Ignition Installation

From: Teddy Wang (f2racer@covad.net)
06/28/2001 07:00 AM

How to Change an FD's Spark Plugs and Wires:
Well I got brave after getting laid off last week and decided to change the spark plug and wires on my 1993 Mazda RX-7.  I'm actually starting to get pretty good at wrenching my rex...  Especially since before this last year that I've spent with 2 rexes, I've not really done too much wrenching and when I have it's on my 1994 Ford Mustang GT which has a 302 and lots of room under the hood which makes most tune-up stuff pretty easy. OK let's get on with the story.  Total time it took for me to get everything apart and put back together was approximately 3 hours.  Probably would have taken me a third the time if I'd done it before.  And it probably would have taken me two to three times longer if not for the great information that I found on Rob Robinette's and Steve Cirian's sites. The only funky tool I needed was a 3/8" flexy head ratchet, and that was for getting the plugs on and off.  There's very little room once you get down to where the plugs actually are and the flexy head will allow you to turn the ratchet more so that you won't have to guess when you've turned the plugs 1/2 turn...
First things first.  Gotta get your plan of attack.  I opened the hood and almost automatically gave up.  Although the info that I found was very helpful, looking a FD's engine bay could make any mechanic cry.  To date, I've done some vacuum tube diagnostics by myself.  I've even removed the stock airbox and gotten down to where the vacuum tubes with the pills are, but that was child's play compared to what I was about to embark on.
The plugs and wires require you to disassemble 3 major components from your automobile.  The intake elbow is fairly straight foward.  The throttle body is a bit more difficult.  And the oil filler neck is pretty straight forward.  First to address the intake elbow.  There's a  hose (air I guess) is connected to the back of the elbow.  This must be disconnected.  Also you've got to disconnect the hose that connects the elbow to the intercooler.  There are 4 x 10mm acorn nuts that hold the intake elbow on.  Remove them and the intake elbow slides off easy.
Next you've gotta prepare the throttle body to be removed.  There are 2 cables which need to be disconnected (one also has a mount that needs to be disconnected from the throttle body) as well as a coolant hose. One cable runs along the intake manifold and is the most evident.  The second goes to the throttle body from the drivers side of the car.  Just push the springs back and release the cables.
The coolant hose is almost directly underneath the throttle body.  As long as you can position the clamp so that you can get pliers on it, you should be all set.  If the hose is really stuck, twist it before trying to pull it off.  Also pulling the hose will result in all the coolant in the throttle body coming draining out.  Be careful of how hard you pull to minimize splashing.  You could also remove the coolant hose at the rear of the throttle body as well, but as you'll see it's unnecessary.
Throttle body removal time.  Remove the 4 x 12mm acorn nuts that hold on the throttle body.  Gently pull the throttle body away from the intake manifold.  Be sure to use care as there's a gasket that sits between these two parts, which you probably want to reuse.  Also use care as when you pull the throttle body off, it's likely to leak some more coolant.  Once the throttle body is off, you should have a little bit of play (if you did not disconnect the rear throttle body coolant hose), use this to rotate the throttle body ontop of the intake manifold.  Be sure to put down a cloth prior to putting the throttle body down.
Remove the oil fill neck.  Mine was held on by 2 x 10mm bolts, but I've heard that some have 3.  You'll have a heck of a time removing the wires if you don't do this.  There are two tubes which connect to the oil fill neck.  Disconnect these.
I'm using Taylor-Vertex custom fit Spiro-Pro wires.  They look a little bit better than the stock NGKs don't they?  I came close to buying MSD wires (which I have on my Mustang), but most people said that they liked the Taylor wires and that the boots were slightly better designed.  Can't believe that they were only $26 from Summit Racing.  They were cheaper than the 4 Platinum plugs I got...
I deinstalled and reinstalled the plugs one by one.  This was to keep my dyslexic self from really screwing up.  I decided on using NGK Platinums (instead of the non) and 7 leading / 9 trailing plugs.  Remember to use a little bit of anti-seize when installing the plugs (on the threads).  I once forgot on a motorcycle that I owned and it was a real bitch removing the plugs.
The prior owner had all non-Platinum's and all trailing (9) heat.  The plugs don't look too bad, but I felt that given the number of performance mods I've got (downpipe and Racing Beat Intake Duct), I'll keep her closer to stock.  When I get my PowerFC, Fluidyne, large SMIC, cat-back, and intake I'll go all 9s. ;)
At this point I took a little break.  I was pretty amazed by all the parts that had been pulled out of my car!  I did my best to wipe off the oil fill neck, throttle body, and intake elbow before the reinstall.  BTW, the black plastic cylinder in the middle of the picture actually has two holes, and it gets put hooked onto the 2 bolts that keep the intake elbow on.  Don't forget this or it'll be swinging around next to your new wires.
The Taylor wires do like nice don't they?  Too bad after she's all beck together you'll never be able to see them again...
Still more back together shots...
Voila!
If ya wanna show friends of your handywork after the fact, get prepared to make them do Yoga to see it.

