Piggyback MS...wideband goes where?
 

I purchased a "Braineack" built piggyback MS and...
I had a couple of questions. I saw that one of the plugs had a wire for wideband input.

I have an AEM uego... and I wanted to use it instead of the stock sensor. Do i need to have another bung to mount the WB so that the stock ecu can function.........or can i just swap the narrowband with the WB and wire it to the plug.

and... can I ground the WB with the same ground wire on the ecu - splitting and sharing the ground? (i don't know electrical terms all too well). As for power on the WB... where should I tap into?

thanks!...

Since you're piggyback, and using an AEM, the stock O2 sensors must remain in place, and an additional bung added for the wideband, preferably on the lower section of the downpipe a foot or so upstream of the cat.

The AEM's ground must be common with the MS's ground.

Power can be sourced from damn near anywhere that's switched. I think I took mine from the ECU's red/white +12 wire.

You could also do what I did and buy an O2 simulator to eliminate the secondary (after cat) O2 sensor. Then you can mount your wideband there.

Wouldn't this make it a little hard to tune unless you hollowed out the cat?

I should also clarify that I have a '91.

I don't have a cat on my car...not sure how the older cars are, but my 99 had a little cat right after the manifold, then the secondary O2 sensor, and then on the midpipe there was another larger cat. I have a 2 1/2" FM downpipe that has 2 bungs for O2 sensors.

This is very simple:

1- Leave the stock O2 sensor completely alone. It shall remain connected to the stock ECU. Besides, its fitting is too close to the engine for a wideband.

2- Install another bung just upstream of the cat, install the wideband here, and connect the wideband output to the MS.

follow joe's advice...

Okie - sounds good. Do you think a shop would be able to weld in a bung at the desired position (between 10 and 2 o'clock") without having to take out the lower half of the manifold?

Better question, what should I expect in terms of pricing, in order to get this thing welded in... just so that I don't get screwed.

By "lower half of the manifold", do you mean the downpipe? That piece most certainly has to come off.

(edit: you must not be turbocharged. In that case, "lower half of manifold" makes sense. And yeah, it's still gotta come off.)

I had three bungs welded into my downpipe by a local non-chain exhaust shop (think Ed's Muffer, not Mineke.) I brought the pipe in to them with the positions pre-drilled, and the fittings in hand. They charged me $20 total to weld all three in. Even if you have them supply the fitting, I can't expect it'd be much more than this. Exhaust shops have O2 fitting lying around, and they're usually $5 to $10 each.

On the other hand, if you drive the car to the shop with the downpipe attached, then you should expect to pay normal shop rate for labor as they put it on the lift, remove the downpipe, install the fitting, and then re-install the downpipe.