keep track of the numbers. Repeat the readout and verify the counts are correct. Then group them in pairs in the order that they came out, thus forming two digit numbers. You may notice that the pause is shorter between the digits of a given number, and longer between the numbers themselves. Then send me a 'follow-up' question telling me the results of your readout. By the way, 55 will be the last number (two groups of 5 flashes each) and that is the code for "end of readout". If not even 55 came out, then I might wonder whether the ecm is bad, otherwise move on using the codes.
I have the troubleshooting manual for several of the engines and we can look up the possibilities of what is wrong based upon what fault codes you show.
There is also an essay on fault codes at the site:
http://www.allpar.com/fix/codes.html
which gives the meaning of the code numbers. But then you need to get specific info for what exactly might be the diagnostic tests or parts to replace to complete the repair. When writing back tell me the engine and displacement if you happen to know it.
Another part that would be very good to check is the exhaust gas recirculation valve which if it is stuck ajar will return excess air to the intake manifold during the attempt to start and will dilute the mixture to such a degree as to prevent the engine from catching and idling.
So ask if he has verified that the stem of the valve is free to move in and out or not. That can usually be corrected with some penetrating fluid spray.
Those are the higher likelihood approaches to solving the problem.
Let me know how this works out.
Roland
