Replaced distributor, no spark now.
#12
Beginning Member
Thread Starter
Join Date: May 2020
Posts: 26

I REPLIED the other day.... hmmmmm seems gone.
Again: Replaced the CPS still no start no spark. throws code P0336 CPS A circuit
range/performance.
Odd that it throws a code now with the new one, but not the old one?
Does this info spark anyone's knowledge base of the issue?
thanks
Again: Replaced the CPS still no start no spark. throws code P0336 CPS A circuit
range/performance.
Odd that it throws a code now with the new one, but not the old one?
Does this info spark anyone's knowledge base of the issue?
thanks
#13
Beginning Member
Thread Starter
Join Date: May 2020
Posts: 26

It seems like the tach needle should move a little while cranking. Maybe somebody who's near their Blazer can confirm? At least on my 2000, the ngine will run, even iff the distributor is unplugged. The crank position sensor is what "tells" the PCM to fire.
If you have a test light, maybe check for voltage at the positive coil terminal. It should have 12V. and if you put a test light on the negative coil terminal, it should flash on and off while cranking.
If you have a test light, maybe check for voltage at the positive coil terminal. It should have 12V. and if you put a test light on the negative coil terminal, it should flash on and off while cranking.
thanks.
The tach needle does not even pretend to move while cranking. ...ONCE just once it jump a tiny bit while I was fidgeting with the key, not cranking.
The coil is plug in, no terminals ... so testing while cranking would require wire splicing or something.
#15
Beginning Member
Thread Starter
Join Date: May 2020
Posts: 26

OK, more testing.
Key on good power at the coil connector
good continuity from the coil plug to the ICM plug on both the pick and white/black wires
dismounted and opened up the PCM. everything I could access looked factory new and fine.
Coil tests in spec primary and secondary.(just like the old one it replaced)
still no spark no start. still throws code p0336
Key on good power at the coil connector
good continuity from the coil plug to the ICM plug on both the pick and white/black wires
dismounted and opened up the PCM. everything I could access looked factory new and fine.
Coil tests in spec primary and secondary.(just like the old one it replaced)
still no spark no start. still throws code p0336
#17
Just 5 cents worth.
If the code is P0336 which is the CPS. I would go and check that signal from the sensor first. Make sure the signal gets at least from the CPS to the harness. Should have several connecting points. Probably one close to the sensor. Turning the engine over by hand or with starter should yield a voltage signal.
The PCM will never do anything without that signal. No ignition and most probably also no injection. Without the CPS it's not even aware that the engine is turning.
Check the sensor wiring all the way to the PCM. You may have disturbed that wire while swapping the distributor and if it had previous damage (rodents, chafing, whatever) I have experienced cases where the slight movement when changing something else has grounded that wire and all on a sudden - no signal, no start.
If the code is P0336 which is the CPS. I would go and check that signal from the sensor first. Make sure the signal gets at least from the CPS to the harness. Should have several connecting points. Probably one close to the sensor. Turning the engine over by hand or with starter should yield a voltage signal.
The PCM will never do anything without that signal. No ignition and most probably also no injection. Without the CPS it's not even aware that the engine is turning.
Check the sensor wiring all the way to the PCM. You may have disturbed that wire while swapping the distributor and if it had previous damage (rodents, chafing, whatever) I have experienced cases where the slight movement when changing something else has grounded that wire and all on a sudden - no signal, no start.
#18
Beginning Member
Thread Starter
Join Date: May 2020
Posts: 26

Just 5 cents worth.
If the code is P0336 which is the CPS. I would go and check that signal from the sensor first. Make sure the signal gets at least from the CPS to the harness. Should have several connecting points. Probably one close to the sensor. Turning the engine over by hand or with starter should yield a voltage signal.
The PCM will never do anything without that signal. No ignition and most probably also no injection. Without the CPS it's not even aware that the engine is turning.
Check the sensor wiring all the way to the PCM. You may have disturbed that wire while swapping the distributor and if it had previous damage (rodents, chafing, whatever) I have experienced cases where the slight movement when changing something else has grounded that wire and all on a sudden - no signal, no start.
If the code is P0336 which is the CPS. I would go and check that signal from the sensor first. Make sure the signal gets at least from the CPS to the harness. Should have several connecting points. Probably one close to the sensor. Turning the engine over by hand or with starter should yield a voltage signal.
The PCM will never do anything without that signal. No ignition and most probably also no injection. Without the CPS it's not even aware that the engine is turning.
Check the sensor wiring all the way to the PCM. You may have disturbed that wire while swapping the distributor and if it had previous damage (rodents, chafing, whatever) I have experienced cases where the slight movement when changing something else has grounded that wire and all on a sudden - no signal, no start.
I have been looking over my wiring for weeks. I have no rodent damage and never saw any chaffing or corrosion. ( i did not open all the corrugated protective tubing). I see no problems with any wiring or connections. The wiring is in nice appearance for this old bucket. I should get some photos up. may be tonight.
The grounds are all good. I even grounded the engine/battery neg and body externally.
My thoughts are going to that ring which triggers the CPS. How much work in getting a look at that? What is the procedure?
My idea is to try and peek through the hole where the cps mounts and check for movement while turning the engine. Is this correct?
thanks
#19
Beginning Member
Thread Starter
Join Date: May 2020
Posts: 26

And nothing holds the handle on but friction?
I am afraid to try that

Can a bunch of you all confirm this before I destroy my lever?
Thanks
#20
Junior Member
Join Date: Apr 2013
Posts: 461

Uggggh, distributor failure. I had one go on me just before I went in to a parking lot. No idea what happened but $150 later ? It ran fine.
Then something else went, but.. Distributor.. Truck really does run great, almost like that is a tune-up item.
When my engine came it did not have the distributor in it and we had to re-use the old one.
I do believe that if the dash has a tachometer (my 1996 does not, even the digital Gen1 dashes do I think. . I do not exactly remember but. Anyways) that it will move consistent with engine rotation, even if cranking but not starting. I think.
Then something else went, but.. Distributor.. Truck really does run great, almost like that is a tune-up item.
When my engine came it did not have the distributor in it and we had to re-use the old one.
I do believe that if the dash has a tachometer (my 1996 does not, even the digital Gen1 dashes do I think. . I do not exactly remember but. Anyways) that it will move consistent with engine rotation, even if cranking but not starting. I think.
Last edited by 93S10TahoeLT; 05-21-2020 at 06:51 PM.





