Hello Friends,

I bought a 92 GS-R last week. Has a few things to fix, but the pressing issue is the fluctuating idle. It bounces between 2000 RPMs and 750 RPMs. Sometimes it stalls out. I replaced the fuel pump, and swapped out 2 MAP sensors, but it still fluctuates. No codes on ECM. Previous owner says that it would stall out when it got to a half tank.

How do I get the idle under control?

Thunder

 

oxygen sensor maybe?

Your problem seems worse than mine but to resolve mine i had the whole engine flushed of all the carbon deposits

 

Take off the intake, their will be a hole in the throttle body for your IACV (idle air control valve), plug this hole with your finger with the MAP sensor unhooked and the car idling. If the car stalls, it is your IACV, if it doesn't, it's a vacuum leak somewhere else.

 

whoa, just adjust the cold air idle valve first. Taking the whole intake off first is overkill. not to mention a pain in the ass. You should make sure u have a full amount of coolant.

If you're gonna shotgun parts, can I have the old ones???

 

When does the idle bounce? Does it happen when the engine is cold, the engine has warmed up, or both?

 

definitely check the idle control valve first. easiest to check too.

 

Try bleeding the coolant system valve. We did this on one of our g2's and it fxed the fluctuating idle.

 

yeah, bball has the right idea.. OR it's the cold air idle valve. This is a problem that most early 90's hondas/acuras share. I should get some digital pics on how to check and adjust it. maybe put it in that other part of the forum.

 

Here's the idle troubleshooting guide from my Helms manual.

One problem that people sometimes have is the IACV goes bad without throwing a code so there's no real way to check if it works in the Helms.

I've also attatched the pages on how to set the idle speed with the adjusting screw and how to check if the fast idle thermo valve is working properly.