I have had my B18C throttle body bored to 63.5mm.
When i install it it it was idle around 2000 rpms.
TPS has been reset to 0.5V
ECU reset.
Idle screw down to min idle.
There are no leaks around gasket yes i tested by spraying fluid.
Coolant has been bled.
Throttle cable i s set right so its not holding the butterfly open.

I then diabled the FITV idle is now around 1500 rpm.
If i put my finger on the upper hole it dies down to 1100rpm.
If i blip the accellerator it drops to 1100 rpm then goes back up to 1500rpm.

My question is if there is too much air leaking through the throttle plate(bad machining or whatever) does this cause the idle to go up?

The car was running perfectly before the throttle body was changed.

Someone please help.

 

did you use gasket maker when you installed the TB?

 

Nope just the standard one, should i have used gasket maker as well?

 

try not using the paper gasket and just using gasket maker. Other than that it could be a problem with the machining of the TB. Who bored it out? and does it have a new throttle plate?

 

Who bored your TB? The throttle plate is not a simple flat circle, but is slightly elliptical with about a 5 degree canter. If the plate was bored as a flat circle, it will leak excess air and raise your idle.

 

What Dogginator said. Check your vacuum connections and the tb butterfly.

 

cover the entire TB opening with your hand and if it still runs you have a vacuum leak. If not, cover the 2 holes inside the TB and if it still runs you have a leak around the butterfly. Do that and post the results.

 

Yeah engine dies if you cover the opening with your hand. About 2 seconds after.
There is a slight whisling sound not sure if this is a vacuum leak or the air passing through the throttle body.

If i cover the two holes inside the throttle body it only drops by ~300rpms.
Yeah this throttle body was machined correctly with new plate, I see a slight ring of light if you hold it behind some light?

The car drives fine with it on, however when the throttle plate is closed during driving and i step on the gas again there is a bit of jerk.

The TPS reads from 0.5V to 4.45V WOT.
Any other checks? Thanks

 

You should not see a ring of light around the trhottle plate. Perhaps a few pinholes near the throttle plate axis, but certainly not a ring. That ring of light shows your vacuum leak, resulting in your high idle. Try adjusting the throttle plate set screw for the closed position to minimize the light ring.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 2fknlo &raquo;</TD></TR><TR><TD CLASS="quote">Yeah engine dies if you cover the opening with your hand. About 2 seconds after.
There is a slight whisling sound not sure if this is a vacuum leak or the air passing through the throttle body.

If i cover the two holes inside the throttle body it only drops by ~300rpms.
Yeah this throttle body was machined correctly with new plate, I see a slight ring of light if you hold it behind some light?

The car drives fine with it on, however when the throttle plate is closed during driving and i step on the gas again there is a bit of jerk.

The TPS reads from 0.5V to 4.45V WOT.
Any other checks? Thanks </TD></TR></TABLE>


If you cover those two holes at idle the car should die completely just as if you covered the entire TB(those two holes suck in air for idle/fast idle), thus you have a problem with the butterfly not sealing correctly.