Help with a Moutaineer!

[Jeremy airjer W]

I have an 01 Mercury Mountaineer with a 5.0 AWD. It came in with a check engine light on and the customer complaining of a rough run at around 60mph. I test drove the vehicle and under load it did feel like a missfire intermittently but would do it at any speed as long as there was some load. The code is P0340 camshaft position circuit error. The first step was to clear the code and run the vehicle. It came back right away without having to raise the idle. The scantool always read cam position error. I ran through the rest of the diagnostic steps and everything checks out. I double check thinking I am missing something and had the same results. I decide to replace the sensor. Cleared the code and started the vehicle. No cam position failure so I think to myself, SWEET! Took it for a test drive and about a mile down the road it triggers the same code, uh oh! drive back to the shop and was waiting for the door to open and noticed the scan tool switched back to no cam fault, weird, raise the idle and the cam fault returns. Thats where I left it for tonight.

Knowing that Mitchel is not the most reliable resource for ford diagnostics I am starting to wonder if I am missing a step or two? What do you think?

[Shack]

Have you checked wiring and connector? Seem to me I remember a similar concern like this in the past. Where did they order the crank shaft positioning sensor?

Would not be the first bad new one to be thrown in.

[Jeremy airjer W]

Straight from ford. The connector looked fine. No corrosion wires look sound.

I'm thinking my next step is to watch it with a lab scope to see if the signal is correct out of the sensor, then check at the PCM to see if the same signal is making it there. If it is I would Probably lean towards a PCM, if not than I know there is an issue with the wiring with the engine running and or hot. Doesn't quite seem logical since its fine at idle but acts up off idle.

[Shack]

I had PCM in my original post, before I edited it out. I just hate saying PCM, because it’s the holy grail of shot gun parts and it sucks when it does not fix it. I feel it turnouts to be a wiring issue, even it the technician does not admit it in the end .

Lets us know and good luck

[Shack]

 Originally Posted By: airjer

Doesn't quite seem logical since its fine at idle but acts up off idle.

Slight movement of the eng????

Hopefully 4wandering can do a T.B.S. search or knows further. With Oasis and WDS right in front of you, things seem much easier .

[deadeye]

The only thing I remember about the ford camshaft position sensors is that when they are put in the need to be clocked to the right position...I have sold the otc tools for that several times but, I'm not sure how you go about doing it.

[Scott K]

Airjer, the best way to diag this would be with a lab scope, watch for a jumpy pattern. Most comon concerns with them are the cmp syncronizer. What happens is the shaft bushing it in starts to bind, then it j-erks instead of freely spins, you get a bad wave pattern. Then after being tight and jerky for awhile the bushing wears out and is sloppy. Some times when it is tight the syncronizer seizes and snaps the shaft that goes to the oil pump. There is a tsb, 02-22-01, that gives you the scope waveforms and the tool #s to realign the syncro when reinstalling. These are simular to the 3.0u taurus, if you have done any of them.

[Eric Wettschreck]

Jer, you know way more about this stuff than I do, but here goes.

My co-worker, same ride, same problem, about 2 weeks ago. After replacement of the cam position sensor the problem still existed.

To make what could be a very long story short, it turned out to be water in the fuel. A new fill up and fuel filter and problem solved.

Why the cam position error code punched up is a mystery to everyone.

[Jeremy airjer W]

 Originally Posted By: 4wanderingeyes

These are simular to the 3.0u taurus, if you have done any of them.

Usually the tuarus is pretty cut and dry becuase they typically make that noise thats stumped all of us the first time we heard it. Sounds just like a belt squeal but from the wrong side of the engine. The lab scope will be step one today.

Shack, PCM is always the last on my list as well. I had a saturn a couple of months ago no spark out of the 2/3 coil figured it was a module since I swapped the coil and the 2/3 coil worked in the 1/4 spot, wrong. Ended up being no 2/3 coil control from the PCM. That was officially the first saturn PCM replaced at our shop.

Boiler, all kinds of theories could be made over that one! It just proves that just about anything can cause just about anything!

[Jeremy airjer W]

Success! The first thing I did was check the wave patterns and found nothing unusuall. Decided to pull the CMP shaft to see if there was any play or binding. It seemed tight and smooth. Reinstalled and synchronized the shaft. Cleared the code and test drove. Problem solved.

Thanks for the help gentleman!

[DTro]

Just curious what the shop rate is for FM advice

[Jeremy airjer W]

FREE! No Charge, Nada, & Nothing

[Shack]

Last words from a Tech, I smell come back .

I all most made a couple of calls today.

Lets hope messing around down there helped.

Good luck!!!!

Dtro,

About a $110.00 an hour now-a-days..

[Shack]

But for FM members free!

[Jeremy airjer W]

Your are correct. The customer called back about a half hour after picking it up and said it ran great for about 20 minutes and then started again. After further fact seeking we found out it started right after he filled up the tank. Coincidence? Based on what Boilerguy posted I am wondering if this could be a fuel issue since he also stated that he has never filled up there before! I ran through everything that I had done with the customer and we decided to run out this tank of gas and fill up at his regular filling station to rule out the gas factor. Cross my fingers and hope that this falls under the goofiest problems have the simplest fix!!

[Eric Wettschreck]

Jer, I'm no tech. I'm a shadetree mechanic at best. Please let us know how this pans out.

I honestly don't understand how a bottle of Heet, a fuel filter, and a fresh fill can cure this problem, but it did for my co-worker. My small brain tells me water in the fuel would present with different symptoms, but what do I know?????

[Jeremy airjer W]

This one is officially fixed! It came back on Friday after running a fresh tank of gas. I started at the top with the diagnostic steps and everything check out as expected until the last step. They want you to check for switching voltage on the two wires going to the sensor at the unplugged PCM connector while cranking the engine. I checked with two DVOM's and found no voltage. Since the previous steps panned out I was confident the wiring and connection where not the issue. The CMP sensor was replaced again with A dealer part. The vehicle was test driven several times on Saturday with no issues and the customer has had it for 3 days with no previous symptoms showing up.