Hey everyone,

I did some searching, but haven't found an answer. I had my CPS recall done last summer, just failed the other day. I replaced on the side of the road with a "new" black spare. Ran fine for a few days, truck just died again today and haven't received replacement CPS yet. Just walked home.

The tach is not moving engine cranks, no start, same as the other day. What are the chances another CPS went out? It has been rattling around the glove box for a few years, that have any effect? I also have a DP-Tuner chip installed, don't know if that could have any effect. I did wiggle the connection to the CPS before I left the vehicle, no luck. Any ideas? I need some quick advice, I am having someone come take me to get a cps, but It's freezing out and needed any input. They are a pain to change with cold hands, thought maybe something else? Has anyone seen 2 go out within a few days? What else might cause the same symptoms, tach not moving etc? BTW, I have a 2003 Excursion with the 7.3.
Thanks,
Steve

 

On your '03 you will not see the tach move until it starts up.

With the gray one failing then the black one, I would think you may have another issue. maybe a damaged wire or moisture on the end of the sensor?

You should be able to get another gray sensor at the dealer for around $30. Also Bosch makes one that you can get at the parts stores for about the same price. In a pinch it will work.

Have you verified that your fuel bowl heater didn't blow any fuses? It is tied to the same circuit as your PCM.

 

Same thing happened to my buddy's truck yesterday. Died while running, good crank, no movement on tach. Changed the CPS and it was fine. I personally feel like it doesn't matter which color CPS you picked up, it seems like there are more and more posts about them all going bad.....

 

I'm going to run back to the truck before I go to the dealership, what number is that fuse? I took a quick look before I left, but mostly at the number 9 fuse because that was in my head, now I recall that was the one you remove when changing, which I didn't do last time.

 

this will be number three for me if, in fact it's bad. Seem odd to have 2 failures in a few days. Regarding the other message, I thought the same thing about the tach, but my engine cranks a bit before starting normally (just a little) and the tach moves right away? I thought I remembered reading that that was earlier models. I guess I will see. Any other input is appreciated as I will be checking messages on my phone while on the way to the truck.
Thanks,
Steve

 

I believe it is Fuse #22 on your truck.

Edit: Looks like 30 AMP F2-64, not #22

 

Steve,
When my original went bad, I honestly had my truck towed in four times in three weeks for bad sensors. They just kept going bad one after another. I had the extended warranty on the truck when this was happening so I just let them handle it and pay for a rental. By the time it was all said and done I went through 6 CPS's in three months before the one in it now lasted. This one has been in for about three years now, of course I've just cursed myself......

 

Too funny!

Sounds like I should purchase a spare CPS for my spare CPS.

 

fuse box layout.

 

Well, just went back and it started. Now I'm not sure what it is? Could still be a CPS problem, but it doesn't seem likely. Now I don't want to drive it anywhere. Maybe a fuel system problem, I have a modified fuel system and I have a lifter pump before the high pressure pump, maybe it's having issues, although I replaced it recently. May have to see if I can get it to the dealer to see if any codes come up. Might try spraying the cps contacts with electrical cleaner and see if that helps.

 

Pull the CPS and apply a thin layer of dielectric grease to it. Several have complained about issues like that.

I also know another member who cannot run the black CPS in his truck. He was running an Edge tuner and was having issues every morning on start-up. Put in a gray one and no problems. Something to think about.

Beyond that, I would look at the wire harness closely for any type of chafe damage.

 

When your truck died, what was the weather like? Mine died on me 3 different times..... only in the rain and after I drove through a big water puddle. It was a CPS cause but only because water was getting into it. Finally pulled it out dryed it off and greased up the o-ring, sealed the electrical connection.... alll is good.

 

Hi guys,

Thanks for all the input. I went to the dealer and picked up the CPS and put it in today, we'll see if he keeps running. I had already ordered a black CPS from guzzles site so that gets here soon, now I need a spare. I may have a few spares, if in fact, the CPS is not the problem.

I was also pretty low on oil, probably 2 to 3 quarts. I've heard that that can be a problem? While I was at it, I changed my fuel filters and checked the wires that I could see. There was no apparent sign of any chafing on the wires.

I did add some dielectric grease to the CPS before installation. I'm still nervous about driving, there's nothing worse than getting stranded in cold weather and trying to fix your vehicle on the side of the road.

Anyway, thanks for everyone's help, if anyone has more ideas of what could cause this feel free to chime in. I've read some things about the ICP etc. I hope it's not something I have to hunt for. If it dies one more time, I guess it's into the dealer to check if any codes have been thrown.
Thanks again,
Steve

 

I didn't know the fuel bowl heater is on the same fuse. Not very smart on Fords part. Or do you think there is a reason they would do that? Also I think I remember reading something about CPS's and gauging them and shimming them so they are at the correct clearance or gap. You needed a special tool for the hole in the front where the CPS goes. You know anything about that I think I read it here on FTE I wish I would have saved it. Because if I remember correctly if the gap is wrong it will burn up the CPS or it won't work correctly ? I don't remember. And if anyone would know it would be "Woodnthings". You are like the Shell Answer Man. LOL Now I bring that up because in the tread it was in it had to do with eating CPS

 

The ideal air gap per International is 0.025" - 0.030" between the cam targets and the sensor. The shim kit was designed for the OBS trucks as there was an issue on them with run-out on the cam. The wheel would strike the sensor and damage it. The SD trucks have not had this issue so far. Here are the INSTRUCTIONS FOR SHIMMING

The shim kit is P/N 1826583C91. It comes with 4 shims (2) .005" and (2) .010". This allows you to adjust the gap in .005" increments. I have built a tool to measure the distance of the cam targets using a dial gauge.

The OEM black CPS is about 0.010" longer than the gray or dark blue CPS. This does change the gap and in theory can take it out of the 0.025" - 0.030" zone unless the black one sits at 0.020". With the gray and dark blue CPS being shorter, shimming it does little to no good.

I did some testing on the different sensors with AE awhile back. I posted the outcome on a few forums, but I have it posted on on my site too.

7.3L Cam Position Sensor Perdels Testing

Here are a few pictures of the tool I made and the shims, also a few of the different CPS's. Also a great cutaway shot I found that shows the CPS and the target wheel.