Rich at 5-10psi and part throttle

[chilort]

My car is running super rich at part throttle and 5-10psi (10.0 AFR on a AEM WBO2). If I mash the throttle and jam the air in (15psi) I get much better AFRs (11.5).

Below 5 psi (0-5psi) it is lean (15-16).

In vacuum it is normal (14.7).

I also have knock on the top end. I get up to 14* of retard at full throttle, full boost (15psi) and winding it out (most of the time I get less than 14* of knock retard).

I used to run an MSD 6a but it $h!t the bed. I did not have 5-10psi boost issue with the 6a. I need to get it fixed and reinstalled.

Additionally, my fuel mileage has gone to hell and I can smell gas when I'm in the 5-10psi range.

Edit: Injectors are 804s. Cal is Stage III '86 cal from FWD Performance, new fuel pump, Acufab AFPR set to 42psi base.

[GLHNSLHT2]

what'd you change other than the 6a? Did you bump or replace any vac lines? The AFR is different at WOT cause you're on a whole other curve.

[minigts]

I swear my first impression when I saw the title was Rich Bryant at 5-10psi and full throttle, like a video or something. LOL :p

[chilort]

I did nothing other than replace the 6a. I have a Blaster 2 coil. I thought the MSD may have fried it so I threw my stock factory coil back in and it does the exact same thing.

Vac lines are all new and I have great idle vacuum (18-19 inHg).

I ran for over a year with the 6a and no problems like this until it died. I guess shorting out the case to the battery when I was installing it wasn't actually good for it after all.

While I do have some parts from Rich in my car, I do not have Rich in my car. Sorry, no video. :nod:

[chilort]

Nothing huh? :bump2:

[Gaboon]

O2 sensor crap out?

[chilort]

Watching the O2 on a 4000e and it looks to be reading correctly. It knows it is really rich too (NGK/NTK sensor that is maybe 2 years old).

[chilort]

Would a cat that is starting to get clogged up do this?

[chilort]

Okay, I've now got my base pressure turned down to 40psi. In the 5-10 psi of boost at part throttle I am now running around 11.5 afr and the fuel smell is gone. The problem is that in the 0-5 range and transitioning around 5 psi it wants to go lean (17). When it goes this lean it sort of stalls out a bit.

I've talked to Cindy some about this since I am running her cal. A question that came out of our conversation was what kind of duty cycles I am seeing on the injectors during all of this. My 4000e doesn't give me duty cycle that I know of but I do get ms pulse width for the injectors. What kind of pulse width should I be seeing here at part throttle across the boost range.

If it helps, my max boost is 14.7 (or what ever it is limited to with the 2 bar map). It is hard to get more than 10psi of boost unless I take it to full throttle (or full throttle via TPS positions regardless of if I have it fully to the mat). When I am at full throttle my afr will start around 12 but goes to 11.5 or so and stays there nice and solid even with the lowered fuel pressure.

[chilort]

About 11ms in the lean region of 5-10 psi. Good? Bad? Thoughts? Help?

[chilort]

I know this is a difficult problem because it has been driving me nuts for a while. I still didn't expect crickets.

Could it act like this with a bad injector? Would would be a way to test that?

Or is everyone too busy flaming in the lounge?:(

[chilort]

Car seemed to learn that the fuel pressure was lower. Now it is back to running rich rich rich at 5-10psi. Cranked the fuel pressure down to 36 psi and still pig rich.

[chilort]

Dying PM. Got a PM from a member here (thanks Jay!) and now I need to add some fuel back in.