No Start

[jt20]

217k miles '91 non-turbo LH 2.4.2

Pump works and can pressurize the rail with a jumper between fuses.

Pump relay works - tested

.013V across pins #85 and #86 on the pump relay pins when cranking - not sufficient.

Ground signal is present @ pin #17 on the LH Control Unit harness.



It appears to be the control unit, Correct?

[peva]

Originally Posted by jt20

217k miles '91 non-turbo LH 2.4.2

Pump works and can pressurize the rail with a jumper between fuses.

Pump relay works - tested

.013V across pins #85 and #86 on the pump relay pins when cranking - not sufficient.

Ground signal is present @ pin #17 on the LH Control Unit harness.



It appears to be the control unit, Correct?

Is there a spark? No spark = no fuel.

[jt20]

Thank you. I will check the ignition system tomorrow.

What is the common failure by 200k miles? Coil, ignition control unit, hall sensor etc..?

[peva]

Impossible to pick one above the other. They are all known to often go on forever. Saying that, the CPS (Crank Position Sensor), which is the hall sensor at the rear of the crankcase is known to fail occasionally.

[jt20]

There is no spark. From a functioning, non-turbo '93 I swapped the EZK unit, amplifier and ECU - still no start and no spark.

What clever ideas do you folks have for rotating the crankshaft with the engine in place? It appears to be impossible after many attempts.


Following the FSM:


Knock sensor - good

power to EZK unit - yes

Power to amplifier - yes

power to coil - yes

coil resistance - good

amplifier switching - could never get 0.0V but the current amp had the same behavior as a known working amp

pulse signal from EZK - good

Hall sensor - can not check due to crank rotation.

[Jim Mesthene]

Originally Posted by jt20

pulse signal from EZK - good

How did you determine that? It's not easy to measure. Is there a pulse at the coil?
Your symptoms match those of a failed Crankshaft Position Sensor. The tests described in the manual are always inconclusive, don't even bother with them. Look for a Primary ignition pulse while cranking.

[jt20]

You are absolutely right. Without an oscilloscope, I had to default to a multimeter and the average was approx 2.8v

I see what you are saying.... but what is "Primary ignition pulse" Is that the 'quick test' by pulling a plug and grounding it?

I did that - no spark.

Is there a recommendation for testing the CPS, or just replace it...?

[Jim Mesthene]

See if the primary side of the Coil (the little wires) show pulsing voltage. The Hall Effect Transmitter (whether on the crankshaft or in the distributor) sends a signal. Try to find it after it has been amplified.

[ragtopper1994]

I am having the same exact problem with my 94 vert, but adding to the mystery is that the wire harness that runs past the shifter burned up and shorted several wires. All of the wires have been replaced and rechecked. I have not checked for a pulse signal but will do this ASAP. There was a condenser wired between the coil and distributor but the wire is broken. Is this for radio noise reduction or is it required for normal engine operation?

Had my hand on the phone several times to call the junk yard to come and get it but I just can't seem to let it go.

[16saabs]

don't junkyard it sort it, but even if you want to get rid of it sell it someoe will give it a go, and give you more than a junk yard

[jt20]

Just an update.

Replacing the CPS via the tutorial on this site got the engine running again. There are other issues, but we solved the big one.

Thanks to all!

[QuickOrange]

Funny how that little sensor can cause so much trouble.