Miata Service

VVT or VTCS?

VVT Dyno Runs

I was led to the VVT system by the CEL fault code that the car keeps throwing, P0012, which translates to “A” Camshaft Position – Timing Over-Retarded because the VVT controls the intake (A) cam. The image above is from the fine folks at Flying Miata who actually dyno tested the effects of the VVT system; the blue lines show the system operating and the red lines show it disconnected. Looking at the lines there are no noticeable bumps at any RPM value, they are relatively parallel with the only difference being that the numbers are higher with. than without.

Well, it turns out my idea of the VVT kick, that feeling of a surge of power at certain RPM, is not really from the Variable Valve Timing system after all. With further research I now find out it is from something called the Variable Tumble Control System (VTCS) that was created to help emissions at low RPMs. A valve closes part of the intake path, increasing the velocity of the intake charge. The butterflies are closed if two conditions are met: the coolant temperature is less than 65C and the engine RPM is less than 3000.

I’ve always sort of felt that this problem only occurs when the car is fully warmed up, so I wonder if maybe those butterflies stay closed once the car is warm and that is what is causing the slight out of tune feeling at higher RPMs. The only problem with this theory is that the VTCS has its own fault code, P2006, and I’m not getting one of those.

I guess as an elimination test for the VVT system I could go ahead and pull the electrical connector off the oil control valve, thereby disabling it and drive the car until it gets warm and see if my symptoms are still there. Maybe tomorrow.

#%&!@#$

Subtitle: The Check Engine Light Comes On Again

Monday afternoon I backed the Emperor underneath the metal awning in the driveway and raised up the driver’s side of the car as high as my compact aluminum jack could go, propping it up with jack stands. The goal was to change out the mid-pipe and muffler with the OEM pieces borrowed from John. Listing from front to back there was one butterfly shaped brace with six 21mm nuts holding it on, then 4 more cross braces at various intervals with two 21mm nuts apiece and one cross brace with, for whatever reason, four 19mm nuts.

It looked like I could remove a couple of the regular cross braces and leave a couple on, but that big 6 bolt brace was definitely going to come off. Because of my limited clearance under the car for hammer swinging and my wimpy foot long 3/8″ breaker bar I managed to get only one of the six to loosen any after 10 minutes of struggle. So doing what any non-mechanically inclined individual would do, I gave that task up. I knew I could change mufflers, so I did take off the Racing Beat and put the stock one on.

Dropped the car back onto the ground and took a drive around the neighborhood. Quieter for sure, so I took it out a bit further and stomped on it. And while it was quieter overall than the Racing Beat, once over 4000 RPM it had still had that ugly undertone.

When I got back home I went and got the Kindle with the Torque app installed on it. Turns out after monkeying with around with the app for a while I had discovered it can log real time data, so I got back in the car and took it back out for a ride. Around to the first spot I can get on it and I do a rolling start in second gear. Run it up to almost redline before shifting into 3rd and keeping on it until near redline again before having to coast to the stop sign ahead.

Turn right readying to make another run through the gears and I notice my old friend the Master Caution1 light has illuminated. Hmmmm, I figure what the heck, I’m logging the drive and I’m less than a mile from home – I mash the gas pedal and go. High speed through 2nd and 3rd, u-turn, repeat the pattern and return to the hanger2.

After a couple tries I figured out the right way to transfer the log to the PC. It is comma separated value format so I open it up in Excel. Blank column, Time, Blank, Blank, Blank, G(x), G(y), G(z), some more blank columns and some more random parameters. Turns out that even though I had a “dashboard” set up with dials of the parameters I wanted to record you have to actually add what you want to the list of PIDs to be measured, what I got the first time are some sort of default measurements.

I select Time, Engine Temperature, Engine RPM, Vehicle Speed and Timing Advance to be logged. CEL be damned I go for a little longer drive running it through the gears to redline six to eight times before returning home. I dumped the log file to the PC and attached to an email to Steve at Panic. We’ll see what he has to say.

1. The Master Caution light in an aircraft is front and center where the pilot can see it immediately. It alerts him to take a look around the cockpit at the other 100 or so lighted buttons for the one that will tell him what is wrong with the aircraft. The Check Engine Light in the car equivalent to this; we just have to wait until we get home and read the code.
2. Continuing the aircraft analogy.

62,000 Micro-inch Pounds of Torque

Red Valve Cover II

After the last time I put the valve cover on it ended up leaking, so I thought I’d just get a new gasket and start over. Relying on my vast mechanical experience, I also thought maybe because last time I just tightened the eleven bolts holding it down by feel I may have under or over tightened them. The cure to hopefully not create another leaker maybe would be to maybe actually read the manual and torque the bolts to the proper value.

