Cam sensor wiring and testing 5.0

[Paul eanes]

Hello everybody have a 2001 explorer XLT 5.0 runs rough at idle after water pump replacement testing cam sensor wiring .diagrams I find are not the same mine has blue wire with orange tracer and gray wire with white tracer can't find any info on testing this can anyone help me?

 

[J_C]

Welcome to the forum!

Do you have specific reason to suspect this sensor? Did you remove the connector or damage the wire or get an OBD2 code for that sensor? If not, I would also check the vac lines, and if you haven't hooked up a scan tool to pull codes, I'd do that and better still a scan tool that can show live data.

I see something on a wiring diagram called an "output shaft speed sensor", is this the same as cam sensor or is that for the transmission? It does show slightly different colors, gray/red and dark blue/yellow.

If that's it, or even if not and it's still just a two wire sensor, then it should be an inductive sensor so (best guess) sensor coil should read at least a few hundred ohms but not more than a few thousand, I mean just not an extreme short circuit or open circuit reading, and produce an AC low voltage signal (or if one of the two wires is ground, then may be DC signal instead of AC) with the engine cranking or running, at a frequency corresponding to engine RPM.

You could also check continuity (more precisely, resistance below 5 ohms or so is the normal ford spec) between the sensor connector and the bulk wiring harness connector to the PCM on same color wires, also checking that those two wires aren't shorting together, but IDK if either should have continuity to ground, and inspecting the bulk connector to PCM, and the connector at the sensor for looseness and corrosion.

Once upon a time ago, on a completely different vehicle ('88 Olds 3800 engine), I put a new water pump on and it idled, and revved poorly and it turned out to be that the new pump had a bad bearing. Swapped the pump and all was right again. Oddly after taking new pump off, it seemed to rotate okay in my hand but not so much on the engine.

 

[Turdle]

99 was a change to a 2 wire cam sensor. You need a 2001 wire diagram..

Again, why do you suspect cam sensor?

Check for trouble code first.

 

[Paul eanes]

Well to do the water pump I had to remove all the wiring in the front of the engine I checked all the other sensors and everything else test good the problem I am having is all the books and wiring diagrams I found show it as a three wire sensor and it says I should have at least 10 volts at the blue and orange wire which I have zero voltage the other wire is gray with a white tracer and goes to ground which I made a ground but I still have no voltage at the blue wire check the wire from the ECM to the sensor and it shows good. but the test is for three-wire sensor so I don't know if that's still applies to my two wire sensor.

 

[J_C]

Okay I have edited my last post and then after seeing your most recent, and looking at a '99 wiring diagram, it shows dark blue/orange-stripe, and gray/red-stripe. I must assume the colors just changed a little from '99 to '01. The gray/red is supposed to be a ground shared with other sensors. The dark blue/orange isn't necessarily supposed to have any voltage until engine is spinning then low voltage DC pulses.

I'm looking at section 25-(n) on this '99 wiring diagram.

I am still wondering if it is just coincidence that you are chasing this cam sensor as the fault when it might be something else. If the cam sensor signal turns out to be okay and if you don't have a scan tool capable of live data, then my low cost of entry choice would be to get an ELM327 based dongle that links to a phone, tablet, laptop, whatever, over a bluetooth or wifi (required for Apple hosts) connection, or USB for a laptop and more "safe" programing if you might ever need that feature, then the host runs Forscan app, free demo version will do one PID (signal at a time) or paid lite version is around $6. There are many choices for ELM327 based dongles, but many cheap ones don't do the J1850 OBD2 protocol that these old Fords use. Bafx on amazon is one of the cheaper options that does.

Once you can see live data, and check OBD2 codes, you can look at the sensor outputs in realtime, and also look at things like long term fuel trim in case a vac line was disturbed or something less obvious like intake manifold gasket started leaking just because it was barely disturbed or something.

I mean, running rough seems more indicative of something like that, not the complete failure of a vital sensor signal unless it is hyper-intermittently shorting out (the dark blue wire in the case of the cam sensor).

 

[Turdle]

Without scanning for trouble codes, you hacked into the wiring?

 

[Paul eanes]

Sorry I didn't say I did check the codes I have a reader I had no codes fuel trim and everything looks good one thing that did pop into my mind was that the fan is cracking and I put some epoxy over the cracks do you think the balance of the fan could be my problem? I did check all the vacuum hoses and have no leaks anywhere.

 

[Paul eanes]

Forgot to say the cam sensor does not show up on the live data readings on the code reader. The Haynes manual I have says it goes to 2001 but the wiring diagram only shows through 99 which shows three wires and tells me for testing I should have at least 10 volts at the blue and orange wire.

 

[J_C]

If it's not getting the camshaft signal, it should generate code P0340 or P0345.

If it were the older design that was 3 wire, you would need a power feed because it's a hall sensor that works like a switch to switch that input power to make a signal, but instead you have a 2 wire which is magnetic/inductive and creates its own AC signal without need of power input, but when one side is pulled to ground, may result in a DC signal instead of AC.

Either it's not getting a signal to the PCM or the code reader isn't checking the correct PID for it so just can't find it. I would now hook up a multimeter at the PCM connector on the respective pins for it and see if you get a low voltage DC, or even AC signal when it is cranking, or if you can access the wires to do it with the PCM connected, then while running.

 

[Turdle]

I wonder if during the water pump repair the wiring for the crankshaft sensor was disturbed. Connector might be unseated. That could cause poor idle

 

[Paul eanes]

The crank sensor I checked all that and the wiring and that all tested okay JC I agree I think that should be an AC signal for the cam sensor I think you're thinking is correct I'm going to check that tomorrow

 

[Pete Deering]

Well to do the water pump I had to remove all the wiring in the front of the engine I checked all the other sensors and everything else test good the problem I am having is all the books and wiring diagrams I found show it as a three wire sensor and it says I should have at least 10 volts at the blue and orange wire which I have zero voltage the other wire is gray with a white tracer and goes to ground which I made a ground but I still have no voltage at the blue wire check the wire from the ECM to the sensor and it shows good. but the test is for three-wire sensor so I don't know if that's still applies to my two wire sensor.

Just disconnect the cam sensor connector. It should throw a code and the CEL will come on. If all the wiring is good. Reconnect the CID connector and the CEL will shut off, but I believe you will have too clear the code.

 

[Paul eanes]

Just disconnect the cam sensor connector. It should throw a code and the CEL will come on. If all the wiring is good. Reconnect the CID connector and the CEL will shut off, but I believe you will have too clear the code.

Yeah that would be the easiest way to do it wouldn't it. Should have thought of that how stupid am I.

 

[Pete Deering]

Ig

Yeah that would be the easiest way to do it wouldn't it. Should have thought of that how stupid am I

you would have to experience a bad CID code and driving went the sensor is going bad..

 

[Mesozoic]

Could be a loose injector connector, perhaps not fully seated.