4agze high idle

[KLR16V]

hi there guys,

ive got a MAP 4agze in a ae82 corolla.

this problem has just started:

-when the engine is warm the idle wont drop below 1500rpm.
and there is a hissing sound comming from the ABV but (i think its normal)


and anouther problem
- and when i take my foot off teh accelorator, the revs drop down as normal (to 1500rpm)...then they bounce up to 2000rpm.... then they go back to 1500rpm. (it only does this once, unless the accelorator is touched)

i have tried to adjust the idle, but its already as far in as it will go

any help will be greatly appreciated,

cheers, Dan

[BeRad]

its not the idle, check the idle up valve (stepper motor), a vacumm leak will also give this result. ( a higher idle). being that it drops to 1500 then steps up to 2000rpm for a bit id point the finger at the stepper motor, check the hoses, connections etc. you shoudlnt hear any hissing unless you have a pod filter then the pod will hiss a little. find the hissing noise and fix it

on occasions the throttle body will get stuck a little open , or the cable itsself will get a little sticky spray a bit of wd40 on the cable , moving parts of the tb, push the tb toward the closed position by hand if it drops, adjust the cable accordingly.

[KLR16V]

problem solved....

turns out it was a crack in the intercooler rubber hose. as soon as i fixed it the car ran fine.

however, i checked the idle up valve thingy, and both hoses running out from it have been blocked off...

is it really nessesary to have the idle up valve connected considering that the car runs fine now...and i dont have air-con either?

[BeRad]

it should help with the engine warming up, no its not a must, alot of aftermarket ecu's dont suport it, but its just another thing that helps the engine run that little bit more smoothly.

depending on the ecu when you back off quickly the idle up will step in and bring it down that little bit slower, but wont be a concern with a standard ecu/tuning. so once again no drama, but you may as well fix it.