93 civic sedan idle surging Cold idle assist?
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93 civic sedan idle surging Cold idle assist?
so ive had this car for just about a year now. its always seemed to have this idle surge even from the beginning. a little history first.
stock d16a6, and i mean bone stock from a crx with the obd1 d15b7 intake swapped on with the obd1 d15b7 dizzy.
as of 2-3 months ago i swapped in a rebuilt d15b8/y8 head engine with y8 intake and cai/header. this intake manifold is from a 99-00 as well as the head and has the cold idle assist crap on it. i removed it and im also running a hondata thermal intake gasket.
the idle still jumps from 1000-2200. ive changed every single sensor on the intake. even the tb. also have tried 3 different working eacv and have routed around the fitv as well. no change. spray carb cleaner all around the intake and no spikes at all. all new rubber hoses when i built the engine. and its running on a p28 with no cels at all.
ive come to the conclusion that the cold idle assist is to blame. then again, since its not even hooked up it shouldnt have anything to do with my issue. im beyond stumped here, and ive read countless post in the search but have yet to find one with my similar issue.
when driving the car under load, this issue is non existent, but as soon as i depress the clutch to coast or come to a stop it instantly starts surging again.
ive also thought that maybe by chance since i dont have the fan thermostat switch hooked up that it could also cause this issue. shouldnt this switch be hooked up to tell the ecu how warm the engine is to control the idle with the eacv, because it trips the relay to the fan when needed to be cooled?
any help would be greatly appreciated. this is driving me nuts!!!!
stock d16a6, and i mean bone stock from a crx with the obd1 d15b7 intake swapped on with the obd1 d15b7 dizzy.
as of 2-3 months ago i swapped in a rebuilt d15b8/y8 head engine with y8 intake and cai/header. this intake manifold is from a 99-00 as well as the head and has the cold idle assist crap on it. i removed it and im also running a hondata thermal intake gasket.
the idle still jumps from 1000-2200. ive changed every single sensor on the intake. even the tb. also have tried 3 different working eacv and have routed around the fitv as well. no change. spray carb cleaner all around the intake and no spikes at all. all new rubber hoses when i built the engine. and its running on a p28 with no cels at all.
ive come to the conclusion that the cold idle assist is to blame. then again, since its not even hooked up it shouldnt have anything to do with my issue. im beyond stumped here, and ive read countless post in the search but have yet to find one with my similar issue.
when driving the car under load, this issue is non existent, but as soon as i depress the clutch to coast or come to a stop it instantly starts surging again.
ive also thought that maybe by chance since i dont have the fan thermostat switch hooked up that it could also cause this issue. shouldnt this switch be hooked up to tell the ecu how warm the engine is to control the idle with the eacv, because it trips the relay to the fan when needed to be cooled?
any help would be greatly appreciated. this is driving me nuts!!!!
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Re: 93 civic sedan idle surging Cold idle assist?
ill try the fitv one, but i already did the iacv that is currently on the car, i have also verified that it works. but that will be done thursday when im off work.
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Re: 93 civic sedan idle surging Cold idle assist?
good call Ron, my fitv diaphragm was completely unscrewed from its threads. as soon as i took off the side of the fitv it fell out into my hands. overall now that its cleaned and installed properly, my idle has dropped over 600RPM's and the car is much easier to drive.
after further inspection, the fitv system needs to be plugged off. i think i will do this thursday. it requires me to pull the intake manifold and plug the cia ports. im going to use a combination of threaded plugs and quick steel to do this. after that the car should idle perfectly.
once again thanks for the info, probably never would have thought of it being the fitv.
after further inspection, the fitv system needs to be plugged off. i think i will do this thursday. it requires me to pull the intake manifold and plug the cia ports. im going to use a combination of threaded plugs and quick steel to do this. after that the car should idle perfectly.
once again thanks for the info, probably never would have thought of it being the fitv.
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Re: 93 civic sedan idle surging Cold idle assist?
oops wrong thing. meant the cold idle assist system lol. the cold idle ports on the intake manifold are causing a vacuum leak do to me running a hondata intake manifold gasket. not sure if i have to plug off the holes on the head itself. maybe i should?
#7
Re: 93 civic sedan idle surging Cold idle assist?
If the vacuum ports serve no purpose, then it would be fine to block them off.
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Re: 93 civic sedan idle surging Cold idle assist?
current specs are,
stock y8 head, y8 intake
stock d15b8 bottom end
y8 head gasket
this puts me at about 10.65:1 CR. i think i can hit the 180 mark pretty easily.
when i am boosted i plan to have a delta 272 straight for the y8 head, and BC valve springs.
bottom end will be a d16a6 block, d17a2 crank and oil pump, b series crank pulley, k1 d17 forged rods, stock bore vitaras as long as the block has good bores.
after all that im going to continue to use the garret t25 until i can get my garret t4 rebuilt and maybe a t3 exhaust housing installed on it.
then Tom Sewell will be seeing a visit from me to hopefully put down well over 300whp.
but those are my plans.
#9
Re: 93 civic sedan idle surging Cold idle assist?
And good luck with the build.
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