2006 was fine, now cranks but no spark
 

I'll describe my 2006 PT non-turbo symptoms, someone will have an Ah-ha ! Fresh fuel pump, plugs & wires, + compression check 2 months ago. Cam pos sensor new a year ago. Been starting instantly & running fine. A week ago, out-of-the-blue it wouldn't fire on 2 consecutive key turns, fired & ran fine on 3rd key turn. Started fine instantly daily until last night when it again ignored my key turn 2x & fired fine on the 3rd. I pulled the car into the garage for the night. 27 degrees here now. Today, repeated key turns produce cranking only, no hint of firing.

Experimentally, I sprayed some starting fluid into the air intake hose & cranked engine, NO HINT OF FIRING. Seems reasonable to think compression & fuel system probably fine, starting fluid not firing suggests lack of spark now. No, I haven't actually confirmed with certainty that there is no spark.

I have no codes. Are there 3 possible primary culprits? Do I understand correctly cam pos sensor, crank pos sensor & coil are the primary suspects?

Given the occasional, intermittent nature of ignition behavior (no firing on 2 key turns then firing fine on 3rd), can anyone suggest one culprit more likely of the 3 ?
Thanks again in advance for your insights.

Wow, 146 views, no replies.
I was looking for agreement that no firing while using the starter fluid validates I have no spark...
And which of the 3 items (Crank sensor, cam sensor or coil) was most likely responsible.
Surely one fails more often than the others...?
I bought all 3 at Advance Auto assuming 1 solves it & I return the other 2, mission accomplished.
Maybe starting at the coil to absolutely verify absence of spark? Hmmmm.

** IMPORTANT UPDATE **
I had AAA tow my '06 PT to my local NAPA shop, and
Tech just disconnected the battery for a bit then reconnected it, and
IT NOW STARTS for him repeatedly, yesterday & today, so far.
I'm told sometimes just resetting the computer solves these issues.
NO new parts installed, 30 minutes labor invested so far...
They're going to see if it continues to start today & tomorrow... wow.
I'm thrilled it starts now, concerned why it didn't before...
wondering if & when it will happen again.
Will update again in 24 hours whether or not it's still consistently OK...

*** IMPORTANT UPDATE 2 ***
The problem reappeared, just a couple days later.
Started instantly & ran fine a few days since the battery disconnect / computer reset solved the no-start.
Yesterday morning wouldn't start, cranks fine, no hint of firing. Exactly as before.
Revised thinking: neither problems with the cam sensor or coil pack would have exactly these intermittent results.
I think the crank sensor is the most likely culprit.
Next update when I have news....

Check camshaft sensor/crankshaft sensor

*** SOLVED *** Since the last post, I'd tried it daily for a week, cranked great, still no hint of ignition. I then let the car sit untouched for 4 months over the winter. Early April, I charged the battery& tried the key a couple weeks ago, it started right up. I knew it was most likely one of 3 things, the CRANK SENSOR. I decided to throw a little money at it, bought CRANK & CAMSHAFT POSITION SENSORS, plus the IGNITION COIL. Bought all 3 at Advance Auto with a 20% off coupon, parts were about $100 total. I immediately drove my car to my local NAPA auto shop that does work reasonably, to install all 3 parts, I think I was out another $100 labor. On reflection, I think a problem with CAMSHAFT SENSOR or COIL PACK would have just caused running poor, but the CRANK SENSOR is a show stopper. But I was happy enough to invest $200 parts/labor & have this car that starts & runs nicely now. Good investment, whether I keep or flip it, I have some reliability peace-of-mind now. I'm leaning toward it having a new home by years end...

*** NOT solved ! ***
Replaced the coil pack, crank sensor & camshaft position sensor back in April, PT has been in daily use ever since, no problems.
It got a new fuel pump last year.

My grand-daughter drove it to the YMCA to work as usual last Sunday, May 19th.
Couple hours later, CRANKS FINE, NO HINT OF COMBUSTION.
She left it at the YMCA, but tried to start it again Monday 20th, still cranks fine, no hint of firing.
She forgot to try Tuesday, but on Wednesday she tried it, IT STARTED normally.
She drove it home immediately, ran fine home, sitting since Wednesday.
Sitting now 5 days, I just tried, it starts immediately & sounds fine.

IT's just so disappointing, unbelievable.
My PT started reliably & ran fine for a month.
But I don't dare drive it anywhere then turn it off..... as it may not restart.
It just makes me crazy, the unreliability.
I'm back to square one.
Short of taking it to a dealer, any other ideas?