Why have cam sensor ? runs without it.

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Originally Posted By: 04SE
I realize you said he has a duratec but my previous 2004 vulcan taurus had the common CPS failure. We replaced it and upon first start up it stumbled/misfired for 3-5 seconds and then smoothed right out. It ran fine for many tens of thousands of miles until I traded it.


I had my 99 Vulcan done some years back, the dealer's service writer said if he did one, he did 3 per week. It died just out of warranty.

Ford, where Wality is Yob Won.
 
The Vulcans used the synchronize where the old distributor use to be, it generally had the bearing go out then seize and usually messed up the engine pretty good. Ford total hosed the Vulcan with the heater core blockage and the synchronizer.

Do they still make it?
 
Originally Posted By: SHOZ
The Vulcans used the synchronize where the old distributor use to be, it generally had the bearing go out then seize and usually messed up the engine pretty good. Ford total hosed the Vulcan with the heater core blockage and the synchronizer.


If the synchronizer is damaged to the point that it can't turn the oil pump, that does do damage.

But generally the synchronizer gives weeks if not months of warning. It can either be a chirping noise, or stumbling on acceleration. A sensor fault code may or may not be present. I have never heard of one failing without warning, but I have heard of people simply ignoring the noise/light/stumbling "because it runs." Those are the people who blow the engine. They probably also ignore the oil pressure dropping to zero and the check gage light coming on when the pump stops turning.

It is a frustrating engineering failure on an otherwise very durable engine, but if you deal with it when the symptoms first show up it's not a major problem at all. Even on my truck where the synchronizer is back up against the firewall, I can swap it out in 30 minutes or less.

The first time mine started to go bad, I heard the chirping noise. Second time, there was no noise, but the truck would stumble and feel like it was going to stall on acceleration.
 
Just got a text back. The car starts and drives fine with the sensor unplugged. No misfires or lack of power. Install the original or the new cam sensor and it runs terrible.


I asked him to disconnect the battery over night. Install the sensor and then reconnect in the morning.
 
Some times too the metal tang that is on the cam and triggers the sensor comes loose and shifts too. You only need to disconnect the battery for a minute.

Here's a pic of the V8 Duratec cam sensor and the tab.

cam_sensor_tab_2.jpg
 
Thanks for the picture. This evening I'll have him disconnect the battery for 10 minutes. Plug the sensor in reconnect battery and see if anything changes.
Maybe have a look at the wiring and pull valve cover next?
 
Ok. Last evening disconnected battery for 15 minutes. Plugged in Cam sensor. Inspected the wire and plug. Looks good. Wrapped in a pretty robust material.
Connected battery and started her up. Missing and running pretty bad.
I can see why my buddy drives it disconnected. He had to get home so he disconnected the sensor and drove home.
The only thing left is to take the valve cover off and inspect the thingy that triggers the sensor.
Thanks. Any other suggestions?
 
The ignition timing is set by the crank sensor. The fuel injection timing is set by the cam sensor.

Assuming the sensor is good it almost has to be the triggering lobe on the cam or something else directly related.

The sensor is pretty dumb. To check it use a volt meter set on AC and wave a metal object repeatedly in front o f it. You will get a pulsed voltage signal that registers as AC on the meter.
 
It sure looks and sounds like a timing issue. Whatever information the cam sensor is sending to the PCM it is not what it wants.


I will check the new sensor operation and pull the valve cover this weekend.
Thanks.
 
i look at the cam sensor as the distributor tells what cylinder to fire.right? mine went out in the Lincoln I replaced it engines runs smooth.
 
Last edited:
Originally Posted By: boxcartommie22
i look at the cam sensor as the distributor tells what cylinder to fire.right? mine went out in the Lincoln I replaced it engines runs smooth.


The cam sensor is new and it does not have a distributor.
 
Originally Posted By: SHOZ
Do you get a check engine light and a DTC code when scanned?


Yes, misfire cylinders 2 and 4.
cam sensor level = low
 
2002 PCED OBDII SECTION 5: Pinpoint Tests

--------------------------------------------------------------------------------
DR: Camshaft Position (CMP) Sensor DR: Introduction

--------------------------------------------------------------------------------

DR1 DTC P0340: CHECK IF ENGINE WILL START
Note: Refer to the Pinpoint Test Schematic to determine the type of CMP sensor.

Start engine.
Will the engine start?
Yes No
GO to DR2 . DTC P0340 is not the cause of the No Start. GO to Section 3 to diagnose the No Start symptom.

DR2 CLEAR AND ATTEMPT TO RE-GENERATE DTC P0340
Complete PCM Reset to clear DTCs.
Increase rpm to greater than 1500 rpm for 10 seconds. Repeat two times.
Retrieve all Continuous Memory DTCs.
Is DTC P0340 present?
Yes No
For VR type CMP:

KEY OFF. GO to DR5

For Hall Effect type CMP:

KEY OFF. GO to DR3 The fault that produced DTC P0340 is intermittent. GO to Z1 .

