Hi,
my 1990 Integra GS has begun to surge while idling in neutral, cold or hot, w no pressure on the accelerator. By surge I mean it bounces from 1000 rpm to 1750 and back again, just keeps bouncing off of 1000 to 1750. As soon as you put it into gear and move, it quits.

I have a video of the tach showing the RPM bounce, but cannot attach until after my 'trial' period expires.

So, Any ideas as to what it is & especially, how to fix it?

Thanks,
G

 

iacv? fitv?

 

thanks for reply, but I don't understand the question:
iacv? fitv?

Don't know if this helps but everything is factory stock on B18a1 engine.

GAry

 

you probably want to clean / inspect and if necessary replace your idle air control valve, located on the back of your intake manifold towards the firewall. they usually get gummed up with **** from the pcv valve... some carburetor cleaner should do the trick if its not completely shot. 15 minute fix with a 10mm wrench.

 

Thanks!! on it in the AM.
G

 

If cleaning out the iacv doesn't help I'd maybe check for a vacuum leak

 

mine was doing the same thing one day then i pushed in all the hoses and it stopped. + 1 on the vacuum leak.

 

Hi,
I been looking for the IDLE AIR CONTROL VALVE as you suggested. There is a part located where you described but the 1990 Accura Integra Service Manual says it is the EACV as in 'Electronic'...I'm thinking this is not a good thing to spray w cleaner! I haven't priced it but maybe replace that...and maybe the PCV valve?

Other choice is another name for the iacv?...does it contain something like a butterfly valve to control air flow?

Thanks a bunch,
Gary

 

it contains a valve inside which opens and shuts allowing a regulated amount of air past the closed throttle plate through a port in the throttle body. the valve is controlled by the pcm which determines its position through various inputs it receives on the engine. a fault in the pcm or any one of those pcm inputs or the iacv itself could cause idle surge.

first thing i'd do is check your codes. on a 90 integra it's as easy as turning the ignition to run, pulling up the passenger side footwell carpet and counting the flashes on the pcm's led. if there is a problem with the pcm or one of it's inputs, it might throw you a code.
check there first.
if you're getting no flashes and no solid led illumination, check for vacuum leaks. spray starter fluid at each vacuum line and vacuum seal area one by one and see if the idle fluctuates when sprayed in a certain area. if it does, that is the area where a vacuum leak resides. if no leaks are detected, clean the iacv. there is a screen inside which can become clogged. use the carb cleaner on it liberally. make sure the o ring seal isn't completely hardened, although, if you perform the vacuum leak check first, and that seal were the problem, you'd find that prior to removing the valve.

so to recap, what i'd do in this order:
1. check codes. if no codes or solid led..
2. check for vac leaks. if no leaks detected..
3. clean the iacv

i say in that order because it is the most logical order for ease and common problems.
if you don't find the problem in those 3 steps, we can move onto further trouble shooting with the fitv and pcm inputs