I changed out the CPS in my car last year with one from advanced auto. Has worked fine until recently. Check engine light came on and car would not start. It would crank over and turn...but not start. Pulled it out and went to same advanced auto....and they warrantied the part. Put it in...car started. Short test drive.....seemed all right. Got up to 4000 rpm....and car dies every time. Tested this theory out several times....same thing. Car dies....but restarts. Could this be from the aftermarket CPS? Pulled it out....filed it lightly to make sure sensor was clean and working......same result on test drive. Dies at 4000 rpm. Gonna order a Bosch CPM and see if that fixes the problem. Again....even though it is a new CPM....could this be the problem...or the clip that connects to it?

 

I don't know if the CPS is the problem, could be.
It is a magnetic reluctance device, essentially an electromagnet ( wire wound magnet ) that is excited by the flywheel teeth.
It generates a sine wave signal at a frequency dependent on RPM. This signal is sent to the PCM via twisted pair wires.
( filing the tip would be detrimental, and if too much filing was done it could become inoperative )
It, and the Camshaft Position Sensor ( a Hall Effect sensor which generates a square wave signal ) are used by the PCM to determine the exact position of all engine components for ignition and fuel injector timing.

This is the reason that all modern engines utilizing this technology must turn over a minimum of 2 revolutions before actually starting.
( Takes 2 revolutions for the PCM to get it's ducks in a row )

 

This is exactly what happened with my Advanced Auto Borg Warner CPS. 4000 rpm and shut off. A Bosch CPS solved the problem.

Les

 

"This is the reason that all modern engines utilizing this technology must turn over a minimum of 2 revolutions before actually starting.( Takes 2 revolutions for the PCM to get it's ducks in a row )"


Careful with the generalities. I have had a number of 88-92 GM 3800s (just have two left now) with CPS and typically all I needed to do was turn the key ON, give it 2 seconds to prime the fuel rail, just barely bump the starter, and the engine would be off. Do know the GM CPS had two rings, one with 3 teeth and the other with 18 but almost always started within 1/8 turn.


Have had quite a few engines with carbs and electric fuel pumps and once I would get done tuning they were the same: bump and go.


XF took some getting used to in that it wants to crank for a while before starting. It does have the autodisengage so I usually just put in neutral, turn the key to START and then push in the clutch until it lights off.


Now that I think on it, the Jeep usually cranks a bit but there I just put my foot on the brake and push the button, everything after is automagic so may crank a bit.

 

88-92 3800's did not have a CPS :