Have a '91 vert w/ moderate to heavy mods. Car has a SS aftermarket exhaust w/o cats or an O2 sensor. Consequently the air-fuel mix is "fat"! Is there a programmable ECU or air-fuel CU that can help me get the mix within acceptable limits?

 

What makes you say it's running rich, and when is it doing it? Idle? Cruising? Load? The stock fuel map is fairly rich all around, but removing the cats will let you smell it. Removing the 02 sensor is a mistake, as that will prevent the ECU from leaning out the mixture while cruising.

Check out the engine management section of the forum. SAFC + wideband would be the cheapest route. You could also do an Rtek 2.0, or you could go all the way to a full standalone EMS (Haltech, Microtech, Megasquirt, PowerFC, etc...).

 

Is that all of your moderate/heave mods? Hardly. Rotaryrocket hit the nail on the head, cheapest/easiest option would be SAFC or an Rtek 2.0 if you don't want to go with a piggy/have few more options in terms of tuning/control.

You could go with a standalone, although if you just want to drive your car and enjoy it, it's hardly worth the $600-$2k it will cost you (depending on what you get)

 

Thanks for the reply. I'm looking at a Bosch 14point7 Wideband WBo2 kit w/ a Bosch UEGO sensor. Hoping this will give adjustability.

 

is there a echo in this thread

 

An AEM UEGO wideband will just tell you what the mixture is; it doesn't give you any ability to adjust it.

You didn't answer any of our questions. What makes you think it's running rich? I see a lot of threads made like this, and there's usually nothing wrong. Maybe you have a reason?

 

It smells VERY rich at idle, cruising, and acceleration. so rich I have to either keep a window or the top down, and I burned a quarter of a tank of fuel when I drove 21 miles this weekend. So, I should install a wideband O2 sensor along with doing the RteK7 ECU upgrade?

 

If you're smelling exhaust inside the car (w/ windows up and top up), you've probably got a leak in the shifter boot seal. It could also be the smell of raw fuel from a leak under the hood. Checking the area on top of the engine around the fuel pulsation damper (PD) would be a good idea. Too many cars have burned to the ground because of leaks from old PDs. You can pressure test the fuel system by jumping the yellow test connector near the AFM & turning the key to 'ON'. Other than that, a catless exhaust will smell. And idle mixture is rich by design, so that'll be when you notice it most.

You could go with an Rtek ECU & wideband, but I think I would track down the problem (if any) in the first place before spending $6-700 on things you may not need.