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HOW TO: IMRC Removal and Repair

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dsi imrc
231K views 191 replies 86 participants last post by  AussieRigby 
#1 ·
First off, credit for this idea goes to an older thread which now seems to be gone. I'm just going into slightly more detail.


This problem is very common, and I suspect 80% of SVT owners need not replace the IMRC but simply clean the internal contacts.


So, do you have this problem? If you answer "no" to the following, it is 90% likely this procedure will work for you:

1) Is my cable broken?
2) Is my lever broken?

What you need:

1/4in ratchet with 8mm & 10mm sockets
Phillips screw driver #1 & #2
Soldering Iron
Thermal paste
RTV



Ok, lets begin.


First, remove the drivers side headlamp, battery, battery tray, and airbox/uper half of CAI/SRI:






You see that the IMRC is located behind the headlamp.

Now, before unbolting the IMRC box, disconnect the cable from the lever. This is done by (with one hand) roatating the lever towards you, while grasping the end of the cable and sliding it off of the post.







Now, unbolt the box and remove it while snaking the cable out along the path shown.



Ok, the hard part is done [thumb]

Next, take the IMRC to your bench to begin disassembly.



First, remove screws securing cover. Then using a straight razor blade cut around the seam to free the RTV.



Now that the unit is open, remove the screws as shown, and desolder the power wires and connector pins.



Remove PCB, and this is what you have.






At this point you will notice, there is not much to this box. Notice the gears are made of metal, thus the odds they will ever strip is very slim. The electrical circuit is very simple as well, and failure of these components under normal operation is slim to none. The motor is nothing more than a glorified coil, and under normal operation coils are basically indestructable.

Leaving us with the true weak point of this unit... the contact [smackbum] Which is the copper strip with a nickel plated contact shown in the above picture.

Now, to remedy the dreaded P1518, we must burnish (clean) said contact.

Notice the grey color. This is not very condusive to conduction. [idea]






Using a piece of fine grit sand paper (paper), or a fine nail file (file), press down gently on the copper strip (DO NOT BEND COPPER STRIP),

Insert paper/file, release copper strip and pull paper/file out. DO NOT MOVE BACK AND FORTH, SIMPLY PULL.

Repeat 3-5 times, and marvel at your new looking contact.




Now, before you reasemble the box, make sure your FET has enough remaining thermal grease to dissapate heat properly... In my case, I wiped it away and used thermally conductive gap pad.

Add thermal grease if you need to.








Now reattach the PCB the reverse of removal.

Using standard RTV, run a bead around the edge and screw the cover back on.




Bolt up the box to its bracket and run the cable along the same path you took it out of. BE SURE TO RUN THE CABLE INTO THE GROOVE BEHIND THE BATTERY TRAY, SO THAT WHEN YOU PUT THE TRAY BACK IN YOU DO NOT SMASH THE CABLE.

Hook up the cable end to the lever post by rotating the lever towards you and sliding the groove of the cable end on to the post.

Replace airbox/upper half CAI/SRI, battery tray, and battery.

Hook up battery... Start car... and enjoy your engine codeless dash [wiggle]

I'm sure I forgot something, I will edit as I remember things or get suggestions from other members.
 
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#7 ·
#10 ·
As a side note to possible failures... If you have the 'marbles in a coffee can rattle' at start up the problem is the plastic pulley that the cable attached to inside the IMRC. See pic #9. The shaft that turns the pulley can strip the engagement pin on the pulley. If you open up your IMRC and have plastic shavings the pulley is toast and unrepairable. In my case this failure was caused by a faulty DSI manifold. The runner that rotates inside the manifold was beginning to 'sag' from the pivot points wearing and the runner was catching/binding causing the pulley in the IMRC to fail. I suspect the runners catching and binding is the actual cause of the broken DSI clip that so many experience.
 
#12 ·
Doing this now as we speak. I'm glad I found this thread! I got the dreaded P1518 code and my DSI clip is still fine so this was the only option left :). Hopefully I don't need a new IMRC actuator box.

It was the original thread I was looking for but glad there are two as this was more in-depth.
 
#13 ·
Well night and day change. It was the spring on mine that that popped off where it should have been. Took it all apart and put the spring back in it's place and threw it all back together(I also sanded the contact while I had it apart) and now I'm CEL free [:D]. Maybe this will be the end of my 20MPG gas millage [woot].
 
#16 ·
I did mine a couple weeks ago, for the lazy people [:p]; I left the headlight in and simply pulled the batt and airbox. If the car on on ramps you can easily get to the IMRC box without removing wheel or fender liner or head light. I also used a bungy cord to hold the airbox lid and MAF/intake tub up out of the way as the stock clips look like they would not clip back on if i pulled the tubes.
 
#17 ·
Yup. I just put a jack stand under the driver side and lifted her up. I only had to remove the battery to get to it. Didn't need to remove my CAI, headlight or tire either.

But my CEL came back on so I gotta take it back up to Autozone again and see if it's the same code again. It came back on after 60 or so miles [:(]. I bet it's that damn spring again.[:(!] That and while I had it up, I noticed some coolant dripping down, it was coming from the top I believe and dripping down off the tranny housing. Now I guess I gotta change out the infamous O-ring lol.
 
#18 · (Edited)
Ok, so I just started getting the P1518 code this week, but I haven't noticed any change in how it runs or MPG. I haven't checked it yet, but I'm pretty sure it's not the cable, and so it is probably inside the IRMC. I guess my question is with 125K on my SVT, is it worth the bother to take the thing off and disassemble it, or am I pretty much assured that the plastic wheel is shot? If that's the case, I'll probably just get a new one and get my mechanic to put it on. Any suggestions? Has anyone else got 125k miles without having DSI/IRMC problems?
 
#20 ·
I'm working on mine right now, we'll see how it goes.

To you guys removing air boxes and battery trays and headlights -- you guys do know all you have to do is reach under the driver's side bumper, in front of the wheel, and it's right there, right?

You don't even have to pop the hood (other than to disconnect the cable from the DSI lever and snake it out). All you've got to do is reach under the bumper, remove the bolts, uplug the wire, and pull it out. [:)] You can do it by feel if you don't want to lay on your back or jack it up.
 
#23 · (Edited)
Either the spring doesn't engage on the first revolution or my spring has popped off - what does it do? I never got a CEL, I just had to remove the IMRC to get the frame straightened. When it rattled like it had marbles in it, I opened it up.

Will it still work without a functional spring or does the spring just float until the shaft has turned 1 rev?
 
#25 ·
The spring puts tension on the gears so it will not operate completely with a faulty spring. Mine just came off so I just had to put it back on the right way. I don't think I've had any problems with it? No CEL anyways but I still get shitty intown driving but highway is still pretty decent.
 
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