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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2000 Crown Vic Cranks but won't start
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
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
41 - 60 of 94 Posts
Thank you so much Dave
I’ll check them out when I get back on the car
Working on my truck right now
I’ll check them out when I get back on the car
Working on my truck right now
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.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.
Agreed that the reluctor wheel is a possibility.
Do a KOEO (key on engine off) scan tool test, might give you direction on what else might have gotten damaged. Timing seems to be the last link, and most important, if everything else looks good. If the coolant hose burst, a good question to ask is...was damage done from overheating?Chris said the cam sensor tested out with no faults.
Agreed that the reluctor wheel is a possibility.
Thanks RadiobenderMost 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.
I went on and put a cam sensor in
I’m getting a signal from both sensors but I’ll check them when I’m on the car again
I’m also working on my truck too
just to add to the informationThanks Radiobender
I went on and put a cam sensor in
I’m getting a signal from both sensors but I’ll check them when I’m on the car again
I’m also working on my truck too
I’ve replaced both the cam and crank sensors
The computer is getting power since I can at least scan it and get an RPM reading on the scanner about 300-500 RPM while cranking
I have an injector pulse according to the noid light
The scan also reports no codes or any issues with the cam sensor
I did replace the intake manifold since it cracked
I replaced the coolant temp sensor while replacing the intake
I’ve checked double checked and triple checked any signs of a wire pinched under the manifold everything looks good
I do recall that once in a while it wouldn’t start on the first attempt but usually starts on the second attempt with a small pop then ran fine before the intake blew
The only thing missing is the switch signal to the coils
I even have 30-35 PSI on the fuel rail
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.
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.
Not up to date on all posts and what has been done or not and dont want to go back and read them all so might be irrelevant . Have you tried spraying easy start whilst cranking engine , is engine turning over fast enough and no excessive draw from starter taking some spark away from plugs ? If rev counter needle moving when cranking usually means spark o.k As said , ignore if already covered
hi DaveQuestion(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.
No issues with the PATS light
It turns off when I turn the key as it should
The CEL turns off when cranking
I agree with you
I don’t think it’s the PATS
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 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.
Thanks Dave
I’ll check it out when I’m under the hood again
I’ll check it out when I’m under the hood again
Well the new pcm is in place
Of course Pats locked it up
Fast flashing security light with the key on
Might have to reprogram the Pats/ECM to go any further unless you or anyone else knows a workaround for this particular model
It’s a 2000 actual production of late 1999
Everything else looks about perfect
Thanks so much for your help
Of course Pats locked it up
Fast flashing security light with the key on
Might have to reprogram the Pats/ECM to go any further unless you or anyone else knows a workaround for this particular model
It’s a 2000 actual production of late 1999
Everything else looks about perfect
Thanks so much for your help
Morning DaveWell the new pcm is in place
Of course Pats locked it up
Fast flashing security light with the key on
Might have to reprogram the Pats/ECM to go any further unless you or anyone else knows a workaround for this particular model
It’s a 2000 actual production of late 1999
Everything else looks about perfect
Thanks so much for your help
I had another thought
Since everything seems to be just fine other than a no start and lack of a switch signal at the coils would it be possible that a coil or coils failed and shorted out when the intake blew up thereby cutting the power for the switch signal?
Just wondering
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.
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.
Hi Dave
I thought the same thing
But I have heard that on rare cases if a coil shorts out that in some cases it could possibly cut off the trigger signal
That and even by some fluke that all 8 were bad I should still get a trigger signal with the coils disconnected
I have yet to see this particular issue happen
Usually it’s a bad sensor bad wiring bad computer or ground
Thanks for your reply
I thought the same thing
But I have heard that on rare cases if a coil shorts out that in some cases it could possibly cut off the trigger signal
That and even by some fluke that all 8 were bad I should still get a trigger signal with the coils disconnected
I have yet to see this particular issue happen
Usually it’s a bad sensor bad wiring bad computer or ground
Thanks for your reply
Worth a shot. Best way to determine this is to measure the OHMS, or resistance of each coil.
Found this pdf showing what each coil should have...Coil resistance check
Found this pdf showing what each coil should have...Coil resistance check
thanks for the info DaveWorth a shot. Best way to determine this is to measure the OHMS, or resistance of each coil.
Found this pdf showing what each coil should have...Coil resistance check
All of the coils are still original equipment except for two
Hi again Davethanks for the info Dave
All of the coils are still original equipment except for two
I’m back on the Crown Vic
I went on and replaced all of the coils because they were still factory
Swapped out the computer with the new one
I know you said that it should send a trigger signal to the coils regardless of the computer being flashed to the security system
Still not getting a trigger signal
I’ve checked every single connector ground and the harness behind the intake and I don’t see anything wrong with all of that
It all looks great
If I recall correctly if the computer wasn’t getting power I wouldn’t have a check engine light a crank sensor signal or fuel pump running
Is there anything else that might be missing?
Thanks so much for your help
Chris
41 - 60 of 94 Posts
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