CAm Position Sensor 7.3 CPS Symptoms

Cam position sensor — 7.3 CPS was one of the first parts I replaced on my 2002 7.3 Powerstroke diesel.

The truck had 202,000 miles on it and was a little neglected. So I took out the old grey version—the original black CPS had long since been replaced—and threw it in my glove box as a spare.

Then I replaced it with this new purple/blue/dark grey 7.3 CPS.

More on the 3 different 7.3 CPS color versions later...

Cam Position Sensor 7.3 CPS
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7.3 Crankshaft Position Sensor?

"Crank" Sensor 7.3 Powerstroke?

Let's get this out of the way right away. The "crank position sensor 7.3 Powerstroke" ... doesn't exist. Ford calls it a "Synchronizer" or "Crankshaft Position Motion Sensor." But the more common and accepted nomenclature is 7.3 camshaft position sensor, or 7.3 CPS.

To be clear, there are not two unique sensors, just the one--7.3 CPS. Sorry, no such thing as a crank sensor on a 7.3 Powerstroke.

7.3 CPS - Cam Position Sensor Function

Simply put, the 7.3 cam position sensor identifies which cylinder is at top dead center—the combustion stroke. Knowing this allows the engine power control module (PCM) to adjust fuel injection timing to provide smooth combustion to your diesel truck.

And that means that it helps your 7.3 Powerstroke diesel engine deliver fuel to the right cylinder at the right moment in the timing sequence.

Here's how it does that:

The inserted end of the 7.3 CPS is a magnet. The magnet's job is to sense the spokes and gaps (windows) on the camshaft wheel. Since the cylinder #1 and cylinder #4 indicator windows are narrower and wider, respectively, than the other windows on teh cam wheel, the 7.3 cam sensor can tell which cylinder is about to hit top dead center—TDC.

Then the PCM can deliver the fuel at the precise moment it's needed. It also helps in adjusting things like RPM to ensure smooth idle and operation of the engine.

So, guess what happens if your 7.3 CPS is malfunctioning?

7.3 Cam Position Sensor Symptoms

7.3 Powerstroke CPS symptoms include:

  • Rough idle
  • Hard start
  • Spontaneous stalling...

Dying at idle over a period of weeks or months can signal an imminent 7.3 CPS failure.

  • Unexpected and sudden failure.

Failed 7.3 CPS sensors have left many 7.3 Powerstroke drivers broken down along the side of the road.

One minute you'll be driving down the road with no issues and the next your trusty 7.3 liter diesel will simply dies. Then your engine will crank but not start.

Because if your 7.3's cam sensor is toast, it can't send a signal to the PCM. And if the PCM doesn't know where the cam is in the cylinder rotation it won't send an injector signal to the Injector Driver Module (IDM). Then your injectors won't fire and your truck won't start.

This is the exact scenario that has many 7.3 Powerstroke owners, myself included, carrying a spare CPS in our glove boxes.

And one quick way to tell if it's your cam sensor is...

  • Tach needle doesn't move during cranking.

During cranking, the tachometer needle on a pre 2002 7.3 Powerstroke won't move. A telltale sign that your 7.3 cam sensor has failed.

After 2002 the 7.3 diesel's instrument cluster changed and the "dead" tach was no longer an indication that the CPS had failed.

  • Idle Miss

Ford's new grey recall-replacement 7.3 CPS created a very noticeable idle miss. And injector #8 would fail a Cylinder Contribution Test (CCT) with a Diagnostic Trouble Code (DTC) p0284.

So, before you get drastic and replace an expensive injector, swap out your CPS.

But complete failure isn't the only 7.3 cps failure symptom to watch out for.

Because whichever cam position sensor 7.3 symptoms your truck has, a failure may not even throw a trouble code.

All of these are symptoms that your 7.3's cam sensor is about to fail.

Other CPS 7.3 Powerstroke symptoms include:

7.3 Cam Position Sensor Part Number

OEM Black 7.3 CPS

Part Number - F7TZ-12K073 or F7TZ-12K073-A

You might be able to find one of these around, but eBay sellers are charging a premium for the original black 7.3 CPS.

