2004 Mercury Gand Marquis will not start
Searched for: My neighbor has a 2004 Mercury Marquis that has and intermittant starting problem. It will operate fine for 3 or 4 weeks, then you go to start it and it will not start. It turns over fine. Battery is good. I tried battery disconnect cycle thinking it might reset the computer logic, key on and off several times, and checked fuses. One time it started right up after that. The next time no help. It was towed to a mechanic and when he got in it, it started. He did a diagnostic on it and determined it was a crank position sensor issue and replaced it. But, 3 weeks later it happend again. I have heard that some makes of cars need to clear old timming circuit faults in the computer to function properly. Is there a manual way that I can try that with this car or do you know anything elase I can try. I think there is a maintenance bulletin out for starting problems on this car, but no recall to fix it. Note: I got it started this last time by removing the cam sensor and crank sensor and reinstalling it along with a battery disconnect reset. it worked, but 3 days later, it would not start again. Now that doesn't work either. Thanks!
Try this the next time it won't start: Either hook up a fuel pressure gauge or reach under and bang on the fuel tank. Your concern is most likely not an electronic concern - these things are practically bullet-proof computer-wise, but the Fuel Pump is a common intermittent failure that will only get worse over time. If you don't have a scan tool that will allow you to watch PIDs, you'll be throwing parts (and money) at it until the cows come home - or you go broke. No such thing as clearing old timing faults or anything like that. If there's a DTC - the Check Engine Light will come on. I've seen it lots and lots of times in our fleet. Dies on the officer or won't restart - gets towed in, runs fine, gets towed in again, finally, someone checks the fuel pressure and the actual voltage and pressure PIDs (or bangs on the fuel tank with a rubber mallet) and the darned thing starts. I'm willing to bet an entire Nickel that your Fuel Pump is failing!
You were right on! did not have the test equipment to check fuel pressures, but Tried the rubber mallet trick on the gas tank and got it started once more. As you thought, the fuel pump finally gave up and my neighbor had it towed to the Ford place where they confirmed the fuel pump was bad and replaced it. Thanks for your help!
You are very welcome!
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