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Old 06-24-2008, 08:54 AM   #1
Focus Rookie
Join Date: Jun 2008
Fan#: 56787
Location: Richards Bay
What I Drive: 2004 Imperial Blue ST170

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ST170 Intake Manifold Runner Control disassembly (PICS!!)

Well evan's post the other day "" got me thinking. I didn't think the IMRC box could be opened before he said he opened his up, so I decided to remove, open, and have a look at mine. My car had been throwing the code P1518 a lot recently, which has to do with the IMRC malfunctioning.

Well what evan doesn't mention is that due to the positioning and way that the IMRC is mounted removing it is a *!!! Don't even try it unless you have a quality 10mm ratchet spanner and a fair amount of patience, and don't mind skinned knuckles and fingers.

Once its off though and you remove the cover held on by four screws this is what you will see.

A circuit board, a johnson 540 motor (as used in almost all basic radio control cars), and a cascade of metal gears, all rather simple and rugged looking.

In order to have a look at the other side of the circuit board I had to remove the 6 screws holding the board to the case and the black electrical connector. The connector is securely epoxied in place and can't be removed. I also had to de-solder the six connections between the board and the electrical connector.

On the underside of the circuit board you can see the points that are activated by the cam on the white plastic wheel that pulls the cable. The points are held open when the car is off or when the IMRC is in the high speed position. At any other time the points are supposed to be closed.
When I disassembled mine the points looked to barely be touching in the closed position and I assume this may have been the cause of my fault code, namely, the points perhaps not being closed properly with the IMRC in the slow speed position.
I gently tweaked the copper points spring with some small pliers to try increase the pressure on the points in the closed position as well as cleaned out the contacts with methylated spirits.

Careful examination showed all the joints on my circuit board to look okay so I gave the gears a small amount of grease and reassembled the circuit board and motor into the housing.

Fitting the IMRC back into the car was a bit easier than removing it, especially with the help of my father.
I then reset the engine light by disconnecting the battery, 30 seconds to a minute is all thats needed, and started the car. That was 22 June '08 and since then the fault has yet to return. I will keep this post updated as to whether it does return or not.


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