Dfdfdsevo

I tried searching around and found no good answers, perhaps I don't know how to exactly word the question to yeild good results any way, I find on my wideband when I let off the throttle most of the time it goes to fully lean "---" like I imagine it should but more frequently I find when I let off the throttle it will bounce from 15.7 to 16, to 17 and then will eventually go full lean, I have the v2 extreme tbe and it makes it sound like the car is struggling, sometimes when it does this the revs/speed reduce and sometimes they stay, I was wondering if this is normal or if I have issues any help would be appreciated so I can put my mind at ease. Thanks again!

Spazpilot

iTrader: (4)

My AEM Wideband does the same. My car doesn't sound like it's struggling though and usually settles back to 14.7 at idle. Just look at your fuel trim at idle. Make sure you LTFT isn't pegging 12.50.

Dfdfdsevo

Yeah my car always goes back to 14.7 at idle, and I guess struggling is a bad word to use its just like putting it is hard to explain but the fact my exhaust is extremely loud due to it being straight piped maybe the sound is just louder than most cars (they probably dont hear it so they dont notice it) but I do, it's like my I injectors keep spraying once I let off but it's not consistent so it makes me wonder my wideband is aem aswell. Does it happen every time you drive because it does for me. I wonder if it's my tune

PSUfan1

iTrader: (2)

My AFR (also from an AEM UEGO) typically reads between 14.7 and 15.7 at idle or cruise on flat ground. During engine breaking (i.e. you let off the throttle completely but leave the car in gear), it will go to full lean pretty quickly.

In regards to your second question about the car struggling? I'm not sure I follow. The rate at which the revs/speed drop when you leave off the gas is going to depend on how fast you were spinning the engine to begin with, the grade of the road you are on, etc... If you are going downhill and leave off of it in 5th gear at 70mph I wouldn't expect it to drop speed too quickly. If you are in first at 6k and going up hill... it'll behave differently.

What are your AFRs when you are at WOT? Does the car stutter or anything like that at WOT? You are going to hear EVERYTHING with an exhaust like the V2 extreme (I have a similar one). When you left off it and engine break it's going to be loud (generally louder then when you were cruising). You also might get some pops and such.

Dfdfdsevo

Yeah idle and cruise I'm at 14.7 which is good, and at WOT I am at 11.2-11.6 which is good. And yeah struggling was a bad choice of words it is more just like a put put put noise because the injectors havent stopped giving fuel, the engine speed part makes sense normally down a hill at 3 or 4k it will go full lean but sometimes it doesn't and normally at highway speeds like 120 kmh I let off at it will just jump from 15 to 16 to 17, and back and forth for a while then go lean, im just wondering if it is normal as in does it happen to other peoples as well. And so up a hill it wouldn't go lean right away? I guess it does eventually go lean. And if it happened when my car was stock id never know because it's so quiet and I put my wideband in the same time as my exhaust but I don't remember it happening before my tune

Dfdfdsevo

I know what the engine break sounds like and that sounds normal to me it's when it doesnt sound like that, that makes me wonder. Sometimes it happens in the same spot that it didnt happen before, when I gear down around the offramp going towards my house it hardly ever goes right lean it just *sounds* like spuddering and I dont slow down as consistantly as the engine break, sorry if this doesn't make sense I'm having a hard time trying to explain

Dfdfdsevo

Nothing eh guys? This is seriously bugging the **** out of me

NFSLancerRA

iTrader: (8)

Alright, I have explained this a couple of times, but I will do so again.

When you let off the throttle and coast with the car still in gear, the motor is not using any fuel. It uses the momentum of the car and the spinning of said gear to keep the motor spinning. It is only when you press down on the clutch pedal or begin to accelerate that the car must then re-introduce fuel to either keep the motor spinning at idle OR accommodate for acceleration. A lot of guys who hyper-mile their cars (not typically Evolution owners) leave their cars in gear for the longest amount of time when coming to a stop in order to conserve fuel. I do this occasionally when I am thinking about it, but most often my automatic reflex is to press on the clutch before it is necessary to to prevent a stall. I hope that this helps.

PSUfan1

iTrader: (2)

What you are describing in terms of Afr is normal. It fluctuates before going full lean because the engine is operating in partial vac (throttle is closed) and no fuel is being added. The exhaust gas velocity passing by the sensor is much lower and isn't an even mixture. As the above poster explained you aren't using any fuel. Your gauge will always eventually go full lean... But depending on the condition that you were running immediately before closing the throttle, it might take a bit longer and it may fluctuate. Nothing in regards to what you described is abnormal in regards to your Afr. My guess is that the sound is normal too given that you have an aggressive exhaust... But its very hard to really diagnose a non descript sound over the message board. With the stock exhaust you would never hear anything close to the engine breaking noise as compared to the v2x (essentially straight pipes)... Are you also running a test pipe? You are probably getting all sorts of crazy reverberations lol!

Dfdfdsevo

Haha yeah I am running the ets test pipe and if it is normal than im glad to hear all in all I just wanted to know that it wasn't an issue thank you for putting my mind at ease!

LOVEMYX

iTrader: (2)

This guy is absolutely correct! Happens to my car too. Completely normal

acidtonic

iTrader: (1)

The ECU also has a strategy for selecting whether to cut fuel and coast or coast with fuel being injected still.

You can feel the difference because the engine braking will be much less and the car will seem to coast much longer distances.

On my car I like to choose which type of coasting depending on whats up ahead. If I have a long coast with a "sure stop" I will leave the clutch out and let fully off the gas, then gently "nudge" the gas pedal without going more than about 10% and immediately let off again. Instead of the normal engine braking the AFR will jump up and the car will coast much longer until revs drop below roughly 2000rpm and it cuts hard again and starts engine braking. I try to time it right to maximize mileage when thinking about it.

Otherwise it's the opposite. You lift to get the hard fuel-cut engine braking until roughly 1500rpm where it decides to start injecting fuel again and the car stops engine braking. Usually at that point you would be pushing the clutch in though.

Once you recognize the feeling you don't even need to look at the wideband to know whats going on.