Miata running lean - fixes?

Viton might be a cool word, but in our experience few aftermarket seals work as well as factory. 949Racing sells some good stuff, but they're also very aggressive on price and sourcing for commodity parts.

rslifkin wrote: I don't know why he wouldn't put the better Viton seals on the intake side too (and that's the side likely to cause decel smoke). If you let it idle for a while and then give it a rev or get on it, does it smoke a little at first? If it does, that further points to valve stem seal leakage. Especially if there's no smoke under steady load (which is when bad rings would smoke the most).

I can't say I recall it smoking after an idle, but I don't drive this car very often.

I have a spare head on the bench. I wonder if I shouldn't undertake a rebuild on that one and have it ready to go.

So I just learned the car is a 94. How does that change things?

It means you've lost your ability to ask the computer what it thinks is going on, unfortunately. I'd stick with measuring fuel pressure.

We just had a Miata in the shop that was showing signs of a fuel problem, but had happy fuel pressure. We peeked into the tank and discovered it was full of crud. Pulled the GM fuel filter, yuk. Turns out that the filter must have overloaded and started passing crap through, and the injectors were all gummed up. New injectors, happy car.

I saw a set of purple 2001 injectors in our scrap metal pile tonight. I'll see if I remember to rescue them on Monday.

I got a set of purple injectors off a friend today and went to install them, only to see that I had the correct tan ones already in there, so I left those in and put the purple ones on the shelf.

I'm waiting some last minute parts and then I'll start to button things up. Anyone have a good guide to checking fuel pressure?

It's pretty straightforward. Tee the gauge into the feed line. Don't put it into the return line coming off the regulator. Read gauge. On your car, it'll vary with manifold pressure.