Cam Position Sensor voltage??

[Jim Jermain]

Does anyone know what voltage I should read at the cam position sensor for a '00 4.0 OHV? My Haynes manual says at least 10 volts when the connector is disconnected from the sensor and the ignition is on run. I am only getting about 0.03 volts at the connector and at the PCM. We checked some other pins on the PCM such as the fuel pump relay and they are reading 12 volts. If it is supposed to be 10 volts or more, any suggestions on why the low voltage? I am fighting an extremely rough running situation where the engine basically won't run and if I force it to run by applying a lot of throttle, the exhaust starts to glow like the timing is way off. I checked compression, firing order, put a new crank position sensor on and still have the problem. I really appreciate any help. Truck has been done for two weeks and wife is getting frustrated.

Thanks!!!

Jim

 

[Runnin'OnEmpty]

......the engine basically won't run and if I force it to run by applying a lot of throttle, the exhaust starts to glow.....

This sounds like a clogged catalytic converter to me.
You can test it by unbolting the cat at the Y-pipe and
seeing if it runs better, or check the intake vacuum
with a vacuum gauge.

Does the cat seem to be very, very hot?

 

[Jim Jermain]

Thanks for the post. I probably should have provided a few more details. I pulled the engine to address several oil leaks and a freeze plug leak. Before I pulled the engine the truck ran great. At one point I was going to have the entire engine rebuilt so I pulled all the sensors (CMP, CKS, coolant, etc.). I reinstalled all the sensors and used the alignment tool on the CMP. When I reinstalled the engine I found it no longer would run. It fires and I can get it to run very rough if I give it a lot of gas, but when I had it running for a few minutes the CATs and muffler were glowing red. It does appear to back fire up the intake and out the exhaust leading me to think it is timing. I checked the compression and all the cylinders read between 120 and 130. The plugs are dark but not wet. It seems to me to be related to timing. I've heard some say misalignment of the cam position sensor will make the engine run horribly, others say it just impacts overall performance.

I really appreciate any advice. Tomorrow I plan to check the Crank position sensor for voltage and also try to determine if the #1 cylinder is firing at TDC.

Jim

 

[Jim Jermain]

Does anyone know what the voltage should be going to the CMP and if it is supposed to be more than 10 volts why I am reading such a low amount?

Thanks,

Jim

 

[Runnin'OnEmpty]

I agree it sounds like a timing problem. Backfiring
out the intake indicates advanced timing; backfiring
out the exhaust indicates retarded timing. You seem
to have both...?

Is it possible when you reinstalled the CMP sensor,
that the engine was at TDC on the exhaust stroke?
Since these engines have a 'lost spark' ignition and
fire on both the compression and exhaust strokes,
they might run with the CMP installed that way.
That might explain the backfiring and the hot exhaust
manifolds, since the injectors would be opening on the
exhaust stroke (with the CMP out of phase)...

 

[craigssvt]

Did anyone ever answer your question? I'm having the same problem after a rebuild. It is in time but no voltage at the cam sensor.

 

[Pete Deering]

Does anyone know what voltage I should read at the cam position sensor for a '00 4.0 OHV? My Haynes manual says at least 10 volts when the connector is disconnected from the sensor and the ignition is on run. I am only getting about 0.03 volts at the connector and at the PCM. We checked some other pins on the PCM such as the fuel pump relay and they are reading 12 volts. If it is supposed to be 10 volts or more, any suggestions on why the low voltage? I am fighting an extremely rough running situation where the engine basically won't run and if I force it to run by applying a lot of throttle, the exhaust starts to glow like the timing is way off. I checked compression, firing order, put a new crank position sensor on and still have the problem. I really appreciate any help. Truck has been done for two weeks and wife is getting frustrated.

Thanks!!!

Jim

It should be the same as battery voltage.

 

[Mackdapitz92]

It should be the same as battery voltage.

Did anyone ever find a fix. I have the ame issue with no resolve

 

[Pete Deering]

Did anyone ever find a fix. I have the ame issue with no resolve

What a AME issue?

 

[Mbrooks420]

Same issue.

 

[Pete Deering]

Did anyone ever find a fix. I have the ame issue with no resolve

What issue are you having? I post a writeup on replacing and adjusting the CMP

Can CMP Synch be changed with engine in place (4.0 OHV)?

See my e-mail to you...

www.explorerforum.com

 

[Mackdapitz92]

What a AME issue?

Pulled motor and now have no voltage to cam sensor

What issue are you having? I post a writeup on replacing and adjusting the CMP

Can CMP Synch be changed with engine in place (4.0 OHV)?

See my e-mail to you...

www.explorerforum.com

 

[Mackdapitz92]

Pulled motor and now have no voltage to cam sensor

No voltage to cam sensor or ignition coil for the drivers. Ram before engine removal. Two pcm and wiring checked. I’m at a loss

 

[Pete Deering]

Pulled motor and now have no voltage to cam sensor

When adjusting CMP. Ford tells you to apply voltage to CMP, when adjusting it.
If you are stating, the engine is installed, car wiring harness in installed. And now you don't have voltage at CMP?
With everything correctly installed car running: you would have the following:
1. The voltage at the CMP is a on and off voltage. Its like adjusting points on a distributor. You need too rotated the CMP or crankshaft too read voltage.
2. The voltage should be a reference voltage from PCM; 5 volts
3. If you don't have voltage after step 1and 2. Check the pins at the PCM connector. Ring out the wires.
Please be more clear on what your problem is.

 

[Mbrooks420]

Is your theft light flashing rapidly?