Removing the plenum to access the rear spark plugs (V6)

[Mille]

My car has started to hesitate under acceleration and my thinking this was due to the back spark plugs as these are rarely changed .

My question would it be a DIY job and where to get the best priced plugs ?

Thanks

[colm_mcm]

Here's my guide from doing them at the weekend:



Changing spark plugs is usually a straight forward job. If you've ever worked on a 4 cylinder car, you'll know that's it's rarely more than a 15 minute job.
Because the FTO uses a transverse mounted V6, the rear bank of cylinders are obscured by the intake manifold.
The Plenum has a number of items bolted to it. These include the throttle butterfly, Variable induction motor, throttle cable adjuster, and various brackets securing the wiring loom.


1) Remove the engine cover. This is secured by some 10mm nuts which can also be undone with a Philips screwdriver.

(it may be a good idea at this early stage to change the easy front 3 plugs, mainly to ensure your plug tool is correct)




2) Unbolt the Variable Induction Motor (pictured below) and unplug the connector at the back left corner of the plenum.



3) Undo the top half of the air filter assembly and loosen the jubilee clip that attaches the air intake hose to the throttle butterfly. remove the pipe and the attached section of the air filter box.




4) Unbolt the brackets for the wiring harnesses that are attached to the plenum. re-attach any removed securing bolts to the plenum, and eliminate the risk of losing them. The throttle butterfly (pictured below) is now ready to be removed.




5) The throttle butterfly is secured by 5 bolts, 4 on the side, and one sneaky one at the back. undo all 5 bolts and the butterfly should move freely around. It's now (finally!) time to take the plenum off.




6) The plenum is secured by a number of bolts. It is bolted to the engine and to 4 brackets at the back of the plenum (pictured above)
The 4 bolts towards the front of the plenum are pretty obvious. Less obvious are the 2 nuts at the corners (highlighted with arrows)

7) The plenum has a tube connected at the back, undo this, and you can remove the plenum. This is done by pulling the plenum straight up. this will reveal the air inlets for the engine. be careful not do drop anything, even dirt, into these inlets.

The spark plugs can be accessed by first unbolting the corresponding coil packs and then pulling out the plug lead.

Changing the plugs themselves is the same as with any car, and the same precautions apply. The OE Mitsubishi spark plug tool has a rubber ring that makes for easy plug removal, and aids correct threading of the plug.




Hope that's some help. I did it in just over an hour.
Denso Irisiums from Camskill are the way to go

[Bernard]

That was a pretty good reply Colm

[colm_mcm]

cheers B!

[kevinod]

No need to actually take off the stepper motor or the throttle body. You don't need to take the plenum off completely, just turn/move it enough to access the plugs.

[colm_mcm]

access to the back plugs was a lot easier when I removed the stepper. otherwise the plenum is sort of hanging there! (gives you a chance to clean it, and it's only 3 bolts!)
taking off the throttle meant I didn't have to disconnect the throttle cable either, which could be fiddly. I think you'd spend more time working around the plenum than it'd take to remove it.

[CJ]

Good guide Colm, off to the KB.

CJ

[Baldrick]

Excellent 'How to'

[kevinod]

I turned mine about 60 degrees, didn't disconnect the throttle cable, and it was still sitting on top of the engine with easy access to the plugs.

I'm not saying there's anything wrong with taking it off, but you don't HAVE to. Good pics btw, especially the 'cut out' bit!

[Sebastian]

nice work Colm

you free this weekend to do mine? only messing

this is how every thread in this section should look like

[steelroe]

Why not just unplug the electrical connectors rather than removing the Variable induction motor. Then just lift off the plenum.

[colm_mcm]

cos mine needed a clean, what better time to do it?

[steelroe]

bit confused that motor you removed is not the ISC, it is on the opposite side of the plenum

[steelroe]

Excellent pics.
It is a lot easier if you leave the throttle body on. You also eliminate the risk of having an air leak at that gaskets afterswards

[CJ]

bit confused that motor you removed is not the ISC, it is on the opposite side of the plenum

Actually, you're right Rory, I've always wondered what that part was in Colms pic. Stepper (black) can be seen in the bottom LH corner below the throttle body intake. The Thottle Position sensor (TPS) is indicated by arrows.



CJ

[Mille]

Great guide Colm - thanks ... its doesen't look like as hard a job as I first thought

[colm_mcm]

sorry Rory, misread your post

[ftolam13]

kool guide very helpfull

[Kace]

Some learnings from doing this today :

1. Removing the bolts mounting plenum at the back are the most difficult thing in this whole job. You need to have quite good reach, decent tools, good strength to get these off. I have scraped knuckes and wrists after my ordeals today.
2. There is an electrical conector to come off the back left of the plenum (described in the guide). Took me a good while to work out how it actually comes off though without breaking it. You need to pry off the little wire locking mechanism. This slides upwards off the connector - you can do this with a little screwdriver.
3. Keep track of where your bolts are - there's lots to take out.
4. There are two tubes that come out of the back of the plenum - a 1cm tube on the back right hand side. This slides off by squeezing the spring clip. There is another little one in the middle at the back (about 5mm diameter) - this just slides off.
5. Job took me more than 2 hours to install new plugs and leads. Sure it can be done in 1, but only if you're confident you know what you're doing, don't have any issues with tight bolts or getting the plenum off or back on.

[lee hallett]

any pics please