FordExcursions.com Forums
Dave Sullivan
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• Kitchener, XX, Canada |
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• Registered on 2/27/2003 |
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• 199 posts |
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 Posted:6/3/2004 11:01 |
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Too my utter astonishment, the EX died at an intersection just as the lights changed.
And it would not restart again. Called CAA and got a tow home ( about 2 miles) and settled into figguring out what the problem was.
Changed the fuel filter which (*fortunately) needed to be changed anyways. The cost was 70 bucks.
Nope, that was not the problem.
Went through the troubleshooting procedures in the book and was horified to discover the number of things that can go wrong. Well, No brainer,, out of my league. So...... (reluctantly) it was off to the local ford dealer for a diagnosis. (expensive). Also checked to see if the PSD still had some waranty. It did :-) :-)
Two days later, I get the story. The CMP Sensor was bad. (naughty little sensor) For those in the dark, the CMP sensor is the cam postion sensor. It detects The iron as it passes by and it also detects the # 1 and the #4 cylender position and sends the digital stream to the module. It works via the hall effect. Thats the short story about the sensor.
The effect of this thing not doing its job is to shut down the injectors thus shutting down the engine.
Obviously, ford needs a better idea. If any sensor quits, the engine should still be able to run, even if only in a limited capacity, A visual indication of the sensor issue/failiure would be nice too.
The cost to me was the 100 dollar deductable and the cost to who ever was 300 and change.
Thank goodness for waranty.
Dave S. |
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E. Long
 
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• Subscriber since 1/1/2001 |
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• Atlanta, GA, USA |
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• Registered on 1/23/2001 |
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• 2,229 posts |
• 1 Vehicle
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Posted:6/4/2004 19:13 |
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The same thing happened to me. It was over the 4th of July weekend and I was out of town. It happened on Friday, and due to the holiday weekend, the dealer I mistakenly had it towed to was closed all weekend. So I had to take an additional day of vacation to get the thing fixed. Ford wasn't sure what the problem was right away because naturally whent hey went to start it, it operated fine and gave no indication that anything was wrong. It took me having to drive it off the lot only to have it die again and get it towed back again to prove to them that something was wrong. Then I had to tell them it was probably the CMP because they didn't really know where to start. Thank God for the forums is all I can say.
But yes, I agree with you -- this sensor leaves you completely stranded. A "service engine soon" light seems a bit more appropriate. I'm sure there's a really good reason behind leaving the vehicle completly disabled when this sensor fails but it sure is major bummer when it happens.
-Eric
'67 Galaxie 500 - 390 FE, .030" over, FE to AOD adapter, disc brake conversion. The Daily Driver.
'00 Excursion - 7.3L PSD, LANDYOT Gen-II Radius Rods, Factory Tech Valve Body, 200K+ miles and going |
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Dave Sullivan
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• Kitchener, XX, Canada |
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• Registered on 2/27/2003 |
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• 199 posts |
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Posted:6/5/2004 23:15 |
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I guess I was lucky. The diesel mechanic at the dealer I took mine too seems to know his stuff when it comes to trouble shooting. IT took him a couple of hours to do it but he followed the right path. I have the Powertrain Control / Emissions Dagnosis manual So its easy to check to see.
He started under the hard to start Diagnosis followed by KOEO check, KOEO self test, Scan tool test, Fuel Pump pressure test. This all makes good sense since generaly, you go for the easy stuff first.
Then it was on to Engine Performance Diagnosis, KOER check, Ignition Control Pressure test and Boost pressure test.
After all that, he must have caught on to something because he changed the CMP and retested.
I had originaly suspected that perhaps the High pressure oil system had a leak or something since this is what controls the fuel injectors. Fortunately that was not the case.
Interestingly enough, the Injection Control system requires the CMP signal before the IPR is comanded above 14%.
The Camshaft position sensor (CMP) is a hall effect type sensor that generates a digital frequency, as windows in a target wheel pass through its magnetic field. The frequency of the windows passing by the sensor as well as the width of selected windows allows the powertrain control module (PCM) to detect engine speed and position.
Engine speed is determined by counting the 12 windows on the cam gear each camshaft revolution.
Fuel timing control involves the position of cylinders 1 and 4 which is detected by distinguishing a narrow or wide window on the camshaft gear.
Engine Mode selection allows the PCM to discern when the engine is in the off, crank or run mode.
Injection control pressure involves engine speed and is one of the controlling variables in the calculation of desired injection control pressure.
Exaust back pressure control is a function of engine speed and load.
As you can see, the failure of this little gizzmo can cause a whole host of SYMPTOMS.
So here's a suggestion to FORD. Put 2 or 3 CMP's on board and have them monitored for failures.
IF one fails, the other two take over and an error code is generated. An indication of a failure is sent to the drivers console either as plain text, or as a simple blinking LED flashing a code. Damn..... thats so simple.
The engine keeps on going, the driver gets a visual warning and CAA or AAA gets to have coffe and doughnuts instead of having to go do a rescue in a buisy intersection or on a more grim note, your wife doesn't have the thing quit at 10 or 11 at night on some back road in the middle of no where's ville with the kids on board. Kudo's to Cell Phones.
Fair warning I would say and its much better than stress pills and bills. THe EX is a great machine but it appears the reliability aspect needs some T>L>C.
Dave S.
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