dre_2ooo

I just adjusted my ignition timing so it's dead on. WOW! The torque is alot more noticable (the little bit i have, anyways).

BUT, the TRAILING wire only got the timing light to flash like 30% of the time, however, the leadind wire was really fast bright nice stobe action.

HHMm.... its not a problem with the light, so how come the trailing only fires some of the time... could it be the coil itself?? I thought there was an error codefor that ?????

BTW i just put new plugs in last year with the new engine...

Anyone know the reason??? Wires??

Any help is appreciated.

Wankel7

To my knowledge the leading coil will fire more than the trailing. For each pass of a rotor face the leading fires twice while the trailing fires once. So for each rev of the rotor the leading has fired six times while the trailing fired three times.

That maybe it

James

SpeedRacer

Yep, thats why. Leading plug fires twice as often as the trailing.

dre_2ooo

really???? THANKS!

tweaked

iTrader: (4)

does any one know why.
also, is there a way to use an msd box or something and make them fire everytime.
I was thinking that the crank angle sensor has two leads coming out of it. wire up a leading coil in place of the trailing coil just like the leading is from that one lead. then you connect the MSD and presto. you fire everytime and possible make more power from a more complete fuel burn.

Sniper_X

There is a ingenious reason this is this way.

It makes the computer less expensive to make...
Fires twice as much because it cost too much to make it fir only once, no harm no foul...

No pun intended...

Read this, really! (15 minutes)

http://www.teamfc3s.org/info/articles/demystifying.html

Sniper_X
Always Tinkering

HAILERS

DRE_2000.......You left me wondering. When you are on trail number one and have the light aimed at the marks on the pulley, is the light flashing consistently, or does it flash and the maybe a long pause of no flashing followed with the light flahing? It should be flashing consistently and at the same rate. What I got out of your post was that the light when put on the trail plugs, was not showing it to be firing all the time.

akageals

My car does the same thing....sometimes there are long pauses with no flashing. I was told by some of the experts on the list that this is normal if you use an inductive light. I have forgotten the reason why.

Todd

SpeedRacer

http://www.rotaryengineillustrated.c...nition101.html

dre_2ooo

YES, that is exatcly what happens, it just pauses for a while.

IT's an inductive (i think) light, it has 2 clips that goto the battery ( + & -) and a box end clip that goes around the plug wire, that's it.

Do i have a problem then?

dre_2ooo

Hailers!!???

Anyone??
^ Bumpy McBump ^

Don Hammond

The trailing plugs fire consistently following the leading plugs. In fact, to test the trailing plugs, you can disconnect the leading igniter and the engine should still idle, although a little lower RPM on the trailing.
My '88 TurboII which I purchased new had a trailing plug problem, which I won't go into great detail now, but Mazda bought back & I recieved an '89 for a very small difference. A great number of people use a snap-on, highly sensitive timing light, which will flash even if there's a very small amount of voltage in the wires, but the plugs are not firing.
An inductive light is the way to go. It should flash consistently with the leading. If you think there is a problem, keep the light connected to the trailing wire, and ground same....You'll see the light flash all the time!

Felix Wankel

The leading uses wasted spark, so that L1 and L2 fire simultaneously. If you were to do this with the trailing plugs, you'd likely break something as the apex seals are in a bad place (right in front of the trailing plug hole) to use wasted spark on the trailing side

Don Hammond

Leading 1 & 2 do not fire @ the same time. If they were to fire @ the same time, the rotors would need to be in identical rotation with one another, and this is not the case, wheather 2 or 3 rotor. Also they fire 1 time and the trailing plugs fire 15 degrees later to complete the combustion process a/c chamber size.

HAILERS

DRE-2OOO I don't think you really have a problem. Next time you try the trailing plug, put the clamp(clip) that goes around the wire close to where it goes into the coil instead of at the plug and see if there is a difference. Also if you get those long pauses, try holding the clamp that goes around the wire at a slightly different angle.
To have some faith that they are indeed firing you could do what Hammond said and disconnect the Lead coils by pulling that little white connector off, and starting the car. Like he said, the car will run without the leads and vice versa. Just not recommended for any period of time.

