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

[AL92]

You have 550s and a 50 trim..I would say you are going over 100 % on your injectors..that could be your wot leaness especially since if you do have 40 PSI with line off then you are making those 550s more like 500 or 450s maybe.
Also idle problems can be easily caused by leaking tb gaskets or o ring leaks on the throttle body shaft..change out the o rings and like everyone said make a boost leak checker. If your pump,filter ,rail and afpr are good not much else in the fuel system to be causing problems. And race gas might wreck the o2 sensors if its leaded.. And agree you better get a logger right quick..wideband is not going to tell you if you have knock and other problems.

 

[SpoolingSpyder]

Get a logger and then get a FPR. It looks like you are still running on the stock pump which is a big no no. And if you aren't and are using a 255 with no FPR that's an even bigger no no. That will usually cause a rich situation though.

I have a 4 year old walbro 255. I dont have a FPR but will try and get a link in this week.
I changed my spark plugs and went to Autozone to check my engine code. I get a cylender 2 missfire. I get home and check the plugs, FROSTY WHITE! OK, i know im running very lean now and will try and check my fuel trims with a logger and check for any leaks.

I dont think a FPR is needed to tune the 255 walbro because its running lean at idle and not cruising. Thanks for the tips!

 

[SpoolingSpyder]

You have 550s and a 50 trim..I would say you are going over 100 % on your injectors..that could be your wot leaness especially since if you do have 40 PSI with line off then you are making those 550s more like 500 or 450s maybe.
Also idle problems can be easily caused by leaking tb gaskets or o ring leaks on the throttle body shaft..change out the o rings and like everyone said make a boost leak checker. If your pump,filter ,rail and afpr are good not much else in the fuel system to be causing problems. And race gas might wreck the o2 sensors if its leaded.. And agree you better get a logger right quick..wideband is not going to tell you if you have knock and other problems.

Ill remeber to check the Tb gaskets. Didnt know those would have anything to do with running lean at idle and WOT and not while cruising. Im aslo going to check the wiring on the wideband and change out my walbro 255. Very good tips here, thanks!

 

[SpoolingSpyder]

Def go with DSMlINK but throwing more and more parts at the car might not fix our problem but from what you have said all together it's either your safc wiring or something in your fuel delivery leakin. DSMLINK is a good idea cause you can log what's happening and tune more precise than just throwin fuel at the car till it idles better. Good luck with the LINK

I agree, I think its a fuel leak or wiring problem myself. Im going to put in a APEX-I AVC-R this week and redo all my SAFC wiring along with my wideband wiring.

P.S. Im getting a LOUD Humming sound comming from my firewall for some odd reason. Sounds like a supercharger and Im assuming its the oil guage or fuel pressure guage. Going to look into this shortly. Anyone have anything elce to add?

 

[nospinspyder]

Check your safc wiring any resistance between the safc and ecm will lower the voltage going to the ecm making it run leaner. Try a jumper wire between the to MAF wires eliminating the SAFC wiring, also air leaks after the MAF meter, before the turbo will make the engine run lean because it will take outside air that is not going through meter check your hose between the mass air and turbo for a crack!! Good luck

 

[talon_boy69]

What wideband do you have? have you tried to calibrate it?(if posible)

 

[megadan]

So did you figure out the problem? If not, maybe you got a misfire due to bad coil, wire,etc. A misfire would give a lean reading on your wideband. (that is considering the race gas made your plug became white).

 

[44pirate]

So did you figure out the problem? If not, maybe you got a misfire due to bad coil, wire,etc. A misfire would give a lean reading on your wideband. (that is considering the race gas made your plug became white).

Anybody know what happened here? It would be very helpful to complete this thread with a conclusion.

 

[timloomis]

A misfire would make it rich,not lean.The fuel isnt being burned when it misses,and the o2 would see that as rich.

 

[SlowSpyder]

A misfire would make it rich,not lean.The fuel isnt being burned when it misses,and the o2 would see that as rich.

you can have a misfire from being either too rich or too lean

 

[black12]

Anybody know what happened here? It would be very helpful to complete this thread with a conclusion.

maybe you guys can help me conclude this thread. because im having the same problem. ive tried everything stated in this thread. i tried contacting SpoolingSpyder to see if he ever found a solution but i didnt get any response.

 

[jo1]

have you try change the CAS

 

[black12]

no i havent. do u think a bad cas would make me run lean?

 

[jo1]

i have a problem with bad CAS before.... the tunning is like hell... adjusting the fuel to a variable ignition timing to get a right AFR. Does your manifold turning to glowing red after a WOT run?

 

[black12]

no i never noticed if it did. are there other things to tell you if you have a bad cas. i have a 91 cas laying around but i dont think it will work on a 90

 

[jo1]

what i see from the car that have the problem is the AFR is different at the same point of load in every run made and adjusting the fuel doesn't solve the problem. From there we know that the CAS is sending a different reading at every run made.... but i'm very confident that my fuel delivery is in good shape.

 

[black12]

i swapped on another 1g cas today. it came off a 92. i wired it up, adjusted my ignition timing and went out for a pull. the car still runs too lean. anymore suggestions.