trailing ignition
 

I have done some recent work on my '90' GTU.

Here is my problem relating to the relevant recent work:

I was experiencing some misfiring while accelerating uphils, usually prior to the secondaries openning up. I replaced the plugs and plug wires. I also found that the small diaphram which controls the secondaries in the throtlebody to be bad. I replaced that as well.

All is better however during cold starts it surges at idle until it warms up. Also, the "check engine" light is on whenever I let my foot off the gas. I tried resetting the check engine light according to diagnostics but it still comes on. The code it gives relates to not getting a trailing ignition signal however the trailing ignition seems to be firing. All wires are plugged in to their correct respective plugs.


Help!

To clerify, the original problem was; cutting out under loads during rapid acceleration. Usually above 3.5k rpm's up until the secondaries kick in usually around 5.5k. Since replacing the diaphram on the throttle body I have better low end power, but still have the cutting out. Now it surges when it is cold, engine light is on when I take my foot off the gas..

I have been searching this forum for other similair problems and found some similarities. I am currently investigating timming issues . . The trailing ignition is highly suspect, especially since that is what the diagnostic error code indicates.

Any input would be greately appreciated

I have a k&n aircleaner in a modified, drilled out stock housing. A header and 3in. custom exhaust splitting into a Y shortly after the cat. Magnaflow straight through race pipes. I have had the car since '93' when it had only 17.5k miles on it. I now have 153k miles. Over the years I have replaced alot of parts on it. Done alot of work. usually using OEM parts from the factory.

The 02 sensor is connected to the header(not sure what kind of header it is, the mechanic said it is a long race type). I do have the stock cat; not sure if it is doing anything. Last time I looked in it, it looked gutted :fawk: . For some reason it passes smog.. Planning on replacing it soon with a high flow.

is the tach on the dash working correctly?

Yes.

Thanks for the reply.

I am not a mechanic. Oh, it hurts!

I used to have a good RX7 mechanic but he retired. I think I found a sharp mechanic, but I don't think this problem is vary common.

I sent them links to

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

and

https://www.rx7club.com/showthread.p...iling+ignition

I won't let anyone "guess" and expiriment on my car so I am doing the research. Sort of self teaching myself all this. I don't have any diagnostics equipment. No shop...

I know I suck because I can't tune it.

I am afraid the trailing plugs are way out of timming. I am thinking about disconnecting the plug wires at the trailing coil for now so just the leadings are firing. I have been poring over the threads on "trailing ignition" and understand why Mazda has leading and trailing, but I also don't want to crack a rotar or mess up a seal. (make shift solution for now..)

Again; the "check engine" light is on at idle(surges at idle) or when I stop giving it gas. It cuts out during acceleration under load; uphills etc...

The mechanic told me the diagnostic error was something to the effect of "trailing plugs not getting signal/not firing..." He said there firing.

I have new NGK's. New plug wires. replaced the diaphram on the trottle body. I just need someone to help me time this thing which will fix it, or I can move on to another hypothiosis.

The tach runs off the trailing coils, so if it's working right, then most likely so is the trailing coil.

yep, that's exactly right My5ABaby and why I asked it.

The signal to the ECU from the trailing coils is the same signal that the tach in the dash uses. So if the tach in the dash is working fine, then the trailing coils are working fine.

So your next step will be going to the ECU and checking that same signal there.

:icon_tup: I was just translating. :)

The tach works with the trailing coil T1 and T2 disconnected. It still surges at idle while cold and the engine light is still on unless I'm giving it gas. I re connected the trailing. It sounds healthier with trailings connected. I was just ruling it out.

Surging is a clear sign of either TPS bad or out of adjustment or the timing is way off.

And the tach will not work if the trailing coils are not connectioned. Perhaps you mean if the trailing coils are not attached to the spark plug cables but still connected to power and the ignitor assembly

If your going down the road and the trailing coils are misfiring will you notice it??? I didnt figure you would since there not the primary source of ignition, but my car misses hard and my tach goes to almost 0 then jumps back up everytime it does it so does this mean I have a problem with my trailing coil???