car thread, sorry. 94 civic 1.6 DOHC vtec

[lukamon]

basically my idle bounces up and down from 1k - 1500. i have changed for _known_ good items: throttle position, iacv, FITV, and have checked all the vaccuum lines i can see from on top of the inlet mani by pulling them off and starting the car with my finger over the hole on the mani. its recently had the head off but was doing it before that anyway. new distributor too. i put the new dizzy where the old one was by marks, but turning it to either extent of adjustment only makes it bounce slower / faster.

now for the wierd bit: if idling anong with no throttle in 1st or second, the engine will "pull" and start accelerating (slowly) when you hit say 1350 rmp it _cuts_ out really jerkily and when it gets to 1k it jerks back in again, and repeat. car otherwise drives fine no loss of power ect. no check engine light and no codes with the conector jumped either.

help!
____________________
killa wrote: Im an ass man myself

[Livefast123]

Sounds like an air leak.......somewhere
____________________
Current ride - Yamaha MT-07

[MaybeGuy]

its an FI with all these gay sensors.

my money is on airflow sensor
____________________
Blue_SV650S wrote: it was a sh1te wheelie, but it proves that he can get it up in 3rd and can do angles. In summery, mattsprattuk is a gobby little sh1tebag, dopehead tw4t, but sadly for all of us, he probably isn't THAT full of sh1te!!
Kickstart wrote: Hi I tend to agree with Matt. All the best Keith

[fiery tupp]

It does sound like vaccum & you have checked pipes , but I had one doing similar & a tiny leak in a pipe on manifold had me going for daft ages
____________________
If you can't fix it with a hammer , use your head .

[stonesie]

Brake cleaner, spray it about all around near the inlet manifold and vac pipes, when you find the leak the engine revs will rise and smooth out as it burns the brake cleaner

[lukamon]

just changed the MAF sensor - no affect.
____________________
killa wrote: Im an ass man myself

[MaybeGuy]

cam timing or low compression on 1 or more pots.

if not, im out of ideas
____________________
Blue_SV650S wrote: it was a sh1te wheelie, but it proves that he can get it up in 3rd and can do angles. In summery, mattsprattuk is a gobby little sh1tebag, dopehead tw4t, but sadly for all of us, he probably isn't THAT full of sh1te!!
Kickstart wrote: Hi I tend to agree with Matt. All the best Keith

[lukamon]

only thing i seem to not have touched now is the maP sensor. dont have another of those though.
____________________
killa wrote: Im an ass man myself

[Kickstart]

Hi

First guess would be the idle control valve, but if that is OK then I would go for an air leak.

My guess with the idle hitting 1350 and then dropping is that the car is set up to cut the fuel when the throttle is closed and the revs are high (common way to save fuel). The air leak lets the revs rise until 1350rpm when it cuts the fuel and the revs drop.

All the best

Keith
____________________
Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[lukamon]

If i block off the vacuum pipes and then put my hand over the intake i get a good song vacuum that lasts for quite a while. It still does it though! Argh!
____________________
killa wrote: Im an ass man myself

[0l0dom0l0]

I watched a video with another honda (cant remember the make) doing exactly the same thing. Have a search around and see what you can find. I can't remember what the problem lol. Atleast you know your not the only one

[lukamon]

If i unplug the iacv, it steadied at 1200 with the bypass screw as far in as it'll go :\
____________________
killa wrote: Im an ass man myself

[lukamon]

FIXED

throttle plate was either stuck open fractionally or bent, not a clue how/ why. but that was what was making the engine rev and cut fuel at 1.5k.
____________________
killa wrote: Im an ass man myself