sgraber
|
| posted on 28/8/03 at 06:21 PM |
|
|
Help Identifying this 4AGE VSV thingy
This is is a vaccum switching valve of some type from a 1985 Toyota MR2. I want to know what it does and do I need to keep it on the engine?
I think it routes air from in front of the throttle body to behind the throttle body so if the butterfly is closed some air still makes it past when
this vsv is energized... I'm just guessing. I can't seem to find any information about it in my Chiltons...
Thanks for your help.
You can see bigger photos of that vsv here http://www.newtier.com/graber/mid-engine/Images/MR2%20hoses%20and%20wiring/index.html
[Edited on 8/28/03 by sgraber]
Steve Graber
http://www.grabercars.com/
"Quickness through lightness"
|
|
|
|
|
Rob Lane
|
| posted on 28/8/03 at 07:43 PM |
|
|
That's the TVIS version of the idle up VSV.
It's not needed but blank the small inlet on the throttle body.
I used a dab of silicone sealant and a pop rivet fastened in. Leave it to cure for a day.
[Edited on 28/8/03 by Rob Lane]
|
|
|
GO
|
| posted on 29/8/03 at 09:25 AM |
|
|
Yep, Robs right, its the idle-up valve. Its not really needed unless you live in alaska. If you're not familiar with the 4AGE on a day-to-day
basis you'll find they idle at about 2000rpm until warmed up! Which is a little annoying but perfectly normal.
|
|
|
paulbeyer
|
| posted on 29/8/03 at 12:59 PM |
|
|
My Corolla donor also revs at 2000 until it has warmed up but this isn't normal. I read a post on another forum a while back about this problem
and a simple cure involving a tyre valve dust cap and a 5mm hole. If I find it tonight I'll cut and paste it here.
7 out of 10 people suffer with hemorrhoids. Does that mean the other 3 enjoy them?
|
|
|
paulbeyer
|
| posted on 29/8/03 at 09:31 PM |
|
|
As promised...................
COLD START TICKOVER (KEVIN ) - 24 Jan 2001
I have recently purchased a 1990 mr2
1600 cc when starting from cold it revs
to 2000 rpm after several minutes this figure drops to about 900rpm is this normal as the cold start revs seem high
although selecting a gear and pulling away seems ok at this 2000 figure ??
any info much appreciated
COLD START TICKOVER (Nick Challoner ) - 26 Jan 2001
Presumably you're talking about a Mk1 MR2? (guess so from the 1600cc reference). If so, then yeah, most Mk1s do just that: idle around 2000 when
cold, dropping gradually to around 800 when warmed up. It's not a problem, although they shouldn't do it. Basically the problem is caused
by something called a 'waxstat' (thermostat operated by a sticky wax moving around) in the cold idle system. It can be fixed by buying a
new waxstat (probably expensive from Mr T), or drilling a 5mm hole in a tyre dust cap and inserting that into the correct orifice in the throttle
body/TVIS box - i can't remember the exact details, but i can dig them out if need be (from the MR2 Mk1 Club magazine).
...Nick (85 NA).
COLD START TICKOVER (KEVIN ) - 31 Jan 2001
Yes nick
that would be helpfull.
(Nick Challoner ) - 4 Feb 2001
Here goes:
The waxstat is auxiliary air valve (AAV).
Disconnect the pipe from the air filter to the throttle body at the throttle body end.
The AAV supply recess is at the bottom right of the throttle body just upstream of the throttle plate - it's 10mm in diameter - this is where to
fit the tyre dust cap.
Drill a 5mm hole in the tyre dust cap (you can experiment with different sizes)
Push cap into recess cap top first, using medium finger pressure.
That's it! Cold idle speed should be substantially lower. Hot idle might now be incorrect (should be 800 +/- 50rpm), so that may need adjusting
(adjustment screw on rear throttle body).
I must stress that most of the above is an abridged version of an article that appeared in a recent Toyota MR2 Mk1 Club magazine, so they should take
the credit. I'm sure they won't mind me posting the above, especially as i'm a big fan of the club and i urge all Mk1 owners to join
up - details at
...Nick (85 NA).
COLD START TICKOVER (KEVIN ) - 19 Feb 2001
I Did the the "tyre cap mod" AND IT WORKED PERFECT
no more 2 second growl when starting up
thanks for the info.
7 out of 10 people suffer with hemorrhoids. Does that mean the other 3 enjoy them?
|
|
|
Rob Lane
|
| posted on 30/8/03 at 10:07 AM |
|
|
The reason it revs up to 2000 when cold is because the mixture is richened by the cold start injector and air fed by the AAV.
The revs increase prevents the plugs sooting up, prevents bore wash taking place and aids a faster warm up.
It's when cold that most engines suffer wear.
All this is caused by the auxillary air valve unit attached to the throttle body which is fed with a water feed from engine. This has a small plug
unit which is spring loaded. This blocks the small drilled airway between front of throttle and rear of throttle butterfly.
When cold the unit is 'open' and lets an air feed through which raises the revs, once it starts to warm up it gradually decreases the
opening and finally closes it when engine up to temp.
This unit can be disabled by using the method described, but why?
It performs a valuable service and isn't fitted by Toyota for the fun of it.
I would suggest that if it's doing this when engine is warm then it has a small air lock in the water in AAV which causes it to open, quickly
closing once started.
Mine does not do this and once warm will start 'on the button' at tickover revs.
Rob Lane
|
|
|
paulbeyer
|
| posted on 31/8/03 at 10:01 PM |
|
|
Rob,
Tried this on my donor today and it works exactly as you described. From cold it sat at about 2000 revs until it warmed up then slowly started to
decrease revs until it was ticking over at approximately 800rpm. Then it started every time on the button and ticked over the same revs, so ignore my
last post. 
[Edited on 31/8/2003 by paulbeyer]
7 out of 10 people suffer with hemorrhoids. Does that mean the other 3 enjoy them?
|
|
|
GO
|
| posted on 1/9/03 at 10:52 AM |
|
|
As already stated, it is perfectly normal for 4AGEs to idle at 2000 until warm, its not due to a problem its the way it was designed - I'm
pretty sure that the owners manual for my mk1 MR2 (my main car) says that it idles at 2000rpm. As mentioned in this thread, once warm the idle should
stay around 800-900rpm. If you find the revs temporarily rising and falling quite quickly this is a common and known problem. It's 99% of the
time caused by airlocks in the coolant. As the air lock passes the temp sensor the ECU is tricked into thinking the engine is cold and kicks in the
high idle until the air lock has past. Coolant just need bleeding, which is a right pain the ar$e in an MR2, but thats a different story!
|
|
|
