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Edward, Service Technician
Category: Car
Satisfied Customers: 3136
Experience:  20 + years experience on various makes and models.
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I have a 2002 Mercury Sable with the Duratec engine that cranks

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I have a 2002 Mercury Sable with the Duratec engine that cranks but will not start. The car has 130,000 miles and was running great up until today. Yesterday I parked the car in the garage and when I tried to start it this morning it would not start. It turns over normally but does not fire. So far these are the checks I have made.

The battery and starter are less than three mounts old and both are strong. The engine turns over rapidly.

I have checked for power at the plugs with a timing light and am getting a flashing indication that there is power reaching the plugs.

I can hear the fuel pump in the tank start when the key is turned to the run position. When I checked the bleed off on the fuel rail I get a spray of gas showing fuel is reaching the engine.

The check engine light comes on when the key is placed in the run position and goes out during cranking.

The anti-theft light blinks slowly until the key is placed in the ignition and turned on then it properly goes out.

All of the fuses checked OK and I the PCM relay was replaced just to be safe.

I checked the throttle body and made sure it was opening to get air.

I used a Actron AutoScanner and no trouble codes came up.

I am not a mechanic but in the past with the help of the internet and shop manuals I have managed to keep my vehicles running but this one has me buffaloed.

I am open to any suggestions that anyone can offer.
Hello, I will try to help. It sounds like you have fuel pressure and spark via the timing light flashing, Can you unplug an injector harness, and with a noid light, or a 12 volt test light, check between the 2 injector harness pins, get someone to crank the engine and tell me if you have injector pulse?
Customer: replied 4 years ago.

It will be tomorrow before I can check that. I will check power to the injectors and let you know what I find out.

OK, sounds good. let me know.
Customer: replied 4 years ago.

I believe you're right about the need for checking power to the injectors, but when I finally got around to the project I can't see any way to get to the injector harness except by removing the upper intake manifold. This appears to be a lot of work just to get to a connector to check for power.


If I'm correct the check is to determine one of several things


The PCM may be bad....the fact that the check engine light comes on and I can access it with a scanner I don't believe that's the case.


The injectors may be bad and I feel there is just no way all six injectors went bad at once overnight.


The wiring harness from the PCM could be bad.


The crankshaft positioning sensor may be bad.


I believe I should take a chance and replace the CPS. This seems the most likely suspect and for $20 and less time than it take to get to the injector harness it's worth a try.


What do you think, is this worth a try?



Customer: replied 4 years ago.

From the info you supplied I was able to track the problem to the crankshaft positioning sensor being bad. Once it was replaced the car started right up. I really appreciate your help. THANKS

Your quite welcome and great job!! I'm sorry I wasn't able to respond earlier as I was out of town. If you feel I have helped please rate me positive. and thank you for using

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