What happens is there are plastic bushings that hold the acuator linkage in. These are available from ford dealers. They are about $10. I had the same deal on my 98. Without the plastic bushings the linkage won't stay in.

 

That was not the case in my situation.Both of my actuators were bad.I wish it had only been the bushings.

 

I have both a 1996 Windstar 3.8 and a 1997 F-150 4.2. They both have the IMRC setup. Very cool design! At any rate, these runners (inside the intake) can get clogged up with intake gunk. Ford says you can and should use injector cleaner spray to keep these things operating freely. You simply need to remove the upper intake manifold and spray them out. On the F-150 the vacuum pots are at the back of the engine (pain!). There are little black, snap in bushings that connect the actuator rod of the pots to the IMRC rod. Ford says that you should replace these bushings if you ever need to disconnect them. I personally have reused them if they don't break. The part is available from Ford for about $8.00. Dorman also makes the part for cheaper (rockatuto.com) Part# 47099.

At any rate, when vacuum is applied to the pot it closes the IMRC butterflys. If vacuum is off or inoperative the IMRC will remain open. For most around town driving the IMRC is closed. The IMRC opens at about 3500RPMs.

Quoted:

The IMRC system has two intake manifold runners per cylinder for air flow into the combustion chamber. One runner is always open and the other is commanded open by the Powertrain Control Module (PCM). Below approximately 3000 rpm, the valve plates are closed and above approximately 3600 rpm, the valve plates are opened. The PCM also receives a signal from the IMRC system indicating valve plate position. The quantity of air metered to the engine is controlled by the throttle body assembly.

The IMRC system also has a housing and actuator assemblies. The IMRC housing assembly is an aluminum casting with two air intake passages for each cylinder. One passage is always open and the other is opened or closed with a butterfly valve plate. The IMRC Actuator is either a remote mounted electro-mechanical control actuator or a direct mounted vacuum actuator type system. In the remote system, the IMRC housing valve plates are held closed with a return spring located on the valve plate shaft. When commanded open by the PCM, the IMRC actuator pulls on the IMRC shaft assembly using an accelerator type cable. On the direct mounted vacuum actuator system, the return springs are located within the vacuum actuator. The PCM commands a vacuum control solenoid allowing the vacuum to pass to the vacuum actuator drawing the valve plates closed or releasing the vacuum allowing the actuator to push the valve plates open. Substantial opening and closing torque is applied in both systems. Care should be taken to keep fingers away from the lever mechanisms when actuated. It also provides a switch signal to the PCM for the plate position.

End Quoted

Regardless, I have never had the actuators fail. Probably because I kept the butterflys clean by blasting them off with spray once every year or so. I simply remove the upper intake and get in there. Not too big a job at all. But that way the butterflys move freely and don't put undue strain on the actuator's diaphragm.

Hope this helps.

 

Mine both failed! One failed on the electrical side,the other failed on the vacuum side.

 

Yes, that's unfortunate and expensive!! Try removing your upper intake and getting in there and cleaning it out. You'll see all that usual maple syrup and gunk that hinders their proper operation. If those actuators have to fight the gunk in there and it is sticking, you'll be replacing them again.

Ouch!

 

Nah,I wont! I sold that truck!

 

thanks to all the helpful information on this forum you all have helped me figure out the problem with my 1997 F 150 4.2. i will be taking the manifold off this morning and getting to the actuators today. i could reach behind the engine and feel that the arm on the right side has fallen out of it's place. i will try to take some pics of the process.

 

Make dang sure you use the updated lower intake gaskets! If not you take a chance of getting hydro lock!
https://www.f150online.com/forums/v6...hydrolock.html

 

thanks Blue! i ordered the exact same ones that came out of the engine. Lowers are Fel-Pro 98010 and 98009. the upper didn't have a number on it but they all came together in the order. i laid them all on top of each other when the new ones came in and they are exactly the same.

do you have any advice for putting her back together? i've got the service manual and plan on following it step by step but some input is always helpful. thank you for your response.

 

If it were mine I would have ordered the improved updated gaskets from Ford.

 

too late. gonna role the dice with the old style gaskets. there didn't seem to be a problem there. the old ones still look great. she is a good around the town work truck for my pressure washing business. the 2001 F350 with the 7.3 is my commercial fishing / farm truck that has to be 100 % reliable and so far has been a dream come true.

 

GOOD LUCK!
When it hydro locks just remember, I TOLD YOU SO!

 

yes when i install the gaskets improperly and my truck hydrolocks i'm going to start running around my driveway screaming "Then said I, Woe is me! for I am undone; because I am a man of unclean gaskets, and I dwell in the midst of a parts store with unclean gaskets: for mine eyes have seen the posts of truth, the lord BlueOvalFitter hath told me so."

 

Yep, I told you so.

 

my truck runneth over... and over and over! so it's been a month since the fix and whitey ford is running like brand new. i appreciate the insight and help from this forum!