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Author Topic: 95 Grand Marq Engine stalls at idle  (Read 1391 times)

rjstat

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95 Grand Marq Engine stalls at idle
« on: December 18, 2006, 01:52:52 AM »
OK this is a 95 Grand Marq with a 4.6L 2v the engine would stall when you let your foot off the gas. So I told my nephew that it was his IAC he thought I was joking around with him I told him again after he replaced the o2 sensors and there was no change so I told him again change the IAC and he looked at me and said sure unlce I'll go right out and get a ID10T. I told him I'm not joke you need to replace the IAC I explained it idle air control and I showed him where it was in his car. So here is some if about the IAC.
Description and Operation

PURPOSE
The Idle Air Control (IAC) valve controls engine idle speed.

OPERATION
The idle air control valve allows air to bypass the throttle plate. The amount of air allowed to bypass is determined by the Powertrain Control Module (PCM) and is controlled by a duty cycle signal.

REMOVAL


Disconnect battery ground cable. NOTE : When the battery has been disconnected or reconnected, some abnormal drive symptoms may occur while the Powertrain Control Module (PCM) relearns its adaptive strategy. The vehicle may need to be driven 16 km (10 miles) or more to relearn the strategy.
Disconnect the fuel charging wiring from the idle air control valve.
Remove the two idle air control valve retaining bolts.
Remove the idle air control valve and gasket.
INSTALLATION


Clean idle air control valve gasket mating surfaces. NOTE: If scraping is necessary, do not damage the idle air control valve gasket surfaces or drop gasket material into throttle body or throttle body adapter (depending upon application).
To install idle air control valve, reverse Removal procedure. Tighten retaining bolts to 8-12 Nm (71-106 lb in).
Service Precautions

 CAUTION: Do not use Carburetor Tune-Up Cleaner or any other type of solvent or damage to the valve internal components may result.

The Idle Air Control (IAC) valve cannot be cleaned. The idle air control valve must be replaced.



« Last Edit: December 18, 2006, 08:09:27 AM by J.Miller »
97 - 4.6L Alpine Green Cougar XR-7 w/ Fiber Concepts Hood, SPC cold air intake, 2.5 SLP Dual Exhaust, Eclipse CD4000 w/ Polk's speakers, Koni Shocks, 11/4" Addco sway bars, and Vogtland more to come.
08 Volvo XC90 loaded.

J dot Miller

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Re: Engine stalls at idle
« Reply #1 on: December 18, 2006, 08:07:34 AM »
I am not sure it is the IAC.  I am thinking other things...  Before you go nuts why not look at my IAC Diagnostics Tech Article???

I know some people have had a hard time figuring it out but if you click on the yellow boxes you can move to that section.

To use this help area do the following:
1) If the next test is below the test you are on scroll down.
2)  f there is a test not shown on the page click on the box.
3) If you do not goto the box only KE and 7 tests are selectable. Sorry but I did not go that far and chances are your IAC is not the problem.

After you go thru it then lets talk...  ;)
The 5.4 swap has been called a bad idea, and considered an underpowered considerable waste of time, since 2007.

Nice to see that most donít think that anymore.
Bondfreak13 07/28/09 09:05 PM

rjstat

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Re: 95 Grand Marq Engine stalls at idle
« Reply #2 on: December 18, 2006, 02:43:05 PM »
Well :miller: I have read your diagnostic tech article which by the why should be posted somewhere on this site but you think :ralph: dose not have access to the flow charts  O0. Maybe I was not clear with the symptoms of the problem  ???. The car would not start unless you depressed the accelerator to start if you let off the accelerator the car would stall so the car would not idle unless you open the throttle plates to get air into the engine. I even though I relized the problem I did go threw the list the kid dosen't have alot of money and with the holidays Idid not want him wasting money not needed into his car  :).
97 - 4.6L Alpine Green Cougar XR-7 w/ Fiber Concepts Hood, SPC cold air intake, 2.5 SLP Dual Exhaust, Eclipse CD4000 w/ Polk's speakers, Koni Shocks, 11/4" Addco sway bars, and Vogtland more to come.
08 Volvo XC90 loaded.

J dot Miller

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Re: 95 Grand Marq Engine stalls at idle
« Reply #3 on: December 19, 2006, 11:07:35 AM »
I would check the charging system.  My 95 acted like that when the alternator went bad...  8)

The 97 was even worse.  When the charging system fails on that car lights blink and it acts like it is haunted...  :D
The 5.4 swap has been called a bad idea, and considered an underpowered considerable waste of time, since 2007.