Ford Grey Recall-Replacement 7.3 CPS

Part Number - F7TZ-12K073-B

Cam Position Sensor 7.3 - Grey
Cam Position Sensor 7.3 - Grey

"NEW" Purple/Dark Grey/Blue 7.3 CPS

Part Number - F4TZ12K073C

Cam Position Sensor 7.3 - Blue
Cam Position Sensor 7.3 - Blue

7.3 CPS Repair Pigtail Part Number

Part Number - 7U2Z-14S411-SA

7.3 CPS Bolt Size and Torque

7.3 cam sensor bolt size

10mm - M8x1.25x15mm

7.3 cam position sensor bolt torque spec

18 lb/ft.

7.3 Cam Sensor Recall

After a lot of failures and unhappy 7.3 owners' complaints, Ford issued a safety recall—07S57—for the light grey OEM 7.3 powerstroke cam sensor.

In grand fashion, Ford's cure turned out to be worse than the disease and many owners went back to the original black version of the 7.3 cam sensor or just lived with occasional misses on the light grey CPS. (see light grey 7.3 CPS Symptoms above)

Until...

Ford released the new dark grey/"purple" CPS sensor mentioned above. 7.3 Powerstroke owners found that it provided better idle and increases in 7.3 MPG.

This is the one I run in my truck and it smoothed things out considerably.

7.3 CPS Location

7.3 Powerstroke CPS Location

The Ford 7.3 Powerstroke cam position sensor location is at 11 'o clock just above the crankshaft damper. It's easier to access the 7.3 CPS from beneath the engine bay on the passenger side.

7.3 CPS Replacement

7.3 Cam Position Sensor Change Video

Here's Fordtekmakuloco's excellent 7.3 cam position sensor replacement video on YouTube.

How to change Cam Position Sensor 7.3

And here are the details on 7.3 CPS replacement:

Tools you'll need

  • 10mm socket
  • 3" socket extension
  • Socket Wrench
  • Torque wrench
  • 12-20" pry bar or long flathead screwdriver
  • Rust Breaker/Bolt release agent
  • Anti-seize
  • Dielectric grease
  • A little bit of new engine oil

Disconnect the negative battery cables

Any time you're working on your 7.3 diesel's electrical system, it's a good idea to remove the battery cables.

Remove the serpentine belt (Optional)

Some 7.3 owners remove the serpentine belt to make it easier to get a socket around the 7.3 CPS bolt head. But I've changed several of them with a 10mm socket and a 3" socket extension without having to remove the serp belt at all. It's up to you...

Disconnect the 7.3 CPS wiring harness connector

There's a retaining tab on the side of the connector. lift this tab away from the center of the connector a bit and then lift the connector off of the CPS.

I know, easier said than done.

So be careful because all the plastic in an almost 20 year old 7.3 diesel's gonna be brittle.

Loosen and remove the 7.3 CPS bolt

There are many ways to break a rusted or seized bolt free. Personally, I use some kind of bolt breaker like WD40 Rust Release or better yet, PB Blaster (Amazon Links). After stripping several bolts on my 200K plus mileage 7.3 Powerstroke, I hit most bolts with release before I try to remove them.

Spray a little rust release on about 30-60 minutes before you try to remove the CPS bolt.

After that, use your 10mm socket and 3" extension or a 10mm deep well with a 3/8" socket wrench to easily break the 7.3 bolt free and remove it.

Remove the 7.3 CPS

I've read where you should wiggle the CPS back and forth and then pull it out. I don't know about that because I've never been able to do it. My suggestion—20" pry bar and some GENTLE leverage applied behind the little CPS retaining bracket.

I think it's more that I can't reach my arm all the way up to the 7.3's CPS to grip it really well and the pry bar gives me the reach.

Your results may vary...

Lubricate and install the 7.3 CPS

Put a little bit of fresh engine oil around your new 7.3 cam position sensor and simply put it back into the CPS socket. This may take a little wiggling this time, so be patient and go slowly. But you'll feel the o-ring "bump" in and then it's seated.

Rotate the CPS retaining bracket so it's inline with the CPS bolt hole.

Whether your 7.3's CPS bolt came out easy or hard, do yourself a favor and apply some anti-seize to the new bolt before you torque it back in. You'll thank yourself the next time you have to change out your CPS.

Then re-install the 7.3 CPS bolt and torque it to specs—18 lb/ft. Yes, you'll need a small 3/8" torque wrench for this.