DR3 CHECK VPWR VOLTAGE TO CMP SENSOR
Disconnect CMP sensor.
Key on, engine off.
Measure VPWR circuit voltage between CMP sensor harness connector and battery negative post.
Is voltage greater than 10.5 volts?
Yes No
KEY OFF. GO to DR4 . REPAIR open circuit.

DR4 CHECK PWR GND TO CMP SENSOR
Measure resistance of PWR GND circuit between CMP sensor harness connector and battery negative post.
Is resistance less than 5.0 ohms?
Yes No
GO to DR5 . REPAIR open circuit.

DR5 CHECK FOR OPEN CMP, SIG RTN/CMP GND AND PWR GND CIRCUITS BETWEEN PCM AND CMP SENSOR
Note: Refer to the PCM connector pin numbers in the beginning of this pinpoint test.

Disconnect PCM and CMP sensor.
If VR type CMP: Measure resistance of CMP, CMP GND/SIG RTN circuits between PCM harness connector pin and CMP sensor harness connector.
If Hall type CMP: Measure resistance of CMP, VPWR and PWR GND circuits between PCM harness connector and CMP sensor harness connector.
Are resistance measurements less than 5.0 ohms?
Yes No
GO to DR6 . REPAIR open circuit.

DR6 CHECK CMP CIRCUIT FOR SHORT TO POWER IN HARNESS
Key on, engine off.
If Hall type CMP: Measure voltage between CMP and VPWR circuits at the PCM harness connector.
If VR type CMP: Measure voltage between CMP and CMP GND/SIG RTN circuits at the PCM connector.
Is voltage less than 1.0 volt?
Yes No
KEY OFF. GO to DR7 . REPAIR short circuit.

DR7 CHECK CMP CIRCUIT FOR SHORT TO GND AND SIG RTN IN HARNESS
If VR type CMP: Measure resistance between CMP and CMP GND/SIG RTN at the PCM harness connector.
If Hall type CMP: Measure resistance between CMP and PWR GND at the PCM harness connector.
Is each resistance greater than 10,000 ohms?
Yes No
GO to DR8 . REPAIR short circuit.

DR8 CHECK FOR SHORTS IN PCM
Reconnect PCM.
For VR type CMP: Measure resistance between CMP and CMP GND/SIG RTN circuits at the CMP harness connector.
For Hall Effect type CMP: Measure resistance between CMP and VPWR and CMP and PWR GND circuits at the CMP harness connector.
Is each resistance greater than 500 ohms?
Yes No
For VR type CMP:

GO to DR9 .

For Hall Effect type CMP:

GO to DR10 . REPLACE PCM (refer to Section 2, Flash Electrically Erasable Programmable Read Only Memory (EEPROM) .

DR9 CHECK CMP SENSOR OUTPUT
Reconnect CMP sensor.
Digital multimeter on ac scale (to monitor less than 5.0 volts).
Measure voltage between CMP and CMP GND/SIG RTN circuits while running engine at varying rpm.
Does AC voltage vary greater than 0.2 volt AC?
Yes No
REPLACE PCM (refer to Section 2, Flash Electrically Erasable Programmable Read Only Memory (EEPROM) . REPLACE CMP sensor.

DR10 CHECK CMP SENSOR OUTPUT DURING CRANK MODE
Disconnect PCM.
Reconnect CMP sensor.
Connect digital multimeter between CMP and the CMP sensor GND circuit.
Bump engine in short bursts with the starter without starting engine for at least 10 engine revolutions.
Does voltage reading switch between low (less than 2.0 volts dc) and high (greater than 8.0 volts dc)?
Yes No
A CMP sensor that is installed out of synchronization will produce a DTC. VERIFY the correct installation by referring to Electronic Engine Controls, Section 303-14 in the Workshop Manual. If CMP is installed properly, REPLACE PCM (refer to Section 2, Flash Electrically Erasable Programmable Read Only Memory (EEPROM) .
Note: If vehicle has a miss with the P0340 code, ignition/ alternator noise, RFI, and CKP concerns should be considered.
REPLACE CMP sensor.
 
Just background: There are two types of cam sensors. Old school cam sensors (on engines that do not have variable cam timing) are only used to tell the PCM what cylinder is firing, and this info is only used to sync up the fuel injectors on SEFI systems. The PCM always knows what the crankshaft position is due to the crank sensor, but that information doesn't tell the PCM if the cylinder is on the compression or the exhaust stroke. These have a 180 degree shutter/reluctor, many times in a stub housing (like a 3.0 Vulcan).

Later cam sensors (really the PCM) keep track of the above, but also keep track of actual cam timing (vs crank timing) so as to act as VCT feedback to verify the cam timing is where the PCM is telling it to be.
 
Here's the dirt on it from the manual.

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 also use the CMP signal to select the proper ignition coil to fire. The input circuit to the PCM is referred to as the CMP input or circuit.

There are two types of CMP sensors: the three pin connector Hall-effect type sensor (Figure 22) and the two pin connector variable reluctance sensor (Figure 23).
 
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