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As Joe says, it is easy to do the job from below. I have also included posts on how to do it from above, as the shop manual recommends. --Steve

Date: Thu, 6 Nov 1997 11:34:49 -0800
From: jramos@sunup.Corp.Sun.COM (Joe Ramos)

It is very easy to change the plugs from the bottom through the A-arm using a short ratchet.

The following are instructions provided by Racing Beat for installation of the Ultra "Red Hot" ignition wires. I have copied them as provided except in steps 2 through 5 where the size nut they indicate is dif- ferent than that on my parts. I have included their size in [x] im- mediately following what I have. Also, in step 7 I used different length wire than indicated by them. Again, I put their item in [x] after mine.

*********************************************************************

I11510

INSTALLATION INSTRUCTIONS FOR PART NUMBERS 11510 AND 11511

CAUTION: Attempting to perform this installation task with the engine hot will likely lead to burned flesh!

1. Remove the end of the throttle cable from its attachment on the "constant radius" arm, on which it pulls, by holding the arm in the open position and slipping the barrel-shaped end out of its mounting slot.

2. Remove the clamp on the forward end of the rigid tube leading to the throttle body. Remove the (4) four 10mm [6mm] nuts that retain this rigid tube to the throttle body. It is NOT necessary to dis- connect the small hose at the rear of this rigid tube.

3. Remove the (2) two 12mm [8mm] acorn nuts at the top of the throttle body. Slip the cable clamp off of the rear stud, then re-position the rigid tube (loosened in step 2) over the top of the engine, out of the way of the stock ignition wires.

4. Remove the (2) two 12mm [8mm] chrome acorn nuts from the underside of the throttle body. Gently pull the throttle body off of the studs, exercising caution to keep from destroying the gasket. Ro- tate this throttle body unit up, at the front, to expose the igni- tion coil terminals.

5. Now, loosen the (2) two 10mm [6mm] bolts holding the oil filler neck in place, but do not remove them completely.

6. After detaching the (2) two small hoses attached near the filler cap, the upper portion of the oil filler neck must now be pulled away from the "Trailing Number 1" coil wire to allow its removal.

7. Remove the stock wires and replace with the ULTRA 8MM IGNITION WIRES using the following guide:

WE STRONGLY RECOMMEND REPLACING ONE WIRE AT A TIME TO AVOID ERRORS AND POSSIBLY DAMAGING THE ENGINE.!

        The shortest wire supplied - Trailing Number 1 [2] Coil/Plug
        The second shortest wire   - Trailing [Leading] Number 1 [2] 
                                     Coil/Plug
        The second longest wire    - Leading Number 2 Coil/Plug
        The longest wire           - Leading [Trailing] Number 1 Coil/
                                     Plug

        Use the blunt end of a screwdriver to fully push the coil caps
        into place.

