1986-5MT

My buddy just gave me a 1986 Civic coupe 5 speed for a daily driver - but among other small things the idle doesn't stay consistant.

I do not know the engine size, if I had to guess I would say its about a 1.5L or so, it looks small.

When you start the car it goes to high idle as it should to warm up, though upon reaching temperature the idle drops, but jumps back up.. constantly. Probably goes between 800 where I had it set at, and about 1,600 or so? vroom, vroom, vroom, vroom, vroom.

While the car is driving, this doesn't happen (with any throttle input it doesn't happen.) Just when the throttle is not being used and it wants to idle but just bounces.

Any ideas on what it might be? IACV? Leaky IM gasket? Etc. If anybody had this resolved, please also share your price so I can see if it's worth fixing.

thanks in advance for any replys - All I know about it is what you see here, I can't even read the VIN number, it looks like someone hit it with sand paper. (Yes the car is legal, clean title just used to be modded and now it's back to stock, kinda.)

D16Z6_owner

check your vaccuum lines or the IACV

1986-5MT

I disconnected, and reconnected all the vaccum lines just now, took off the intake, and throttle body etc.. put all that back together, but still doing nutty things.

The idle now is like.. 800-1,200 real fast, then it dips to almost stall, then back to bouncing, then dips to stall, then bouncing.. Hmmmm

D16Z6_owner

are the vaccuum lines cracked? thats what happened to my car when i disconected my vaccuum line to pour in some seafoam cleaner

1986-5MT

Today I had AAA flatbed the car to my mechanic, should be good with in a week or so, I'll post back and post what was fixed if anything to confirm what it was incanse anybody ever has the same issue.

Thanks for the tips!

PowerWheels86

it's actually a common problem for our cars... if i remember properly it has something to do with the throttle body... you might want to also check out this forum... www.redpeperracing.com they specialize in 3rd gen civics and 1st gen crx...

1986-5MT

Strangest thing, I had a dream last night that I was working on the car - and I dreamed it had something to do with the throttle body.. here I come sign on today and find you left this reply lol I hope were both right! I got the car back yesterday so I can go fail inspection, then give it back to the mechanic. haha.. I needed something to drive, he fixed the clutch cable with a big washer.. the bracket which holds it in place busted off the firewall behind the dash. We did a ghetto rig, and it should work for a few years.

Anyway I checked out that websiute but the link doesn't work I'll google it up and check to see if its spelled correctly?

ink_u_bus

I have a 95 civic ex and it started doing that and it was a bad sensor.

1986-5MT

looks like its the TPS, ill have to replace the entire throttle body though! UGH. I wish it wasn't that big of a deal, but aparently its connected perminantly? I dunno where I'm going to find a new complete throttle body with tps for this old *** car.. any ideas? junkyard doesnt help much cuz i cant find any cars with the SI engine from 86 in them... EW4 or someting like that

gearbox

iTrader: (95)

ya i was just gonna say, tps out of adjustment causes jumpy idle. you can drill out the rivets and install screws for the tps, and try to adjust it, but its easier said than done lol. you need to know how to tap new screws and make sure it stays where you tighten it. and then you need a service manual and a multimeter prolly to show you how to adjust the voltage and what the range is. its alot simpler to get another tb. preferably new, but id just check a junkyard

1986-5MT

I'm just gonna have to sell it dirt cheap, I cant put anymore money into this thing already costed more then it's worth for the new clutch haha.

badpenny

Geez, I hope you didn't sell it. All you needed to do is find the plate on the throttle body that has the 2 phillips screws (they are #4 heads) undo that, remove the plate, save the rubber ring (try not to break it while removing, and if the ring doesnt budge, leave it but keep track of it) and find a chisel or something large and flat enough to place inside and twist it down. Put all back together with rtv sealant. Let set overnight to cure. and this should solve your problem with surging idle.


I own 2 now, have owned them before.