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#1452345 12/05/05 07:06 AM
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Hi all

I have a Cougar with the 2.5 Duratec. About a month and a half ago I went through the process of removing and cleaning my LIM/UIM, changing plugs and wires, and changing all oxygen sensors

The car started and ran fine for about a month. Then one day the car wouldnt start. I thought that was a little strange that it decided not to start. So I tried starting the car by pushing the accelerator about half way and it fired right up. I thought it might have been a glitch or something. It ran fine for almost 2 weeks and then the car didnt start anymore. Then I got annoyed. The problem isnt with the battery since it is new. The engine cranks, but will not fire. Someone on here suggested in another post to someone with a similar problem that the IAC may be going bad...and the way to test that is if the car starts by depressing the accelerator...and that has happened to me. I have also tried cranking with the pdeal depressed all the way down. Here is my question...if the IAC *is* bad and not functioning...will the car even fire even by pushing the accelerator? What about the work that I did earlier? Can a faulty O2 sensor (I bought the Bosch ones) prevent the engine from firing? Also...I went to Autozone and rented out an OBDII scanner and no codes came up. I will appreciate it if anyone has any suggestions.

-alan

#1452346 12/05/05 07:33 AM
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It could very well be the IAC. I did the teardown cleaning a couple months ago, and the same thing happened to me. The IAC was stuck wide open, so the engine would crank and crank and crank, and never fire. Dumped a fair amount of gas too, so the engine was flooded.

From Ray's UIM/LIM cleaning in the Duratec maintenance FAQ:

Replacing the IAC gasket:
(From IAC faq)
Over time, the IAC (Idle Air Control) valve becomes sticky due to buildup from the EGR and PCV systems. It can stick partially open such that idle quality is adversely affected, and engine RPM's will not drop below 1500. For a while, blipping the throttle will restore normal idle, but this only works for so long.

The fix is to remove the IAC valve by unbolting the two 8mm bolts that hold it on and disconnected the wiring plug. If you are careful enough, replacement of the gasket will not be necessary. The gasket costs less than US $1.00, so it is no tragedy if you destroy it. Once the valve is off, spray it out with some carb/intake cleaner and make sure any gunky residue is gone. Reattach, and you are done. It is a lot cheaper than a new IAC, which runs around US $70. Note: Ford claims the IAC cannot be cleaned, but this is not true in my experience.

You can pick up a brand new valve from Advance Auto Online or Napa for about forty bucks. Don't forget the gasket.

Hope that solves the problem for ya, good luck.


RIP 1997 Mercury Mystique LS - 2.5 L Duratec "Everything that's good is gone...." - Fuel
#1452347 12/05/05 10:47 AM
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Did you reuse gaskets when you did the LIM/UIM cleaning? If you did one could be leaking which would cause the car to stall. Especialy check the gasket for the IAC, EGR, and the TB. And if you're pulling the IAC off you can clean it.


1998 SE Duratec V6 ATX Ebay intake with K&N Filter Trubendz Exhaust Custom Hood
#1452348 12/05/05 05:19 PM
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I replaced all my gaskets when I performed the cleaning. I dont have a stalling problem...the car wont start at all...itll only crank and nothing happens. I am almost positive that the engine is flooded right now. I will look into the IAC first and hopefully that is the problem. Thanks guys for your help. Ill write back when I try it out...

-alan

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I replaced the IAC...after a few attempts at cranking...the engine eventually fired. I let it run for a bit...then shut the engine off. Tried starting it again and it worked. Took it around the block with success and everything ran fine. When I tried starting it about 3 hours later...back to square one. Cranks like its about to fire...but doesnt. Im thinking maybe the injectors arent dumping enough fuel at startup. Ill just pull all the plugs (and check gap) to make sure they are getting fuel. Could it be that maybe a few injectors are not dispensing enough fuel at startup? But I would figure that the engine would still fire but on less cylinders. Here is something that is worth mentioning at this point...when I was cleaning the heads...I noticed that inside cylinders 2 and 3 it was really dirty compared to the others. They were dirty to the point that there wasnt a "path" where the fuel flows down the head to where the plug is. Anyone think that I may have 2 failing injectors that dont properly dispense fuel? I did not get a cel while the car was running either. I am completely baffled at this point!

-alan

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Maybe stuck injectors, which will drop fuel pressure, if you have a fuel pressure gauge, see if the pressure stays up after shutoff. Should be 30-40.

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Here is another update:

I finally got the car started again a few days ago. I decided to try pulling the electrical cable on the camshaft sensor...and then the car fired right up. So I thought that might be the issue. It worked fine for about a day and then it did the same thing again...cranked but didnt fire. I tried pulling the sensor again but the engine didnt fire this time. I played with some electrical wires and jiggled them around...tried cranking and then she fired right up! I believe that I have an elctrical wire issue somewhere that I need to look at. I went ahead and replaced the cam and crankshaft sensor anyway...Im at 65k miles and I read that they should get replaced at around 60k...plus they were pretty cheap. Right now the car has been running well without any problems starting the past few days without me looking at anything...so hopefully all goes well...thanks for your help and suggestions

-alan

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Maybe that cam sensor was intermittent, enjoy driving your Cougar


Moderated by  horseydug_dup1, Ray_dup1 

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