Nice to see that most donít think that anymore.
Bondfreak13 07/28/09 09:05 PM

rjstat

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Re: 95 Grand Marq Engine stalls at idle
« Reply #4 on: December 19, 2006, 11:59:53 AM »
I would check the charging system.  My 95 acted like that when the alternator went bad...  8)

The 97 was even worse.  When the charging system fails on that car lights blink and it acts like it is haunted...  :D
Yes :ralph: will agree with you there. When I had the power problems with the cougar it was a car from hell all the symptoms would change so you could not diagnose the problem. But the battery was three weeks old and the alternator was tested using a load bank test form ACE Generator (a local generator and starter re-builder) the alternator checked out fine.
97 - 4.6L Alpine Green Cougar XR-7 w/ Fiber Concepts Hood, SPC cold air intake, 2.5 SLP Dual Exhaust, Eclipse CD4000 w/ Polk's speakers, Koni Shocks, 11/4" Addco sway bars, and Vogtland more to come.
08 Volvo XC90 loaded.

J dot Miller

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Re: 95 Grand Marq Engine stalls at idle
« Reply #5 on: December 19, 2006, 08:53:43 PM »
Alternators can be off and on...  One minute they work and the next no workie!! Put a volt meter to it and the battery when you are having problems!!!  :-*
The 5.4 swap has been called a bad idea, and considered an underpowered considerable waste of time, since 2007.

Nice to see that most donít think that anymore.
Bondfreak13 07/28/09 09:05 PM

rjstat

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Re: 95 Grand Marq Engine stalls at idle
« Reply #6 on: December 20, 2006, 09:36:21 AM »
Alternators can be off and on...  One minute they work and the next no workie!! Put a volt meter to it and the battery when you are having problems!!!  :-*
ACE Generator did one better they removed the alternator from the car and bench tested the altenator with load bank for 3 hours amd no problems.
97 - 4.6L Alpine Green Cougar XR-7 w/ Fiber Concepts Hood, SPC cold air intake, 2.5 SLP Dual Exhaust, Eclipse CD4000 w/ Polk's speakers, Koni Shocks, 11/4" Addco sway bars, and Vogtland more to come.
08 Volvo XC90 loaded.

KevSha

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Re: 95 Grand Marq Engine stalls at idle
« Reply #7 on: December 20, 2006, 10:22:26 PM »
excessive EGR flow at idle can also cause a stall, and is a common problem on the 4.6 cars. also, smacking the IAC with something blunt and heavy is a good way to rule that out, or accomplish nothing if the problem is not mechanical in the IAC.

you can unplug the EGR vacume line to the valve and see if the vehicle will stay running. this will prove if the problem is electrical or vacume related. hevever you could have a stuck EGR valve.

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J dot Miller

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Re: 95 Grand Marq Engine stalls at idle
« Reply #8 on: December 21, 2006, 12:08:52 PM »
Kev makes a good point and reminds me of another thing to check.  I am not sure if it was you or not but if you have had problems with lean codes and O2 sensors your EGR hoses could have melted.  Check the two silicon hoses going to the EGR.   :naut:

Plus since you recently installed an intake make sure you did not swap the two silicon hoses by accident??   :bdth:
The 5.4 swap has been called a bad idea, and considered an underpowered considerable waste of time, since 2007.

Nice to see that most donít think that anymore.
Bondfreak13 07/28/09 09:05 PM

rjstat

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Re: 95 Grand Marq Engine stalls at idle
« Reply #9 on: December 21, 2006, 12:41:23 PM »
I should of told you he had this problem before and they replaced his EGR Valve and the pressure differential sensor. This is where I came in it was intermittant at first so we went down the flow chart to rule out problems. When I told him I think it was the IAC he wanted to know it's location I rapped it with the handle of a socket wrench when he started the car it idled and it worked for a couple of days it started stalling again this time he wrapped it it worked for a couple of more days thats when I was sure it was the IAC.
97 - 4.6L Alpine Green Cougar XR-7 w/ Fiber Concepts Hood, SPC cold air intake, 2.5 SLP Dual Exhaust, Eclipse CD4000 w/ Polk's speakers, Koni Shocks, 11/4" Addco sway bars, and Vogtland more to come.
08 Volvo XC90 loaded.