Wideband lean at idle and under boost! Ive changed everything! Expert Advice needed

[SpoolingSpyder]

Ok, my wideband suddenly goes lean while idle. Just noticed it the other day. My tuning mods are an SAFC2 and a Wideband and Fuel pressure guage to check fuel pressue. Before this my car was running beautiful. 11.5 @ WOT and 60 psi fuel pressure and 20 PSI. Now at idle my car goes all the way lean no matter what I set my afc2. It was -8% at idle and the wideband read 14.5 thru 15.7 when things were good, and now i can set the SAFC at idle to +40% and it goes rich for afew seconds then goes all the way lean again. Even under boost, I get on it, and below 8 PSI things are where they normally are, then after 9 PSI it goes ALL THE WAY LEAN. I used to be at 20 PSI with the 11.5 A/F @ WOT.

Ok, so I decide to check afew things. I bought a fuel pressure guage. And I get 40 PSI at idle, and it goes to 60 PSI when boosting, perfect fuel pressure. I check my spark plugs, they are Extreemly White= Very Lean, so I know the wideband is telling the truth. I still swap out my wideband O2. Same problem, still lean at idle. I swap out my SAFC with a friends, still lean. I swap out my injectors (550's) problem still there. I check my fuel pump and redo the O-Ring. Problem still there. I swap out my ECU, still goes lean at idle no matter how rich I set the SAFC. I check my comprssion, 185 accross the board(2.4L fully built btw). I swap out my FPR with a friends, nope, still lean at idle.

What the hell can be the problem. Im going to change my fuel Filter today even tho I dont think its the problem. I get awsome fuel pressure at idle and under boost. Anyone ever experiance this before. I need some advise on what to check next. I have no, check engine lights on atm. So I dont know who, what, when, where or why I am getting the lean readings from my wideband.

Whoever discovers my problem, and it fixes my problem, I will buy them a new air filter and ship it to your door, my treat!

Thanks Gents!

 

[97gstnick]

if your not getting any knock and your sensor is brand new, then i would think you have an exhaust leak. somewhere there is air getting in and passing by your sensor giving you a false lean reading.

 

[tstkl]

but he said the plugs were white. so he is combusting lean.

since your getting good pressure and you tried new injectors, unless theres a clog in your fuel rail or something, your gonna want to try your wiring harness. did it get wet recently or something? might just be the age of the wires. take it to a dealer and have them test it. (just the harness not the whole car, I will never be giving a dealership the keys to my cars again)

 

[andytalon]

run some seafoam through your car, and it will tell you if you do have any ex. leaks!!! try it doesnt hurt to spend 5 bucks!

 

[tstkl]

run some seafoam through you car, and it will tell you if you do have any ex. leaks!!! try it doesnt hurt to spend 5 bucks!

when i tried that, my whole engine was smoking like none other it seemed. I do have a huge crack in my exhaust manifold, but it scared the shit out of me to see smoke everywhere in a matter of seconds.

 

[T9S1i]

arent 2g's supposed to have 43.5 psi fuel pressure at idle? not 40... try uppin it to 43.

hope this helps

 

[andymoraitis]

arent 2g's supposed to have 43.5 psi fuel pressure at idle? not 40... try uppin it to 43.

hope this helps

Bingo! There's a step in the right direction. Fuel pressure is supposed to be 43 with the vacuum line off. It would also help if we could see a log at 20psi.

Start with the fuel pressure and let us know if that helps.

Andy

 

[unclesam099]

How about a boost leak test?

Are your O2 sensor(s) that go to the ECU good? Or did they just crap out?

If you do Seafoam, do you have to change your oil? I've heard both yes and no...

 

[SpoolingSpyder]

but he said the plugs were white. so he is combusting lean.

since your getting good pressure and you tried new injectors, unless theres a clog in your fuel rail or something, your gonna want to try your wiring harness. did it get wet recently or something? might just be the age of the wires. take it to a dealer and have them test it. (just the harness not the whole car, I will never be giving a dealership the keys to my cars again)

If it was the wiring harness what would be the reason i would be getting a lean reading on the spark plugs? I took my fuel rail out and checks ok. I went to the dealership and changed my fuel filter and nothing changed. If I had a short in the wiring, wouldent I get a engine code? On of the mechanics said It would throw a code almost immediatly if it was fuel related. Im just curious, what in the wiring harness would cause a lean condition?

 

[SpoolingSpyder]

Bingo! There's a step in the right direction. Fuel pressure is supposed to be 43 with the vacuum line off. It would also help if we could see a log at 20psi.

Start with the fuel pressure and let us know if that helps.

Andy

My fuel pressure with the vaccume line off ill check later on today. but atm my fuel pressrue responds quickly and goes to 60 PSI when boosting. The guy who built my car has the same setup and is the one i switched everything over with. His car runs 40 psi at idle and his car is reading perfectly on the wideband. There is no diffrence on what our fuel mods/tuning devices are. The only thing thats off is mine are lean.

We stared and compared everything so far except chaning the whole wideband and the fuel pump which I might later on do. A log at 20 PSI will be very unlikely because I dont want to detonate my engine to hell if something is really wrong.

I will also change my plugs today and see if they turn frosty white again. because the race gas I was using could have also caused them to turn white as well. I appreciate your help and I will let everyone know hourly if anything changes. Looks like I might be sending afew people some air filters

 

[SpoolingSpyder]

How about a boost leak test?

Are your O2 sensor(s) that go to the ECU good? Or did they just crap out?

If you do Seafoam, do you have to change your oil? I've heard both yes and no...

My o2 sensor is good to the wideband. I swapped it out with a friends and nothing changed on the wideband. And my front o2 would not make the car go lean, because i just replaced it and I only had crappy cruise gas milage.

