Hallo,

to the beginning of this season i have a high idle problem.
i searched already but only found some hunting idle problems. I've also know, read and tried the standard IACV FAQ pages around the net.

Here is the phenomen:
When i warmup the car, everything is normal, starting with 2000rpm when the engine is cold, going down to 900rpm when it is warm. So far so good.

When i then drive and stop at the lights for example and press the clutch, i have a idle of around 2000rpm (sometimes it's 1400rpm, but mostly 2000rpm)... the idle is absolutly stable, no hunting or anything, just too high.

When i then give it a little stump on the gas pegal the revs go up to 2500-3000rpm and then fall to the normal 900rpm at are stedy there.

i can reproduce this as often as i want on a warmed up car...

Engine is a B16A1 in a 1991 CRX EF8.

I have a IACV, FITV.

IACV is checked and is working properly, also on hot engine.
Vacuum leacks are not presend, already checked three times.
TPS voltage is 0,43v at idle
normal idle setting procedure is done correct - engines runs warm at stable 650-700rpm with IACV unpugged.
Bottom hole in the Throttle body has no airflow on warm engine (FITV seems to be ok)
Ignition timing is set correctly 16°BTDC
cooling system should be bleeded

what else can it be?

Best regards

 

sounds like the throttle isn't closing - could be in throttle cable - does it still have the dashpot on the throttle body?

 

Sorry, fotgot to write... throttle cable is ok, throttle plate is closing completely. I've also already cleaned the throttle from the inside from deposits.

concerning the dashpot, it is disconnected.

If the throttle place or something static itself would be to wide open or some kind of vacuum leack, i would expect that the idle is high all the time, but it's strange, when i give it a gas stump, everything is ok until i drive of and press the clutch again.

Throttle place is stock by the way and not sticking or something like this...

 

i'm in for a solution, i've got the same set of problems..

 

Hey, good to hear that i'am not the only one with this problem :-)

 

so it's only when you push the clutch in at a stop this happens right?

 

Mainly yes... not always but there it is most prone to occure.

i can also sometimes rev the engine up in standstill, hold lets say 3500rpm for a few seconds, let the throttle off and then it also happens that he only fall down to 2000rpm instead of 1000rpm.

Give him a shot of gas and all is normal.

But it's mostly when driving. I imagine that it is worse while the car is rolling but also often when i'am in standstill.

I just thought about reading that the ECU makes a difference in idle if the car is standing or rolling, but even if i stand, noting changes.

 

replace your tps ...even thought it seem fine but your tps is ****ed ...

 

check out your MAP sensor. Make sure it's measuring correctly otherwise a bad pressure reading could cause what you're experiencing.

 

p.s. tell me if this works

 

not to thread jack, but i'm gonna look into the MAP. replaced the TPS, didn't change anything. replaced the ECU as well. I'm guessing MAP's the culprit.

 

Both MAP Sensor as well as TPS sensor are ok. Checked two MAP Sensors and two TPS sensors as well as a complete third throttle body... problem is the same with all three.

ECU works well in two different cars. I've also testes two different ECUs in this car already too... same problem there...

but i have a little update: i've tightend teh FITV yesterday and it got a littlebit better. Revs are now only 1400rpm when moving and most of the time it falls down to 1000rpm when the car stops... if it keeps this way i think i can life with.

 

oh i thought you said you already did the FITV earlier which is why i didn't suggest that.

 

Yes, i did so... but it might be loosen itself again... even if i could not feel a airflow thru the lower hole in the TB, it seems to had an effect... could not explain this to me either...