Flyin' Miata 1 800 FLY MX5s

TIMING TIPS FOR THE 1.6

Lots of people have asked for these, so I finally wrote them down. I would be happy to hear any suggestions for revision. Please read entire mess before starting. Not everything is in perfect chronological order.

Most Miata engines can benefit from advancing the ignition timing. How far you can safely advance the timing will depend on several factors. One major factor is fuel octane. The higher the octane you are willing to buy, the more timing advance you will be able to run. Ambient temperature also plays a role--the hotter the weather, the less timing your engine will tolerate. Different Miatas also have their own idiosyncrasies about timing. As engines pile on the miles they develop an “octane appetite” from carbon deposits in the combustion chamber which can cause hot spots and actually raise the compression ratio of the engine by reducing the size of the combustion chamber.Redline fuel injection cleaner can help prevent your car developing an octane appetite. Enough theory, on to the work...

Your timing light gets hooked up to the number one (closest to the front) spark plug wire. You can get +12 volts from the blue connector located near the front of the driver’s side fender. You can ground the negative lead of the light to the valve cover.

There is a diagnostic box located near the top of the left front shock mount. This box is about an inch square and is black in color. Open the lid and you will find a little map of the terminals in it. Use a paper clip or piece of wire to jump the GND and TEN terminals together. You want to do this after warming up the car to normal operating temperature. With the jumper installed, your idle should be about 850 RPM. If it is incorrect, adjust it with the idle air bypass screw located on the throttle body. The screw is under a black rubber cap. Clockwise lowers the idle, CCW raises it.

Once you have the idle corrected, you can check the timing. Leave the jumper installed. There is a notch on the crankshaft pulley that should line up with the 10 degree mark if nobody has messed with the timing in the past. The marks are found on the left (driver’s side) front of the timing cover.

At this point you have to find the cam sensor. The sensor on a 1.6 engine is located at the right (pass side) rear of the cylinder head. Just follow the right side “hump” in the valve cover all the way back and you will find a round object with an electrical connector on it. This is the sensor. It is about 3 1/2” in diameter. There is one bolt with a 12 mm head on it that is the hold down. Use a 12 mm box wrench to loosen this bolt so that you can rotate the sensor to make adjustments. Many people have suggested that gorillas or other large primates tighten this bolt at the factory. Any difficulty in loosening this bolt is strictly a result of not eating the correct breakfast foods. I recommend scribing a line from the head to the cam sensor before you move anything so that you can always return to stock without dragging out the timing light again.

Loosen the hold down and rotate the sensor. If you are willing to run premium fuel you may be able to get away with 18 degrees of advance. Remember that every mark is two degrees. Most Miatas can get away with 14 degrees on regular or mid-grade fuel. Once you have set the timing where you want to try it, lock down the hold down bolt and reset the idle speed to 850 RPM, because it will probably have increased as you advanced the timing. After you get the idle speed correct, pull the jumper lead out, disconnect your light and go for a test ride.

While test driving, keep an ear out for any pinging or rattling sounds. If you hear any at all, you have the choice of reducing the timing (just go back toward the mark you so smartly scribed), or running better gas. Do NOT drive the car with any pinging at all. You may find that you have to run less advance in the summer months.

Hope this helps!

Bill Cardell

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Timing tips for the 1.8 (94>)

These tips are meant to be an addition to our tips for timing the 1.6 (early) cars. Basically, there are only a few differences. The most obvious one is that the cam sensor has been moved to the driver's side rear of the cylinder head. Follow the "hump" in the valve cover on the driver's side back to the cam sensor. It is a round object with an electrical plug mounted on top of it. Same as the 1.6, it has one bolt with a 12mm head acting as a hold-down. The other (important) difference is that there are two marks on the crankshaft pulley. Contrary to what Mazda's shop manual says (possibly corrected by now), you have to use the yellow mark, NOT the white one. Same specs apply as given in the 1.6 directions. Remember to scribe a mark *before* rotating the cam sensor, to guide you if you need to head back towards stock.

