How to tell if IMRC runners are operating properly?

[96cobraboy]

I have a 96 cobra with 127k. Vehicle runs good with no real apparant issues atall.

This is myfirst cobra and ive been reading about the IMRCS. It doesnt have a code thrown or anything but how do I tell if they are opening and closeing as designed?

I had a integra with the secondary runners and you could hear them clearly open but Im not so sure about a cobra..

can these get stuck and now throw codes? Id hope this may be the case because it doesnt seem like it has 300hp but I could be wrong.

 

[Kilgore Trout]

They can absolutely stop working, I believe the OBDII system will throw a code if they do...

 

[96cobraboy]

everyone talks about cleaning them.... i did a archive post and not eveyone reported they had a code , maybe they arnt opening all the way?

im just trying to learn how to do some prediagnosics to determine if it needs to be torn down and cleaned or not.

 

[COBRA90GT]

A '96 with 127K miles on it would definitely benefit from a weekend project of cleaning up the IMRCs....do it.

 

[96cobraboy]

What Will I gain from doing this? I guess Im tryng to see what will be best for me...

 

[na svt]

What Will I gain from doing this? I guess Im tryng to see what will be best for me...

Don't mess with it until you find out if they are working.

Put one hand on the IMRC cables at the point where they connect to the IMRC plates/shafts. Using your other hand, open the throttle to bring the rpm to about 5k. At 3250 rpm (give or take a few), you sould feel the IMRC shafts move/rotate. If you feel nothing, they aren't working.

 

[AntL97Cobra]

I'll piggyback on this thread to ask a question. How much would you guess the charge would be to clean the IMRC? I've done most of the bolt-ons for my Cobra but not sure I feel comfortable taking off and apart the intake.

Thanks for the help

 

[KeAnBe46]

There will be a code that gets thrown...Its P1390 or something like that. It will also throw your O2 Sensor codes as well. The code will state - "IMRC Stuck Open/Closed"...then it will throw - "O2 sensor registering lean", "O2 sensor registering rich", and it will show that the back O2 sensors "Not testing". I found that when my IMRC's were stuck open/closed that my gas milage was cut in half. I tried some little backyard solutions that temporarily fixed the issue. Then I went to Firestone and had them perform a Fuel Tune. That fixed the issue, but the code that got thrown was an O2 Sensor was out of wack, i replaced the O2 Sensor and no more Check Engine Light.

So to those who read this, if you come across this issue, try a fuel tune from Firestone. Its about $100 and it takes less time than tearing apart the whole intake manifold to clean the inside and to clean the Intake Runners.

 

[na svt]

I'll piggyback on this thread to ask a question. How much would you guess the charge would be to clean the IMRC? I've done most of the bolt-ons for my Cobra but not sure I feel comfortable taking off and apart the intake.

Thanks for the help

It's relatively painless task that even the inexperienced mechanic can handle with the right instructions. Get yourself a Haynes manual and tool set and have at it. I can probable even scan the necessary pages for you if you want to seee what you would be getting into.

 

[cold96snake]

I plan on doing it in a couple weeks.

A pretty good how to.

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