Engine revs hunting.... help and advice needed please...

ohmtastic

Member
Messages
24
Hey guys

Just came back from taking my dc5 for its MOT it failed because the engine was hunting/seeking with its revs which means that an emmisions test couldn't be carried out.

It revs from 1500 up to about 3500, and when driving isn't noticably happening, when stationary it will then hunt/seek. I've given it some beans (kept to speed limit but was revving the engine more that normal) on the way home and since putting it on my drive it seems to have settled at around 1100-1400 revs, which is fine to carry out an emissions test as it needs to be below 1500 revs but from what i've read on the forums this is quite high as others seem to idle around 800-900 revs.

I have had the airbox removed and a Cold air induction kit installed, apart from that nothing else has been done to the car. She has been off road for a month and a half and the battery ran flat so i had a mate jump (with jump leads) her, she didn't start straight away but on the 2nd attempt (5 seconds of cranking each) she started and was running fine at about 1600 revs on a cold start cycle, after the jump leads were taken off and the cold cycle ended she then started hunting, i thought this was because of the low battery, turns out this isn't the case as i've had a new battery installed.

i've also found that when parked up and car warm i can't push her into the v-tec is this normal as i can't seem to remember this happening to me before, she seems to go into the v-tec fine when driving.

i think it could be a vacuum problem, but any advice would be great

cheers

ohm
 

JT3173

Advanced Member
Messages
1,733
I had this happen for an MOT I had done a while back, could not hold it at a constant RPM under 4k. If you search on the forum for IAC or Idle Air Control valve you will find all you need to know and this should cure your problems as it sounds to me as if it's dirty and needs a clean.
Search Club RSX too, there are some good photographic step by steps on this topic.

HTH
 

nefor

Advanced Member
Messages
235
ohmtastic said:
Hey guys
i've also found that when parked up and car warm i can't push her into the v-tec is this normal as i can't seem to remember this happening to me before, she seems to go into the v-tec fine when driving.
You can't get the car into VTEC when stationary. It's a safety feature to prevent engine damage. IIRC
 

ohmtastic

Member
Messages
24
Thanks for the info guys i'll check out the air valve, having a look on various sites seem to sugest the same thing with it sticking and being dirty etc...

I know i shouldn't be taking the car into the v-tec when stationary but having the car sat doing nothing for a month it could be bad fuel or crap in the intake system, so i thought some high revs would clear it out (with bikes sometimes crap gets pulled through and some nice high revs blast it through).

would you say the IAC would be easy to get to and clean? or would it have to be a garage job?

thanks
 

Toxic Rides

New Member
Messages
1
It is most likely the idle control valve on the bottom of your throttle body. If its got filth and grime in it, this will cause the engine to hunt. Mugen race engines take this out because they tick over at a very high rpm. Duncan
 

ohmtastic

Member
Messages
24
Cool well its in at the garage atm, having it done and having the plug in the bottom of the screen wash bottle put back in as when i was filling it up it just dumped itself all over my feet :?

Also having an MOT done to it aswell so i should hopefully be back on the road and in it tonight for a quick but sensible blast in it down the local A-road behind my house before tucking her in.
 
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