Strange problem?

[MDK87]

Actually I remember now, it's bolted onto the throttle body from underneath. My GGSR was hunting a lot, to bypass it, I filled the chambers FIAV with metal reinforced epoxy and it fixed it. If you're gonna do that, maybe buy the rubber gasket that goes with it, cos they're usually buggered. And IIRC, the screws to remove it are usually hard to remove due to corrosion.
Anyway before I lead you astray, it might not even be your problem, just have a read of this, it's a really good site for us VR4 owners. http://www.vfaq.com/index-main.html

 

[4piknup]

The fiav does the cold start. When engine is cold the valve is open allowing more air to bypass around the throttle. When engine is warm the valve is closed.
Any faults here will be to do will slow idle when cold but fine when warm (valve pinned closed) or good cold idle and fast hot idle (valve pinned open) this assumes that all other things are ok.

 

[4piknup]

But I would check the isc (idle speed controller) its under the tb next to the fiav. Just undo the screws and remove it. With it plugged in, it should project and retract as you key on and off.

 

[MDK87]

You'd think so right?
But two 4G's (61 and 63) of mine were hunting really bad and bypassing the FIAV fixed it. Same for Tim.
I think when it's pinned open, it allows too much air to flow through and the ECU realises the AFM is metering too much air for idle and doesn this weird hunting thing as a result. If it's pinned closed, it'd effectively be the same as plugging the thing up with epoxy.

The fiav does the cold start. When engine is cold the valve is open allowing more air to bypass around the throttle. When engine is warm the valve is closed.
Any faults here will be to do will slow idle when cold but fine when warm (valve pinned closed) or good cold idle and fast hot idle (valve pinned open) this assumes that all other things are ok.

 

[4piknup]

So this is your tb (this is a gsr but yours will be similar)
The isc is bottom left, and feeds from the corresponding port in the tb. The fiav has the waterpipes and is bottom right and corresponding port in tb.
This tb has a stuffed fiav and will fast idle when hot. I tested this by blocking the rh port with masking tape after warming engine up. Idle slowed indicating the fiav is jammed open...
I replaced with a good one and set tps and biss and timing and now idle is perfect.
I would pull the isc and check it, and if you are going to block your fiav, do so temporarily first and make sure the rest is fine first. Know that blocking the fiav will not allow the car to idle properly when warming up.

 

[4piknup]

I dont recall it hunting with the stuffed fiav. Did you only block the rhs port mdk87?

 

[MDK87]

I jammed the whole thing with epoxy, both ports.
Did you also try blocking both ports Jack?
Both of my engines idled nicely afterwards, even when cold.
If you don't wish to use epoxy, I believe there are special block off plates you can buy, or at least you could back in the day.

 

[MDK87]

What's the bike in the background Jack?

 

[4piknup]

Streetfighter '00 zx9r 'THEHULK'. Yoshi, k&n, dynojet. 7kg of plastic and crap removed from the front end. Mean and green. You ride it like a dirtbike, lean right forward to keep the front end down....
I think about changing up to a new 10r but I love this one and have had it 12 yrs now.

 

[4piknup]

I jammed the whole thing with epoxy, both ports.
Did you also try blocking both ports Jack?
Both of my engines idled nicely afterwards, even when cold.

If you don't wish to use epoxy, I believe there are special block off plates you can buy, or at least you could back in the day.

Yep, I tested both together and separately. That was before I wrote the sticky for idle issues thats in the 1-3 section. Thats how I first worked out I had isc issues as well. But its easier to just pull the isc and watch it.
Its well known that a stuffed isc will cause hunting. But I know that its a bit off topic for the op. Sorry

 

[MDK87]

Nice one Jack.
I've had this fella for about a year now but I'm still cautious of it's power and ride it like a pussy tbh haha
I had the 250 and 600 fireblades before it but I've only been riding a couple years so still pretty much a novice.
Idk why but I'm kinda of afraid of modifying my bike.. To me it's my dream bike and already so perfect so I don't feel like touching it, scared I'll ruin something.
Sorry for hijacking the thread lol

 

[evo-gsr]

Soooo...how did the OP go with the immobiliser suggestion?

 

[kyle-reece]

Just about to re join the fat wires now!! Will the wires stick out to me? Don't want to go cutting and rejoining the wrong wires

 

[turbovr4]

when the FIAV is not hooked up to the water lines the hunting is caused by the car trying to idle above 1500RPM , if the idle switch on the throttle is on because the throttle is not being touched, then the injectors switch off (fuel saving technique ). the motor will then of course start to die until around 900RPM which then will switch the injectors on and the cycle starts again , hence the hunting. If you want to test that theory the disconnect the idle switch and the car wont cut out, it will rev high and the injectors will never switch off when coasting down hills etc. Oh and by the way I blocked my valve off in the MG by just removing the 3 bolt plate near the throttle and then screwing the seat for the valve all the way down, refit a the plate and perfect idle is now spot on with no water pipes connected.
But on saying that , it doesn't sound like the problem which has been happening in this cars case.
Have you checked for a cracked inlet pipe, e.g airflow meter to turbo. mine cracked right in the concertina bit and the car would splutter and die on take off sometimes and other times was great.

 

[4piknup]

That sounds right to me turbo. I did my tb shaft seals and the tps was slightly out when I replaced it. The idle switch wasnt triggering and the fuel wouldnt shut off on decel. Did the tps compensation in ecmlink and fuelcut on decel works again.


Yep, you will see the wires. Will only be one cut under thecolumn. Tho that will be the crank wire. You need to follow the other black wires and see if there is another wire cut and joined through the alarm.

 

[kyle-reece]

Re joined the wires and still no difference.. Cars got a date with my mechanic tomorrow

 

[kyle-reece]

No visible cracks on afm, inlet pipes, and haven't yet checked tb but will do this arvo

 

[croket]

seal the inlet to afm with very thick plastic , put engine at tdc and fill the whole system with air that will tell you if you have leaks pre turbo and also any boost leaks too. Id do this before mechanic gets it so you can tell them its not vacum or boost related

 

[croket]

also i know this may sound stupid but have you tried disconnecting the ecu over night ? Ive had cars that do strange things , reset ecu by removing power source over night and clears it up sometimes

 

[MDK87]

Is TDC sufficient to close all of the valves in cylinders 2 and 3 with stock cams?

seal the inlet to afm with very thick plastic , put engine at tdc and fill the whole system with air that will tell you if you have leaks pre turbo and also any boost leaks too. Id do this before mechanic gets it so you can tell them its not vacum or boost related