8. Reassemble in reverse order.

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Date: Fri, 11 Jun 1999 21:04:52 +0000
From: Gordon Monsen (gmonsen@fast.net)

You need one of those small 2-jointed snap-on rachets to do it, but... i just jack up the front end and do it from underneath the car. if you try to do it from the top, you have to remove way too much stuff. doing it from down below, suing the double-jointed small ractchet, its pretty easy and takes less than half an hour. the only problem is that you do the front leading plug pretty much by feel, since you have to contort yourself a bit to get at it.

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Joe re-posted the above after Dennis' account of his ordeal (below). I thought I would leave Dennis' here as well, since the more info the better. --Steve

Date: Thu, 6 Nov 1997 11:16:00 -0700
From: Dennis S Pedersen

I'm a bit of a do-it-yourselfer, so when I decided that my new-to-me '93 Touring model needed new spark plugs and wires, I didn't hesitate to rush out and buy some to install myself. "Shouldn't be any tougher than a clutch job! A ten-minute project" I thought -- I was wrong! Maybe I missed something obvious to the rest of the world, but I came dangerously close to losing it over this "minor project!"

So on the fateful day designated for the plugs 'n wires project, I pulled out my Mazda shop manual (wouldn't have any other, right?), my tools, and my bright, clean new wires and plugs ready to spend a few rewarding minutes tending to my car's wants. The manual says to remove the old parts one at a time, then install the new parts, torque to specs etc. Sounds easy.

Step 1: pop the hood. That's when I realised I might be in trouble, though exactly _how much_ was still something I could only dimly perceive. I could barely even _see_ the wires and plugs, much less get at them to yank them off. So...

Step 2: remove the duct that goes from the intercooler to the throttle body. Not too difficult, and at least then I could see where everything was. It still took a while for me to track down which wires woven in with the other wires and vacuum and coolant hoses were the wires I'd need to replace. Hmmmm. Maybe a pain, but certainly feasible right?

Step 3: remove old plug and coil wires. I started with the "upper-right" (#2) wire end (where it goes into the coil) since it is the most accessible. I like to remove old parts intact, just in case, so I like to use my hands to remove plug wires. No go here though. I ended up using plyers as I just couldn't get enough purchase in the cramped quarters to remove it properly. Oh well, "move on with your life." The spark plug end was no problemo. The double coil-wires in the center were next, and not too bad either. I just had to make a mental note of how they all went in so I could put everything back in the same configuration.

Step 3 (Again? Yes, I still have more work to do here!): remove left (#1) plug wire from coil. Aaarrrgggghhhhh!!!!!!! There's no way that will ever come out! It is under the throttle body, and jammed up against the back of the oil filler tube. After much grunting and straining (ouch... the back of my knees are starting to get really sore from all this bending over!), I finally managed to have it mostly pulled off, but not enough for removal. So I started tearing away at the boot in order to make enough clearance to pull it out. Still no way. I briefly thought about removing the tube, but then I'd have to pull out the throttly body too to get at the bolts. Too much work for a "minor project." I finally used an extra battery J-bolt as a hook to yank the #1 wire out. Pheww! Looked like a rat gnawed on it (that actually happened to my previous car... 'nother story), but it's out!

Step 4: Remove old plugs: No problem. Except of course there was so little room that my ratchet could barely move enough to turn the socket. I was a little steamed at this point and completely forgot that I own an electric ratchet. Oh well, it probably would've died right then anyway.

Step 5: Install new plugs. Yippeeee! Fun! I coated each one with a touch of anti-sieze and torqued to factory specs. Careful not to confuse the trailing and leading plugs though. I love it when things go that smoothly, and I get such a warm, contented feeling when I use that beautiful torque wrench! (Used the smaller lbs/inch one here.)

Step 6: Install new plug and coil wires. Arrgghhh. That's when I realised that the stupid oil filler tube was still in the way, and there was no way I'd ever get that #1 wire onto the coil with it in place. Deep breath (actually a sigh of resignation).

