ryskyline

hey so i have a 93 civic with a jdm d15b motor and i noticed my car has a rough idle and would always dip under idle sometimes i checked for vaccum leaks and what not and there was none, but i dont know exactly what i was looking at but at the rear of the manifold it was leaking some fluid, a little help please?

p.s i am new to this forum

ol Dusty

iTrader: (2)

rear of the manifold where? Sorry just need a little more specific, if you mean up where the IAC is then that's easy, it's coolant and the hoses going to it are the likely culprit. This could also be the cause of the idle issue. If the IAC is fine and not leaking then it may be the FITV under the throttle body, sometimes these go, less common but could be the issue. My guess though is that your leaking coolant and the IAC can't operate as intended because it's at the top of the motor and likely full of air instead of coolant.

A high idle would be more likely also if you had a vac leak as more air would be getting in then the ECU knows and adjust for. Air in the coolant system cause by a leak throws the temp readings off between the IAC and the ECT sensor and the engine will search for idle and not be able to find it within the range that the IAC can do.

If the leak is down where the IM mates to the head, then it might not be coolant, it could be oil, from the head gasket and/or (less likely unless you have real big problems) the ports for the intake side of the head. It could still be coolant though as the IM does have a coolant passage in it that has lines going up to the TB, IAC and FITV. If It's leaking at this part of the IM, then I suggest, clean the heck outta that area, then pressure test the coolant system. If the leak shows up then it's coolant, if not then it's oil. There's a slight chance that you have an injector leak but if you checked for a vacuum leak then this is less likely as that should also show up there, usually.

Start with this and let us know what you find, if needed I can explain each of these and a few other options in a little more detail. Good luck and post a pic of the leak area if this hasn't helped.

ryskyline

yeah man sorry it is by the IACV and i noticed also when it gets hot the fluid fizzes out and starts to steam and evaporate because of the heat on the intake manifold so your guess is coolant?

ol Dusty

iTrader: (2)

My guess is one or more of the hoses that go to the IAC are cracked. Replace them both and then pressure test again. usually when one part of the coolant system goes, it was the weakest link and what ever else is weak, will go shortly after you change the first one. Better to test and break at home or the shop when your ready for it then on the 401 in traffic after work tomorrow.

ryskyline

thats true man it makes sense! but the car is sitting right now insurance is a bitch, thanks alot tho man i appreciate it

ol Dusty

iTrader: (2)

Well at least if it's sitting your in less of a hurry to fix it. good luck either way and I'll bet that's what the problem is. The coolant leak could be the cause of the idle issue. Sometimes my 93 will idle weird if it sits too long also then I drive it for a bit and it comes back to normal, that is if I checked and everything else is fine, but my civic sits for 3 months or more sometimes more. I haven't driven it since Aug now and won't be able to for a while yet I can't wait to see how much has gone wrong with it since then!

ryskyline

ahah mines been sitting for a year so atleast i know im not the only one going through the struggle!

ol Dusty

iTrader: (2)

I blew the motor outta mine 2 days before I finished school last spring and still managed to have it running, new motor installed long enough to drive it across the country and out to Vancouver Island and kept it going for a bit but when I swapped the motor I had no money left to fix things like I know the clutch disk is cracked around the torsion springs and will fail soon and the input shaft bearing needs to be replaced, plus I have most of the parts for the turbo build I've been planning for it but still need a few more things, combined with the cost of getting it to pass safety and register it out here, it made sense for me to spend 2g's on another car I always wanted, my CRX and drive it in the mean time. Then a few things changed and now I need to fix them both up, the CRX still being driven 60k a day, is about to go under the knife and have a motor swap done and then I'm moving back to Ontario this year so no point in wasting a bunch of money on the civic to make it legal here just to switch back in a few months, it'll prolly get the few things it need to get running or towed behind a u-haul then when I'm back in T.O. I'll strip it right down and rebuild it while I continue to drive my d16a1 swapped (hopefully soon) CRX. Course being back in Ontario I'll need to find a beater for the winters again!

ryskyline

word that sounds like a serious mission right now, i thought me being 17 with a coupe and no money for insurance was serious, but you soildered that, that motivates me!