The only thing thats wierd is when Im cruising. My wideband readings are right on. Between 14.7 and 15.9. I dont get it!

 

[andytalon]

No you dont have to, unless you put the seafoam in your oil, then you would have to. I guess some could go by the rings but even if it did it would be a Very very small amount which wouldn't harm anything so dont worry about it.

How about a boost leak test?

Are your O2 sensor(s) that go to the ECU good? Or did they just crap out?

If you do Seafoam, do you have to change your oil? I've heard both yes and no...

 

[unclesam099]

Andytalon, thanks.

Spooling, did you say you did a boost leak test?

If you're leaking anywhere after the air sensor, that'd do it especially when you get on boost. How about an exhaust leak? Is your tubular manifold cracked or leaking anywhere? If you are leaking near your narrowband, that'd throw the ECU off. Altho it doesn't matter when you go WOT, the ECU disregards that signal (I believe). But you do have the problem at idle too.

I have no clue other than that. Just trying to brainstorm here.

 

[Necromancer69]

Race gas turns your plugs white. And i'm thinking the culprit for the a/f gauge is an exhaust leak.

 

[T9S1i]

im telling you, whatever the guy who built your motor said could be ok, but the STOCK 2G SETTINGS are 43psi base fuel pressure... that extra 3psi might make a world of difference.... Try upping it to 43psi, stock, where it should be, and see if your problems go away..
It wont hurt to try, unlike a 20psi log in a lean condition ha

I really dont see any reason for running your fuel pressure lower than stock, i see no good coming from that. even if you are running stoich at idle.

and hey, if im right, forget about the air filter, go to problem diagnosis and help me with my 2g maf install!!!

 

[Slippi84]

Is that 40psi base pressure with the vacume off or on cause the way you said you were going to go check it with it off made it sounded like you hadn't before. Your base fuel pressure should be at 43.5psi with the vacume OFF. I know your buddy might be running the same stuff but you can't compare two cars even if your running the same stuff cause every car is diffrent. Like the other guy said I doubt it's exhaust leak cause your plugs are white what you could do is try changing out the plugs with some brp7es go a step colder or two and adjust your base fuel pressure with the vacume OFF and see what happens. Good Luck

 

[SpoolingSpyder]

im telling you, whatever the guy who built your motor said could be ok, but the STOCK 2G SETTINGS are 43psi base fuel pressure... that extra 3psi might make a world of difference.... Try upping it to 43psi, stock, where it should be, and see if your problems go away..
It wont hurt to try, unlike a 20psi log in a lean condition ha

I really dont see any reason for running your fuel pressure lower than stock, i see no good coming from that. even if you are running stoich at idle.

and hey, if im right, forget about the air filter, go to problem diagnosis and help me with my 2g maf install!!!

Ill look into this and see if I find anything. Thanks!

 

[SpoolingSpyder]

Is that 40psi base pressure with the vacume off or on cause the way you said you were going to go check it with it off made it sounded like you hadn't before. Your base fuel pressure should be at 43.5psi with the vacume OFF. I know your buddy might be running the same stuff but you can't compare two cars even if your running the same stuff cause every car is diffrent. Like the other guy said I doubt it's exhaust leak cause your plugs are white what you could do is try changing out the plugs with some brp7es go a step colder or two and adjust your base fuel pressure with the vacume OFF and see what happens. Good Luck

Yeah, going to look into the 43.5 psi. But that would not explain why the car is going lean at WOT. I get 60 PSI of fuel pressure @ WOT which is more than enough fuel pressure, right?

 

[97gstnick]

when are you checking your plugs? if you want an accurate sample, you have to do a WOT run and immediately shut it off and remove to check them.

 

[97gstnick]

i noticed you checked everything, but have you tried swapping your MAF with your friend? is yours hacked really bad?

 

[SpoolingSpyder]

when are you checking your plugs? if you want an accurate sample, you have to do a WOT run and immediately shut it off and remove to check them.

Ive got an extra set of plugs in the car. Ill do that tonight after work or tomorrow when im running errands.


<------------Oh btw like the new Pewter paint job

 

[97gstnick]

Ive got an extra set of plugs in the car. Ill do that tonight after work or tomorrow when im running errands.


<------------Oh btw like the new Pewter paint job

hey, it looks like you have the turbo wing thats only on the coupes. is that it? if so, send me some pics dude, im thinkin bout doing that to my spyder.

 

[Slippi84]

Woah I didn't knwo your car was going lean at idle and at WOT! You should go back and double check your safc wiring and everything make sure that's workin right cause it's startin to sound more like a tuning problem cause if you added that much fuel at idle like you say you did and you didn't notcie ANY diffrence than something isn't right with that safc cause your idle should start to fluxuiate and ac like you have cams if you add to much fuel at your idle rpm.

 

[97gstnick]

Woah I didn't knwo your car was going lean at idle and at WOT! You should go back and double check your safc wiring and everything make sure that's workin right cause it's startin to sound more like a tuning problem cause if you added that much fuel at idle like you say you did and you didn't notcie ANY diffrence than something isn't right with that safc cause your idle should start to fluxuiate and ac like you have cams if you add to much fuel at your idle rpm.

this guy may be right

 

[T9S1i]

i was under the impression that afpr adds fuel 1:1 along with boost. If you were at 40 psi base pressure, and 60 under boost than that seems right. If you were at 43 base pressure then under boost you should be at 63... correct? There is your lean condition... Im not sure about the safc thing as thats past my knowledge, but it seems like if you are adding fuel and getting no difference, than something is wrong...

correct me if im wrong anyone... as im no newb, but not a wiseman by any means...