Built 1.6 acting funky
 

OK, to start off, I'm not 100% new here....been lurking an readin stuff every now and then, and havn't really had much to contribute, but I do have a question now, that I can't seem to find a straight answer about. I figured I'd come to you guys, seeings how you where reckomended to me by a trusted source.

Anyhow, here's the deal. I know this is a F/I forum, and I have an N/A issue but I'm hoping ya'll can still help.

A buddy mine has a 91 miata with a high comp 1.6 in it. It's built to run the "D" prepared class in SCCA solo II competition...gutted to the sheet metal kinda deal.

The motor specs are as follows

13:1 comp
forged guts
Cams are 302 Duration 400 lift
C/A Inake, Header, all the free flowing noisey awsome
Stock valve sizes in the head
Adjustable cam timing gears
MSD coils
computer was reset for a 9k redline

I'm pretty sure that's about it...anyhow, the car is running pig rich at idle, and most likely across the rpm band, as the car bogs down pretty bad for a few moments when he has to lift off the gas and get back on it. Now my previous experiance (with other brands of cars) says to get a wideband O2 sensor, and maybe an Apexi unit or some other piggyback to help sort this out. We'd like to go that route for ease of use, and cost. But are we right or wrong about this? We're open to the idea of a standalone, but neither one of us has any experiance with one, so I will then be newb bombing another part of this forum if we have to go that route.

pull the vacuum line on the FPR, any fuel?

The FPR is good, he put a new stock one on and it's doing the same thing as described in the OP, unless pulling the vac. line serves another purpose I'm unaware of? Either way he's got an adjustable FPR on it's way.

clean your AFM and make sure your O2 is good

the AFM (I'm assuming this is air flow meter, or the MAF) is clean, and the current O2 is is brand new, albeit an OEM replacement.

Try new plugs gapped to .025 and report back. Are the wires new?

We can do the plugs tomorrow, and I'm pretty sure the wires are either brand new, or new when he built that car for autox last year.....so maybe 10 events total on em.

Im curious to how an open header, 9K redline sounds like on a miata.


Im going on youtube!

it sounds very angry, I assure you :cool:

Anyhow, we got set up with a megasquirt kit from DIY Auto Tune. A couple phone calls to RotorNut and an e-mail or two to DIY, and I think we're all set. Got the MS, WB 02, a couple sensors here an there, and some other shit (I don't have the list infront of me) For just under $1100 ain't too shabby...

LuckY!!