wont idle when cold...

[l1ttle_d3vil]

pretty much everything else has been fixed but now im just having problems with my 4age bluetop idling at cold. once it warms up a little bit it'll idle by itself sweet, until then I have to hold the revs above an idle myself.
what would be causing this? is it likely to be the cold start injector not working? or a vacuum leak? thats about all I can think of off the top of my head.
it also seems to have some lag when I put my foot down [from an idle], its as if its going to stall at first then the revs start to lift like they should.
this also fixes itself once it warms up, or if I unplug the map sensor from the loom or take the vacuum hose off the manifold.

i've checked the map sensor and TPS and they are both fine so it can't be a faulty reading from them. anyone got any other ideas?

[Crucible]

pretty much everything else has been fixed but now im just having problems with my 4age bluetop idling at cold. once it warms up a little bit it'll idle by itself sweet, until then I have to hold the revs above an idle myself.
what would be causing this? is it likely to be the cold start injector not working? or a vacuum leak? thats about all I can think of off the top of my head.
it also seems to have some lag when I put my foot down [from an idle], its as if its going to stall at first then the revs start to lift like they should.
this also fixes itself once it warms up, or if I unplug the map sensor from the loom or take the vacuum hose off the manifold.

i've checked the map sensor and TPS and they are both fine so it can't be a faulty reading from them. anyone got any other ideas?

Im not familiar with Idle up systems on 4ages Its more than likely a stepper motor or Aux Bypass Valve at fault. They allow air to bypass the throttle when cold, etc so the engine wont stall.
I know 4ages have this system because when the coolant level is low the Revs Pulse. This is common on Early Honda Preludes also with the same type of Valve. Normally situated by the throttle body and have coolant lines running to it.

Someone here will be more familiar than me on where its located.

TNT

[l1ttle_d3vil]

cheers, im not familiar with the stepper motor or bypass valve you're talking about on any of the 4ages, i've only heard of them but have no idea what they look like

anyone got pics or can elaborate? cheers

[Crucible]

cheers, im not familiar with the stepper motor or bypass valve you're talking about on any of the 4ages, i've only heard of them but have no idea what they look like

anyone got pics or can elaborate? cheers

It will be situated on or around the throttle body.

It will have a port which runs under or around the throttle plate. If you take off the air ducting to the throttle body there will be a port or hole which you should be able to see before the throttle plate, this is more likely to be the port which runs to a Auxially air valve or stepper motor then into the plenum chamber of the manifold. There may be also coolant hoses running to and from the valve which are visable.

Someone here is bound to know.

Hope this helps a bit, good luck!

TNT

[Mr Revhead]

yes its on the t/b
follow his description.. its spot on

[Mr Revhead]

oh and its a valve, not a stepper motor

[Crucible]

oh and its a valve, not a stepper motor

Thanks for the correction Mr Revhead, I wasnt certain!

TNT

[l1ttle_d3vil]

cheers for that, i must be missing that all together. i'll get some photos of my throttle body tommorrow and post them up, theres basically no hoses anywhere on it

I have seen a vacuum valve or somthing on the throttle body of another 4age, it looked similar to the black cylinder on the TVIS from memory. is that what you're talking about?

edit - this what you're talking about? I definitely don't have this.. where to now? is there a way around it by tricking the computer or something, or is it straightforward to get one and stick it on? [keeping in mind none of my waterlines etc are standard, so Im guessing I will need to modify them to run to the valve - thats how I understand it anyway]

[2LTR Rona]

l1ttle_d3vil - here is a pic of my throttle body etc from my blue top, I had a similar if not exactly the same issue as you when I put mine all back together after replacing the CAM belt, it turned out that someone before me thought it would be fun to wedge as much paper in there as possible, blocking the valve, which opens and closes based on the temp of the coolant passing by it.

Are you actually running the TVIS on your bluetop? I just ask as your post above says that you have nothing like it

In the pic the larger hose almost in the center directly below the intake on the throttle body is the coolant intake, runs from the block to the underside of the valve



If you are able to take pics of your engine bay I can supply pics of mine for comparision to try and make it easier if that helps

[l1ttle_d3vil]

here's a couple of pics. looks as though its been removed and blocked off. is the round thing sticking down on the left where the water is meant to run? cos thats blocked off with a rubber grommet thing and theres a plate next to it which you can see.

and in the second pic, whats the hose in the box for? anything? are they meant to run from one to the other like they do?

[l1ttle_d3vil]

ok heres some pics of another throttle body ive found with the bypass valve. whats the rest of the hoses/pipes etc for and where do they go?? are they needed?
hope this makes sense and you can help unconfuse me!!!

is #8 anything to do with it? do I even need that?
is #5 where the waterline needs to run to? whats #6 for then? if I blow air through #5 it just comes out #6 and vice versa.

[2LTR Rona]

On mine #8 is left just like that with nothing on it (see pic above)

#5 & #6 are the intake and return for the coolant from the block, there should be a rail that runs along the drivers side of the block which then ties in with the piping at the back.

#1 links back up to the top of the throttle body as in the pic above

#3 & #7 are one in the same, but havent benn able to trace it from the pics I have.

So that leaves, #2 & #4 to track as well.

[Jebus]

5 & 6 are all you need

[l1ttle_d3vil]

sweet so I'm guessing 5 is for the water, whats 6 for?

[Crucible]

sweet so I'm guessing 5 is for the water, whats 6 for?

5 & 6 are both coolant pipes, Coolant needs to flow in and out of the valve. When the engine is cold the valve is open allowing air to bypass the throttle, as engine comes up to op/temp hot coolant causes the valve to close and decrease Idle speed.

The valve uses a wax pellet like a thermostat that expands when hot and causes the valve to close.

Sometimes when topping up the coolant level if drained, They can get air locks in em and the revs will fluctuate at high rpm, If this happens pull a hose off the valve to bleed.

The revs should then drop back to normal.

TNT

[Crucible]

#5 & #6 are the intake and return for the coolant from the block, there should be a rail that runs along the drivers side of the block which then ties in with the piping at the back.

Sorry..... 2LTR Rona already explained what and where

[l1ttle_d3vil]

2LTR Rona's post wasn't showing up when I asked that...

thanks for that. ive tried blowing air into #2 and #4 to see where it comes out of but can't work out where its coming out of, i think they are linked to each other so I blow into one and it just comes out the other.

I will have another look at my waterlines and see where abouts I can run the coolant from. I can't blow anything into #7 but air will suck out of it easy.

[*Steph*]

My 4AGE does same thing and i got told its my faulty air bypass valve.

[2LTR Rona]

l1ttle_d3vil - here is a pic I took while I had the head off, its not the best but will give you a better idea of where the water lines run, you'll see that the run to the back of the block and join up to the T section at the back.



If you want I can email the original to which should make it a bit more clear to see

[2LTR Rona]

My 4AGE does same thing and i got told its my faulty air bypass valve.

when I took mine off someone had attempted to shut it off by stuffing as much paper in there as they could end result was that it was jammed, after a bit of elbow grease and some four letter words things started to move again