The _real_ step 6: Remove throttle body and oil filler tube (should have been step 3). Started yanking off the hoses and wires going into the throttle body. Not laughing any more. It's easy to write "yanking off the hoses" but it's never as easy as it sounds when those hoses are five years old and have never been removed from their cramped quarters. And I really didn't want to use plyers on them. So of course that was another major hassle that left my hands with numerous small scars. (I'd long since pulled off my gloves to get better clearance and feel.) But the throttle body finally came off, and, in short order, the oil filler tube! (Then I think I just stood there for a while moaning and staring at the engine compartment... but I don't know for sure as my wife wasn't around to verify this and I can't remember anything during that short period of time. That's not really required for step 6/3, but I couldn't help it.)

Step 7: Install new plug and coil wires. For real this time! Went fairly smoothly too, though the plug ends of the wires don't have a lot of metal for clipping onto the plugs, so I was never sure that they were seated properly. Still, it wasn't too bad.

Step 8: Re-install throttle body and oil filler tube. Not bad.

Step 9: Re-install the duct that goes from the intercooler to the throttle body. Piece of cake.

Step 10: Re-connect all hoses and wires that were supposed to be re-connected in steps 8 and 9, and remove all the tools lying around in the engine compartment. Optional: Retrieve the socket and extension that fell down onto the top of that plastic shroud underneath the engine. Experience brief panic when you fear that you'll have to pull the shroud off in order to find the socket and extension.

Step 11: Start engine and test drive. Re-connect that vacuum hose that was supposed to be re-connected in steps 8, 9 and 10 that is causing your engine to run like a turn-of-the-century farm tractor.

Now enjoy the pride and satisfaction that comes from knowing that you're doing everything you can to make sure your car runs in tip-top shape! And, yes, it _does_ run smoother and stronger with the new plugs and wires.

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Date: Thu, 20 Nov 97 22:15:44 PST
From: John Lockwood

Here is an easy way to remember which wires go to which plugs.

Start counting from the front of the engine to the back. The front rotor is 1, the back rotor is 2.

The TOP plug is T. The LOWER plug is L.

So looking at the plug side of the engine you have.

        T1              T2
        L1              L2

Just a simple tip to make hooking those plug wires back up a snap!

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Date: Mon, 30 Mar 1998 11:45:37 -0800 (PST)
From: Bill Geiger

Installing new plugs and wires is a royal pain. I won't bore you with all the problems I had this weekend, but here are some things to keep in mind if you do this yourself.

• The work shop manual says to change the wires you remove the intake/throttle assembly on top of the engine as one piece (section G i think). Don't try this because there are about 20 hose/wires that need to be removed, some of which are very difficult to get to. Do following the steps in the ENGINE section to remove this assembly. Keep track of where the hoses and wires you disconnect come from!
• It's easier to disconnect the plug wires from the ingition coils if you remove the coils first. It's also easier to first firmly connect the new wires to the coils, and then reinstall them.
• Have patience when removing the old plugs. You don't have a lot of room to work with, so you just have to take your time. Some of the plugs are easier to get to from the bottom.
• Be sure you reconnect all the hoses to the right places.

The results:

My old plugs were 33k miles old. I didn't realize how rough the engine ran until now. The engine is noticably smoother. I certainly won't wait 33k miles to change plugs again (although I may never do the wires again!)

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Date: Fri, 31 Jul 1998 18:29:02 -0400
From: "Houseman, Carl W. x1323"

To access the coils, you need to remove the throttle body and oil filler tube but not the extension manifold (that big aluminum thing). The TB has 2 water lines, be prepared to plug them ASAP when you pull them off. Draining the coolant isn't really necessary.

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Date: Mon, 3 Aug 1998 03:40:39 -0500
From: Pat

Ok, well I spent Sat. afternoon changing the plugs and wires on my '94 Touring. All told it took me 6 hours of fumbling and three trips to Auto Zone. But I think I (or you) could do it again in 2 hours with the right info).

The info I found on the web really wasn't very helpful. I've started to write up a more detailed description of the process to put on the web... but pictures would really help with that and I've discovered that drawing from memory is harder than I'd thought.

