# 2000 Lincoln Navigator IACV replacement



## Bigplanz (Apr 10, 2009)

2nd video (10 minutes long!) putting the new IAC valve on the car.


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## Bigplanz (Apr 10, 2009)

3rd video: how did it perform, this new IAC valve?






Well, the idle is perfect. No issues at all. EXCEPT IT STILL DIES WHEN I PUT THE CAR IN REVERSE!!

GRRR. The car runs perfect, except it dies when I put it in reverse. Sigh.

I will test from a cold start tomorrow.


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## de-nagorg (Feb 23, 2014)

Ya gotta give it time to realize that it has a new part, and reset it's defaults. 

Before saying that this did not correct the problem, the "brain" don't know yet that it has been changed.


ED


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## Bigplanz (Apr 10, 2009)

de-nagorg said:


> Ya gotta give it time to realize that it has a new part, and reset it's defaults.
> 
> Before saying that this did not correct the problem, the "brain" don't know yet that it has been changed.
> 
> ...



I understand. I will give it a few days. Tomorrow will be a cold start, so I will repeat the relearn procedure. A minute or two in park at idle, a minute or two in drive, no AC, a minute or two in drive with AC. Then drive 10 miles or so. Idle is perfect right now. Only issue, dies when I put it in reverse.


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## de-nagorg (Feb 23, 2014)

In BC that signified a vacuum leak.

BC = before computerization. :devil3:


ED


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## Bigplanz (Apr 10, 2009)

de-nagorg said:


> In BC that signified a vacuum leak.
> 
> BC = before computerization. :devil3:
> 
> ...


 I was thinking the same thing. Weird part is the idle with the new IACV is perfect, no hunting, nothing. Except a shift to reverse. Dies.


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## de-nagorg (Feb 23, 2014)

The vacuum modulator activates the internal shift of the transmission, and uses most vacuum when trying reverse, so if the modulator has developed a leaky bladder, it might be causing a massive vacuum leak only when trying to go to reverse. 

The modulator also aids the transmission to shift up or down depending on vehicle speed. 

Does the Nav, shift a little HARD when traveling forward?


ED


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## Bigplanz (Apr 10, 2009)

de-nagorg said:


> The vacuum modulator activates the internal shift of the transmission, and uses most vacuum when trying reverse, so if the modulator has developed a leaky bladder, it might be causing a massive vacuum leak only when trying to go to reverse.
> 
> The modulator also aids the transmission to shift up or down depending on vehicle speed.
> 
> ...


I don't even know if there is a "modulator." I checked the topside vacuum lines and saw no problems. Not to say there aren't any, just didn't see anything. All the hoses look good, no dry rot, etc.

I just replaced the IACV today, but there are no hard shifts (nor have there been) while in drive. Cleaning the throttle body and, especially, replacing the IACV, has made idle and acceleration noticably better. Put it in reverse though, dead. Not every time, but still, enough times to make you say, WTF?


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## de-nagorg (Feb 23, 2014)

The vacuum modulator would be mounted on the transmission, it is usually about the size of a 1.5 inch X 2.5 inch nipple, with a vacuum line on the end not screwed into the transmission. 

I have seen them develop a rupture of the internal diaphragm, and quit aiding the shifting process.

Sometimes there is consumption of the transmission fluid, sometimes not. 

A good way to test one is to use a vacuum test pump to see if the modulator holds pressure. 


ED


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## Bigplanz (Apr 10, 2009)

Another Blair WItch video. Me looking for the modulator. You will see the hose right behind the IAC which, from what I have read, goes to the transmission modulator. Question: when the hose leaves the manifold, it goes a short distance to a box/device bolted to the back firewall, and from there it disappears under the vehicle, presumably to connect to the transmission. What is the box/device on the firewall? Thanks.


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## de-nagorg (Feb 23, 2014)

I could not tell, Does that box have any wiring, or other hoses attached to it.
Did you read this location , from a manual of some kind, or find info on you-tube?

If you-tube, verify it a couple of more times.



It might be a junction distribution type thing.


ED


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## Bigplanz (Apr 10, 2009)

A couple of photos of the device on the firewall. The hose behind the IACV runs to this device, the hose then goes down out of sight, presumably to the transmission. I don't know what this is, but it has an electrical connector so it must be sensor of some kind. In the photo with my fingers, the top part I am touching spins freely, but is not screwed onto the device. There are small holes on the spinning part, as if to let air into the sensor. If anyone knows what this is, please let me know.


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## de-nagorg (Feb 23, 2014)

That looks like a Vacuum Regulator Solenoid, usually in the E G R system. 



ED


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## Brainbucket (Mar 30, 2015)

Bigplanz said:


> OK. I went to Autozone today and bought a replacement IAC valve. Three videos: 1st the part I bought.


