ok here is the deal i have an 87 TII. i am not getting any spark from either the trailing or leading coils. i have checked for voltage from the black and yellow wire and it has power. i have checked the fuses and the relay and they are also fine. i have replaced the coils and they still wont spark. i pulled the CAS and turned it counter clockwise to see if that would create a spark but still nothing. The car has not run since i had my last problem which was my egi comp fuse was blowing and this was due to a wire being grounded out. i fixed that and now i am not getting any spark. If Hailers or anyone else can help me i would really appreciate it. I am in So. Cal and you can e-mail me or reply with another post.
fc3stom@hotmail.com
(714)931-8585

 

Oooops. That's sad. If the 12v is there on the little white plug, then the only other thing it takes to make the spark is the TRIGGER SIGNAL from the ECU.

One trait of a failed(blown) ECU is that there is no REF voltage present. So go to your boost/pressure sensor. Take the plug off and get your meter on the brown/red wire and turn the key to ON, not start ... You should have a reference voltage of about 4-5volts. Write back. I'm open to any other ideas. I'll think on it. The cas plug is connected?? Yes, of course.

Hey, when you go to start the engine, does the tach needle sort of bump up a bit. Say half a needle width?? And fall back down? Probably not.

EDIT: The trigger signal is that other wire along side the black/yellow wire.

Make sure all three plugs are on the ECU.

Jpg of the coils : https://www.rx7club.com/forum/attach...postid=1398836 the trigger signal on the lead coil assy is the GY wire.

You could ring out the wires for the cas using this jpg: https://www.rx7club.com/forum/attach...&postid=580160 the crankangle sensor is show to the far right of the jpg. Go to the ECU and ring from N to P and T to Q on the harness side of the ECU

The plugs at the ECU are like this picture looking into the back of the plugs with them connected: https://www.rx7club.com/forum/attach...postid=1291996

 

I bet the ECU got fried.. I have an extra I will sell you if needed.

Jarrett

 

Just to clarify. I did not mean to imply the boost/pressure sensor is bad. Its just that that is an easy place to see if the ECU has a reference voltage to put out. A number of items use the reference voltage like the tps and I'm convinced the trigger for the coils uses that same 4-5 volts to fire the coils. So if it ain't there at the pressure/boost wire, it probably ain't there at the item that fires the coils.

 

And or you can go to this page https://www.rx7club.com/forum/attach...&postid=532724

and this page: https://www.rx7club.com/forum/attach...&postid=532728

and this page: https://www.rx7club.com/forum/attach...postid=1291996

and turn you key to ON, and put a meter lead up the backside of each pin of the ECU and compare the results that are shown on the pages with the key to ON.

I kinda think its the ECU. But I think the lack of a reference voltage would clinch it.