I'll summarize the important stuff in this email.

You need:

Replacement plugs -
    I got mine from my Mazda dealer
    cost: 4 plugs (2 leading, 2 trailing) about $32

Replacement wires -
    I used Magnecor 10mm wires per someone's recommendation
    cost: ordered from Mazdatrix about $50

- - 10mm wratchet with about a 2+ inch extension.
- - 10mm crescent wrench (for one hard job)
- - A wire coat hanger (very important!)
- - Plyers
- - Phillips and a flat head screw drivers
- - Possibly a vise grip plyers
- - A light of some kind
- - Some towels to wipe grease off your hands and help you grip and turn 
   loosened bolts.

Cutting to the chase, here's what I found:

You can change the plugs and wires from the top of the car by removing the rigid air intake tube and by loosening (but not completely removing) the oil filler tube. There are a couple of things that require some creativity, but nothing impossible.

Important tip - Make a flat hook with the coat hanger and use it to pull off the coil end boots of the wires. With the coat hanger it's easy, without it's impossible.

Now, the oil filler tube is your enemy... you must defeat it.

The oil filler tube has *three* bolts (not two as one FAQ noted). The first is obvious. The 2nd one corresponds and it is a major pain, as it's behind the tube itself. It seems impossible at first, but you can get it if you remove two center coil plugs first. I think you also may want to disconnect an electrical connector for a cable that's in the way. With the coil plugs removed you have room to get the 10mm crescent wrench back there and one painful notch at a time loosen the bolt. I would *not* remove this one all the way... it's not necessary.

The third bold is a 10mm that's to the left of the other two and under the main body of the oil filler. You can't see it, but you can feel it. You can see the welded nut on the opposite side... (for a while I thought *that* was the one I had to reach... Ug!) Use a 10mm wrachet on an extension... If you can't get the whole wratchet in there (steering fluid hose in the way) then try putting just the extension on and using the vise grip to loosen the bolt. Don't take it off... just loosen everything so that you can pull the oil filler body away from the #1 plug coil by an inch or so... enough to weasel off the plug and get another one on. Note: you won't really have enough room, but you can do it.

My Magnecor info says to "burp" the wire boots using a coat hanger, but I had no success with this... hard to tell if it was working. I have to say that I was not thrilled with how the boots for all the wires fit. They didn't seem as snug as the stock ones (but maybe after 15K miles they will?)

It also helped to remove the oil filter to get to the #4 coil boot.

Oh, and the two ostensible plug/coil wire maps that I found on the other instruction web site were completely useless: one contained no info and the other was incomprehensibly muddled. For the record, here it is (the numbers are arbitrary - just match them):

            coil 1     coil 2      coil4

                       coil 3

  (trailing) plug 1                plug 4 (trailing)

  (leading)  plug 2                plug 3 (leading)

I think that's it.

My symptoms were jerking / weak under WOT over the top half of the rev range. The new wires/plugs seem to have fixed the problem.

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Date: Mon, 3 Aug 1998 12:57:56 -0600
From: David Beale

To make the boots slip on and off easier, I spray them with 7% (the good stuff) silicone spray before putting them on. It's good for the boots, repells water, and makes the job MUCH easier. Course if you get too much on the outside of the boots they will be slippery.

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Date: Mon, 3 Aug 1998 18:02:58 -0700
From: "Derek Vanditmars"

The only thing I can add, is that instead of removing the oil filler pipe, I removed the coil to remove/re-attach the plug wire to. The coil seemed like a better choice for me.

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Date: Sat, 9 Jan 1999 10:58:00 -0800
From: "Derek Vanditmars" (dvandit@istar.ca)

>Can somebody please tell me what the factory specs are for tightening the
>spark plugs.

