IMRC Cleaning Question

[Low Class Yuppie]

Alright, I got the dreaded "IMRC stuck closed" code on my '96. Tonight I'm going to try Seafoaming the car to see if it helps. Should I clear the code before or after? Should I just disconnect the battery first? Is the ECU smart enough to check every time on startup (thus negating the need to do anything at all)?

 

[GRUSE]

To clear the code disconnect battery for around an hour,some recommend switching headlights on to drain all power.Clear the code before or after probably doesn't matter.Did it CEL bank for 1 or 2,have you checked the cable or worked the IMRC by hand?
Eventuality you will need to pull the IMRC's out for a proper cleaning or delete.


Good luck with the Seafoam,hope it works for you.

 

[mwolson]

After you disconnect the battery, just press the brake pedal for a few seconds to drain the cap that keeps the data in the KAM alive. That way you don't have to wait for an hour to clear your DTCs.

Seafoam won't touch the crud in your IMRCs. I tried it and it did not work at all.

 

[ViciousBlack97]

Check the functionality of the cables that run from the controller first. I had the same problem as you, it just turned out that one of the cables had snapped coming from the controller, and all of the seafoam in the world couldn't help that. If you rev the engine past the IMRC opening point, you should be able to see the cables moving, even if the IMRC is stuck shut. If you do have to remove them and clean them, this link helped me and a buddy do it in about 8 hours time, and that was at a very lazy pace. http://www.ozzy.net/jdscott/cobra/documents/IMRC_Cleaning.pdf

 

[cobra_neill]

Alright, I got the dreaded "IMRC stuck closed" code on my '96. Tonight I'm going to try Seafoaming the car to see if it helps. Should I clear the code before or after? Should I just disconnect the battery first? Is the ECU smart enough to check every time on startup (thus negating the need to do anything at all)?

The old seafoam trick.

Clearing the code wouldn't make a difference regards before and after. It only throws a code over the 3250rpm point.

I personally ran seafoam recently with good success after a bank 1 closed IMRC error. First time I used it too. At first I was like "aww no smoke" driving it normally. Then I took it to 4k and it opened them IMRC bitches up and left like the batmobile in a cloud of smoke.


Nanananananananaseafoaaaam

 

[Low Class Yuppie]

The old seafoam trick.

Clearing the code wouldn't make a difference regards before and after. It only throws a code over the 3250rpm point.

I personally ran seafoam recently with good success after a bank 1 closed IMRC error. First time I used it too. At first I was like "aww no smoke" driving it normally. Then I took it to 4k and it opened them IMRC bitches up and left like the batmobile in a cloud of smoke.


Nanananananananaseafoaaaam

Seems to have worked, similar experience to what cobra_neill said. Car felt MUCH stronger afterwards and I definitely noticed a difference in performance after 3250 RPM. Just to be safe, I'll double check the cables - if they're working fine, then I'll just remove everything and give it a good cleaning. If my control box is bad, I'll just delete the system with the MMR plates. Either way, I'm installing a catch can.

Thanks for everyone's help!

 

[ZeroDCX]

Seafoam will not do justice cleaning the IMRCs. The intake must be removed and the valves/IMRC plates must be cleaned by hand. Here are my IMRCs post Seafoam treatment and also vs cleaning manually.

Seafoamed IMRCs (Secondary Intake Port/Valve)

Post Berryman's B12 Chemtool and Toothbrush Cleaning (Secondary Intake Port/Valve)

IMRC plates Post Seafoam Treatment (Right) and Post Carb/Brake Cleaner (Left)

 

[Low Class Yuppie]

Wow, thanks for sharing.

I figured I'd have to get in there and clean them regardless, I was just trying to buy a little time until I get a chance to rip things apart. What kind of shape were your intake gaskets in at that point? Did you have to replace them? I know they're supposed to be reusable, but after twenty years I'm sure they aren't as pliable as they used to be.

 

[mwolson]

My gaskets looked as good as new when I did my delete. Don't use solvent to clean them. I used hot soapy water. Worked great.

 

[ZeroDCX]

Wow, thanks for sharing.

I figured I'd have to get in there and clean them regardless, I was just trying to buy a little time until I get a chance to rip things apart. What kind of shape were your intake gaskets in at that point? Did you have to replace them? I know they're supposed to be reusable, but after twenty years I'm sure they aren't as pliable as they used to be.

I had to replace nothing, it just took 4-5 hours of my time (I was taking my time, being extra careful). Gaskets are reusable as long as they are in good shape. As mwolson stated, do not use solvents to clean them. Soap and water worked for me.

 

[Martin6107]

If you have the IMRCs out, do yourself a favor and replace the o-rings on the end of each shaft. You can get new o-rings at just about any local hardware store for about a buck each. Making time to source a set of bearings would be a good idea too since the stock bearings tend to freeze from the heat cycles and chemicals.

Here is some detail from one of my previous posts ....

Rebuilding the aluminum IMRCs is pretty straight forward.

Remove two small screws from each butterfly. Heating each screw up with a small torch makes removal simple. Once the butterflies are off, slide the main shaft out the back of each plate. You will find an o-ring on each end of the shaft that is probably so dried up you will swear that it is something else. Cut it off. Each IMRC plate has a small bearings on each end of the plate where the main shaft goes through. They probably are not rotating well at all. Work them out of the IMRC plate using a small punch from the butterfly opening side. They will come out eventually.

With everything apart you will be able to clean the IMRC easily. I had a local machine shop run mine through an ultrasonic and they looked great. You can get the same effect with brake cleaner and a brush.

