Year: 2016

Whenever there is something that just doesn’t seem right and you get an opinion as to what it might be it is always a good idea to get a second opinion, have someone else take a look.

Well, the Emperor is sick, he’s just not right. The check engine light is off (for right now anyway), but I swear it seems slightly out of tune. Worried that maybe that is just the way it has always felt and the slightly off exhaust note has convinced me that it is not running right. I needed an another expert for a different butt dyno measurement. Because I have been working on the theory that it is VVT related, I needed someone who had the same year range car, 2001-2005, as our Miata. There are two that match that criteria in the MMC and one was the clear choice, David ‘Dr. Kildare’ Adcock.

David agreed to come over to the house yesterday evening so we could take turns driving each other cars to compare the two back to back. First up was me driving his car. The first thing I noticed was how much newer his car felt than mine even though it is one year older. Turns out the secret to this is to have 120,000 miles less on the car. Where people find these “driven by a little old lady to church on Sunday” cars is amazing! Second thing I noticed was that his clutch take up point was lower than mine so it took me by surprise – one time. Once we got out of the neighborhood and I could put a lot more travel downwards on the gas pedal, it was obvious to me that this is how my car used to feel when under hard acceleration, it responded to your demands.

After 5 or 6 miles and 20 minutes we were back in my driveway and it was David’s turn behind the wheel of the Emperor. Backing out of the driveway the different clutch take up point took him by surprise here too – one time. He proceeded to drive the same loop. David run it through the rev range a few times as well and came to the same conclusion as I did, the car is fine in neighborhood style driving, but once you get above 4,000 RPM using a lot of gas pedal, it is missing something. He also noticed the same thing I did and that is the slight kick when the VVT actuates is a lot higher in the RPM range than normal, around 4500 as opposed to his which is in the 3000-3500 range. And when it does occur in the Emperor it doesn’t seem to make as much difference as it should.

So, let’s sum up. I’m not crazy (at least in this regard) there is something wrong with the Miata. It certainly seems VVT related. David agrees, but Dr. Kildare is a General Practitioner (like me) and doesn’t have a magic pill to make it better. And to continue that analogy, David said he can recommend a specialist, but it is in the upstate about 100 miles away. I told him I’d keep it in mind, first I was going to try one more quick and easy fix, another Cam Position Sensor. It was available on Amazon Prime and will be here Saturday.

Frustration with the Miata has got Donna to the point of suggesting that we leave in the Kroger parking lot with the keys in and walk away. Me, I wanted to take it to Panic Motorsports and let the experts figure it out. So I emailed Steve and gave him the run down of what is going on and asked when could I bring him the car. His response:

I’d check the gap on the crank sensor, replace the VVT oil control valve, and throw a cam sensor at it in that order. MAYBE an ECU if I got real desperate.

Solid advice from the Master, so I wrote back:

Steve,

I see what you did there – trying to teach a man to fish. So I tied a hook to my 3/8 drive and dug right in…

After reading several threads on Miata.net I would have bet $100 the chuckleheads at the local shop just replaced the crank angle sensor and didn’t bother to align it.Good thing I didn’t, as it measured right around .049 inch which is in between the .020-.059.

If by oil control valve you mean this – YIKES! – that’s pricey (around $300.) I tested it as best I could per the folks at M.net instructed and it passed. Resistance between terminals, 7.5Ω which is between the 6.9-7.9Ω they mention. I slapped 12v to it and it fully opened. Disconnected the 12v and it returned to the starting point. I think I’ll take it to work tomorrow and have the guys in the lab apply a variable voltage to see if it moves along its travel path.

The Cam Position Sensor I can swing ($60 from a seller on Amazon), but the oil control valve or heaven forbid the ECU and it may be time to quit throwing good money after bad…the ND is looking mighty tempting.

While I had the wrench in my hand I pulled the actuator thing off the valve cover to check the o-rings inside. They don’t seem to be as dry and brittle like some of the photos I found on the forum. I’m tempted to buy the kit that MiataRoadster sells with all the o-rings and then some.I guess I could pry the o-rings out and measure them, I work at a place that makes valves and we use a ton of o-rings, including viton ones.

Thanks for the advice, I’ll keep you posted.
Brian

I’ll keep you posted…the valve is a 2-position deal, no sliding, just on or off. I’m thinking this ain’t the problem. Those o-rings, we didn’t have them at the Valve Store(TM), so I did order the kit. Its coming from California via USPS so it won’t be here until next week sometime. ‘Til then, the Emperor sits .