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2000 Crown Vic Cranks but won't start

1919 Views 93 Replies 7 Participants Last post by  R.S.LOGAN
Hello from Louisiana y'all
I have a 2000 Crown Vic LX 4.6 L Windsor
Recently the intake manifold cracked and of course blew coolant everywhere
It actually cracked at the fitting where the coolant temp sensor was, yes I said was. It blew the sensor out of the fitting.
Of course I pulled the old manifold off and replaced it
Fairly simple and straightforward right?
Now, the engine was running before the intake replacement.
Now, with the new intake and various other items, thermostat, upper radiator hose, and spark plugs, all of which it needed anyway, it will not start.
First obvious check, fuel pressure. Bingo right at 35 PSI
Next, code check, No codes
Next, spark, no spark, power at the coil leads
Next, injector pulse, No pulse, power at the injector leads
First thought, crankshaft position sensor, Just put a new one in, not without much agony and colorful expressions.
Still no start, no pulse, no trigger voltage at the coils.
Scan for crankshaft position sensor RPM when cranking. The ECU is getting a signal from the sensor.
All fuses and relays appear to be operating as expected, either by testing with a test light or by swapping known working relays.
Still no start.

If anyone has any suggestions on where to go next, PLEASE let me know.
Thank y'all so much
Chris Ellington
1 - 20 of 94 Posts
Sounds like something is still unplugged somewhere. Follow the wire harness from the coils and injectors back, and check it where it plugs into the PCM and in between.
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Thanks Dave
Could it be a ground wire attached to the impossible to remove and install on the bracket behind the driver side cylinder head?
That thing is a PITA
Worth a try.
Are you getting power to the coils and injectors yet?
ALL vacuum lines connected? No open ports?
Everything is hooked up exactly how it should be and also the way it was running
Not quite following...are you saying you've got it running? Or that it is still not running but everything is connected as before?
Try cycling the fuel pump a few times...turn the key "on" without cranking, wait 3 seconds, and turn "off."
Repeat this 2 more times, then on the 3rd time, try starting it. Could have air in the lines and this might help to prime it.
Maybe wiggle wires at the PCM/ECM while cranking, Also could still be a bum relay or corrosion issues at the fuse/relay block in the engine compartment.
Might be PCM. Just throwing suggestions here. Main point being: ALL connections between the PCM and coils should be checked.
Power to coils and injectors but no trigger for the coils indicates either crank position circuit fault or PCM circuit fault.
Given what you've done, I'd look at these areas, maybe checking the connector to the Crank Position Sensor even though you replaced it, check that connector anyways and make sure it has good contact as it seems to be a somewhat common issue in those models.
I'd also like to add: what's the voltage reading at the PCM?
Looks like that might be an issue. The ECM might have to be reprogrammed to accept it.
One way to find out, though.

TPS voltage sounds about right.
As for the ECM, I was talking about any power lead supplying the ECM itself.
Hey Dave
I’m pretty sure there’s power to the ECM
I have power to the scanner power everywhere else
If I wasn’t seeing power to the computer I’d suspect that too
My question was: How much power? What's the actual voltage reading on each supply lead?
Should be full 12 volts at the ECM connector.
Here's a diagram of a typical Ford ECM from that year, shouldn't really be any different IRT the main power leads.

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Most modern gasoline engines usually need a crank AND cam sensor input, maybe cam signal was damaged. Ive also seen a vehicle with a crank signal, but the reluctor wheel was broken so it was giving an intermittent signal. You wouldnt know this unless you had the cam and crank signal scoped and verified they were aligning properly. Might explain the old pop from timing off.
Chris said the cam sensor tested out with no faults.
Agreed that the reluctor wheel is a possibility.
Question(s): While cranking, does the CEL shut off or remain on?
If CEL shuts off, it means the ECM believes the coils are firing, if CEL stays on while cranking, then it indicates they are not.
What does the theft light do? (kinda doubting the PATS is the problem due to you getting injector pulse)
If the theft light flashed rapidly, then a possibility, if it flashes normally, then likely not.
Another thought: I was just looking at the wire diagram for the ECM and noticed there's a ground wire coming from the plug connector, black and white and the very first (or last) one. Might want to trace it to see where it grounds, and clean the connector where it terminates whether it looks OK or not.
I may be grasping at straws here, but you have nothing to lose doing that, and test the ohms from that to the negative post on the battery, should be zero or very close.
I could see 1 or 2 failing, but all 8? Doubtful.
The PATS of those years usually just disabled the injectors, not the coils.
IIRC, all the coils have a common positive, but the negative side is individually wired.
Even with the "new" unprogrammed ECM, you should still be getting the coil trigger.
1 - 20 of 94 Posts