Ok, That is the first problem. You went to autozone. You replaced a bad part with a piece of junk. 2nd, Either continue to drive vehicle so the adaptives will slowly adjust to the driving practices. Or go to a shop that has a scanner to reset the adaptives. Adaptives are the adjustments the vehicle makes according to the drivers habits. And that valve looks like a evaporative emissions purge valve test port. See the green cap? But I also see a vaccum line coming in from the bottom. Could be an egr component:vs_cool:


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## Bigplanz (Apr 10, 2009)

The thing on the firewall is the EGR vacuum solenoid. Not sure why the car needs one, since there is also an EGR valve, which is not connected to the vacuum solenoid. There is a vacuum line on the intake plenum behind the IACV that goes to the solenoid, then disappears behind the brake booster. I assume it connects to the exhaust manifold.

The IACV sure looks and feels cheap. Makes a big difference to the idle. It hasn't reset, I suppose, since it still dies when I shift to reverse.


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## Bigplanz (Apr 10, 2009)

Correction. The device shown above is actually the EVAP Vapor Canister Purge Valve. I found the vacuum modulator nearby hidden by the horn for the car alarm. I pulled the electrical connector for the EVAP purge valve and found the harness side socket scorched. That's can't be good. Still showed 12V but I suspect the purge valve is shot. Not sure this would effect idle, but it looks like a definite problem. Video below.


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## Brainbucket (Mar 30, 2015)

A purge valve stuck open will cause a vacuum leak. It is sucking the fuel vapors into the intake when commanded. Replace valve and connector. Solder connections and heat shrink it.:vs_cool:


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## de-nagorg (Feb 23, 2014)

Brainbucket said:


> A purge valve stuck open will cause a vacuum leak. It is sucking the fuel vapors into the intake when commanded. Replace valve and connector. Solder connections and heat shrink it.:vs_cool:


BINGO We have a winner.

If that purge valve is stuck open, there is your vacuum leak. 

Get a replacement, repair the wire harness, Ford will have a new connector, you might have to special order it, a regular wire connector and shrink wrap will get you going if you don't want to wait to get the FORD connector. 


ED 

P.S. I have gotten bad parts at NAPA before, so it ain't only auto-zone that tries to hand off inferior parts to repairmen.


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## Bigplanz (Apr 10, 2009)

New IACV made a big difference. It obviously needed to be replaced, but the idle was still off (die in reverse), so that's what got me looking for some other cause. Scorched connector pretty conclusive proof of a defective part. No CEL though. There is 12 volts at the harness though. Makes me wonder what would scorch the connector but not blow a fuse?


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## Bigplanz (Apr 10, 2009)

$51 for a Motorcraft purge valve at Rockauto. $32 for a connector. May look for the connector in a junkyard. Find one not burnt, cut it off, replace mine with it. 

$10 for a junk yard purge valve. Any way to test it first? I figure I will take it off, and test it to make sure it's good before I go to the trouble of replacing one bad part with another. I'll consult my hanynes manual but they are spotty with this sort of troubleshooting.


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## de-nagorg (Feb 23, 2014)

The purge should be a normally closed, and only opens when activated.

Me I would put a hose on the outlet side, and see if I can draw through the thing with it unplugged, Draw like with a squeeze bulb, or even your mouth if you are not too finicky.

Then apply a current to the wires, and draw again.


Have you shopped E-bay?

There are often Ford Parts sales there, that run great deals on N O S parts.

I recently bought 12 FOMOCO oil filters there NIB for the price of 2 at my local dealership. 

ED


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## Bigplanz (Apr 10, 2009)

de-nagorg said:


> The purge should be a normally closed, and only opens when activated.
> 
> ED


From my research, and the above, I think the + is always hot (key in run) and the other is ground only when commanded by the ECM. Thus, the valve is closed until the ECM grounds it. If the connector is burnt, I surmise that the purge valve must have been stuck open (connector got hot from continuous use). I also surmise the valve is still drawing voltage continuously. 

Whatever the case, I will replace it.


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## de-nagorg (Feb 23, 2014)

Bigplanz said:


> From my research, and the above, I think the + is always hot (key in run) and the other is ground only when commanded by the ECM. Thus, the valve is closed until the ECM grounds it. If the connector is burnt, I surmise that the purge valve must have been stuck open (connector got hot from continuous use). I also surmise the valve is still drawing voltage continuously.
> 
> Whatever the case, I will replace it.


You may be right. I am not positive, I did a little research, but My manuals are limited , as you discovered in yours.

I found a used one on e-bay for about $12.00, with a 30 day guarantee, off of a Fort V8 pickup, that should be the same as yours. 

They claim to have tested it, but I don't know how.

Anyway if that is stuck open, it is definitely a vacuum leak.

I remember in 65 when the carbon canister first came out, it was just a can that looked very much like a juice can, that was hooked direct to a vacuum port under the carburetor, but now with all this electronics, those are ancient history.


ED


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## Bigplanz (Apr 10, 2009)

I disconnected the connector and started the car to see what effect, if any, would occur. Idle was about the same. It did throw a code though, because the SES light came on. I will go down to autozone and get them to read and clear it for me. Throwing a code indicates something is going on with the valve. The car computer knew it wasn't working. Probably didn't get a signal from it when it was commanded to open.


