On highway decel MAP is around 9 and car is lean

[TomFraser]

When going around 80-90 on the highway I let go of the gas and the car's MAP is around 9 @ 3000ish RPMs which causes a lean condition because the 9 MAP means the car is in "LOW" but it is so low that when I tune low at 3000 I can't make it richer because I would ruin my actual 3000 at low when cruising

I am totally new to this so It may be a stupid question, but I am trying to learn , if the question is unclear I can try to rephrase

Thanks for any help

 

[Fletch124]

Your supposed to get a lean condition when your dragging the car in gear. Its pretty much shutting the injectors off. If your trying to get really good MPG you would downshift as much as possible instead of using the break. Your using less fuel this way.

 

[TomFraser]

Your supposed to get a lean condition when your dragging the car in gear. Its pretty much shutting the injectors off. If your trying to get really good MPG you would downshift as much as possible instead of using the break. Your using less fuel this way.

Ok... So it isn't a big deal?

I am only worried because I cannot measure how lean it is as it is above 19:1

 

[grimreaper]

its normal.

 

[Jeff Lange]

The injectors should be OFF. Completely lean, no fuel. Do not try to add fuel. You are in decel, and the inertia of the vehicle is keeping the engine spinning.

Jeff

 

[FullNelson]

Off topic, but if there is no fuel how come the engine still makes produces the sound of the cylinders combusting, if that makes sense?

 

[CRE]

Off topic, but if there is no fuel how come the engine still makes produces the sound of the cylinders combusting, if that makes sense?

It doesn't.... the sound is of the cylinders still releasing compressed air... the sound is different though. Just because there's no fuel doesn't mean the valves stay open and the engine stops compressing air.