no spark on trailing plugs

[njkid]

Just put in a JDM 13B motor in my son's 1993 RX7. Had some problems I have fixed except both trailing spark plugs don't fire as it is idling. The car sounds like it is not firing on all plugs and after doing the check for a spark at the boot that connects to plug, I found the problem. Both lead plugs fire but both trailing plugs do not. Connectors on coils are on and spark plug wires are good. Being the coil packs for each trailing plug are seperate, what is common between them that would cause them both not to fire? This car has been a winter project but my son and I are ready to kill each other. We have had enough and want to get this thing back on the road again. I do have the factory manual but it has not helped me yet. There seems to be alot of special tools you need to check alot of stuff. I know there is an igniter box that seems to feed the coils. Is there a way to check things with a basic digital meter?

[drftk1d]

maybe you switched leading and trailing plugs?

[njkid]

Originally Posted by drftk1d

maybe you switched leading and trailing plugs?

Even if they were switched should I still not get an ark at the boot by the plug when I bring it close to a ground? Here is the crazy part. The motor was replaced because it had over heated and combustion chamber was pressurizing the cooloing system thru a bad seal in the water jacket. Otherwise the motor ran strong. When we pulled the trailing plugs from the original motor they were like new and the lead plugs had carbon buildup from firing. I thought this was normal as this is our first rotory. We had to swap over alot of stuff from the original motor to the JDM motor because of differences. When we fired up the JDM motor it sounded like it was not firing on all plugs which lead me to check the spark. I don't think the original motors trail plugs were firing because they were so clean, but how come it ran strong with only the lead plugs firing. Is this possible? I might have swapped over bad coils, but 2 of them?? Seems odd that 2 coils would go bad at the same time. I am going to try and find another igniter pack and put that in. Evidently I need the special SST box to check the igniter box. The crank angle sensors are the ones that came with the JDM motor and should be good. I should see all 4 plugs with some carbon build up if they were firing? Right? I think I brought a problem over from the original motor.

[drftk1d]

i just thought, is your tachometer working? because it would not work without the trailing plugs firing.

[tubjub]

i have a non-working tachometer... and my trailing plugs are firing.... so... what's up /w that ?

[njkid]

Just to update situation. I found 2 wires that were cut that went to the igniter box. This car never did run on all 4 plugs. When my son bought the car it ran for a few days before we realized the severity of the antifreeze leaking out. Supposedly this car had its engine rebuilt by a company in PA that uses blue vacuum lines when they do their job. I am not mentioning any names. I called the guy my son bought the car from and he knew nothing about the 2 wires that were cut and said what ever the rebuild company did was the reason. Those 2 wires were signals to each of the trailing plugs. The tach was still working on the car so maybe one of the replys to my problem about the tach not working if no trailing spark applies to other RX7 years. Mine is a 1993. Bottom line is that my son got beat in this purchase which I knew right from the beginning. He did not listen to his dad and just fell in love with the car and did not check it out properly. Of course when us dad's were young we never would have done any thing like this. After correcting a vacuum leak the car now purrs. Thanks for the input guys!!!

[drftk1d]

good stuff.

PICS!!!