The specifications I have, thanks to a friendly Miata.net Forum member, 68.6 to 96.3 in/lbs, but the torque wrench to use, not so much. When I started looking for an in/lb torque wrench I was surprised at how much they wanted for them and I really didn’t want to spend that kind of money on something I might not use very much. I thought maybe I might be able borrow one. I could have bought one off Amazon for $22, but how good could it be for that price?

I had a line on one from a co-worker, but he couldn’t find his or forgot or something or other, so that was a bust. Today we were at a birthday part at a friend’s house and I asked a fellow MMC member who as there too if he had an in/lb torque wrench and if so could I borrow it. He did, so I told him I’d call later to see about getting it. When I called, he told me his was a beam type wrench, but it was for a lot higher range than I needed because the gradient marks were 50 in/lbs apart. That meant I would have to find the spot a little more than halfway between mark number one and mark number two. And even if I did, how accurate would that rating be with it so close to the bottom of the scale?

Figuring I had wasted enough time and effort chasing the whole borrowing thing, it was time to bite the bullet and just buy one., So I did some internet shopping of the local places and there was only one auto parts store that one in stock, but they wanted $120 for it. So I checked the local BBHIW stores and Home Depot had one for $70. I am now the proud owner of a Husky 20-200 in/lb click style torque wrench.

If you compare the above photo of the red valve cover with the one from earlier this month, you’ll notice that while I had the cover off this time I did some more painting on it – the lettering is now black.

Yesterday on the way home from work the Purple Whale slipped past the 62,000 miles.

Bonus Time

Sneak Peek 2a - Valve Train Issues

Walked by the neglected Moss Motoring Challenge list on the desk yesterday and noticed that the cutoff date for the second sneak peek photos was fast approaching. July 1st was just next Friday and because of the timing and exhaust issues on the Emperor we really haven’t been very active Challenge-wise. Right now the Miata is sitting in the garage with the valve cover off so I can change the cover gasket which is leaking (from the last time I had it off.) The perfect opportunity at least for the first one of the possible two sneak peeks was just waiting for us in the garage.

Fingers crossed I’ve got the VVT timing issue solved, but now I have to figure out the ugly exhaust sound. Almost 2 months ago Rudy brought me his Borla muffler and a spare stock muffler along with a stock mid-pipe from John. I picked the Borla, but it turns out that was the wrong choice. So guess what Donna and I did Tuesday evening? Right, drove the Sonata to John’s house and re-borrowed the stock mid-pipe and muffler.

Plan for tomorrow is to put the valve cover back on, with a new gasket this time and on Sunday maybe start on the exhaust issues. The muffler should be no real problem, while the mid-pipe is a whole ‘nother story, as it has about a four undercarriage braces that need to come off first. Then the two bolts on the mid-pipe upstream near the header (and higher temperatures) that haven’t yet been removed, so they probably will be harder to break loose and require more hammering that ones at the muffler a few weeks ago.

Motoring Challenge Points 1, Approx Miles Driven 0
Totals So Far: 58 points & 970 miles

Fun With A Scan Tool

So I answered Steve’s last email:

Steve,

There are a couple of plugs/sensors back there, not sure which is which, but both connectors seem intact and the wires look OK.
…
Worth trying to swap that Engine Temp sensor back there? What other signals is the ECU relying on to actuate the VVT system that might provide a cheap troubleshooting method?

Brian

He replied:
I don’t really believe the VVT stuff is tied to the temp sensor, just that if it were out of whack, it may default to some other map. Do you have a scan tool? It would show the timing advance real time if it’s a decent one.

Well of course I don’t have a scan tool, so I asked the MMC and I got several replies, but the first one was from my new best friend David. He had one and seeing as he was going to be in the neighborhood this afternoon he would drop it by my house. And that’s right, it is the same David who tried to give me the muffler off his back and made a trip to see me to let me drive his car to see what a real NB2 Miata should drive like. I think I need to add a codicil to my will and cut him in on some of that Bogardus thousandaire wealth in the event of my demise.

