420a turbo still running lean

[wbrigante]

Having issues with my boost, installed wideband aem at an idle it sets around 11 but when my boost gauge hits 7 psi it becomes so lean it will not register so I hooked up my fmu which is a 12:1 but even with this hooked up the car will still go lean however the car still does not pull like I know it should any ideas.

 

[99RedGs]

I have no idea what your setup is. In order for us to help you, you need to either update your profile to show all of your mods, or post a complete list of what you are running.

For example, what fuel pump are you running? Do you have some sort of fcd (Missing link or otherwise)?

If you aren't running and fcd you need one and that is why you are lean. When the stock ecu sees positive manifold pressure it cuts fuel, thus you are then lean.

 

[wbrigante]

Here is the setup
Bottom end completely built
Star turbo system
Which has the 12:1 fmu (obx)
Walbro fuel pump
Hks blow off valve
Aem wideband
When I bought this car it already had the turbo system on it but as I did the research on it that is when I found out it was missing the fmu, and the missing link. The car runs great other than the fact that the boost gauge shows 8lb of boost but it just does not have the pull that I know it should so I ordered what I found to be missing. I installed the missing link plus my aem wide band to see what it is doing ( took out the front o2 sensor and put in the wide band their) can when the car spools up to the 8lb it shoots to lean, so I went ahead and put in the fmu it still goes to lean just not as quick and it still does not have the pull a turbo should. Any ideas or is there any one close to Brighton, co that would be willing to look at it. Could it be due to the fact that I do not have the upstream o2 sensor in?

 

[95TalonOwner]

Could it be due to the fact that I do not have the upstream o2 sensor in?

YES.

You need that o2 sensor. Put it back in and put your wideband where the downstream senor is or weld a new bung in below the stock upstream sensor.

 

[wbrigante]

thanks i will try it

 

[wbrigante]

I finally got the time to pull the car out of the garage and ran it down the highway it still feels like it just does not pull like it should the turbo boost gauge hits 5lb of boost. Is there anyone in the n. Denver area that would be willing to look at it or just give me more ideas on what it could be.

 

[96 420a-t]

Why are your boost readings all over the place? You say you have a wally but which one?

Check which pump, do a BLT, what size injectors?

 

[wbrigante]

the fuel pump is WALBRO GSS342 this is what is on the fuel pump, injector size is unknow i will try to do a boost leak test today.

 

[96 420a-t]

Well thats the right pump. Have you verified your fuel pressure under boost? Unhook the ling going from you manifold to the fmu and add 8psi with compressed air. My gss342 was bad brand new from walboro and was only hitting 62 psi under full boost.

Sound a lot like we had the same problem. I ended up running bigger injectors and a safc with a gss317 wally pump.

 

[wbrigante]

what size injectors did you end up going to?

 

[2GJeremy]

you don't know what size injectors you have? does that mean they are stock? if so, that's your problem on running lean

 

[bryanwheat]

Did you ever install an o2 sensor?

 

[wbrigante]

The o2 sensor is back in but no difference in performance. I do believe the injectors are still stock

 

[bryanwheat]

IT should run the same at idle as it did without the turbo. You don't need bigger injectors at this point because you have the fmu. By the way, 11:1 is rich, not lean so you are pretty rich at idle. Do you have the missing link?

 

[96 420a-t]

With a 12:1 fmu you can run stock injectors. I ran 275 cc injectors and a 6 or 8 to 1 fmu.

 

[wbrigante]

yes i have the missing link

 

[96 420a-t]

I didn't like the missing link. Kept giving me a CEL and the car idled like poop. I switched to the zeiner diode mod and never looked back.

 

[wbrigante]

my car dose have a rough idle

 

[eclipse420ags]

Missing links are crap come off your wallet and buy the fuel cut defender from synergy labs it's awesome 50 bucks and you should be good. Also what are you tuning with?

 

[96 420a-t]

He's tuning fuel. Check the missing link. Take it off and see if it idles.

 

[wbrigante]

i will try that tomorrow and let you know thanks

 

[glowryder]

if your Idling at 11 afr, thats what you need to fix first. and that would tell me your static FP is set wrong, or something to do with the FMU.. i would figure that out before you do anything with your boost problem. When you did boost what was your AFR?

id suggest run a Missing link to protect your map sensor, and run an FCD to do the real work of voltage clamping. Id test your map , if its FUBAR, then it could be casuing the idle issue, check you plugs too. they are probably fouled by now.

 

[96 420a-t]

The way the missing link works is they create a HUGE vacuum leak right before the map sensor. I am recommding he only check the idle with the missing link off to see if is idle AFR comes back into line.

 

[wbrigante]

it still has the rough idle i just ordered the fuel defender so as soon as it gets here i will try it

 

[96 420a-t]

You need to figure out your rough idle snd go from there. Also check you fuel pressure when the fmu sees positive pressure. I have a feeling those will be your two issues.