1993 Honda prelude si, h23a1 engine, tuning on a aem fic. Non turbo, 1000cc injector dynamics, aem fuel rail. I've got a decent tune worked up for this car but every time i drive it it goes lean when engine is completely warm and rolling down a hill with the throttle closed. This is the only time it goes lean. As soon as I press very slightly on the gas pedal it goes to 14.5 Afr but like I said it goes so lean when im rolling that a wide band uego gage can not read anything. Is this common or do I have something wrong here that im missing?

 

Normal. It called fuel cut, when your off the accelerator pedal the injectors stop injecting fuel hence your lean condition. When the engine speed is too low, say 900rpm, the injectors fire back to prevent engine stalling.

 

Yeah thats totally normal,

I tune with NeptuneRTP on an NA H22A and I notice that when you cruise with about a 300mbar load on the car, basically not going downhill or uphill.

I run no cat and love the popping when I deceleration and go down hill part throttle I get in a lean condition due to the fact that there is less load on the car and its accessing the lower load are af the fuel map. There is less then 300-200 mbar.

So basically the way to prevent this is to increase the amount of fueling at decal however its not hurting anything as the car isn't under any load.

its normal, I tuned my really really lean on those lower values of the map because I tend to like the popping noise at deceleration.

 

OK very good I was having alota trouble trying to make this lean condition go richer. Now that I know this is normal (and I also like the pop I hear, race sounding)(I also have no cat) and as long as I am doing no harm, I am not worried. And yes it only happens when im completely off the accelerator. If i very lightly press the throttle car goes to normal 14.7 AFR.

 

Good deal!

Honestly the way you learn about tuning and this stuff is dont take peoples advice just experiment and read some tuning books, best advice I have is to learn yourself, and talk to tuners in person that know a thing or two.

 

??? mitt "flip flopper" romney is that you ??? lol

 

What?

 

dont take peoples advice.....take peoples advice

 

Likwidchz you have been helpful. I knew exactly what you ment in the post. I belive you ment is not to reley on the infomation people submit. Usually others are very helpful but sometime you get wrong or bad feedback, then you find yourself tring to compensate. Civickiller why are you trolling. This is a helpful website for many, please go elsewhere. Thank you for the help likewidchz! Any other input on the post subject matter will be very useful and acceptable. Is it usual for the AFR to go so lean the the AEM UEGO Gage can't read anything at all during these periods of no load/ no throttle?( I think the aem uego tops out around 16-17 AFR)

 

Yes, as he already told you.

 

yup im trolling