Grease and reinstall the CPS pigtail connector

Push some dielectric grease down into the round female connector on your 7.3 CPS and clip the connector pigtail back onto the CPS.

NOTE: during the removal of my 7.3 CPS, the wiring harness broke loose from the cable retainer that was holding it to the water pump. I simply replaced that retainer with a zip tie and clipped the end.

The harness retainer is important because it keeps the wiring out of the way of the spinning serpentine belt.

Now, reattach your battery cables, fire up your 7.3 Powerstroke, and enjoy!

Leave a Comment:

MICHAEL HENMAN says

I’ve been bangin my head for 3 weeks ! My 2002 F-350 7.3 suddenly died waiting in the shade with the A/C on.Popped hood and coolant was everywhere (sinister remote coolant line split). I assumed sensor shut it down. Refilled degas tank, made it 4 miles from home a truck shut off. Called tow truck ( waited 2 hours in sun ), turned key over and drove it home….Ordered new CPS, installed, test drove, it shut down 2 miles from home !…..For grins, threw in ICP and another CPS. It idled for hour, headed for a Sunday outing, 2.2 miles from house shut down !!!……I give up

Reply
    Steve says

    Michael,

    I feel for you—been there done that! Sorry to hear the trouble you’re having… I read and reread your symptoms and it sounds like you are only dying after the engine heats up to operating temp. Cold oil is different than warm/hot oil in that it will flow past worn out o-rings pretty easily. From what I can find, assuming that you’ve dealt with the root cause of the leaking coolant first, check these things:

    HPOP reservoir oil level – If it’s up to 3/4″ from top you reservoir is okay. If not you may have 7.3 HPOP Leak. Check for oil in the Valley.
    I’ve read a couple forums calling out the IPR “coil”/solenoid failing and causing engine to die at running temp. Check the ICP duty cycle to determine if IPR is failing. Assuming you have access to a scan tool. I’ve used a Forescan light app on my iPhone with an ELM327 WIFI Wireless ELM327 OBD2 OBDII Auto Diagnostic Scanner Tool Adapter (Amazon Product Link)to check the ICP.
    Injector o-rings – if these fail, the injectors can’t get up the pressure once the engine gets hot and they won’t actuate, causing engine to die from fuel starvation.
    Some guys have done what you’ve done and chased it with new CPSs only to find out it was deeper fuel delivery or oil pressure related problems.

    Hope that helps.

    Steve

    Reply
      James says

      My 2002 F350 is having the same problem as Michael was having. I changed out the CPS three times but it still stalls when the engine gets up to operating temperature. Once it cools it will start but until then when I turn it over the tach s dead. If it is a bad IPR would that cause a dead tach?

      Reply
        Steve says

        I think you’re headed in the right direction , looking at the IPR for when a 7.3 Powerstroke will run and then die and you have to wait to start it back up. Also, getting up to operating temp and then dying is a symptom of leaking oil from the HPOP as thin oil can leak easier and then the HPOP doesn’t have enough pressure to keep firing the injectors.

        The dead tach signal doesn’t always mean bad CPS.

        1999 through 2001 the tach signal came from the IPS, but on 2002-03 that signal comes from outside the CPS circuit.

        Reply
Bill says

I have a 2001 F350 7.3 with 180,000 miles. It dies the other day just as it got to hwy speed. Checked code and it showed CPS failure. Keep a spare, replaced it. Truck started and ran. Took it out again after about a week, same thing. This time it restarted. Mow it has died while idling in the driveway. No failure code. Replaced CPS. same symptoms as a failed CPS, but no code and won’t start. Any suggestions as to where I should check next ?

Reply
    Steve says

    This is one of those times where, without codes or information, it’s hard to get yourself pointed in the right direction. Multiple CPS failures in a row, depending on what CPS brand you’re using, isn’t unheard of. However, since you also have no codes now, I’d check wiring harness, IPR Valve. IDM, UVCH, ICP Sensor, fuel heater blowing the #22 maxifuse… Without codes or some obvious leaks in the HPOP, etc.. you really are chasing the problem. Though, it could be a bad wiring harness to the CPS or electrical on the way there that’s shorting out a fuse or frying the CPS itself.

    Let me know what you find out as this is more common than you might think. Chasing CPSs… Not my favorite.

