Headscratcher of an intake problem

[Paul Guilfoil]

1998 v8 sho. Runs beautifully when first cranked. Once it goes over 3k it will not run at less than 2krpm. Turn off key or reset codes, perfection. Go over 3k rpm, misery.

Recurring imrc stuck open error code. It isn’t! I can see the actuator and the butterflies move smoothly to closed position against stop. Butterflies were cleaned to brand new recently.

No other error codes. Help?

 

[rubydist]

moved to proper forum.

sounds like you have an issue with the irmc sensor or wiring.

 

[Paul Guilfoil]

moved to proper forum.

sounds like you have an issue with the irmc sensor or wiring.

Where is irmc sensor?

 

[Paul Guilfoil]

Where is irmc sensor?

 

[E1]

Intake Manifold Runner Control is under the engine appearance cover.
It has a plug and a cable. Cable runs to the butterfly linkage you have been watching.
Most of them failed already or so it seems. Most owners have just wired open the secondaries because the actuator no longer works. Yours seems to work but the little position switch inside the actuator is no longer signalling when the cable has been pulled in.

If you simply unplug the actuator and clear the code 1518 or 1519 the code should stay away. I know the secondaries won't work, but this is troubleshooting just to see if the car will run past 3400 rpms and not throw a code or go into limp mode.

 

[Paul Guilfoil]

Intake Manifold Runner Control is under the engine appearance cover.
It has a plug and a cable. Cable runs to the butterfly linkage you have been watching.
Most of them failed already or so it seems. Most owners have just wired open the secondaries because the actuator no longer works. Yours seems to work but the little position switch inside the actuator is no longer signalling when the cable has been pulled in.

If you simply unplug the actuator and clear the code 1518 or 1519 the code should stay away. I know the secondaries won't work, but this is troubleshooting just to see if the car will run past 3400 rpms and not throw a code or go into limp mode.

Intake Manifold Runner Control is under the engine appearance cover.
It has a plug and a cable. Cable runs to the butterfly linkage you have been watching.
Most of them failed already or so it seems. Most owners have just wired open the secondaries because the actuator no longer works. Yours seems to work but the little position switch inside the actuator is no longer signalling when the cable has been pulled in.

If you simply unplug the actuator and clear the code 1518 or 1519 the code should stay away. I know the secondaries won't work, but this is troubleshooting just to see if the car will run past 3400 rpms and not throw a code or go into limp mode.

I was SO hoping there was a sensor I had overlooked. What can I expect the car to run like if I wire the butterflies open? Is there any chance I can get a new actuator?

 

[stephen newberg]

A lot of messing about with dynos and such went into looking into the butterflies and IMRC and it turned out that just leaving them wired open all the time works fine. You can skip having the actuator completely, using the comments from Eric above to clear the initial codes. After that, they will not come back again. Some people even remove the butterflies completely and fill the axle holes for them in the intake. Works just great without them.

pax, smn

 

[E1]

Hi Paul
About the only side effect of just wiring them open is a rough idle in weather colder than ~30'F until the car warms up. Probably not a major issue around where you live...

The chances of getting a proper part number IMRC Actuator for a V8 SHO? We have a word for that - Unobtainium.

Good news is that the similar actuator from a 24v Duratec 3.0 will plug and play. It mounts a little different and the cable is a bit longer but once one gets it mounted, it works perfect and plugs right in.

Average junkyard price around me is $10.00.

 

[Paul Guilfoil]

Hi Paul
About the only side effect of just wiring them open is a rough idle in weather colder than ~30'F until the car warms up. Probably not a major issue around where you live...

The chances of getting a proper part number IMRC Actuator for a V8 SHO? We have a word for that - Unobtainium.

Good news is that the similar actuator from a 24v Duratec 3.0 will plug and play. It mounts a little different and the cable is a bit longer but once one gets it mounted, it works perfect and plugs right in.

Average junkyard price around me is $10.00.

 

[Paul Guilfoil]

Thank you! I will wire it up tonight!

Will post result.

 

[99sho-time]

I'm becoming increasingly intrigued by the imrc delete idea.

 

[Paul Guilfoil]

Hi Paul
About the only side effect of just wiring them open is a rough idle in weather colder than ~30'F until the car warms up. Probably not a major issue around where you live...

The chances of getting a proper part number IMRC Actuator for a V8 SHO? We have a word for that - Unobtainium.

Good news is that the similar actuator from a 24v Duratec 3.0 will plug and play. It mounts a little different and the cable is a bit longer but once one gets it mounted, it works perfect and plugs right in.

Average junkyard price around me is $10.00.

I found this wire disconnected on back side of engine. Green wire and white wire. Cannot find its home. Any idea?

 

[99sho-time]

Pic?

 

[gamefanatic]

O2 sensor or possibly knock. Picture or specific wire color / location.

 

[Paul Guilfoil]

Pic?

 

[99sho-time]

Looks like that goes to one if the egr cmponents. Hard see but there's a noise capacitor and I thought coil packs had white dots on them

 

[Paul Guilfoil]

It

Looks like that goes to one if the egr cmponents. Hard see but there's a noise capacitor and I thought coil packs had white dots on them

the white paint seems to be marking from prior repairman. Looks like whiteout. Sorry for bad pic. I have to stretch it to make it visible. Have looked with mirrors and a flex camera for hours. The end is clean so it has not been loose for long.

 

[Paul Guilfoil]

It

the white paint seems to be marking from prior repairman. Looks like whiteout. Sorry for bad pic. I have to stretch it to make it visible. Have looked with mirrors and a flex camera for hours. The end is clean so it has not been loose for long.

Could it be coil wire??!!

 

[99sho-time]

You'd have a code and bad vibration.

 

[gamefanatic]

I was thinking knock sensor, but thats only a two wire. Looks like the coil connector, but you should have a code if that is true.