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## Bigplanz (Apr 10, 2009)

When I disconnected the electrical connector, it set a code P0443, open circuit, purge valve. Autozone apparently can't erase a code. They told me they could only read them. I guess I will buy a cheap OBD II scanner so I can clear it. Need one (a scanner) anyway.

I am going to test the valve to see if it holds vacuum. The photo below shows where I think I connect the MightyVac. Circled in blue. It is a regular vacuum line nipple. The two large ports on the left are the inlet and outlet from the canister to the intake manifold. The thing with the green cap is where I assume you would hook up a smoke machine. Is that right?


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## Bigplanz (Apr 10, 2009)

I put a MTYVAC vacuum pump on the nipple, car off, key out, and it would not hold vacuum. I turned the engine on, put the pump on the vacuum source to use the pump as a meter. It measured 21 inches of vacuum, steady.

Make sure you have multiple copies of any adapter or socket you use on an engine in 20 degree weather. Dropped a vacuum pump adapter, first thing, down in the engine. Just got another one. Never found the first one. I keep at least two sets of the same size sockets in the car for this very reason. Trust me, if it is vital to the repair, you WILL drop it down into the abyss.


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## de-nagorg (Feb 23, 2014)

That does sound as if the valve is stuck open, allowing a leak.

Next I would use a golf tee in the hose from the source to the unit to plug it.

Run the car and see if it still stalls when shifted to Reverse.

Odds are that it will purr right along as if it was correct.

If so the valve is due to be retired.

If it still stalls , check to see if everything is plugged in right, and the Tee is in place.


ED


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## Brainbucket (Mar 30, 2015)

If the connector is burnt, then the item that it was connected to is also burnt. Replace both. To smoke test, it's that green cap you see. The shrader valve has backwards threads if you need to remove it for testing. And you need a scanner to command it on and off. Also the command the vent valve on and off to close the system while smokin it.:vs_cool:


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## Bigplanz (Apr 10, 2009)

I bought a used Vapor Canister Purge Valve at Pull A Part. It was 14 bucks. 
Two, actually, since the first one wouldn’t hold vacuum I returned it and got another one. I tested it by first putting 12V to the device and testing if it would hold vacuum. When no voltage is present, the device doesn’t hold vacuum at all, so the valve is open. When 12V is applied to the device, the device will hold vacuum but in a way I didn’t expect. I pumped the vacuum pump, got vacuum to hold but it slowing bled off to less than 2 inches of vacuum.

So, the valve was closed but not an air tight seal. I am not sure it is designed to hold an airtight seal. When on the car, it is subjected to a continuous 21 inches of vacuum. I assume it closes enough for a vacuum to be established sufficient to purge the canister, even if the valve isn’t air tight. Anybody know if this is correct? From what I read, the ECM will send pulses to the device to pull a little vacuum or a lot, depending on operating conditions. I assume the continuous vacuum source is sufficient to accomplish this goal with the valve closed, even if it isn’t air tight. 

The hardest part of getting the valve off the junk yard car (an Expedition) was getting the blankety blank connectors off for the manifold and canister side of the valve. In a cramped engine compartment, on a firewall, way in the back and below the device, getting a grip on the connector, pressing in the little tabs hard enough to undo the latch mechanism and then twisting and pulling it off the connector was a trial. I finally cut the line on one, just because I was on a junk yard car and who cares? I will have to be more patient on mine, though I did get some spare connectors from the junk yard, so even if I break one, I have spares.

Below is a video of me testing the new (used) valve.


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## Brainbucket (Mar 30, 2015)

That is one test. Now somehow blow in the big tube and see if it comes out the other big tube with your breath. With voltage and without. Your not suppose to exceed 1 lb of pressure. No leaks when commanded closed. That's the test you really want to see. Not sure on the vacuum test your doing as I didn't see you make the pump hold vacuum to see if the vac pump is holding vac. It might be the thing leaking down. If the pump is ok, I would say that that valve is bad. What is your other valve doing? Compare the two.:vs_cool:


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## Bigplanz (Apr 10, 2009)

I wasn't sure how much vacuum it was supposed to hold. I would put vacuum on it (circuit energized) and it would leak down to 1 pound then hold it. It held 1 pound vacuum steady for five minutes. Then I de-energized the circuit and it dropped to zero.

It has been pretty cold this week. 15 degrees right now. The original part is still on the vehicle. I have 12V at the connector, but haven't tested the device yet with my powerpack.

I snipped off the connector on the junk yard car, so I can plug it into mine and use the wires to hook up to the power pack. Lots easier than trying to jury rig test leads. 

I will try to blow through the two ports to see what happens. Supposed to warm up to 60 Saturday, I so I will swap parts then. Should take less than 30 minutes. Hardest part is getting the blankety blank connectors off.


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