idle messed up

[slipvayne]

I really need some help. I just got a 86 civic hb si. I start it up and it revs about 2k. And after acouple of minutes of it being on, the idle starts to surge. 1500 to like 100 over and over again. I have looked it up and still cant seem to figure it out. I went ahead and changed my 02 sensor, spark plugs, plug wires, cleaned the (IACV). It also said that it could be my idle postioning sensor but when i went to the parts store they say that there isnt one for my car. Could it be called the angle control sensor or something like that. And is there a way to see if its out. Anything will help. Thanx

 

[slipvayne]

today when i checked my iac it was fine. but i wanted to kill the engine buy taking the positive and negitive off my battery. when i did the car still ran. is it supposed to keep running after the battery has been disconnected?

 

[tab]

It'll die if you unplug the alternator. The alternator will keep your car running, your car just needs a battery to store the juice.

 

[Gen2Teg]

Could be a vacum leak, I'd check that too. Change your PCV valve too, i had the same problem, cleaned out the IACV too and it worked fine for about a minute, changed it with a used but low mileage JDM one, but before i did i cleaned the hell out of it and when i put it in i still had the same problem. Well while i was in the motor bay, I said fuck it might as well change the PCV valve too while im here and since i already bought it. After i changed it, no problem. Weird, but it worked.

 

[R6Elmo]

The Throttle position sensor goes bad sometimes. But if it does, you'll notice some hesitation as you rev the motor as well as a bad idle.

Check for vacuum leaks.

ALso, the TPS can only be bought if you buy a new Throttle body. YOu could just try to buy a used throttle body on ebay and use the TPS. they are almost universal to every honda.

 

[randerson165]

I have the exact same problem, except my idle jumps from 2K to 1.5k back and forth.

What is the PCV valve ? And what is the TPS ? Where are these on the engine bay. I have a D16Y8.

 

[Gen2Teg]

PCV Valve is on the intake manifold, under the fuel rail. Its a little elbow plastic thing. The TPS is on the throtle body.

 

[slipvayne]

lol they want 540 bucks for the tb and tps because on mine they dont come apart. we have a salvage yard here but all they have is a 86 honda civic hb carbbed. and mines fi.Is there a different one i can put on? they have a 88 prelude and the tb looks nice. would that work?