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Discussion Starter #1
Had this problem a while but cant seem to get to the bottom of it... my CTR idle speed seems pretty low, it looks around 700 on the gauge... occasionally when i press the clutch in whilst idling, the idle speed drops enough to confuse the ecu, causing the oil pressure light to flash very quickly - as it does when you almost stall. Lately it has started doing it without pressing in the clutch, just sat at lights or in traffic, its annoying more than anything,as the oil pressure light will rapidly ping about 3-4 times before the idle stabilises slightly.
I did have Flashpro and adjusted the idle speed to 925 which completely solved the issue... however due to unforseen circumstances I had to sell the FP.. But surely there is a reason why this is happening, I have a new batt, new sparks, new oil, hamp short, valve clearances done... none have made any difference... incidently when my car was standard it didnt have this issue, though all i have is a mugen intake and a Js racing catback.. surely those cant be responsible for the low idle speed?
Anyone else had a similar issue? Any advice most appreciated
Cheers!
 

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How old is the battery?

What oil viscosity are you running?

How's the oil level?

When was it last serviced?
 

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Discussion Starter #3
The battery is brand new as are the plugs
serviced last wk using hamp short & shell helix ultra 5w40- was previously running 0w-30 but still had the issue.
oil is at the correct mark.
 

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Enjoying life
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Idle air control valve?
 

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Discussion Starter #5
Fn2 dosent have one
 

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Enjoying life
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What does it use to control idle rate?
 

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Discussion Starter #7
Electronically, its drive by wire
 

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Ah, ok. Not my forte :laugh2:
 

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250bhp.... finally :)
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My 1st port of call would be a torn breather hose / check mugen intake around the MAF onwards.

A poorly sealed MAF or vacuum leak after it may cause a bad idle as air is lost / added and not accounted for. Remove the whole intake assembly from box to throttle body and give it a check, super easy to do. Check the two hoses that go from the intake to the engine too.

Might be worth cleaning the throttle body whilst you're at it as it stays slighty open for idle but if there's gunk it might be affecting it. If it's super clogged a new PCV kit might be worth it too. Be careful when opening the butterfly valve and disconnect the battery, some DBW TBs don't like to be manually opened so ensure it's getting no power from the battery before you move it.

Other things could be a dodgy throttle position sensor or poor TB gasket seal, fuel pump not providing enough juice but highly doubtful and not worth throwing parts at it without a garage checking it first.
 

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Discussion Starter #10
Cheers, Ive had the intake totally dismantled and checked all pipes, ive ordered an oil pressure switch, might aswell change it out for the sake of £7.00 might be a pain to access though.
 

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If none of those solutions fixes the problem then it could be the ECU. My EP3 developed a similar problem and I had to have the ECU replaced to fix it.
 

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Discussion Starter #12
doesnt sound cheap! ill try this pressure switch, if that fails ill jam a shim in the accelerator pedal and chop it in for a forester!
 

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Discussion Starter #15
Yeah ill give that a go aswell, cheers... Shall report back with any fixes/findings
 

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Discussion Starter #16
So... today i stripped the mugen intake, checked all pipe work/hoses, all were fine, and cleaned the throttle body. Also removed the rocker cover, did valve clearances and replaced the oil pressure sensor.. fired it up and it was twice as bad as before, removed the new oil sensor, put the old one back on, still just as bad... removed sensor again, cleaned out the sensor hole and wiggled a screwdriver inside.. put sensor back on and the fault was solved... for 10 mins then it started again.. Decided the idle speed is fine, its just that oil pressure light only blinks at dead idle..
So i unplugged the sensor.. obviously not the ultimate solution but im convinced its some sort of electrical fault, be it in the wiring harness or the ecu incorrectly interpreting the sensors signal.. Incidently surely the check engine light should come on with this sensor unplugged? It dosent, car drives spot on, no rattling, no knocks nothing.. driven about 100 miles and honestly the car drives the best it has in a long time...
 

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Discussion Starter #17
Another update, borrowed an oil pressure gauge, which turned out to be the wrong thread pitch, found out as id already rethreaded a good few mill of the block! Anyway, cleaned out the thread with a thin rifle barrel wire brush, decided to reconnect the oil pressure sensor. and as if by majic its back to normal.
Still dont really know the true cause, maybe had gunked up threads and wasnt grounding properly... god knows
 
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