Rough and bouncing idle when cold?

Christoff

New Member
Hey guys. I have a 1994 Integra GSR. It didn't do this when I first got it. I've installed an ebay CAI which I suppose could cause it but I believe it happened after I ran seafoam through the throttle body. Since then I've changed the spark plugs, cap/rotor, and fuel filter.


When I start my car cold the car idles high, 1600+, then the RPMs bouncesup and down for a while every so often. It does this until it is completely warmed up. Any ideas? Spark plug wires? 02 sensor? CAI? Eventually it'll go to 1000 rpm idle then slowly to 800-900 once I've been driving for a while. Sometimes the RPMs will drop so low it seems like it will almost bog down and stall.


Also, what are the best mods for MPG? Besides the tune up bits I've done already. Do intake and exhaust make much of a difference?

Thanks in advance
 

jznsn2u

Active Member
Welcome to Club Integra. I recommend cleaning your IACV. (idle air control valve). What size tires do you have? Tire width contributes to miles-per-gallon. Yes intake and exhaust make a difference.
 

Christoff

New Member
Brake cleaner is some pretty heavy duty stuff, no? Anything else I can use? WD40?

Where is the IACV exactly?

Thanks for the help guys. I'm on normal OEM sized wheels/tires. My wheels are actually Acura chrome gsr blade looking ones. They're not originally from my particular Integra. Not even sure if they're from the integra line. I'll post a picture later.

I'm on the fence about an exhaust because of the price. I assume to see any benefit I'd need at least a catback exhaust.
 


Christoff

New Member
When I first start it actually jumps up to about 2,500 RPMs or so. When it's cold the biggest thing I notice is when I press in the clutch the RPMS will drop low really fast. Then the idle will start to bounce up and down.
 

McMahon

JackTuned
I just cleaned my IAC valve the other day! It didnt help me.so now I move on to the FIT valve.
 


spegs

New Member
I had this issue of my idle being at 1500 all the time, and constantly bouncing up and down from 1000-1500. I took off my IACV and cleaned that, but it was already extremely clean. I noticed that my engine was never heating up, and figured thats why it was probably always idling so high, as it was always trying to warm up the engine.

So I ended up getting a new thermostat. After I installed the new one my idle would start around 1500 in this winter cold, and then drop once the engine warmed up, and no more bouncing idle. Worked like a charm for me, so maybe check your thermo if your engine is never getting warm. Or even if it does get warm and the idle still stays high, thermo may always be open.

Just thought id share my success.
 

JohnCarter

New Member
It is my opinion that most mods adversely affect gas mileage. Try synthetic oil, maybe higher tire pressure...there's only so much you can do short of buying a car that gets better gas mileage.
 

Christoff

New Member
Well the GSR is by no means a gas guzzler. I'm getting just above 30 on the highway. Looking into getting an exhaust. I assume it'll have to be at least catback to see any MPG/power benefit at all.


Anyways! It's only been two days but I *think* the problem is gone. My mechanic removed the IAC and disassembled quite a bit and scraped and cleaned it with different products. It definitely looked really dirty. Car only has 110k miles, though. Now my car jumps up to 1600 when it's cold (quite cold here, 30 ish degrees in mornings and nights) And I haven't noticed the idle bouncing up and down anymore. Before if I was driving at low speeds I could feel the bounce and it'd give the car that extra gas. I'll give it a couple more days but as of now I think it's fixed.

My car was also burning oil. Apparently behind the filter there was an O-ring that needed to be replaced and that is possibly where the smell was coming from as well since the oil dripped on the exhaust. However, I still smell burnt oil if I smell real close to the hood. I don't think it's as bad but still there. But then again that could just be the occasional high rpm burst, etc. Could be residual oil who knows. Also had to replace a coolant hose. I've dumped about $800 now and I'm hoping this thing will finally last me a while. All these things conveniently showed up right after I bought it. Also fixed a broken bolt on the manifold and replaced the PCV valve? I think it is. That regulates the oil something.


Possibly related. Now my viper remote start isn't working, though. I'm assuming something got unplugged. It'll start and you can almost hear it start to run on it's own but then it just dies. So going to have to look into that. It definitely started after I fixed all the above. Maybe a bad ground or something? I know certain light flashes tell you x problem, etc.


I've been using Castrol GTX. Would it be a bad idea to switch to synthetic now? Maybe a blend? I know synthetic is quite a bit more expensive. Would that even outweigh the potential gas savings?

Thanks!
 
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