Am I running Lean?

[4G63dsmpwr]

Hey everyone here's my problem:

The car runs alright, if anything feels sort of rich. Exhaust end is BLACK, also a sign of running rich, right? Plenty of timing, 21 degrees + at WOT. Pulled the plugs, they look extremely RICH...

Boost only at 12lbs on a new 14B. Other mods/maitenence, than pertain to fuel - an AFC2, new fuel filter, new ECU, new Walbro 255, datalogger... Still the stock 450s, but besides that the fuel system is pretty much updated, right?

My O2 readings are 0.78V at WOT Theres my problem... I replaced the O2 sensor, and the ECU so that should be working right? I used to have a 92 AWD, and in that thing the O2s were steady at .90-.92 - whats going on here?

I've even put the AFC2 up to +40%, and it still doesn't change the O2s...

Knock/Timing: Getting plenty of timing, and seeing barely any knock right around +20% on the AFC - right where everything should be. If I tune the car by timing advance/knock I can get it to feel pretty strong.

Fuel Trims are at 118%... I've been having this problem for a long time, and can't figure it out, replaced a ton of stuff. Hoping someone else might have had something similiar!

Any opinions at all would be appreciated!

 

[4G63dsmpwr]

Anyone have any ideas at all? Thanks!

 

[HokieDSM]

Have you checked for leaks/cracks throughout the exhaust, including manifold, turbine housing, etc? If you're still running the stock 1G manifold, you're more than likely to have a couple cracks in there.

I've got similar readings/issues, but I'm almost certain they're due to a couple leaks I know I have from bad gasket seals from the head to the manifold and a crack in my turbine housing. Also, according to what I've read from the fuel trims VFAQ and stuff over at Digital Tuning's website, '90s apparently read a little bit lower for some reason.

 

[4geze63]

you need an aftermarket fpr, thats why your running rich, you cant use stock fpr with 255.

 

[InjenTalon96]

FPR, fuel pump regualtor, so if i get a 255 for my car i need a diff FPR, where do i get that

 

[Budget90GST]

Bypass your fuel pressure regulator solenoid. It's probably bad. Do a search on FPR solenoid.

 

[adam355]

Why is this always an issue? Don't people read what else they need when they put a bigger pump on?

 

[HokieDSM]

I think the question was why his readings were lean, not why he was running rich - did I miss something here? His ECU is richening up his fuel trims because it's seening a lean condition - I think the question got diverted somehow

 

[4geze63]

you need one of these with walbro 255 http://www.dsmtuners.com/parts/product_info.php?cPath=2_140_81&products_id=644

it overrunns the stock fpr because the sping cannot withstand the higher pressure from your bigger pump. Get that fpr and adjust your fuel presure

 

[4G63dsmpwr]

HokieDSM: I have replaced both the manifold, and the entire 14B turbo - these are both i great condition. O2 readings are the same with both turbos - I doubt that they both have the exact same problem... The 14B looked great, no cracking, supposedly had 30K on it - don't know if I believe that, but it looked great. Ported it also.

I've also read that 90s read lower! Do you know what there supposed to be around? I'm unsure about this. Thanks for your help man!

4geze63: Well, I don't think this is causing the false O2 readings... If I was running rich, why would the O2s be like .78V? And not to argue, but I had a 92, with a 255 no FPR/with an AFC, I had .92V all day long, with an 18G, 20lbs of boost, etc.

Budget90GST: I'm going to do a search for the solenoid. Thanks for the heads up!!

adam355: Please read my response to 4geze63. My question was about the O2s...

HokieDSM: THANKS for clearing it all up!

4geze63: Ok... My O2s are really LOW, and it seems I'm actually running RICH, this is my question...

Thanks everyone who helped me out! Please don't tell me about the FPR, I'm asking about the O2s..

 

[4G63dsmpwr]

Budget90GST: Hey man, any negative effects with performing that solenoid thing?

I searched, and can't find anything - can you provide a link?

Later!

 

[Budget90GST]

No, not really. It's suppose to maintain fuel line pressure that helps in warm start up. I bypassed mine since it was stuck closed and not letting the regulator go up and down with changing vacuum and boost. My o2 was bottoming out at .72 and when I bypassed it it went up to as high as .87. 90's are suppose to read lower (not sure on this one just what I read on people's thread). Just bypass it and see if you have any problems afterwards. You can easily reverse this anyway if you don't think it helps.

 

[4G63dsmpwr]

How do I do it...?

 

[Budget90GST]

Find the group of solenoids on the drivers side firewall. There will be three of them grouped together. The middle one should be the FPR (The one you tee off for your boost gauge). Non California car will probably have less so I'm not sure on those cars. Anyway, the idea is to just bypass the solenoid. Unplug the vacuum hose from one end of the solenoid and just hook it up directly with the other end from the other side of the solenoid. Leave the electrical part hooked up and start the car.

 

[4G63dsmpwr]

Alright, I'll check it out tomorrow, I understand what your saying though, look for the 1/4" vacuum line, which runs through the little black plastic piece, right?

Is there more than one vacuum line, or is everything else electrical? Will try this tomorrow, and let you know how it all works out.

Thanks for the help!