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A little more theory to go with the timing tips....Another factor governing timing and octane requirements is altitude, something that I just found out after moving to Colorado. "High test" at this altitude is only 91 octane. The reasoning behind this is that the engine is breathing air that is much less dense than sea level air. This effectively reduces the combustion chamber pressures, as the air the engine breathes is at less atmospheric pressure to begin with. All well and good until you add abnormal aspiration to the mix, as in turbocharging. A turbo will effectively compensate for the less dense air, thus combustion pressures are maintained at near sea level values. What it boils down to for turbo people such as myself, is that not as much boost can be run, due to the crappy gas. Or, for a knock sensor equipped turbo car, more ignition retard will be called for by the knock sensor. FWIW. I thought it was interesting--maybe you have to live here....

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This will be short one, inspired by a question on the Miata listserver.
This is a technique for tracking down battery drains that may be killing your battery when the car is parked. There is always some current flowing from the battery, even when the car is shut off. This is known as dark current and is what keeps radio memory and clocks going, as well as many alarm systems and cellular phones.
A typical allowable number for dark current would be in the 40-60 milliamp range. This can be measured by installing a milliammeter in series with the negative post of your battery. If you don't have a milliammeter, you can disconnect the negative cable and hook up a 12 volt test light between the removed cable and the battery post.
If the light lights at all with the doors shut and key out of the ignition, it will be enough to kill your battery.
If you do show either a milliamp draw over 60 or your test light lights, you must find the problem. To do this, leave your light or meter hooked up and start pulling fuses one by one. After you pull each fuse, look to see if the current draw has dropped or the light has gone out. Do not reinstall the fuses as you pull them. In other words, keep pulling without reinstalling 'til one of them makes your light go out or meter drop.
Once you have narrowed it down to a specific fuse, it's time to go to the wiring diagram or owner's manual to see what circuits are controlled by that fuse. Some common culprits are power antennas that don't shut off, alarms, power mirror switches, courtesy lights and radios.
Hope this helps somebody! Late breaking news! Just looked in the factory manual and Mazda calls for 20 milliamps of dark current for a Miata. The lazy man's way around hunting for battery drains is to use a Priority Start. This is a little box that straps onto the side of your battery and monitors its voltage. If the battery voltage drops to a preset level the Priority Start will disconnect the battery, leaving you enough juice to start. Doesn't require resetting, just open the door and the courtesy light drain will reconnect the battery for you. Great for cars that sit between weekends!

PS Don't forget, while pulling fuses, you either have to shut the door after pulling each one, hold the door switch in, or make sure that the courtesy lights are turned off.

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Well, Turkey day is over and it's time to get back to work, so here goes (or comes) the follow up to Chassis braces.
The Miata comes with a sophisticated suspension right from the factory. In a wonderful win of the enthusiast designers over the corporate bean counters, Mazda went with an upper and lower control arm suspension design instead of the ubiquitous (big word for someone that turns wrenches!) McPherson or Chapman struts found in 90% of recent cars.
With the upper and lower control arms comes a tremendous amount of adjustability in the alignment department, and Mazda has made it very easy for us to set the cars up for our particular driving styles. More on that later.
The elements I will cover here are the parts that can be easily changed to improve your Miata's already stellar handling. When replacing suspension parts, it is very easy to screw things up. The factory actually did a pretty good job in choosing their compromises regarding ride vs handling. Go too far from their specs and you may end up with a great race car/lousy street car. (This seems to be what happened with the third gen RX7.) All of the magazine writers would review sports cars and say something to the effect of "the handling is compromised toward ride quality, too bad, blah, blah." Mazda went and built a "no-compromise sports car" in the RX7 and everyone whined that it rode too hard (even me, 'til we left New Jersey).
Over the years, I have experimented with a lot of set-ups on our cars and have come up with a few that I really like. After the addition of good tires (a must in the Miata's case), I would recommend a good set of sway bars. Sway bars are one of the few components in the suspension that don't have much of a ride quality trade-off. Upping the diameter of the front and rear sway bars and changing to a poly-urethane bushing will make your car corner flatter, with almost no body roll. This helps keep the contact patch of the tires on the ground while cornering. Almost no ride penalty will be felt from the installation of sway bars.
Once the bars have been installed, the next steps will involve some trade-offs. Springs control the height of the car and the stiffness of the ride. Miatas handle (and look) a lot better when they are lowered. After a lot of experimenting with springs, we have our own "Flyin' Miata" spring sets that drop the car about an inch and a quarter. They do make your car ride stiffer and this is one of those dangerous "subjective" areas, where one person's "firm" is another person's "painful". Having said that, my calibrated derriere likes the Flyin' Miata springs!
Having made the mistake myself once, I would never recommend installing new springs with the stock shocks. The job of the shock absorbers is to control the motion of the springs. Without shocks your springs would just keep bouncing 'til they ran out of energy. Stock shocks just do not have the damping required to control a stiffer spring. My favorite shocks are the KYB AGX.
We sell a complete package of springs, shocks, sway bars and strut brace, or sell all the components separately.

