WOT air fuel is rich.

[niksevig119]

First, big thanks to everyone on here for the tech tips and diag. It really helps. Much appreciated

Im finishing up this svo swap. Finally installed my wideband yesterday, made some pulls and im finding a/f to be a bit rich at 10-11lbs of boost, reading 10:5 at full boost. Idle seems good in the 14-15 range, cruise and tip in all seem smooth in the 12-13 range. Ive only noticed that, if idle, if you rev the car and let it come down, it will kind of lope a hair and a/f will read lean, but then catch its idle and be smooth as glass

A little back story, the car is a 79, so i made a fuel system for the swap. Walbro 255, 40micron pre filter, -6 ptfe feed and return and i have a kirban regulator set to 39lbs with vaccum off

Timing is at 10 degrees
Motorcraft wires.
Ap104 gapped to .030
Brown tops have been matched, flow tested and cleaned.
Stinger Manual boost controller
3” downpipe

The only codes i have are 25,77. The car pulls and functions great( as soon as it gets near 2800)

I would like to lean it out a little bit, even 11:0 would be ok. I have tested the VAM somewhat,
Maybe its the volume of the fuel system? Tighten up gap more? Add a lb of boost and see what the wideband does?

Im open to any suggestions. I also have a factory o2 to swap in. Im new to the whole 2.3t so im sorry if i sound like an idiot. Thanks for any input.

[Stinger]

It's just the way the factory calibration is. It will be in the 10's for AFR until you run enough boost that it's exceeding factory airflow, at which point it will start leaning out. Only means of tuning is adjusting fuel pressure and it only works for a small range before it starts affecting idle and cruise AFR.

[niksevig119]

Ok. Thank you so much. It feels great, i just didnt know if i could clean it up any.

Do you recommend anything else? Im content with 12lbs of boost as a commuter. Not
Trying to push it

[Stinger]

If it's intercooled then stock is 15psi. If it is not intercooled, 12psi is certainly plenty, assuming premium fuel is being used.

What ECU?

[niksevig119]

It has the stock intercooler. 86 svo using PE computer in premium mode.

[Stinger]

Gotcha. Stock boost is 15psi then so there should be no harm in running at least that much as long as you're running premium fuel.

[niksevig119]

Can i get your opinion on TB upgrade? Ive read it helps with some of the sluggish feel at low rpm and improved throttle response. What is your take on it and what route (fox body tb, or sn95) would you go with. And obviously, open up the inlet on the upper to accept the larger TB?

[Stinger]

It is no different than just pressing the throttle farther down.

94-95 5.0 and Super Coupe are the only one that can relatively easily be made to fit.

[niksevig119]

I have a spare 95 tb and upper to open up and match. I may try it On a rainy day. What iac is used?

[Stinger]

Either IAC is fine. You'll have to slot 3 throttle body holes to make it bolt on.

[niksevig119]

Just checking in with some good news

I found my fuel pressure gauge to be inaccurate. There was 60lbs of fuel at the rail!! Made some adjustments there and air/fuel is really nice now. I set it to about 14lbs of
Boost and the car will richen up a hair
More right at WOT. Its fun to drive. Everything works. I may do the idle relearn test soon if needed, but everything seems to be normal.

Thanks to Stinger and everyone else for the help with this!

[Stinger]

Good to hear!