d15b7 IDLE/MPG problem

[SiCRX88]

Hey I currently have a d15b7 in my Crx. It starts up fine but sometime after about 5-10mins of driving when i come to a stop (in nuetral) the idle irregularly bounces between 1k-2k rmp's; I'm thinking this could be a map/o2 sensor problem or electrical problem? Anyone have this happen before? Any thoughts or suggestions would be greatly appreciated... Oh yea & my mgp is horrible ...

 

[murray195]

Some possibilities:

O2 sensor
02 sensor heater element
IACV (most likely)
Air in the coolant system

Are you throwing any codes?

Check this link
http://ecomodder.com/forum/showthread.php/honda-iacv-explained-967.html

 

[SiCRX88]

Wow, thanks 100 for the article, I am going to try to adjust my air bypass screw on the throttle body and see if that helps.. and I do not think I am throwing any codes... but cylinder #3 WAS not firing but I swapped injectors (3 & 4) and put in new spark plugs then all 4 fired fine if that might have anything to do with it...

 

[99sidude]

It sounds life your FITV (fast idle thermo valve). This is a very common problem, and has heppened to me twice. The part is located on the underside of the throttle body. Take the metal plate off and you should see the valve. It is common for the valve to unscrew from its housing. Screw that thing back in, put the cover back on, and be done.

The FITV is a mechanical valve that opens and closes based on coolant temp. Whe the valve comes out of the housing, the valve always stays open. That's why your car runs fine for the first 5-10 minutes. When the coolant temp sensor reads that the car is warmed up, the ecu goes into regular open loop mode. The ecu doesn't expect the valve to still be open, so in essence it's a big vacuum leak.

Id be willing to bet money that this is your problem.

 

[SiCRX88]

Genius...




thanks all for your help, I will let you guys' know how it goes...

 

[SiCRX88]

So I simply adjusted a couple things on my TB and now my ideal is around 750 rmp's, a little low i think, but MUCH better than before.. THANK YOU

 

[labe lincoln]

Its the idle air control valve most likely. all honda will start doing it soon enough. Its very common. im about 100 percent sure its that. my 95 civic dx d15b7 had the same problem. any my buddies 93 integra. cheap part so nothing to loose. good luck