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The Miata is a tough car to write tech tips for--there really isn't too much that breaks on them! I'll cover a maintenance procedure here that often gets ignored, by both shops and home mechanics. The Miata's four wheel disc brake system is self adjusting in the front, but requires periodic caliper adjustment in the rear for proper pedal height and parking brake function. At my shop, we always set the rear calipers when doing oil changes and it was usually noticed by the customers.
Anyway, here goes: There is a bolt with a 14mm head on the back of each rear caliper. Actually there are two bolts of this size, one holds the bracket for the handbrake, one unscrews to gain access to the caliper adjuster. Pull the one covering the adjuster (don't worry, no fluid should come out!) and you will find an allen type adjusting screw. It takes a 4mm wrench to turn it. The technique is to (with the handbrake off) turn the adjuster in (clockwise) while rotating the brake rotor by hand. As soon as it stops or you feel a heavy drag, stop and back the adjuster off 1/3 turn. Make sure that the rotor now turns freely. Reinstall the 14mm bolt and repeat the procedure on the other side.
*If* your allen bolt strips.....Don't panic! You can use a magnet or a snap ring pliers (stick the points in the socket of the allen bolt and expand to grab the adjuster) to get the damaged adjuster out. When you get it out you will see that the teeth on the adjuster are ground up. Either file or grind the damaged end 'til it's cleaned up, grease it up and reinstall. A little spray grease whenever you're adjusting is always a good idea and will help prevent this problem in the first place. Hope this helps!

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Suspension improvements and what they do: I'll try to cover this one in a couple of chunks. Many people are confused by chassis braces and swaybars and what their respective jobs are. Chassis braces are intended to stiffen the chassis of the car, giving you a more stable platform for the suspension to work from. The chassis of your car is (supposed to be) a passive component, while your suspension is active. If your chassis is flexing around, you don't have stable anchor points for your suspension and can end up with some unpredictable handling, as well as the "afterthump" that is common on Miatas, especially older ones.

Mazda recognized that there was room (need) for improvement and has added braces over the years, starting with a rear subframe brace in 1992. This brace is a pretty simple one, basically a piece of pipe with both ends squashed flat, tying the open bottom of the rear subframe "U" together. The aftermarket has several offerings to accomplish the same job. My personal favorite is the Cannon brace, developed by Miata.netter Skip Cannon. It is constructed of 1/4" aluminum plate and ties four points on the subframe together, as opposed to the factory's two points.

In 1994, with the introduction of the 1.8 litre cars, Mazda added two longitudinal stiffeners to the rear subframe brace. In 1996, they cheaped out and made this part of the Popular Equipment Package or R Package. Also in 1994, a front subframe brace was added, as well as a brace behind the rear seats, tying the shoulder belt towers together. My favorite aftermarket piece for the front lower brace is the Racing Beat one. We now offer a rear brace for behind the seats on the '90-'93 cars, which is even stiffer than the factory one. This one makes a big difference!

Not offered by the factory, but available from us, is the Flyin' Miata front strut tower brace. This piece ties the tops of the front shock mounts together across the engine bay. This piece can make a substantial difference in the way your car feels.

By adding the above mentioned aftermarket braces to an early model Miata, substantial improvements can be made to the stiffness of the platform, resulting in better handling, less aftershock over bumps and a general tighter feeling. The only improvement I would recommend for a 94> car would be the front strut tower brace and adding the factory rear subframe brace if your '96 didn't come with it.

Next up will be suspension mods.

