Idle acts like a carb return spring hanging up...

[RedneckRicer]

i just swapped my auto to a 5 speed, and now my idle is all messed up, i tried adjusting it, but its all funked up now. the it'll idle okay for awhile, but then it'll go and change rpm to anywhere between 250 - 3000, barely running to revving all to hell .... any idea what it could be? i haven't ruled out vacuum but which hose # could it be? (i have diagrams and it all looked hooked up) tell me if ya guys have any experince with this.... thanks

[rocky2]

Manual transmissions use less gas at idle then a automatic, Plus you have efi,so now I "THINK" there could be a confused 3-g computer in your ride possibly?? I'd for the hell of it put in a brainbox from a 3-g with a 5-sp and EFI and see what that does.off to boneyard with yourself!

[RedneckRicer]

i already have a 5 speed EFI brain in it

[rocky2]

It sounds like a MAP senser. But Honda doesn't call it that. Manifold Absolute Pressue. I had a 1988 caravan v-6 efi that did the same thing only at idle when you drove it above idle it would run ok. But when you idled down it would do what yours is doing.Find out what its called by Honda.

[RedneckRicer]

i'm kinda wondering if it could be the throttle position sensor?

[YK86]

Is the ECU from a 88 or 89?? Make sure it is or it will run like crap.

[RedneckRicer]

from an 89 LXI 5 speed mines an 88

[POS carb]

hey, I think I know, is yours carbed?

[POS carb]

n/m it says LXi

umm I'd say check the vacuum lines that go to the trans, apparently there are some cars that have vacuum lines to the trans. I don't have that.

[RedneckRicer]

there was one line coming out of the top of the tranny, i assumed it to be a vent or something of the like..... was i wrong? if so.... wheres it go?

[A20A1]

what? is that a vacuum line connector and not a vent hole?

[RedneckRicer]

i dunno, lol, i thought it was a vent.... its got a tube on it that goes up and curves back down with a bracket, but i didn't think it went to anything

[A20A1]

thats for auto trans fluid???

[RedneckRicer]

in a moment of clarity in the albertsons parking lot, i figured it out... with the automatic - 5pseed swap my cruise control seemingly stopped working.... well i think it was still engaged somehow. anyways, i disconnected the vacuum line to the a/t cruise control thing and toned down the idle, and shizam it was gone

[Kevin]

I have an 87 Lxi with 5spd and when i shift gears the moter doesnt always drop revs!!! Usally it does this when its cold!!! Is there anything else that could stick open or closed or something other than the choke??? HELP PLEASE!!!

[YK86]

I swapped to 5 speed and my cruise control still works.

Kevin-As for the motor not dropping in idle speed, the fast idle valve is operated by a valve on the back of the intake manifold that has coolant running through it so as the engine/coolant warms up, the idle drops. Don't know if this is the answer to your problem though.

[Kevin]

hmmm...... where does that go?? Like i replaced my TB Bc of a broken vacumn nipple!!! When i pulled the old one out there was a hose hanging from the bottem!! I heard that coolent was suppose to run through it!! Is that bad?? The thing you mentioned??? It doesnt leak coolent anywhere!!! I had to repalce a couple of hoses and i think some one just by passed it!!!! what should i do??

[YK86]

You shouldn't have any hoses dangling around there for sure. On the back side beside the TB, there should be a thing with a flat lid (held down by two + screws) which is the fast idle valve. If you look on the bottom of that unit, there should be two hoses attached to it with one of them coming from the TB (if I remember right). If that has been bypassed, your car will probably think it's cold and idle too high.

[Kevin]

ok!! Thanks ill check it put!!!