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Discussion Starter #1
First of all Thankyou guys for letting me join the group, I purchased a non running 1996 cougar with a 4.6. I was told it had been sitting for 12-18 months, So we replaced fuel pump,fuel filter, crank sensor and the PCM, We checked fuel pressure with gages great pressure, checked for spark, allso checked for a injectors for pulsing, everything working as it should, The car is not showing any codes, BUT she will not start. When she sits overnight and with a fresh hot battery she will almost go, but after that she will spin until you run down the battery and never try again, Please any suggestions at this point even bad ones. Thankyou
 

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Super Moderator
1994 Cougar XR7 DOHC/5-Speed
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Have you verified it’s getting spark or fuel while cranking? If you’re getting fuel and have no or weak spark and cranking and cranking til the battery dies you’re flooding the engine and it won’t start no matter what you do, and as the battery gets weak the PCM will eventually be below its operating voltage threshold.
 

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Discussion Starter #3
Yes it is getting spark as it cranks over, the spark seems a bit week, we replaced and gaped the plugs, but it seems a bit week to me
 

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You need to find out why; the spark system in a 96 is not weak.

I use one of these coils to fire up a tesla coil; they're good for 160kV easy.

Make sure the wires go to the right plugs, that's easy to Fsck up.

Check the injectors with a noid light; Check for pressure at the fuel rail.

Suck, squeeze, bang, blow; it's all the same.

If it turns over really easily, you might do a compression test.
 

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Discussion Starter #5
Yes we did check the injectors with a Noid Light. And to be honest we checked the spark after we had lost a good bit of juice from the battery, I need to check it again with a hot battery
 

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1997 Thunderbird 4.6, 1998 Mark VIII LSC
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Have you checked for vacuum leaks? Another thing to check is the IAC valve - if it gets stuck closed the car won't fire due to no air getting in. If you crack the throttle slightly when cranking it will help determine if that's the case. Also if you crank for a while and it doesn't fire, if you hold WOT and crank it disables the injectors to help you clear a flooded condition.
 

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Discussion Starter #7
I’ll try pulling the idle control valve and clean it up good until I can get one orderd and see if it helps
 

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If you take the operation of the IAC into your thought process, the holding of the throttle down just a bit will overcome the non-operation of the IAC.

I drove Lazarus like this for two days, while I waited on a motorcraft IAC.
 

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Discussion Starter #9
But if the idle control is not working. Why will she still not fire on starter fluid. I swear this car has me baffled, I allways thought spark, fuel run
 

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1997 Thunderbird 4.6, 1998 Mark VIII LSC
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Combustion = fuel + spark + air. Starter fluid is a replacement for fuel. You need air too. If the IAC is stuck closed, you won't get any air.

Have you tried holding the throttle open slightly while trying to start to see what it does?
 

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Discussion Starter #11
Ok guys this morning so far I have try to start her with a commercial 200 jumper. Allso. I removed the iac and cleaned it good, allso orderd a new one, I tried to start her with the peddle in ever position on the car, she still almost starts after sitting, but after that nothing, And she turns over slower and slower even with the big box. I’m so lost. I checked the spark with the fresh batter nice white spark, Is it to spin her over with the IAC removed

I have noticed 1 thing. If I wait 20 minutes or so and hold the pedal flat to the floor she will sputter and actually ran once for a cpl seconds, Any chance she flooding the plugs after you spin her for a bit your really smell gas under the hood and that’s with no pedal
 

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1997 Thunderbird 4.6, 1998 Mark VIII LSC
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Yeah, it's probably filling the combustion chambers with fuel. Yeah, you can try to start it with the IAC removed. You could also try starting it with the MAF sensor disconnected just to see what it does, although it's not used as much during startup as it is when running.
 

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If you have good supplemental power with that commercial 200 jumper and then the more you crank it the slower it gets, could it be that the exhaust is severely clogged and no air is getting out of the cylinders?

What about the camshaft position sensor? I think I read somewhere that computer only sees it on startup.
 

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Try disconnecting the exhaust, or removing the first two o2 sensors, to open the exhaust up.

It should start if it's mostly blocked, but possibly it's totally blocked.

Also, put an old school timing light on #1 spark plug, and see if it lines up with the mark on the balancer when it cranks.
 

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1997 Thunderbird 4.6, 1998 Mark VIII LSC
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Without vacuum you should see 39.5 PSI.
 

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The Parts Guy
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Without vacuum you should see 43.5 PSI. With vacuum it should be 39 PSI.
The delta spec is 39.5 psi, meaning without the vacuum line attached to the FPR, you should see 39.5 psi.
 

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Discussion Starter #19
I wanted to take a second and thank all you guys, I’m still fighting this old girl but thanks for your patience so far
 

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What about the camshaft position sensor? I think I read somewhere that computer only sees it on startup.
Cam sensor input is required to run. Without it the ECM doesn't know when to fire. I don't know if that is the issue but whenever otherwise healthy appearing engines don't start, I always suspect the cam and crank sensors. They can be tested...
 
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