Page G-18 of the good book says, 13-17 N*m {1.3-1.8 kgf*m, 9.5-13 ft*lbf}

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Date: Mon, 15 Mar 1999 12:07:38 -0600
From: "Stover, Steve" (Steve.Stover@ies.msfc.nasa.gov)

Editor's comment: Steve's note is an add-on for Rob's instructions. --Steve

Here are a couple things you may want to footnote with the instructions. Or maybe not... :-)

Step 3 - I removed the bolt holding the boost control bracket, which made swinging the rigid tube over the top of the engine a lot easier.

Step 4 - To remove the throttle body I HAD to disconnect the coolant hose directly below the throttle body. A definite pain to get off and on.

Step 5 - I had to move the filler neck to remove the front plug wire. On my car there is a 3rd bolt holding the filler neck in place, under the horizontal part of the removable neck. Another pain to get to. Since I had all the bolts loose I figured I might as well remove the neck completely. It did make access easier, but when I went to bolt it back on I couldn't get the rear vertical bolt to line up and start threading. I had to remove a coil wire to get the bolt started. Then the wire was interesting to put back on. Hmm, which came first, the wire or the bolt???

Step 8 - I was VERY careful removing the throttle body to try and keep from breaking the gasket. The gasket looked fine till I was putting the throttle body back on, when it tore. Next time I will set the gasket aside while working, and place it on the intake side when putting it together. On the bright side, the broken gasket hasn't affected the idle much more than 50 RPM, and that might just be the colder weather today. So I guess I'll drive it until the new gasket gets here.

BTW, the best tool I've gotten in a long time is a hose remover. Like a reverse pliers, squeeze the handle and the thin V-notched jaws separate. I think it's a MAC tool. Makes removing a lot of fuel lines, ect a lot easier.

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Date: Mon, 15 Mar 1999 14:03:30 -0500
From: skight@enterprise.reliacom.com

There is a newer revision of the throttle body gasket. All metal design. The rip you have will get worse as it works its way loose over time.

I would suggest going to get the new one, I think it was 18 dollars at the dealership.

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Date: Mon, 10 May 1999 23:16:48 -0400
From: Sandy Linthicum (sandy_linthicum@mindspring.com)

Do it from the top & get the proper tools. Stubby socket wrench with swivel head & deep socket sparkplug socket (not with the rubber stuff to hold the plug). Break it loose and once started, remove by had. Screw in new plug by hand and then tighten. USE ANTISEEZE on all plug treads. Do one plug at a time (impossible to get the wire confused this way)

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Spencer Hutchings used White Out dots to idiot-proof the plug wire repalcement process:

Date: Thu, 18 Dec 97 13:40:37 -0500
From: "Kyle Krutilek" (kekr@lubrizol.com)

I recently had a Hi-6 installed in my 94 R2 and I love it. I strongly considered the Jacobs given the sales pitch from both Jacobs and Rotary Performance, however, I am now so glad that I went Hi-6. I have sent some private e-mails to others on this subject but have not posted to the list yet. I think its time. What I have attached to this note is relevant copy of several messages ...

Date: Mon, 3 Apr 2000 14:02:54 -0400
From: "Karagiannis, Demetrios Mr ODCSINT/GD" (Demetrios.Karagiannis@hqda.army.mil)
Subject: RE: (rx7) [3] Testing Ignition Coils

>...I would test the ignition coils.  The shop manual says that the
>resistance across the terminals should be "UNDER 1 Ohm" to be within spec.
>I measured exactly 1.0 Ohm resistance for both of my trailing coils.  The
>leading coil was 0.6 Ohms.  Since I measured 1.0 Ohm on both the leading
>coils, they are technically out of spec, but juuuuusst barely.  I'd hate to
>replace the coils if there is no need to do so. Does anyone have any
>experience with this?  Should I replace them or not?  Any opinions?

That is funny I just did it yesterday. But you have to remember to minus the resistance of the leads for the meter. For example if you touch your meters leads together and get .4 you need to minus that from you reading because you want the resistance of just the coil not the coil and the leads from your meter.

Date: Tue, 20 Mar 2001 21:41:42 -0500 (EST)
From: Shane Baker (sbaker@null.net)