No spark, have fuel, have 150 PSI compression

1995 Tacoma single ingnition coil with distributor & rotor. 386K miles of flawless running. Was driving 35 MPH when it just stop abruptly as if the key was suddenly turned offer. Fuses and relays good. Assuming sensors & ECM is good otherwise there would be no fuel as well. No CEL codes and CEL illuminates when key turned to on position. I am looking for any suggestions to likely causes. I'm leaning towards a bad ignition coil inside distributor and would appreciate how to test. Links to existing post also appreciated especial to older gen 1 that have the distributor. Thanks

 

here you go

 

THANKS! I work on this today and report back.

 

Testing confirmed:
1) battery voltage to the distributor when the key is in the run position.
2) all distributor resistances were within spec as was the air gap inside the distributor.
3) again no spark, has fuel, and 150 psi compression in all 4 cylinders.
Am I correct to believe that since I have fuel and power to distributor all sensors must be working?
I am inclined to believe that the issue has to be inside the distributor, despite all tests being within spec.
it was running fine, driving 35 MPH, without any hint of trouble the engine just stopped running as if I turned off the ignition.
Any suggestions?

 

How have you confirmed no fuel? I've seen ign rotors get a microscopic hole thru them that lets it short out to distributor.

 

The truck HAS fuel. This was confirmed by smell, visual on spark plug upon removal, and visual by seeing fuel vapor excaping through spark plug hole while cranking.

IF the crankshaft senor were bad, would it stop fuel also?

 

Yes and no. When the ignition key is turned to the crank position the circuit opening relay has an internal bypass to provide power to the fuel pump. When you release to key back tio the run position the signal from the CKP (crankshaft position sensor) tells the PCM that the motor is turning and another circuit inside the circuit opening relay is energized to provide power to the fuel pump.

Air, fuel, spark… you can substitute fuel with a squirt of starting fluid, if it fires and dies then you can suspect the pump. There has to be enough fuel pressure to the injectors to have them work.

Example of circuitry. See circuit opening relay at the bottom right of the page.

 

I disconnected the crankcase sensor electrical cable and tested the resistance came in right in specs. Also the car would try to start when cranking and this is not happening.

Because of the abrupt nature of the issue with zero warning, I am leaning towards replacing the iignition coil. I will also replace the rotor because it is common to all four cylinders. The cap looks good and there is no way all four contact points would fail at the exact same time.

 

SOLVED BY @mechanicjon on 9/25/2023 at 12:11 AM
I've seen ign rotors get a microscopic hole thru them that lets it short out to distributor.
Thank you! Thank you! Thank you!

Replacing the rotor SOLVED my issue. I have looked at the rotor under a magnifying glass and see no issues. There is continuity from the center of the rotor to the tip. I would have said my old rotor was good and I rebuilt my first engine back in 1975. The only reason I tried this as my first part to replace was I was at the parts store for a different vehicle and the rotor cost was just $8.29. Plus I could try the rotor before ordering a replacement coil from Amazon without slipping deliver day. New rotor and the Tacoma fired right up like never missing a beat. In disbelief I reinstalled the old rotor and cranks all day long and didnt try to start. Re-installed the new rotor and it sounds like it is good for another 386K miles.

I would have expected a rotor to gradually fail with occasional misses getting more and more signficant. My Tacoma went from running great, to a sudden stopping while driving 35 mph on a four lane road, coasting to a parking lot wihout any engine, to a tow home, to several hours of trouble shooting.

Seems like there needs to be one last step in Toyato's trouble shototing proceedure. If everything is in spec try a new rotor. I cannot think of a test other than visual inspection and resistance from center to tip of rotor. My bad rotor would likely have passed.

Hope sharing the solution helps someone else.

 

Nice easy fix

This was my issue…

 

At least your issue was visually apparent. I spent more time troubleshooting, but you spent more on the required repairs.

 

Thank you for the update! Glad you got it fixed. I learned that rotor issues by years of experience as a mechanic back in the 80s and 90s. Before all the distributorless ignition systems.