    Steve

    Reply
Bob Romanoski says

I have a 2003 7.3 that is giveng me CPS nightmares. Would be driving down the road and just quit. Threw CPS code so I replaced it. Worked perfect for a couple of weeks. Started to rain and it quit and it threw the same code. checked conections and made sure I had enough dialectric grease on them. looked harness over and couldnt see any bare wires or problems. Quit raining, runs perfect. Drive in the rain it takes about 15 miles and it quits and throws the code. Frustrated so I replaced sensor again. Still does the same thing. Dry roads runs perfect. Wet roads quits afteer 15 miles or so, Lastly it always starts up after a bit but will quit again after 10 miles or so.

Reply
    Steve says

    Couple of things:
    Sounds like your 7.3 CPS may have a short in its circuit somewhere. Make sure you have plenty of dialectric grease on the CPS connector harness leads.

    Also, I’ve read about reports of the windshield wiper circuit interfering with the 7.3 CPS signal, causing the CPS to throw a false positive code. You might try an alternative 7.3 CPS to the one you’re using, preferably OEM, to see if that fixes the problem.

    The more I research it, the more it seems like multiple people have issues with wiper interference with aftermarket CPS… Not everyone, but several…

    Reply
Charles Porcaro says

I have a 2000 Ford F-350 4 Wheel Dr. with a 7.3 turbo diesel 153 000 miles I’ve been doing some engine modifications I have an oil leak on the right side of the motor on the oil row but it’s very hard to get two Took the exhaust pipe off to get to it have a question if anybody can answer I would like to change The fuel lines that go from fuel go two the right side and left side heada Watch some YouTube videos they said that there are Check valves screwed into the heads wondering if I can Remove the check valves and put high flow adapters removing the check valves would that cause a problem

Reply
    Steve says

    Specifically to your question, I removed and replaced my stock 1/4″ fuel lines with 3/8″ braided fuel lines rated for diesel fuel and AN fittings in the fuel rails and the Fuel bowl. (REMOVED the check valve fittings)

    Engine performance went up, rough running went down–smoothed out the engine at idle and acceleration.

    Reply
CFIV says

Does the grey CPS recall affect only the new body styles?

It was recommended by a Powerstroke specialist at my local International to use the grey CPS on my 1996 7.3. I’m not sure of the P/N of the OBS gray CPS.

Reply
    Steve says

    I’d go with the new – “purple”- one that I list in this post. F4TZ12K073C (Amazon link). Mine’s still going and it’s stated to run on 1994 7.3 to 2003 7.3 diesel engine.

    Reply
PJ Dionne says

Hi,
I recently bought my 3rd 7.3, sold the first one and regretted it so.bought a 2nd one but that one was stollen so here I am, with the 3rd one.
I had very bad glow plugs so the truck had to be plugged in overnight, I live in Canada, and one day it just wouldn’t start even after being plugged. So I thought my CPS was done, I did change all 8 glow plugs, and put a brand new lite grey CPS in and still no start. The rpm gauge doesn’t move when I crank even my lil OBD2 app on my phone does not show any revs either still. I know these were recalled but could it actually be a bad one from the manufacturer?
It is a 2002 F350 7.3 automatic.
Any help or pointers is greatly appreciated,
Thanks

Reply
    Steve says

    First, I’ve regretted every 7.3 I sold and wish I could get them back. As a “new” 7.3 that’s 20 years old and in great condition are now selling for what I paid for them 20 years ago! Crazy
    Second, sorry to hear about the theft of your second one. You don’t happen to live in Revelstoke, do you? I’ve had buddies lose an entire trailer of snowmobiles AND their 7.3 in the time it took them to stop for lunch!

    Down to business…

    Normally, I’d say get a purple-NEW-one. There have been many reports of “new” grey or other CPSs showing up DOA from the manufacturer. However…

    2002, 2003s and some 2001s won’t show cranking rpm at all until the engine starts. Several things will cause a no start, but the tach not moving during cranking is by design after 2001. As Ford upgraded how the electrical signal is sent to the tach.

    Make sure your Wait to Start WTS light turns on as soon as you turn the key on? This tells you that the computer is running.

    Do try another CPS just to make sure. It’s a cheap test.

    Darin the fuel bowl with the yellow drain lever on back of fuel bowl. Close the lever and then turn the key to activate the fuel pump and make sure it refills.

    You might be low on fuel…

    Is it cranking hard enough?

    Reply
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