551 EEC IV 3 digit code (IMRC)

[rktmn]

I am getting a 551 code

"Problem in Intake Manifold Runner Control(IMRC) solenoid/circuit"

Can someone identify where the solenoid circuit is, or the solenoid itself?

I am also getting a check engine light coming on and going away. The problem does not seem to be constant, but it does cause the engine to stumble and run a bit rough at times.

When it runs well, it hauls, but evntually the problem comes back.

Thanks,

Jose

 

[jonheese]

I've never personally seen this code in a Gen2 before, but the IMRC is the secondaries. A wire runs from the ECU to a vacuum valve that passes vacuum to the butterfly actuators and and this is how the ECU tells the secondaries to open.

Again, I have no direct experience with this code, but my first suggestion would be to check the wiring/connector at the vacuum valve, which is bolted to the back of the intake (follow the vacuum lines from the butterfly actuators).

Good luck.

Regards,
Jon Heese

 

[jmpSHO]

Sounds like you have a bad IMRC unless for some reason it got disconnected.

 

[rktmn]

Where is the IMRC and what does it look like?

Jose

 

[shotime1994]

It bolts behind the intake there is a two pin connector and some vacuum hoses. Its closer to the driver side near the firewall its on the intake.

 

[jonheese]

Where is the IMRC and what does it look like?

...the vacuum valve, which is bolted to the back of the intake (follow the vacuum lines from the butterfly actuators).

Is this thing on?

Here are a couple pics of the IMRC control valve on my spare engine (yours should actually be connected to vacuum and electrical):

Regards,
Jon Heese

 

[rktmn]

Jon,
I exchanged the IMRC from my spare manifold, diconnected the battery to clear the codes, and so far that seems to have worked.

My check engine light has not come on, and the engine is running strong without any stumbles.

Thanks guys.

Jose

 

[jonheese]

Glad to hear it.

Keep in mind that the IMRC only does anything when the secondaries open; when you're under 3950 RPM (or wherever your opening point is), it's just sitting there doing nothing.

So if you were having stumbling/rough running under 3950 RPM (or whatever), then the only reason I can think of is that it was a vacuum leak. Either way, if swapping in a "new" one fixes the problem, it doesn't really matter what went wrong with the old one.

Edit: I suppose it's also possible that the valve failed in an "open" state, meaning that you're secondaries were always open. This should cause the car to run more sluggishly at low RPMs, but I wouldn't expect it to cause any stumbling...

Regards,
Jon Heese

 

[rktmn]

Actually, the worst sympton it had, was when I was accelerating, the engine would suddenly kick down as if it had lost electric power for a second, and then it would stumble, loose power and come back on again, stutter a bit and clear up.

The engine would never turn off while this happend, but it would run rough for a bit.

The problem was sporadic. The engine would run fine for a while, but eventually the problem would surface again.

So far it has not done it yet, so hopefully it is fixed.

Jose

 

[jonheese]

Actually, the worst sympton it had, was when I was accelerating, the engine would suddenly kick down as if it had lost electric power for a second, and then it would stumble, loose power and come back on again, stutter a bit and clear up.

The engine would never turn off while this happend, but it would run rough for a bit.

The problem was sporadic. The engine would run fine for a while, but eventually the problem would surface again.

So far it has not done it yet, so hopefully it is fixed.

Jose

Hmmm... That's a really odd symptom to have associated with the IMRC. I suppose the electrical side of the IMRC might have been dead-shorting, but it only has power when the EEC commands the secondaries to open, and it should only 5V, so that doesn't really make much sense....

I got nothin'. :Shrug: Let's just hope it was the IMRC and the problem is in the past.

Regards,
Jon Heese