toddmc

hello i have a 2002 tracker 4x4 2 door i get no spark vehicle was driven into a puddle by previous owner and now wont run it will turn over but no spark to start things replaced spark plugs ,pcm coils but wont start

hanky

You might want to look down by the crank pulley for wiring to the crank sensor. It may have been damaged.

L84sky

In all three 2001 engine options (1.6 L, 2.0 L and 2.5 L) the PCM fires the ignition coils and fuel injectors based on timing signals from the Camshaft Position Sensor (CMP) .
The ignition circuit shown above is for the 2.5 L.


The Hall effect CMP sensor described above is 3-wire device used in the 2.0 L and 1.6 L engines. The 2.5 L uses a 4-wire optical CMP. The 2.5 and 2.0 L CMP's are adjustable.
The 1.6 L CMP is not adjustable.

toddmc

thank you i will look for it

toddmc

thanks for the info i will look

hanky

The Cam (CMP) sensor is used mainly to provide the spark to the correct cyl at the right time. Once the engine is started , it will continue to run without a CMP signal.
The crank sensor (CKP) provides the RPM info,initiates the sequence to let the system know the engine is turning over

It does require to have a CMP signal to start though.
Have you had a chance to look down at the crank sensor location for any wires that might have been disconnected?

L84sky

The Chevrolet service manual says the CMP supplies the input for ignition and fuel timing.
All three engines use the CKP sensor to detect engine misfires.


As a test, I disconnected the CKP at 0630 this morning. My 2001 V6 Tracker started and ran
normally. I did generate a "check engine" light which I cleared after reconnecting the CKP.

toddmc

thank so much for your help0 i will try and take a look at this next weekend i hope its just a simple fix

L84sky

I spent yesterday researching this CKP/CMP issue. The headline is the
2.5L and the 2.0L seem to share the same CKP sensor but have completely
different CMP sensors. The rest of this post is just the wonky details.


Above is an excerpt from the 2.0L section of the 2001 Chevy service manual.
It shows a magnetic induction type CKP sensor. It does not require any
outside power to operate. It's really a 2-wire device. The third wire is just
a shield ground.


The output of a generic magnetic CKP looks like this. I'm not yet sure if the PCM treats this
signal as analog or digital but somehow it reads it.


The 2.0L CKP waveform shown in the 2001 Suzuki service manual (above) looks just like the generic CKP waveform.
If RockAuto part numbers are to be believed, the 2.0L and 2.5L use the same CKP sensor. (Edit: Note the even spacing
on the reluctor wheel teeth. This produces six evenly spaced pulses for every revoution of the crankshaft. The frequency
of the pulses varies with engine speed. According to the Chevy service manual all three engines only use the CKP
sensor to measure tiny variations in crankshaft rotation to identify engine misfires.

The 2.0L (L4) engine uses a 3-wire Hall-effect CMP sensor. It is a solid-state device
that requires an external power source (12 volts) to operate. The digital output of the
CMP sensor is fed to pin 26 on the PCM.


This is the waveform from a generic Hall-effect CMP sensor.


This is the service manual waveform shown for the 2.0L CMP sensor. Note that the Tracker waveform is more complex
than the generic example. This is due to the odd spacing of the reluctor wheel cogs (item 3). That odd spacing on the
reluctor wheel produces pulses with four different pulse widths. Each width corresponds to a particular piston. This
is how the CMP knows which piston is at TDC in the 1.6 and 2.0 engines.


In comparison, the 2.5L (V6) uses a 4-wire optical CMP with an internal LED transmitter
and a photo-transistor receiver.


Light shines through slits in a wafer-like disk. As the disk turns light pulses are counted by the PCM.
The 2.5 L CMP has slits in two concentric rings. The outer ring has 360 evenly space slits
around the circumfrence. The 360° slits produce the position (POS) pulses. The inner ring has six gaps
each with a unique width. Each width corresponds to a specific piston. These six gaps produce the
reference (REF) pulses.


The 2.5 L CMP sends two different signals to the PCM


The REF signal comes from the outer ring. The POS signal comes from the inner ring.


The sequence of the REF slots is determined by the firing order (1-6-5-4-3-2)


The width of the REF pulse identifies which piston is at TDC.


The V6 CMP sensor puts out two separate waveforms. One is the REFERENCE waveform
that looks a lot like the 2.0L CMP waveform. The second is the POSITION waveform which
supplies 360 pulses per camshaft rotation. My 2.5 L (V6) will run without the CKP signal but
will not start without the CMP signal. I don't know if that is true for the 1.6 and 2.0L engines.

hanky

Thank you for the info. I did read what you posted earlier and realize it did not agree with the info in my GM manuals
I have had instances where an open CKP sensor prevented an engine from starting or running until they were cooled off with cold water.

If you are obtaining your info from other than GM manuals I have noticed there are many areas of incorrect info.out there
Having worked for a dealership and attended their service training classes we do learn we don't know everything.

I have to add something here, there are so many variations of ignition system design for some GM vehicles you can't remember them all without referencing information.