Intake Manifold Runner Control - !Help!

[thxone]

Ok so the first code that pops up is 551 "Intake Manifold Runner Control". Apparently something is wrong with it but I have no clue what it is. My memory codes are for the right O2 sensor, one code says it was lean, the other code says rich... it's the same O2 sensor. The last mem code was for the EGR. This is all that pops up when I read the codes.

Ok, so how do I fix the "IMRC" or diagnose it? What is it? Where is it? I thought about it... Control, so it acts on something... Q: what? A: The intake runners. Q: How? Well I had to think about that too. The runners have a vacuum control on each side that opens the butterflies. A: By vacuum. Ok so I got that far and I thought some more... A: Locate and trace the vacuum lines from those runners. I did and they terminate at a T fitting that connects to a device behind the TB on the intake on the runner side (Inside) Q: Is this the "IMRC"?

Can this Control module be cleaned or serviced?

All Symptoms this 1995 ATX SHO is showing:

1. When cold - Drives great albeit with very firm first to second gear shifts.
2. When cold - Smells a little rich.
3. When Warm - Check engine light comes on.
4. When Warm - Anything more than a quarter throttle makes the car sluggish until almost 4,000rpm then it hauls ****.
5. When Warm - Smells very rich.
6. When Warm - If I give it full throttle it acts funny when it shifts... kinda like it is thinking about it. Does not do this when cold.
7. When Warm - Does not always want to fully kick down on the tranny and go go go...
8. When Warm - Check engine light comes on... goes off... comes on.......

 

[kevinspann]

That is the idle air control valve. The IMRC is on the back of the intake, close to the firewall, approximately in the middle. You'll see a round canister with vacuum lines, then on the intake a little closer to the driver's side the electronic portion that should have a plug with green and red wires plugged into it. That should be what you're looking for.

Let someone else correct me if I'm wrong about this.

 

[lowc]

not sure on the colors of the wires but you are in the right spot. before replacing it make sure its pluged in and all the vacume lines are in

 

[hawkeye18]

not sure on the colors of the wires but you are in the right spot.

Nope, not even close. That's the Idle Air Control valve (IAC). Post #2 had it right.

 

[thxone]

Thanks every one. I have seen the part you are talking about. Can it be cleaned or does it HAVE to be replaced if I see all correct connections and everything is hooked up properly? If it should be replaced does anyone have a part number from AutoZone or a name that they call it? Or an idea of price? Thanks guys.

 

[lowc]

Nope, not even close. That's the Idle Air Control valve (IAC). Post #2 had it right.

yea thats what i was refering to probly should have been a little clearer

 

[kevinspann]

I don't think you can buy one new, used only. can you verify that the secondaries open and close like they are supposed to?

 

[jedhead]

The secondary butterflies should be open on both banks when the engine is off. The butterflies should close when the engine starts.

Bob

 

[thxone]

Ok, so I played with a few things on the car and checked a few things... got me no where. The butterflies don't seem to do anything at all. When the car is off they are in the same position as when the engine is on (running) See pics below. I have located the IMRC... all connections are fine. However the top of the piece with the electrical connection is loose... looks like a cap but it is loose. Is this normal?

Firewall side of engine:


Radiator side of engine:


IMRC:


IMRC Electrical connection loose cap?

 

[thxone]

I also revved the engine from under the hood to see if they would open... hit the limiter twice but the butterflies did not open... now when I drive I can feel them kick in... odd.

 

[HUTCH]

What you are calling the imrc is the iac, or idle air control solenoid.

edit: but you already know that because someone already posted it, LOL

 

[Off Road SHO]

In your third pic, disconnect that little "J" shaped vacuum hose from the intake and check and see if you have vacuum there on the little metal ******. If so plug the hose back in and "trace" that vacuum through that black cannister and then to the electric solenoid valve (the black thingy with the loose vent cap on top). After that the vacuum "the sucking on your finger tip" goes to a vacuum hose that splits into two hoses that feed the two vacuum actuators that you took a pic of in pics 1 and 2.

When good vacuum is applied to those two actuators (hopefully at start-up of the engine), the arms of the acuators pull the secondary butterfly valves shut. When the running engine reaches 3950 rpms, the computer sends a ground to that little black solenoid, which in turn blocks the vacuum from reaching those actuators. When the actuators are de-powered, the springs on the shafts of the butterfly valves snap the butterflies OPEN.

When the engine rpms return to below 3950 rpms, the computer takes away the ground, which causes the solenoid to open and once again supply engine vacuum to the actuators, causing them to close the butterfly valves against the tension of the springs.

Tom

 

[thxone]

Ok, if I understand you correctly, I remove the vacuum line indicated by the RED arrow and check for vacuum... if there is vacuum then hook it back up and check the other (green) arrow for vacuum? Then trace from the Solenoid (loose cap thing) to each vacuum butterfly control to make sure they are getting vacuum?

 

[lowc]

yes thats how you want to check it, also to add that under the iac area there is y fitting that connects the vac line (green arrow) to the two lines that feed the secondaries

 

[thxone]

yes thats how you want to check it, also to add that under the iac area there is y fitting that connects the vac line (green arrow) to the two lines that feed the secondaries

Yes, I have seen that. I will check all the lines for leaks and for vacuum. Thank you!

 

[thxone]

I started the engine... no changed to the actuators. Pulled off the first vacuum line from the intake... idle rose up a little and there was a very good amount of vacuum on the hose. Plugged it back into the canister and pulled off the second hose and there was still very good vacuum at the canister ****** and idle rose again. I hooked it back up and the idle went down. Now, i traced the other vacuum line to the T fitting and removed the line as it entered the T before it splits to the actuators... NO VACUUM. None.

The vacuum at IDLE or below 3,950rpm's should act on those actuators and CLOSE off the butterflies for the short runners correct? When the engine reaches the correct RPM's then a signal is sent to that solenoid and closes the vacuum supply to the actuators letting the spring pressure OPEN the butterflies for the short runners correct?

Help Please!!

Line removed to test if vacuum was present before the T Fitting for the runners. This line is coming FROM the IMRC solenoid. All vacuum lines appear to have no leaks, holes or nicks.

 

[zach44102]

I just added a green dot to your reputation because its not everyday that people post questions with detail, and good pics. Most people who post questions want you to fix their car through the internet. I wish I could help you but I have the same code and the same problem. good luck!

 

[thxone]

Thanks for the point

I just figure if others also have the same issues I will do my best to be detailed, cover all bases and post resolutions. I contacted FORD and they say this solenoid is discontinued and is not compatible with the next gen SHO solenoid which is also becoming harder to find.

Looks like a good, used one is what I will have to source now... I doubt this one is able to be rebuilt.

 

[lowc]

it sounds to me like that hose comming off of the canister to the t has collapsted or is very weak and is closing itself when the vacume is applied i would first replace the hose and go from there

fwiw Ive had this happen to me on the vacume hose for the fuel presure regulator

 

[thxone]

I am removing the solenoid tomorrow to see if I can locate any damage and I will also be removing the vacuum lines from the car fully to inspect them as well... once they are numbered for their locations of course. Thanks lowc.