Mazda3 Forums banner
661 - 680 of 683 Posts

·
Registered
Joined
·
335 Posts
....The only problem I had putting it back together was losing the middle bolt somewhere deep inside where I can't find it. Might've lost it on the road driving afterwards or it might be stuck til I take it apart again to clean it.

Go to the dealer, order the bolt and install it.

Don't mickey mouse stuff, it doesn't save you any time in the long run.
 

·
Registered
Joined
·
335 Posts
and everyone here has left the metal rod OUT of the manifold?

Of course.... Read this entire thread again..

You are really missing something here. Think about how the metal rod is assembled into the flaps and into the linkage.
The metal rod does not go thru end of the intake manifold on the passenger side nor does it go thru the linkage on the drivers side.
The rod is square and the beige pivot link has a square opening in it to lock onto the end of the rod.

The beige pivot link has an o-ring in it to seal the opening while allowing movement.
There are sensors in the vacuum actuator. If the vacuum actuator is disabled you will check a soft CEL indicating a VTCS failure as detailed earlier in this thread.
 

·
Registered
Joined
·
6 Posts
Go to the dealer, order the bolt and install it.

Don't mickey mouse stuff, it doesn't save you any time in the long run.
Completely forgot I made an account and posted here. I found that middle bolt a few weeks ago when I had to replace the IM gaskets cuz one was leaking air. Ended up over torquing the middle bolt and snapping it so I need to get that out somehow. But the more pressing matter is the little black plastic pieces the gaskets go around that the op broke. Some of mine also broke so my gaskets get sucked in a bit and leak and cause a rough idle. Does anyone know the name of the little black plastic pieces? Going to call mazda in the morning to see if they know.
 

·
Registered
Joined
·
421 Posts
A lot of my plastic pieces broke, I had to kind of puzzle them back to put them into the slots, but I kept all the pieces. Those are in place, as well as the rubber gaskets. There is one spot where a tiny corner of a plastic piece broke off which I do not have, and it allows a straight shot for air to get in from the outside. For spots like this (and it isn't pretty but it works), I installed the manifold and tracked down hissing spots. Turn the engine off, otherwise it will suck it straight in. Put some on your fingertip and mash it into the spot. Heat makes it cure faster. Don't start the car to test it for at LEAST an hour, maybe 2 or 3.

This may seem like a roundabout cheesy way to fix it, but honestly I will be switching manifolds at some point to accommodate the 2.5 better, so I don't see the point in buying an adapter plate or anything else to "do the job right". That being said, it all depends on how big the gap is on yours. If you are missing that entire plastic bezel for a port, that might be something that this wouldn't work for, I would have to see it I guess. The fix I'm talking about is for a space that's about a eighth or quarter inch wide.
 

·
Registered
Joined
·
3 Posts
2005 Mazda3 2.0l 5speed.
Had the car since July, it's been painfully slow since I bought it, the rear O2 sensor is missing, no bung on the pipe, sensor wire cut off half way. The check engine light is always on and figured the car was always in limp mode. Anything past half throttle the car got slower, if I pumped the gas pedal twice a second as the RPMs climbed once in a while it would accelerate properly until shifting gears. (Continuously pumping the pedal = 50 times or more, once in a while = 1 in 100 times, so once in 5000 times flooring it, it would accelerate).
Recently the gas millage got worse and I finally pulled the codes. 4 came up, 2 for the rear O2 sensor, 1 for Evap system and DTC P2006 -Variable Shutter Tumble Valve Stuck Closed.
The workshop manual diagrams are vague and I search the VTCS removal threads for info and pictures of the system.
While inspecting the system I notice the shutter valve actuator and lever sat near the top of the throttle body with the engine off. once started the lever was down but never came up even after hours of driving.
From what I read, once the engine is at operating temps it should remain opened.
I had no idea which way the lever needed to be for the shutters to be opened and after removing the throttle body to check the actuator I decided to just pull the intake manifold off and remove the shutters and shaft.

I did not take any pictures because it was raining and my hands where covered in grease and dirt but for all those asking where the manifold bolts are just google images. I didn't bother, I just figured I would keep removing stuff until the manifold came off and it did.

I did however find the perfect image for this but I can't post links or images because of my post count.
The best I can do is post this: ww2.
justanswer.com/uploads/MI/mikeamechanic/2012-11-11_222952_1900033intake.jpg

Connect the ww2. to the rest and paste it in the address bar.

The image shows the assembly inserted from the passenger side but to remove the shaft it comes out next to the throttle body. The image also shows the position of the 8 bolts that hold the manifold to the engine, 6 are highlighted blue and the other two are next to the throttle body flange.

