B16 high idle


jp_ek4ferio

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Jun 11, 2013
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176
Well lads recently completed a engine swap it's a obd1 b16 the problem is when it's started it idles at around 1600 which is normal enough but when it warms up the idle does not drop as it should. I was thinking maybe fast idle valve or iacv ?? Any suggestions?
 
Yeah maybe try cleaning out the IAC with some carb cleaner, that's nearly free. I would also make sure that the throttle body is shutting fully (if you just swapped it the cable could be misadjusted?)
And coolant needs to be fully topped off and bled of air to have a normal idle. So make sure it's full and there's no air in the system. You either have a bleeder or not, both are easy enough methods of bleeding air though.
The FITV makes the car idle fast when cold, so start the car cold with the intake arm off, put your finger on the bottom hole that's in the throttle body opening, it should have suction. Then when it warms up and the fan comes on, it should no longer have suction. If it does, then you have an FITV problem.
Oh and it never hurts to make sure your PCV valve isn't gummed up, that's easy. Vacuum lines, check them while you're poking around as well. They shouldn't be loose, old, kinked, or cracked.

Good luck
 
Yea I did have a problem with the throttle not closing. thanks for the info il try them things :)
 
Also I forgot to say if I turn it off and leave it for a few min and start it again while it's still warm it will idle around 1000 ?
 
So you're saying that if you start it and drive for a while, it'll idle at 1600 still, but if you turn it off and re-start, it'll idle at 1000? Whatever the cause I guess my answer doesn't change too much.

But I wish I ordered my list of things I would try as-
Coolant
Checking function of FITV
Throttle body Cleanliness/Cable Adjustment
PVC function (clicks when you shake it)
Vacuum hose condition and fit
IACV clean
Then throttle screw adjustment

The IACV is last because it's the most time consuming (and still not that bad). And throttle screw is last because that's usually not the problem.
 
thars grand I have a bleeder valve for the coolant. If I open that and coolant comes out and there is a steady flow even when I add more that would mean all the air is removed yea ?
 
If I recall correctly, you make sure your interior heater is set to HOT, to open up that passage as well, with the car cold. Then open up your cap and bleeder screw, and see if it'll take any coolant, squeezing the upper radiator hose to expel air, even shaking the radiator a bit to get some bubbles. When you're adding you should see bubbles and coolant dribbling out of the bleeder. Stop when it's a solid stream.
Close the bleeder, keep the cap off the radiator.

Then run the car till it's warm to open up the thermostat and do the same things, see if the car eats up a bunch of coolant when it gets warm. You'll probably see the coolant drop in the fill cap as soon as that happens. Then add more, doing the same stuff, shaking the rad a bit and squeezing the top hose to expel bubbles. Then try step one again with the bleeder just to make sure.
Keep your coolant reservoir filled to "full cold".

Sorry if this writeup is all over the place but I haven't bled coolant in one with a bleeder in a while. But it's kinda like brake bleeding, you check and recheck.
 
ok thanks very much for your help i willl try this tomorrow and hope thats the problem
 
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