Ford Focus Intake Manifold Replacement

Ok, my fathers 2005 Ford Focus 2.0l duratec has had a noticable tick. I thought it might just be a noisy injector. Well after a bit of research it turns out Ford used something called intake manifold runner control or tumble flaps. These are plastic butterfly valves in the intake controlled by a vacuum solenoid which control airflow into intake valve.

Well the intake is made of plastic and these flaps wear out and cause a racket. If you pull the vacuum hose to the solenoid and sound goes away I think it means imrc valves are dead. Anyone ever replace one of these intake manifolds and is there anything I should know? Thanks for any tips or suggestions.

get a cosworth one and enjoy.

I can't help you other than if you're interested in a replacement stock manifold, I have one that can be yours for the price of shipping...Down side, I also have no idea if IMRC works any better than the one you have or how to check for such without it being on a running engine.

There's a hidden bolt that well and truly sucks.

In reply to Driven5:

Driver5 if you can check the flapper valve things for play I would appreciate it. Looks like new manifold is around $200 plus maybe a few extras for while you are in there stuff.

Knurled I read about hidden bolt between cyl 2 and 3 looks like fun to get at. One fellow pulled the fan and shroud to get at it.

There's a way to get it with a 1/4" extension of a certain length (I use two different ones taped together in situ, there isn't enough room to get a single extension long enough without a ton more work) and a short 10mm socket (again, taped to extension) and I make that the last bolt. The bolt, socket, and extension stay in the manifold.

I've done two Duratec cylinder heads (well, one head for a burnt valve, one re-ring and replace a buncha bent valves) and three intakes to get access to a certain PCV hose that can fail. I have it down to a science, and it REALLY sucks if the bolt falls out of the socket... Then it is time to get really inventive with mirrors and magnets to get the bolt back in the hole, and then the socket back on the bolt.

Thanks for the info Knurled, sounds like I might want to replace pcv valve and the pcv hose while I am at it. Do you know if there are any other parts or gaskets I might want to replace while I am in there. This focus has 130k miles and has been very reliable so it might be time for a little love. Thanks everyone!

I just got a 2006 Mazda 3 that has the same engine, and I plan to just remove them. They are only there to act like a choke when you cold start the engine. (reduces the amount of air so when cold starting the injectors use less gas on cold start) After that they are just a restriction in the intake tract. According to the forum posts I've read, as long as you reattach all the vacuum hoses etc and just let the engine warm normally before starting out there are no issues, and on the plus side, you pick up 10 hp in the midrange.....Not only am I doing this but also replacing the PCV valve and hose and adding a bob's air oil separator while I have it all apart. There is no downside to taking them out, and if you feel bad about it you can always put new ones in or replace them later, I do not plan to.

Chris Rummel

Rumnhammer wrote: I just got a 2006 Mazda 3 that has the same engine, and I plan to just remove them. They are only there to act like a choke when you cold start the engine. (reduces the amount of air so when cold starting the injectors use less gas on cold start)

That's not what they do, at all. (For one, what you are describing is what the throttle plate does...)

It sounds like what they do is increase the air velocity going past the injectors so the fuel gets atomized better, or at least is less likely to wet out against the intake ports on a cold engine.

Knurled wrote:

Rumnhammer wrote: I just got a 2006 Mazda 3 that has the same engine, and I plan to just remove them. They are only there to act like a choke when you cold start the engine. (reduces the amount of air so when cold starting the injectors use less gas on cold start)

That's not what they do, at all. (For one, what you are describing is what the throttle plate does...) It sounds like what they do is increase the air velocity going past the injectors so the fuel gets atomized better, or at least is less likely to wet out against the intake ports on a cold engine.

and how exactly is that not doing exactly what you said they don't do? by reducing the amount of air getting past the valves it increases the velocity of the available air =less air getting through.....mincing words but exactly the same description of what they do....

Rumnhammer wrote:

Knurled wrote:

Rumnhammer wrote: I just got a 2006 Mazda 3 that has the same engine, and I plan to just remove them. They are only there to act like a choke when you cold start the engine. (reduces the amount of air so when cold starting the injectors use less gas on cold start)

That's not what they do, at all. (For one, what you are describing is what the throttle plate does...) It sounds like what they do is increase the air velocity going past the injectors so the fuel gets atomized better, or at least is less likely to wet out against the intake ports on a cold engine.

and how exactly is that not doing exactly what you said they don't do? by reducing the amount of air getting past the valves it increases the velocity of the available air =less air getting through.....mincing words but exactly the same description of what they do....

They are not there to reduce flow, they are there to increase turbulence, which helps low speed combustion stability. Which, then allows for more aggressive cold start calibration to reduce emissions.

Knurled is more right, in other words.

I see this as a necessary evil in order to get ports that are larger relative to cylinder displacement than a four barrel 351 Cleveland

"Hey Boss! We can make some HUUGE high-flowing ports, but in order to meet cold start specs we need a flappy valve thingy."
"Do it! There are people with Miatas who want large port heads to swap in!"

(okay, maybe NOT the ultimate goal at the design strategy meetings)

Whats the milage? In California you have 150k milage warranty on the PZEV stuff. I got a bunch of flappy plastic and solenoids replaced on my wifes 03 Focus at 147k. Same ticking you are describing. Not that I am saying Cosworth isn't the right answer here( because it is). But if you can, why not get it fixed for free before you get a new intake.

Edit. Just saw you are only at 130k. Call your Ford dealership!

Cosworth intake manifold is not CARB, is really meant for the larger port head flow, and typically on the larger displacement engine... At least on the street. I'm not sure how 'dad' usually drives, but I get the impression that it's probably not in a manner conducive to putting the Cossie manifold on the smaller displacement engine with the smaller port head. At most, this might be a tumble flap delete situation, but I don't think even that would be ideal in this instance since there have been some mixed results from that as well. If you can actually get Ford to replace it under emissions warranty, that sounds like the way to go... Otherwise I'll try to take a closer look at the manifold I have this weekend to see how serviceable it looks.

My old man is a pretty hard core driver, told me the fuel cuts at 90mph. He loves blowing past bmw and audi.

Great info emsalex, I will give Ford a call monday, I didn't realize emissions controls had a long warranty, I am in california so pzev or whatever.

Driver5 whenever you get a chance to take a look at it sounds good. First I need to see if I can get ford to do the job for me. I really appreciate your offer, hope I dont need it though.

In reply to Knurled:

Life isn't as far away from that as you seem to think....

Cosworth intake (most out now are chinese knockoffs) is a short runner with internal trumpets, thats designed for high rpm use preferably with a cam upgrade. You could get hp gains from it (all at high rpm) but it is not the thing you want in a daily driver since you lose quite a bit on the low end.