97 Cougar no start..

[Iceman8.6]

Car: 1997 Cougar/4.6l all factory stock that will not start. It cranks over just fine with good fuel pressure. It needed a new battery so put one in it and same deal- no start.

Did some searching and the Crankshaft Position Sensor and the wiring to it was brought up several times as a possible culprit. The Service Engine Soon light does come on and stay on while cranking.

It does have the factory installed theft system on it. I bought a new CPS and will install it and look at the wiring. Is the CPS or wiring to it the most likely culprit?

 

[1997ThunderbirdLXV6]

Having been through CPS CKP issues myself, albeit on the 3.8 (I have a detailed thread about it on here), I didn't experience complete no-starts. It always attempted to start, ran for a few seconds at least. It started with sudden stalling; ultimately, the car was completely immobilized.

In all instances, I had a code. I fixed it in the end by replacing the CKP wires between the sensor and the firewall. I also replaced the PCM around that same time.


In your case, first check for codes. Then, please describe a bit more the starting behavior you see: is there any spark/ignition at all? Any engine running, even if just for a second?

The sensor itself is an extremely basic part, very unlikely to break I think. If you decide to replace the wiring, it has to be wrapped in grounded shielding.

I have no idea how the anti theft works in these cars.

If you know anyone else with a 4.6, try to borrow their PCM so that you can eliminate that as a cause. Others will be able to specify which PCMs would work; I'm guessing anything with a 2V 4.6 from '97 will do (?).


I'll post a link to my CKP thread, which may provide useful reading.

 

[1997ThunderbirdLXV6]

Thread 'P0320 - Car Completely Immobile'

Mar 10, 2024

Alright...this happened to a lesser degree several months ago. Back then I jumped onto @Rodeo Joe 's thread about the camshaft sensor because the two issues seemed related.

I decided to start a new thread at this point because A. I don't want to confuse us all by mixing two separate topics and B. this is now a major problem.


Looking back:

A couple of months ago, I had P0320. Symptoms included tach needle erratically going to zero while engine was running, occasional very rough idle, and on a few occasions engine dying at a stop while in gear.
Back then I replaced the crankshaft...

• 1997ThunderbirdLXV6
• Replies: 23
• Forum: Engine - 3.8L

 

[Iceman8.6]

Hey thanks! Will it show a code with the motor not running? Didn't think it would but I can check for a code easy enough. The SES light does stay on while cranking with the no start. Behavior: If it gets a spark the motor starts right up and runs fine and the SES has never illuminated while running. Every time its no started its been because of no spark and the fuel pressure checks out good at about 40 PSI.

 

[1997ThunderbirdLXV6]

Even if you can't get it running now, there may be a stored or pending code that you can read with just ignition on.

Others on here will be able to provide far better guidance than I. What I can tell you is that my CKP sensor issues never caused a complete no-start situation. There was always at least some rough running.

The only total no-start I faced was a stuck IAC valve. That you can test easily: just give some throttle during starting; if it starts, then dies when the throttle is released, it's likely the IAC.

 

[Iceman8.6]

Hooked up the code reader and it said no codes are stored. Checked all the fuses and they are fine. Think I'm going to swap out the CPS for a new one and see what happens.

 

[theterminator93]

Yeah if the SES light stays on when cranking it means no CKPS signal. I'd focus on that and the harness. You can do a basic continuity test between the harness connector at the sensor and the bulkhead connector at the firewall; do you have the EVTM for the pinouts?

 

[XR7-4.6]

If you don’t have the diagrams the wires at the bulkhead connector for it will be dark blue and light grey, I don’t have my EVTMs handy to tell you which pins they specifically are but if you pop the top cap off the bulk connector(the cap that’s around the 10mm retaining bolt, covering the wires) you should be able to see where they go in it.


I’d wager it’s the wiring and not the sensor personally, I nearly got stranded from this and the fault was in the harness right where it splits out from the AC coil wiring

 

[1997ThunderbirdLXV6]

I’d wager it’s the wiring and not the sensor personally, I nearly got stranded from this and the fault was in the harness right where it splits out from the AC coil wiring

In my case, I never fully investigated the wiring; I'd love to know where the fault was, but I didn't want to pull the whole harness apart.

The frustrating part was that all my continuity tests showed zero issues, both sensor to firewall and firewall to PCM. Many wiring faults only materialize due to engine vibration, etc., so a continuity test at standstill may be inconclusive. Still a useful test to do though!

I just ended up cutting the two wires at the firewall connector and at the sensor. Then I ran two new wires inside a self-concocted shielding past the air filter box and over the wheel arch. Not an elegant solution per se, but effective.