I was checking the timing today and get no pulse on the trailing coil. So i disconnected the leads and checked for spark. I get spark on the trailing wires for about 2 sec then nothing.. What can be the problem.. My tach is working. Also i checked for power to the trailing coil and it's getting 12V while running. I have a S5 N/A vert

 

Bump

 

Can it be the ECU?

 

While car is at ildle, disconnect the leading igniter. If trailing plugs are firing, car will keep running although a little lower idle. If they aren't the car will die. If it dies, replace the plugs and give it a try. You can even pull a trailing plug wire off at idle, and notice a change in smoothness. Some say the timing won't work properly on the trailing at times, but there were a lot of problems with the trailing plugs on the S4.
Replace the plugs to be certain.

 

I tried all that and no spark coming from trailing wires. I even put a spark plug on the end and got spark for 1-2 seconds. I ohm checked the CAS and that checks good. I might stab a ecu in to see if it fixes the prob..

 

the spark is only getting to the plugs for 1-2 sec.. And they are brand new..

 

trailing coil is working if the tach is... How are you checking for spark??? Inductive or ???

 

I am pulling the plug wire off and placing it near a ground.. It will spark for 1-2 sec then stop. I check for power at coil and it's good.. tach works.. Also timing light will not work on traing wires. This is so weird

 

Just swapped in another ECU. Same problem. Can the CAS be bad?

 

I think your test is very suspect, and that you are overheating or shorting the coil with it. The coil is not designed to create a spark to jump more than about a .40 gap.

You need to be hooking it up to the engine and a spark plug in the engine and use an inductive light or tach to check.

Toss in the fact that the tach on the dash is working and every thing points to the coil working fine

 

I hooked up a timing light and nothing on the trailing wires.. I tried the spark check on a friends S5 N/A and he has continuous spark on trailing. Can the CAS be bad?

 

Ok did some more research on it. I have a jumper wire on the leading coil test connector connected to the trailing coil test connector and the tach works. If I disconnect the jumper wire the tach doen't work.. What wire on the trailing coil goes to the tach? I have power at both blk/yell wires going to the trailing coils while the car is running and with just ignition on.... Does anyone have a wiring diagram for a S5? All I see is a S4 diagram..

 

Not unless the leading coil was not fireing as well

 

Coils are wired the same regardless of series.

 

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

 

If i disconnect the jumper wire from the leading test lead to the trailing test lead I get no tach.. If it's connected the tach works. Also I'm getting 12V on both blk/yellow wires to both coils.. What does the four prong plug on the trailing coil go to?

 

https://www.rx7club.com/attachment.p...chmentid=31216

That jpg shows all the wires from the plugs on the Trail and Lead coils.

 

What do you think i should check first? Also what control does the 4 prong connector go to on the car? The diagram is cut off at that control box. Is it the ECU? I think it goes through the dash harness right?

 

Three go to the pins 1X, IU and 1M. the third goes to the black bullet connector near the trail coil to be used for a auxillary tach/diognostic/whatever.

Those three wires are explained in the first url I attached several posts up from this one. Or ECU controlled if you will. http://www.teamfc3s.org/info/articles/demystifying.html

One wire is for triggering the trail ignitor.....one is for Selecting which coil to trigger......the third is a Feedback signal. Just pull the ECU plug off and ring the wires from point to point to see if the wiring is intact.

That is for a series four car. The series five works the same. I don't know the color of the series five wiring. FSM can be bought from Mazdatrix for a low cost.

 

Ok cool. I will do a ohm check from point to point to see if a wire is broken.. Thanks

 

I did a point to point ohm check and all 4 wires are good. three of the wires go to the ecu and the other to the instrument cluster (tach signal). Still no trailing spark.. When you swap ECU's out all i do is disconnect battery right? Can anyone help me try to figure this thing out....

 

I can't figure out what's wrong. Only thing i can think of is the dash harness plug pins at the ecu are recessing when plugged in. I'll check a good running S5 and see what voltage the plug gets at each wire while running and test mine to see if it's the same.. Lke I said before when i crank it I get spark for 1-2 sec then stops. I would think the wiring would be good if this is happening. Is their a relay in the curcuit?

 

My guess is that your igniter is crook and thats why your tacho works. I would suspect that the coil drivers have died. I would interchange the trailing coils with known good ones. Then swap the ignitor if the problem persists. This proves both of these as good or bad. If you still have a problem you need to check you wiring of the trailing select signal as your tacho working means trailing timing signal is getting to the ignitor.
Michael Smith

 

I swapped trailing coils.. My tach only works when i hook up the test connector on both the leading and trailing coils together. I think that test connector is for a another rpm device..

 

What should i check next