Some things I decided to do (possibly been mentioned in the 68 pages this thread has turned into):
1- I removed the shaft and shutters with as little damage as possible in case I had to put them back but I decided to grind down the 8 half circles that remained in the "cups" (4 black plastic pieces that sit in the manifold and hold the gaskets in place). They are there to transition the air over the shaft when the shutters are opened / to direct the air into the shutter when shut and act as a stopper to limit the shutter travel in both directions. I ground them for 2 reasons, 1 they are a huge airflow impedance even with the shaft and shutters installed and 2 the shutter actuator rod limits the shutter and shaft travel (if I had to reinstall them).
2- I felt that something was missing in the process in all the How-To's I read, I could easily understand every step (even without pictures) what I couldn't understand is what blocks the holes between the runners after the shaft was removed? Maybe I missed that step in the write ups, but it seems to me all I read was members that had done the mod repeating remove the shaft and shutter flaps and put everything back together and on the car the way it came off. Which would mean those that did the modification that way did something wrong, you cant have large holes between the intake manifold runners constantly scavenging air from the other runners to the valves that open, that messes up the whole flow of the manifold, why have runners if the all share the same air.... I used 1+ inch pieces of 1 awg gauge wire, it fit snug between runners 1&2 and 2&3 but it seemed loose between 3&4 and 4&end (this one is a factory vacuum leak), so I wrapped the wire piece in electric tape (not recommended oil passes around there and will turn the tape to goosh and maybe suck it through the engine but this is a 347$ car and I was sick of searching for stuff that fit in the holes...).

I am happy to say removing the shaft and flaps (and blocking the holes) solved the acceleration problem, the car has been running with the shutter flaps permanently shut since I got it and so by deductive reasoning the fault lies with the solenoid valve or wiring to the solenoid valve, from what I can tell when vacuum is applied to the actuator it shuts the shutters, if mine is staying shut all the time then the solenoid valve is not cutting air flow when it's supposed to, I will test the solenoid and wiring and still fix the problem to clear the cell.
Unfortunately I have no before to go by, I have driven other Mazda 3 2.0l 5speeds but all I can remember is they are slow, this car went from golf cat to smart car because the shutters where no longer stuck shut.
Could it improve performance, absolutely without a pile of junk in front of the intake port resisting flow.
Does it matter on a 14* horsepower car, absolutely not. Even squeezing 40 more hp still isn't worth the effort, it would be like showing up with a slightly smaller soft ball at a baseball field, you still don't get to play with the big boys.

I was tempted by habit to take a die grinder to the intake ports and port them out, and looked at the throttle body and thought, that's at least a 12mm shaft the flap sits in, with the average flap being 2mm thick that means each side of the shaft is 5mm thick or 5mm flow restriction, as a basic throttle body mod on some cars I pull the flap out, cut the upper half of the shaft off with a hack saw, reinstall the flap and screws and cut the extra thread off the screws. may seem like a small thing but say the TB hole is 2.5", removing 5mm of obstruction across would be 13% flow increase over factory, on a 2" diameter hole 5mm would be about 21% flow increase over factory.
But to me it wasn't worth the time and clean up. This just isn't a car worth modifying for too many reasons, to name a few, the components are too delicate, link kits, tie rods, shock mounts, control arms... So say the engine was easy to tune and with a reflash, some injectors and a turbo you could run some serious boost (not at this compression ratio and not on these engines) then the clutch and transmission aren't up to it and so on.

Back to the VTCS mod, to do it properly you want to grind off the 8 half circles and plug the holes in the 4 inserts flush with the edge, I did not do this I just blocked the holes in the manifold and reinstalled the inserts. Having flush edges without any recesses where the holes are is best for airflow.
 

·
Registered
Joined
·
24 Posts
I too did this mod last weekend.


My intake valves were not that dirty at all. The butterfly valves were dirty. I broken every one of them removing them.
I put an oil catch can on.
Throttle body coolant bypass.
Changed both Oxygen sensors.

Cleaned everything.


Runs great. Much better without the VTCS and I'm happy I did it. Now, to see what the gas mileage improves too.
 

·
Registered
Joined
·
24 Posts
I did mine and can NOT get the car to run right. It does feel like a MAF issue now. Same symptoms as below.
If anyone can figure this out I would appreciate it.

2005 Mazda 3 2.3 AUTO
new O2 Sensors, MAF, rings, vavle job, timing chain, Mazda a freeze,





Yeah sooooo, I did this "mod" 2 nights ago and reverted back in less than 24 hrs. I saw a lot of ppl saying low to mid range gains and thought cool I'll do this. The first thing I noticed was upon first start-up it idled very rough and up and down in RPM's kinda like if the MAF wasn't plugged in (which it was) so I thought well I'll leave it till the computer recognizes it and see then say 50 miles or so. I drove it all day yesterday and it was sluggish mainly in the low to mid range area. Especially noticeable right after shifting (low or high RPM) when it used to push me in to my seat now I was actually getting pushed forward like a slow down.so after 60 miles I decided to re-install the vtcs
last night and 45 mins later test drove it again and the thing went like hell. That was my take on it. IMO I don't recommend this "mod". Now I don't know how this affects FI cars since I don't have a turbo yet. Maybe when I get it installed I'll try it again to see but till then I'll call this a "mod" for ppl who think this car is too fast and want to slow it down maybe more linear to the effect that it averages the output to the low side but definitely no positive effects here.
 
661 - 680 of 683 Posts
Top