98 Mark VIII Intake Manifold Runner Stuck Open?" (Bank 1)

turn_on68

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Does anyone have a step by step instruction on how to fix this problem. I know I have to get to the runner valve motor to replace it, but I cannot even see it except with a mirror as it is on the back of the engine between the firewall and the engine. My thought is to pull the valve cover,but that has a lot of stuff to remove to get it off and if it is not necessary?
 
Removal of the valve cover will not help much. Are you sure the motor is bad? I am pretty sure than on a Gen II the one electric motor controls both. If you have bank 1 stuck and not the other it may be a different problem.

This is not exactly for a Mark VIII, but its good reading:

http://home.flash.net/~ivc1/cobra/imrc.html

But before you venture there I would recommend the proven SeaFoam treatment. Many have reported its success in freeing and improving IMRC operation.

Every so often I put a can (or two if really bad) into the intake. I would let it enter by removing the brake booster vacuum line at the manifold, if the beauty cover is off its really easy to get too. I would them attach another hose to the manifold port.

BTW do it when the engine is plenty warm and be prepared to produce A LOT of white smoke. The neighbors may freak out a little :D

I would then pull the throttle cable to make the engine rev up and then let it start sucking it up. Try not to let it stall until the very end. By letting it stall you kinda "coat" everything. If you let it just suck it all up and keep running the SeaFoam is "cleaned" off of all the surfaces and has less time to clean things. Let sit for 15 minutes to 30 minutes and try to start her back up. It probably wont start too easily but it will.

Now take her out on the highway, again your going to make A LOT of smoke for a few miles if the car is really dirty. The dirtier the more smoke is produced. Drive her kinda hard to clear everything out. Make sure you pass 3k RPM sometimes, this will open and close the IMRCs. I also try to rev her when adding the SeaFoam to open and close them also.

If you run a second can through you can do it right after the first by not letting it stall and start adding the second can or you can do what I prefer which is to get the first one all cleared out then add the second following the same steps. Normally just one can a year is fine unless you do a lot of city driving.

If I do the two cans I usually get an oil change within 100 miles of the treatment. I dont like adding it to the oil, I feel it thins it. If I do I generally take it easy on the car and get an oil change within 200 miles.

When I first did the treatment above to my Mark VIII I noticed a major gain in the butt-o-meter as well as improved gas milage.
 
You can squeeze your hand between the left engine bank and the fire wall to reach the IMRC and the cable running to it from the control motor ! You CAN manipulate the arm of the IMRC by hand ! If is is stuck open , you can probably free the IMRC that way ! The number 2 bank ( right ) is a lot easier to reach than the number 2 bank !

Good Luck,
Sonny
 
Sonny Day Out said:
You can squeeze your hand between the left engine bank and the fire wall to reach the IMRC and the cable running to it from the control motor ! You CAN manipulate the arm of the IMRC by hand ! If is is stuck open , you can probably free the IMRC that way ! The number 2 bank ( right ) is a lot easier to reach than the number 2 bank !

Good Luck,
Sonny

I have used the Seafoam and it didn't fix it. Yes I can feel it and move it so I am pretty sure it is the motor on the left side. I just don't know how to get to it to replace it. Max at Five Star had the motor at a little over $100.
 
There is only one motor controlling both IMRC's. The box is as you said, between the rear of the engine and the firewall, on the driver's side. See if you can reach in there and check that the cable is connected to the IMRC. Then as stated earlier, move the imrc's a few times by hand.

I would think the easiest way to replace the IMCR actuator box is to pull the wiper assembly and the cowl.

I'd take a picture of it, but both of my cameras are in my truck, and it's at the stealership getting some work done on it.
 
Frogman said:
There is only one motor controlling both IMRC's. The box is as you said, between the rear of the engine and the firewall, on the driver's side. See if you can reach in there and check that the cable is connected to the IMRC. Then as stated earlier, move the imrc's a few times by hand.

I would think the easiest way to replace the IMCR actuator box is to pull the wiper assembly and the cowl.

I'd take a picture of it, but both of my cameras are in my truck, and it's at the stealership getting some work done on it.

Are you sure there is not a left and right motor, because Max definitely had a left and right for a '98 and they are electric, not vacuum.
Now how do you remove the wiper assembly and cowl?
 
There's only one motor. I am sure of it. I can look at the back of my engine and see both cables going tot he same assembly.
 
One Motor. Two Cables.

This one is from a.. hell, I dont remember the year. If I can find the back cover and screws you can have it for 25 plus shipping.


_IMRC_Actuator.gif
 
Frogman said:
One Motor. Two Cables.

This one is from a.. hell, I dont remember the year. If I can find the back cover and screws you can have it for 25 plus shipping.


_IMRC_Actuator.gif

If there is one motor and the drivers side still works, then it is just the passenger side that is sticking. However the cable on the the passenger side has since slipped off the rocker piece it went around. I still need to know how to get the windshield wiper cover plate out if that will allow me to be able to see what I am doing.
 
Does anyone have a step by step instruction on how to fix this problem. I know I have to get to the runner valve motor to replace it, but I cannot even see it except with a mirror as it is on the back of the engine between the firewall and the engine. My thought is to pull the valve cover,but that has a lot of stuff to remove to get it off and if it is not necessary?
Did you ever figure this out mines getting stuck close I don’t seem to find them could you help I need to find the location on them
 

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