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Cam & Crank Position Sensor Photos

new 1/5/03, 10/5/2003, 10/6/2003, 12/05/2003, 07/10/2006

Cam sensor tab 2.jpg (79377 bytes)

Cam sensor tab 3.jpg (67654 bytes)

Click to enlarge, Thanks to Paul Nimz

As I understand the cam sensor it will not stop an engine from starting. Only cause a long cranking with initial misfiring. The CPS or a PCM issue will stop the electrons from flowing to the plugs. If all is well the coils have 12V+ at all times when the engine is cranking or running. It is the individual coil ground that is switched. So when in the no start condition see if there is 12V+ at the coil plug.

Paul Nimz
'97 TR
'93 EG mtx

Your right about the cam sensor. I have had and have again a cam sensor issue, I have replaced the trigger switch twice now and I got the code yet again. I have heard of the actual trigger ( looks like a diamond ring on the end of the front exhaust cam) coming loose and fouling things up. It is threaded on the cam like the sprockets are from the start of their life and also gets swedged (locked) into place (supposedly).

The car will start and run but it stumbles abit and throws the cam code, if mine is loose Ill end up welding it in place and change my procedure on the cam welds to accommodate for the other item that can come loose. Because there is no force on this piece, Tim's Loctite solution maybe be a good idea on this piece to secure it from rolling around, the piece has an (tit) point all by its self that swings by the magnetic trigger to keep the timing on par. ( for the do it yourselfer this is easy)

Imagine a clock with one hand swinging, that it what this looks like when under operation. So a single weld on the opposite side won't bother it a bit.

Rich, will it fire at all? Next time this happens pop the hood and the Mega fuse panel cover. Pull the top left (GREEN) (as looking at the fuse box) this will clear the PCM immediately of (keep alive memory). See if she will then re-fire.

I haven't seen any Crank sensors going bad, I have heard of it though.. you may want to pull the vanity cover off and chase the wires down to the CPS. They run just to the left of the oil fill , then the CPS wires break off and go down the outer front edge of the timing cover to the Crank, it is possible that a clip came loose and that a pulley is cutting through the harness.

Kirk J Doucette
NESHOC President
Stormtrooper-97 White

I had a camweld a while back where the cam trigger was loose and in the wrong spot because I must have bumped it during the camweld process. Kicked my butt when it came time to restart the car. Swapped out PCM, CCRM, Cam sensor, Crank sensor, Yada Yada Yada.... Suffice it to say that most of the electronics from a camfailure car in my driveway found themselves on a customer's car during this electronics "lesson".

Always the same - cranks and cranks and ALMOST starts but just won't get it going. Pulled an old camshaft out for a reference and sure enough, the trigger lobe was not the same on the newly welded car and it moved EASILY. I repositioned the trigger and used a center punch to lock it into place. 4 punches on each side where the trigger ring meets the camshaft. The trigger ring is now locked down snug but could still be moved if necessary.

Damn thing fired right up. Spent the next hour putting all the electronics back to where they came from. Painful lesson.

Eric Lehmann
97 Ebony 37k Welded
97 TR 123k Welded, Revived camfailure
91 Jade Plus SHO-fa

Donít think you banged it, its to far and out of the way during the welding process. I bet it came in loose and the car was defaulted into LIMP mode when you drove the car in. Still a crummy lesson! 

Kirk J Doucette
NESHOC President

How things work. I think that if the Cam sensor has an intermittent fault it will fire the coils and injectors out of time with the engine. The engine will flood and not start. Later, the sensor works right, the excess gas has evaporated and the car starts. IMHO.

Camshaft Position Sensor

The Camshaft Position (CMP) sensor detects the position of the camshaft. The CMP sensor identifies when piston No. 1 is on its compression stroke. A signal is then sent to the Powertrain Control Module (PCM) and used for synchronizing the firing of sequential fuel injectors. The Coil On Plug (COP) Ignition applications (Taurus SHO, Mark VIII, 5.4L Expedition/Navigator, 5.4L E/F Series, and 6.8L Econoline) also use the CMP signal to select the proper ignition coil to fire. The input circuit to the PCM is referred to as the Camshaft Position (CMP) input or circuit.

Crankshaft Position Sensor (Integrated Ignition Systems)

The Crankshaft Position (CKP) sensor is a magnetic transducer mounted on the engine block adjacent to a pulse wheel located on the crankshaft. By monitoring the crankshaft mounted pulse wheel, the CKP is the primary sensor for ignition information to the Powertrain Control Module (PCM). The trigger wheel has a total of 35 teeth spaced 10 degrees apart with one empty space for a missing tooth. The 6.8L ten cylinder pulse wheel has 39 teeth spaced 9 degrees apart and one 9 degree empty space for a missing tooth. By monitoring the trigger wheel, the CKP indicates crankshaft position and speed information to the PCM. By monitoring the missing tooth, the CKP is also able to identify piston travel in order to synchronize the ignition system and provide a way of tracking the angular position of the crankshaft relative to fixed reference.

Glen Murdock
Port Lavaca, TX
97 PG 104k
89 CR 142k

I would suspect a problem with the Crank Sensor, the Cam Sensor, or the associated wiring. Inspect the wiring for damage or loose connections. The sensors are easy to replace and relatively inexpensive.

Glen Murdock
Port Lavaca, TX


You CAN take a Cam Position Sensor and make it work in a Crank
Position Sensor Slot in a Pinch.

Larry's Car wouldn't start. It's Sunday. There are NO Parts available
and I had a new Cam Sensor handy. You DO have to file down the face of
the front cover bolt that is right behind the Crank Sensor. Then the
Plug will fit.

Car Runs, It's a Fact.

Eric Lehmann
97 Ebony 42k Welded - With the Angels Now so that I don't have to be.
Long Live the Garage Queen !
96 Medium Willow Green Metallic 95k Resurrected, Welded
96 Rosemist 68k Garage Queen in Training, Welded
97 Pacific Green - Parting this one Out
crank-sensor.jpg (80320 bytes)

This is the crank sensor that came out of SW9 yesterday (07/09/2006) Click on the thumbnail and observe the crack in the ring. Don't know if that was the culprit, but do know it isn't supposed to be there. 

Thanks again to my bud Eric for hauling the mail up from Lombard, IL to Pell Lake WI to help me out. Slim chance I was going to get my stumps up there to grab that puppy. Not to mention the requisite one bolt that just sez no!


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