Once everything is clean and dry, apply a light coat of oil on your new bearings and tap them into place using a socket the same diameter as the outside of the bearing. Put a new o-ring on butterfly shaft closest to the arm, add a light coat of oil to the o-ring, position the return spring on the shaft and insert the shaft through the rear IMRC bearing. Work the shaft through to the last open butterfly hole, install the forward o-ring with a light coat of oil and slide the butterfly shaft the remaining way into the forward bearing. The butterfly shaft should rotate freely but not be able to slide back out too easily. Reinstall the butterfly plates with two small screws on each. I used red loctite on the threads for peace of mind. Once the butterflies are installed, you are good to go.

Bearings should be a S688-2R and o-rings should be a -008 size (or maybe a -106 for a real tight fit).

 

[Low Class Yuppie]

If you have the IMRCs out, do yourself a favor and replace the o-rings on the end of each shaft. You can get new o-rings at just about any local hardware store for about a buck each. Making time to source a set of bearings would be a good idea too since the stock bearings tend to freeze from the heat cycles and chemicals.

Here is some detail from one of my previous posts ....

Rebuilding the aluminum IMRCs is pretty straight forward.

Remove two small screws from each butterfly. Heating each screw up with a small torch makes removal simple. Once the butterflies are off, slide the main shaft out the back of each plate. You will find an o-ring on each end of the shaft that is probably so dried up you will swear that it is something else. Cut it off. Each IMRC plate has a small bearings on each end of the plate where the main shaft goes through. They probably are not rotating well at all. Work them out of the IMRC plate using a small punch from the butterfly opening side. They will come out eventually.

With everything apart you will be able to clean the IMRC easily. I had a local machine shop run mine through an ultrasonic and they looked great. You can get the same effect with brake cleaner and a brush.

Once everything is clean and dry, apply a light coat of oil on your new bearings and tap them into place using a socket the same diameter as the outside of the bearing. Put a new o-ring on butterfly shaft closest to the arm, add a light coat of oil to the o-ring, position the return spring on the shaft and insert the shaft through the rear IMRC bearing. Work the shaft through to the last open butterfly hole, install the forward o-ring with a light coat of oil and slide the butterfly shaft the remaining way into the forward bearing. The butterfly shaft should rotate freely but not be able to slide back out too easily. Reinstall the butterfly plates with two small screws on each. I used red loctite on the threads for peace of mind. Once the butterflies are installed, you are good to go.

Bearings should be a S688-2R and o-rings should be a -008 size (or maybe a -106 for a real tight fit).

Awesome info, thank you! This should be a sticky for sure. When I clean mine, I'll take lots of pictures, and maybe we can combine all of the info that's out there.

I also recall reading that the coolant crossover has to be removed, so I think I'll replace those O-rings while I'm in there, too.

 

[Whit Clark]

how is the performance after ? is it like a night and day difference ? what did you use to get the cleaner back out the ports ? something like a shop vac or just rags ?

 

[ZeroDCX]

how is the performance after ? is it like a night and day difference ? what did you use to get the cleaner back out the ports ? something like a shop vac or just rags ?

Shop vac. By the time it went through the suction tubing, it evaporated anyway.

 

[Martin6107]

I also recall reading that the coolant crossover has to be removed, so I think I'll replace those O-rings while I'm in there, too.

Right on! Replace all 3 of them. After a bit of light sanding and a shot of high temp paint, that crossover tube will look brand new. Inspect the coolant return lines while you are in there. The rubber hose from evaporative canister typically needs replacement too. If the hose is chalky in your hands then replace it. This is also a perfect time to have your injectors cleaned and flow matched. Many repair shops now have ultrasonic cleaners available and will clean injectors for a few bucks each when you walk them in the door.

 

[Martin6107]

There is a night/day difference, especially after the o-rings and bearings are replaced. It is shocking just how much of a vacuum leak is created (x4) once the o-rings start drying up. I usually have to snip the old ones off each shaft with a wire cutter and pick pieces of them off in chunks. This fix pays great dividends for the minimal cost involved.

 

[mwolson]

Check to see if you have a one terminal or two terminal temperature gauge sensor. The one terminal sensor is in the older Cobras like my 96. If you have the one terminal gauge sensor, then you need to ensure that the crossover tube provides a good ground after you paint it or the temperature gauge won't work properly. (in all of our cars, the PCM's temp sensor is a two wire unit.) You need to scratch the paint off the bottom of the tube's mounting tabs so they make a good electrical connection to the heads. Or you can get a two-wire sensor and pigtail from a newer car and ground the non-signal sensor wire. The signal wire is Red with a White stripe. I can't remember the other wire's color off the top of my head.

 

[Whit Clark]

ok so these little bearing? you can get these at a hardware store or a auto parts store. i have all three around me is why im asking, autozone, advance, orielys. in case of replacement. im sorry. i dont mean to tread onto the thread but im also about to do this myself and it will be my first time messing around the inside on a DOHC. ive changed my valve cover gaskets before and thats as far as ive gotten. if i would have known about the IMRCs then i would have done them as well.

 

[Low Class Yuppie]

All great info in here guys, keep it coming!

My coolant crossover is surprisingly clean. 64k car that hasn't seen winter.

Who's that guy that makes the replacement plugs for the Marauder guys?

 

[Martin6107]

The bearings can be ordered online - just search for the bearing number S688-2R. Chances are, you will have to buy a 5 or 10 pack.

http://www.vxb.com/page/bearings/PR...Wze5no0Pk0wz459e4R5lV0hQMkTFN7M61yBoC20nw_wcB

You have to be careful getting the old ones out of the aluminum IMRC body, but they will come.

The Haynes book will walk you through the intake removal and assembly procedure. Take your time, torque the bolts in sequence and you will be fine.