2004 X-type is having problems starting. A DTC alluded to a bad Crankshaft position sensor. I had a new one put in it did not solve the problem. The local mechanic said that the ECU sends 1.5v pulses to the sensor to determine when spark. In my case, the ECU is not sending the 1.5v. He could not locate any wiring or ground issues and said he thinks the ECU is faulty.

Wierd thing is that if it has been sitting overnight and completely cold, it will crank but if I drive it for even a few minutes and turn the engine off, it will not crank back???

Anybody have any clues about this?
Thanks

 

sdreaden, having a bad crankshaft position sensor will not cause the motor not to crank. That will only cause the computer to have problems figuring out when to make the engine fire. So, if you do have a bad crankshaft sensor, the motor will roll when you put the key in the Start position, but will never get running.

What I would like you to try is opening up the hood and accessing the fuse box in the engine compartment. When you look at the fuse box, you will see a bunch of relays in the center and a finned piece in the upper right corner. You will need to buy a new one (or find a friend that has an X-Type like yours and borrow his for a moment) and put it in. See if that fixes your cranking issue. If it doesn't, then you may be looking at a bad ground wire and what is happening is as the wire gets warm complements of the engine, its resistance is going up, leading to insufficent current to allow the starter to turn the engine over. When the car is cold, the starter will roll the engine slower than it should, but is still enough to get the motor to fire.

If you have a multimeter and know how to use it, I can give you a few checks to do to help narrow down where your problem is.

 

The motor does roll over but just won't get running. Can you elaborate on the relay and I do have a multimeter if you can tell me what / where to check.

Thanks for the reply

 

sdreaden, first off, your mechanic has the crank position sensor backwards as the sensor sends the signal to the ECU, not the ECU to the sensor. So, if you are not getting any signal to the ECU, then you have either a bad sensor or a wiring issue. With that being said, to check the sensor, there is an easy check. Unfortunately, getting the sensor out will be the hard part of the whole thing. To get the sensor out, you simply need to get under the car on the passenger side and locate the lower pulley. Now, between it and the block, you should see a little black box sticking out the side held in place by a single bolt. This is the crankshaft position sensor. Pull it out and undo the plug that is attached. Now, at your work bench, connect up a multimeter across the 2 terminals and set the multimeter to read VDC (5 VDC scale or higher). Using a large metal screw driver, pass the screw drive near the end of the sensor that was inside the engine and watch the multimeter. Do you see it jumping around as you pass the screw driver by the tip? If yes, the sensor is working just fine. If you don't see it jumping around, then the sensor is bad. Just because it is a new sensor doesn't mean it works. if the sensor is bad, then you need a new sensor. If the sensor is good, then odds are you have a bad wire for this sensor. At this point, about the only thing you can do is hand over hand the wiring back to the firewall, looking for any spots that may have gotten warm and melted the insulation off of the wire. This can lead to the wire grounding out periodically, leading to the computer being unable to figure out where the crankshaft is in its rotation (uses a 35 minus 1 tooth gear-if you need me to explain how this works, let me know, it is actually pretty neat).

Because your motor cranks (ie, moves when you put the key in the START position), the relay issue is not your problem. If your ECU was bad, your car would not even attempt to start (ie, motor could not crank) because the command to go to the starter goes through the ECU unless you managed to just take out a single part of the ECU which is a very rare occurrence.

 

OK... I got a new Camshaft position sensor. I put it in and it still would not start... So I put the original back in with some test leads connected to it to whach the voltage when the engine was turning over. When attempting to crank it, My multimeter would show the 1.5 volts occassionally but not with each revolution... No sure is the multimeter can't signal quick enough or if the sensor is trully only sending the 1.5 volts some of the time. One other thing I noticed was when I pulled the original sensor out, it was extremely oily. Should I be seeing oil on the sensor?? I have noticed it leaking some oil but it appeared to be from around the oil pan. Also, it has not run hot, etc. If oil should not be there, where would you suspect it is leaking from?
Also, checked both sensors like you sugested and when I would place a metal object near, the magnet would suck it in and voltage would occur.

Thanks for your help

 

Thermo, Should I expect oil on the Camshaft sensor? I wanted to make sure I am not going down the wrong path with looking electrical if the oil should not be there.

Thanks

 

sdreaden, yes, there should be oil on the sensor as it is open to the oil pan. The check I would do is to see if you can remove the sensor and look at the gear that is located behind the sensor. It should be lined up with the center of the hole (ie, inline with the sensor too). If you can, stick a screw driver into the whole and see if you can move the gear side to side in the hole. If the gear moves, you have a problem with the gear and what is happening is as the motor rolls, that gear is wobbling side to side and drifting too far away from the sensor for it to read the teeth.

It sounds like your sensors are good, so, now we need to look at other possibilities. I don't want to send you a lot of small checks, but from the looks of things, we are narrowing down the list of possibilities.