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This is my version of how to install a set of shocks or springs on a Miata. It is not the same procedure recommended by Mazda, but has the advantage of not using any special tools. If you start with the front shocks, the rears will be a breeze when you get to them.
Start by jacking up and safely supporting the car using jackstands.
1. Remove the wheels and the splash pan.
2. Remove the bolts attaching the swaybar to its end links.
3. Remove the cotter pin that goes through the castellated nut on the upper balljoint, then unscrew the castellated nut a few turns. Do not remove it at this time.
4. This is the scary part! Using a good sized hammer, hit the side of the steering knuckle where the shaft of the upper balljoint passes through. You do not want to hit the balljoint or its nut. A couple of good smacks and the balljoint will pop free. I usually ask customers to leave when I'm doing the hammering part. Click on images to see where to hit.(drawing courtesy of Will Brown,real pic from me)
5. Once the balljoint has popped loose, remove the castellated nut. Be careful, the upper control arm will want to pop up and the steering knuckle and everything attached will want to drop down. Don't have any body parts in the way :-(
6. Remove the large through bolt that holds the bottom of the shock to the lower control arm.
7. Remove the two nuts holding the shock mount to the fender. These are accessed from under the hood. Do NOT remove the center nut on the shock or things will get exciting.
8. Now it's time to get the shock assembly out of the car. You will have to pull the upper control arm down, pull the lower control arm down, and finagle the shock assembly out without catching it on the fender lip.
9. Once the shock is out, you will need to use the spring compressor that you were smart enough to rent or borrow. Please follow the directions for the compressor and be very careful! There is a lot of energy waiting to be released in the spring. Once you have the spring compressed enough to be loose on the shock, unscrew the top nut on the shock shaft and remove the shock assembly.
10. If you are only replacing the shock and not the spring, just put the new shock in through the spring, transfer the dust boot/bump stop assembly and reassemble.
11. If you are replacing the springs also, uncompress the stock spring next. If you're using Flyin' Miata springs (of course..), you will not need a compressor to reassemble. This should be true of most aftermarket springs.
12. Different shocks have different torque requirements, so I won't advise on that number. Go by the directions that come with your shocks and tighten the top nut. For a reference figure, Mazda calls for 23-34 ft/lbs of torque on the top nut.
13. At this point you reverse your steps, first finagling the new stuff back into place. Slip the lower bolt through the new shock and control arm and finger tighten it. Put the two nuts on the top of the shock mount and tighten to 17-22ft/lbs.
14. Pull the upper control arm down, guide the balljoint stud through the steering knuckle and install the castellated nut. You will have to pry the control arm down to provide enough pressure on the tapered balljoint stud to keep it from turning while you tighten the nut. The nut gets torqued to 30-45 ft/lbs and a new cotter pin installed. Try torqueing to somewhere in the middle of the range, then tighten enough past that to line up a hole for the cotter pin.
15. Reinstall and hand tighten the end link bolt for the sway bar.
16. Repeat on the other side.
All of the nuts that have only been hand tightened so far will be torqued once the car is back down on its wheels.
Rear shocks
1. Remove the spare tire and the metal shield that covers the fuel filler neck inside the trunk.
2. Remove the two nuts (14mm wrench) that hold the upper shock mounts (inside the trunk). Do not remove or loosen the center nut on the shock shaft at this time!
3. Remove the through bolt that holds the bottom of the shock to the lower control arm. If you have heavier aftermarket sway bars, you will probably want to remove the bolts from the end link to the sway bar. The stock bar is so skinny you probably won't have to bother with disconnecting it.
4. Pry down on the control arm and weasel the shock assembly out. Much easier than the fronts!
5. Follow the procedure given for the front shocks to swap over the spring and shock.
6. Weasel it back in, re-install the nuts inside the trunk and torque to 17-22 fl/lbs. Reinstall spare and filler neck shield.
7. Install the through bolt and hand tighten.
8. If you took off the end link bolt, reinstall and hand tighten.
9. Repeat on other side.

Once you have put the wheels back on and lowered the car, torque the wheels to about 80 ft/lbs first.
Next, bounce the car up and down a few times. Now you can torque the end link bolts (27-40 ft/lbs), and the lower shock bolts (46-69 ft/lbs).
What this does is to center the bushings in a normal ride position before they are locked down.
If you haven't replaced the springs, you will not have affected the alignment by following these directions. If you have installed lowering springs, you will want to do a full four wheel alignment, as the camber will have gone too far in a negative direction for street use.
Hope these help!

