Horn auto-beeps! And an upcoming track day!

[22Silver]

Hi guys!

Quick question...
Has anybody ever had their horn fail in such a way that it BEEEEPS when you go over hefty bumps, or gas it round a sharp corner, or gently "pull" on the steering wheel? I'm really not quite sure what the issue is, but I figure I'll have to somehow pull the cover off my steering wheel. This wont blow the airbag or anything... will it?

I need to do this soon because I have a track day on the 18th at Sandown (driving lessons and hot laps, all the cool things !
My engine was totally rebuilt (new pistons, rings, seals, bearings, gaskets, cams (more aggressive), shrim-under-bucket lifters (because the cams were trying to knock the shims off the top of the buckets!!!) and all the other things you'd expect in an engine rebuild).
I'm going to service the car- clean or replace sparkplugs, Oil+Air+Fuel filters, an oil change... Is there anything else that I should be looking at to make sure my car performs well and that nothing breaks on the day? Almost everything is less than 25,000kms old (radiator, exhaust, alternator, fuel pump, starter-motor, etc).

Also, I took my front ties (in good nick, Kumho KU31) and put them on the rear, threw the rear tires out, and put Kumho HS51 (apparently the KU31 replacement, except directional) and I put the brand new tires on the front. I figure I want the best grip on the front, right?

So I suppose my question, other than the horn-beep issue is- Other that oil+air+fuel filter, oil change, new tires and new (or cleaned up) spark plugs, what would YOU do to your car before a track day? And also, any tips for someone who has never had a driving lesson, who is about to get one??!

I'm excited to learn how to drive

[emily_mx5]

Check brake components! Pads and rotors, and brake fluid. Get the best/highest temp rating you can find. Braided brake lines if money/time permits. Do they clutch fluid while you're there too.

[Trackphotos]

Sounds like a short to me, something making contact intermittently when it shouldn't be. If you can't fix it, you can at least unplug the horn connector for the track day if you don't mind being without a horn entirely for the drive there and home.

To remove the airbag:
- Disconnect the battery
- Use a pry tool or flat blade screwdriver to remove the 2 little rubber plugs on the back/underside of the steering wheel
- Use a 10mm socket to remove the bolts behind those plugs
- Gently pull the airbag unit away, taking care not to pull the connectors behind it. There will be a little yellow connector for the airbag that's clipped onto the back. Release that from the back of the airbag to give yourself a little more room, then unplug that connector altogether.
- Disconnect the horn wire. It's the only other connector there beside the yellow airbag one.
- Reassemble, making sure not to reconnect the battery until everything is in place, connected and tightened.

[hks_kansei]

Check brake components! Pads and rotors, and brake fluid. Get the best/highest temp rating you can find. Braided brake lines if money/time permits. Do they clutch fluid while you're there too.

All good advice.

Personally I wouldn't bother with braided lines, not for a first trackday anyway. sure if your lines are worn/split currently then consider them, but otherwise i'd just leave the factory ones for now.


Fluid wise, high temp is good, but make sure to get the right stuff.
Don't just grab DOT5 and pour it in (or any silicone based brake fluid), all you'll do is ƒü¢k the system and need to spend hours, and hours flushing it about 100x until the silicone crap is out. (silicone based fluids don't mix with regular fluid. apparently they react and can form thick lumpy bits)
Just use some decent DOT4.

[hks_kansei]

as for the horn, it sounds like a wiring fault.

It sounds like one of the contacts has come loose and is intermittently grounding. on the NB the horn contacts etc are mounted in the airbag unit.

[MattR]

For brake fluid get a bottle of Penrite Sin, will be more than good enough for what you are doing and at a reasonable price and available from Repco or Supercrap.

Flush through and make sure you replace all the fluid in the system, pretty easy, just bleed each brake, starting from left rear, right rear, left front and then right front. If your brake fluid is a different colour it makes it even easier.

I would buy two bottles, but one should be enough to flush all the old fluid out.

Tbro wrote a great post on an easy way to bleed brakes, http://mx5cartalk.com/forum/viewtopic.php?f=76&t=37622&hilit=brake

[manga_blue]

and I've just used any SuperDOT 4 fluid for a track car for the last 4 or 5 years. I've never boiled it on the track. Any brand will do - Penrite, Repco, Nulon, PBR have all worked and they're only around $10 per bottle. It's best if you buy a different colour each time you change it so you can see the colour change as you're bleeding.

[madjak]

I'd also put in a fire extinguisher... they are really cheap (like $35) and just need a couple of holes drilled in the floor in front of the passenger seat.

I know the risks are low but it's one thing I've always had in my car. I've only ever used one once... on someone elses car in fact, but it's nice knowing it's there.

Driving a car for the first time on a track is a great experience. Just start slow and work your way up. Remember not to brake hard whilst turning, in fact it's best to just brake in a straight line every time. Use the power of the car from the middle of the corner to stabilize and get a good run out of the corner... ie slow in, power out. If you find yourself getting sloppy and loosing control and can't get the car where you want it on the track, just slow down and build up speed again slowly.

[MattR]

I have had "standard" dot 4 fluid boil on me twice in different cars on track days so for the extra coouple of dollars a bottle the Sin is good insurance, I used in my race car and never had a problem with fluid boiling. I use it in most of my cars as I tend to buy a few bottles at a time.

[22Silver]

Well, thank you all for the advice!
I replaced all the fluid in the car, the spark plugs and the head gasket in the end, and I'm glad I did- no issues.

Only.. it seems the car was misfiring at high RPM (usually after 6000 RPM, just did the exact same thing it usually would do at 7000RPM) but occasionally it would feel like red line at about 4800-5000RPM, which really sucked on the straights, as I would drop about 2km/h and lose the ability to accelerate for half a second. I managed to hit roughly 170km/h on the back straight at Sandown, but could only hit 160-165km/h if the misfire happened.

Anyone have any thoughts on how I could diagnose this?

I found this quote on Miata.net

25th June 2006, 23:28
It's not the plugs, and the wires have maybe 16 months and 10 k on them.
It seems like with every part change, the misfires have happened less often and higher up in the powerband. Heat seems to be related too, because they never happen right away. I hope it's the wires because if it isn't it's probably out of my league. Still no CEL, isn't it supposed to come on after one misfire?

which holds true for me too, except that mine happened more often as the car heated up. Also my sparkplugs are only 1000km old.. Could it be the wires?

[Black_Penguin]

I would definitely be looking at leads as well.

[22Silver]

I would definitely be looking at leads as well.

That's actually what I meant when I said wires. Thanks.