Keith

Hey Don,

You are correct, the front and rear rotors are at their firing point 180 degrees of crankshaft rotation from each other. However, the plugs for both rotors do fire at the same time. Just take a look at the leading coil - it is a coil, singular, not 2 coils. If you take the plastic cover off on top of the ignitor, you will see only 2 wires, 12 volts and trigger. This trigger will occur every 180 degrees of crankshaft rotation, at which time one or the other rotor will be ready for it - the other rotor will be fully decompressed, and for it the spark is wasted (if you have a good timing light, the leading mark will appear to have a line through it, for those times when it fires on the opposite end of the pulley). Don't take my word for it, try these simple tests.
First, swap wires (L1 wire on L2 plug, L2 wire on L1 plug. Very easy to do at the coil.). It will run exactly the same.
Second, remove a leading plug wire - doesn't matter which one. See if the other plug has spark. It won't, you need both plugs hooked up to complete the circuit on the single coil.
Don't feel bad, when I got my first FC, I thought the wires were crossed (After all, those big coils in the back had to be for leading, not that puny thing in the front!). Then I spent almost a month trying to figure out how in the heck the 2 coils in that case got power (After all, both of those wires connected to the coil had to be trigger wires!?).
Have fun all!

Irv, Keith's dad

Don Hammond

Irv-Good morning-I agree with your assessment. I didn't make myself clear. The leading plugs fire only once, I should have added to be precise, on each rotor face during the combustion cycle, but each fires 6 times in 1 revolution. If you connect a timing light to either leading plug wire you will see this. The trailing plugs fire independently. Thanks.

Don Hammond

Here's something to add:
Make: MAZDA Model: RX7 Year: 1987

Service Bulletin Number: G-001/90 Bulletin Sequence Number: 025 Date of Bulletin: 06/90

NHTSA Item Number: SB014429
Component: ELECTRICAL SYSTEM:IGNITION
Summary:
TIMING LIGHT MALFUNCTION-ON DLI SYSTEM DISCHARGE FROM IGNITION COIL IS BIPOLAR O NE SIDE IS (-VE)OTHER (+VE)-THEREFORE IF TIMING LIGHT DESIGNED TO MEET DISCHARGE FROM(-VE)TERMINAL, ONLY IT WILL NOT LIGHT OR WORKS INTERMITTENTLY AT (+VE)TERMIN AL-THIS IS PROBLEM W/DESIGN OF TIMING LIGHT-CHECK TIMING LIGHT, IF IT LIGHTS COR RECTLY ON EACH CYLINDER-LIGHT SHOULD WORK FROM EITHER(+VE)OR(-VE) SIDE-IF LIGHTS CORRECTLY, IT CAN BE USED ON DLI SYTEM-IF IT DOES NOT LIGHT CORRECTLY, DON'T USE IT ON DLI SYSTEM-ALL 1986-90 MAZDA RX7 AND 1990 MIATA W/DLI PM

HAILERS

Soooooo.....D.HAMMOND, me and dre_2ooo have timing lites that are not compatable with the rx7??? Because when on the trail we get long pauses?????What lite is compatable? I think I'll just keep what I have for timing purposes. Works just fine for that purpose. Thanks for looking up that bulletin though.

dre_2ooo

Cool, never even knew about that service bulletin.

Maybe if we get all this stuff figured out solid, then we can put it in the archive if the question ever comes up again...

von

Can someone tell me if the first rotor number one is te rotor closest to the radiator or fan... the 2 rotor is closest to the driver...????right???

Barwick

actually the leading and trailing would BOTH fire all at the same time if they could, just that if the (leading?) fired all the time, it could accidentally light the air/fuel mixture at the wrong time, and bad things happen then.. the leading firing (every?) time is called the "waste spark" I believe