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Here are a couple of quickies.
For '99 Miata owners, we just spent the time (about five seconds, with help from Sam Sharp and Chris Lambert) to find out what was keeping the passenger's seat from going all the way back. There is a stop located at the rear of the seat rail nearest the center of the car, that was installed to make room for the computer being located behind the seat in '94. For some reason, Mazda hasn't removed the stop, even though the computer is now up by the driver's knees. One 14mm nut holds the stop in place. Pull the nut, remove the stop and gain two inches of leg room. Wish we could do something about the driver's side legroom. Mazda swears it is unchanged,but it is reduced.
For any Miata prior to the '99: On long cruises, (especially with the top up) try driving with the headlights up. There is quite a noise reduction with the lights up, makes long trips less fatiguing.
Check out our website, lots of new stuff up there, lots of pictures in our new online store.

We believe that in-car mounting is the way to go for the J&S knock sensor. It eliminates chopping wires in the exposed environment of the underhood area and only requires running the wire for the knock sensor itself through the firewall, instead of all the wires from the unit. There are three different versions of the wiring, 90-93, 94-95, and 96-97. Below are the two earlier cars.

J&S in-car wiring

1.6 litre wiring.

The stock ecu is located under a panel under the passenger's feet (lh drive). Pull back the carpeting and you will find a silver colored metal panel. Unscrew the mounting nuts and bolts and remove panel. You can ground the J&S under one of the screw heads or tap it into either 2A or 2B (black wires at end of larger yellow connector on ecu).

+12 (red wire on J&S) can be pulled from 1B (white/red wire in smaller ecu plug).

Yellow J&S wire taps to red wire at 20 on ecu.

White wire at 2E on ecu plug must be cut (far enough from ecu plug to allow splicing). White wire from J&S goes to ecu connector side of cut wire. Green wire goes to harness side of cut wire.

'94-'95 1.8 litre cars

Ecu on these cars is located behind passenger's seat. Just lift the carpet to expose ecu. If there is a smaller box there, ignore it, it is the ABS brain.

Black wire from J&S can be put under one of the bolt heads or hooked to 2A or 2B (black wires on larger ecu plug).

Red wire from J&S can be hooked to 1B (white/red wire on smaller ecu plug).

Yellow wire from J&S can be hooked to 2O (red/white wire on larger ecu plug).

White wire at 2E on ecu plug must be cut (far enough from ecu plug to allow splicing). White wire from J&S goes to ecu connector side of cut wire. Green wire goes to harness side of cut wire.

'96-'97 1.8 litre cars.

Ecu on these cars is located behind passenger's seat. Just lift the carpet to expose ecu. If there is a smaller box there, ignore it, it is the ABS brain.

Black wire from J&S can be put under one of the bolt heads or hooked to 4C or 4D (black wires on ecu plug).

Red wire from J&S can be hooked to 4B (white/red wire on ecu plug).

Yellow wire from J&S can be hooked to 3B (red/white wire on ecu plug).

White wire at 4F on ecu plug must be cut (far enough from ecu plug to allow splicing). White wire from J&S goes to ecu connector side of cut wire. Green wire goes to harness side of cut wire.

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Today's tech tip probably applies mostly to abnormally aspirated cars.
Quite a few people have reported plug fouling problems when using various
octane boosters, sounds like it's just not worth the aggravation. If you
have been using octane booster and notice misfiring, go straight to the
spark plugs, you will probably find some nasty deposits on them, from the
octane booster.

A problem that we've been seeing a lot of lately is bad radiator caps. One symptom would be hearing a sound like a coffee percolator when you shut down. If the cap does not hold pressure, you will get localized boiling and blow coolant off into the overflow tank, causing overheating. This is particularly critical on turbo and supercharged cars, which are obviously putting more heat into their cooling systems. The caps are easily checked with a radiator cap tester, which nobody has at home ;-). They are cheap enough that you should just plan on replacing your's every year or so, even the one our '99 was bad in less than a year from new. NAPA sells a "Stant" cap (part#703-1406) with a higher pressure rating than stock for about $12.95, or we carry them if you can't find them locally. Hope this saves some of you some aggravation this hot summer!

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