When I got home, sure enough, there was an Innova scan tool in between the storm door and the front door. I opened up the carrying case and David had thoughtfully included the manual. I read through it real quick to see how I go about recording some data, thinking I had it down, I backed the Emperor out of the garage and promptly spent the next 5 minutes idling in the driveway to get to the right spot on the menu. I backed out and headed to the 4-way stop at the end of my street, turned right, then took the next right and I was on a street with a half mile straight that has only two horse racing tracks and one driveway on it. Perfect, all I could do was scare a couple horses, so I stopped the car and launched it. Shifted at more than 6000 RPM in both 1st and 2nd gears before easing to the stop sign. I turned the corner, found a spot to do a u-turn and got back on my nice straight away to repeat the run in the opposite direction. Pulled back into the driveway and hit a couple buttons to go see my live data. “No Live Data Stored.” Hmmm.

The small guide included with the scan tool’s case was not much help, it told me how to get to the Live Data Recording menu and how to choose from one of the three styles of data collection and how to start recording, but was vague on how to stop the recording. It did tell me that if I went to innova.com I could get the full manual. So I did. It was a lot more in depth and after reading its section on Live Data Recording I was sure I had it, I needed to hit the return key instead of the LD/M button. Re-ran my same course, returned home hit the return key a second time and it still continued to record frames. Huh? Pushed the LD/M key to get out and sure enough, “No Live Data Stored.”

Back to the manual. This time I read the Live Data Recording section forward, backward and upside down. It said it records 100 frames several times in that section, I thought that meant it could record up to 100 frames, but as it turns out it needs to record 100 frames before it considers itself through recording. So back on the road I go. This time instead of u-turning after the first high speed run I turned right and ran thru 1st & 2nd again with anger before cruising to the stop light. I check the frame count on the display and it reads 48. So I do the u-turn before crossing the road in front of me and head back while repeating the way too loud and too fast for regular street driving towards home. As I cruise into the garage the Innova 3130c beeps on the passenger seat. Success!

Inside the house I start to review the data I just recorded. Because I recorded using the default settings there were like 50 data points per frame. But because the small display shows only a half dozen lines it takes awhile to read all the info by scrolling, and there are 99 more to go. Obviously the folks who made this know that this is not acceptable, they make it easy to download the info to your PC. All you have to do is download a program called “Innova_V02.03.12_PCLink” and install it. In less than a minute I am double clicking on the .exe file. Not so fast pardner, to run this program you also need to install “Microsoft SQL Server Compact 3.5 SP ENU” & “Microsoft SQL Server Compact 3.5 SP x64 ENU”, still, in short order the link program self starts and a window opens mid-screen with a fancy graphic background and two buttons grayed out.

The left button reads disconnected, so I use the supplied USB cable to hook it into the computer and the unit turns on and the button shines with the word Connected. The right button lights up with the word Diagnose, so I press it. My browser opens up to the home page of Innova, the same place that led me to the manual and the software. I’ve seen this sort of behavior before when you run a program for the first time, so I close the window. Nothing else happens. So I hit the diagnose button again, and the browser opens again. Oh, this is rude, they are going to make me register to download this data.

Oh, well, after all the work it took to get the data I’d like to see it, what’s one more login and password? So I fill out the form with name, address, phone number, email and make up a password. I am informed to check for a confirmation email. Its there, I click on the activation link and I’m back on the Innova website saying thanks, go ahead and sign in, I do and I end up at some sort of dashboard. I now go back to the PC Link software and tap the Diagnose button again, another browser tab opens and before I can go further I am presented with another form to fill out (which you can’t bypass, I tried.) The first thing they want is the year make and model of the car(s) you’ll be using the tool with. I select 2003 and Mazda, but there are only four models listed, none of which are a Miata! So I pick one at random. I use the same strategy for the next few questions by selecting random radio buttons, so when I hit submit this time I’m advanced to the next page. This one has three more blanks that need filling out and one of them is the VIN number. I don’t remember what the other two are because right here is where I decided I didn’t really want that data after all. I closed the browser and uninstalled the software.

The data is still in there and if David wants to read it he can have it. The Emperor hasn’t thrown a CEL in a couple weeks and after changing the last Cam Position Sensor it feels like it is running right. It still sounds crappy at higher RPMs with your foot heavy on the gas, so I wonder if John (Clunk) Haff would still let me try out that stock midpipe and muffler?

Started up, went down, back up, back down, still down.
Miata Top Transitions since 06/25/15: 185

Second Opinion

Calling Dr Kildare
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.

P.S. Waiting three days before curing the wrinkle paint on your valve cover by driving around doesn’t work. There are no more wrinkles there now than there were before.

Started up, went down, went up, back, back up, still up.
Miata Top Transitions since 06/25/15: 178

Fun With VVT

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 .