Hi all. I had a fuel leak a while back and fixed that and a big vac leak. Car was running perfect. Idle at 850 and ran smooth all the way up to red line.
I went for a short slow drive around town and the engine started to run real ruff and had no power. Limped it home and checked the timing.
You should have spark on all the wires coming from the ignitors with an inductive timing light,right? Well the ignitor nearest the drivers seat has no spark going to the trailing plug. And the ignitor in the front of the engine compartment has no spark to the leading plug.
Can somebody tell me whats going on and give a wiring diagram to make sure the spark plug wires are routed correctly. I haven't had them off so I don't think they would be on the wrong plugs.

 

Check the plugs to see if they are fouled. Check the ohms of the plug wires. The leading coil (located near the battery) can have the plug wires switched to the rotors and it doesn't change a thing. The trailing coil (closest to the firewall) needs to be wired properly though). When looking at the coil from the driver's side fender the plug wire on the left goes to the front rotor thus the plug wire on the right goes to the rear rotor. (And leading is lower while trailing is on top).

If the lead coil fires for one plug then it should fire to both plugs thus this is why the wires and plugs would need to be checked out.

 

Would that cause no light from an inductive timing light?

 

I just checked the wires. They are between 6.5K ohms and 8.2.

 

Pulled the plugs and they are a little dirty. Gonna go get new ones and will check back in a bout 2 hours.

 

Changed the plugs after 5 parts places to find the leading plugs and it still runs the same. It sounds like it's running on one rotor. How do you confirm that?
With the timing light I'm getting spark on all four plugs now.

 

I believe those are good numbers.


You could also pull the plug wire off of the coil bores at the lead coil and place the plug wires right near the coil bores to where there is just a fraction of an inch between the plug wire and the bore and w/key to start see if there is a spark at both bores.

 

Could possibly be a compression issue or a lack of fuel. While idling, only the primary injectors are working.

 

It idles like crap to. Hear a grinding noise. Don't know what it is.

 

I'm going to pull the leading coil wires and watch for spark like you said.

 

OK I pulled the leading and trailing wires from the coil and tested them one at a time. Massive spark from all four. Whats next?

 

It's never a good thing to hear and you shouldn't be running the engine in such a situation. You'll need to get advice from someone more familiar w/the grinding you hear, but you could at least do a compression test.

 

OK I'll do a compression test. Gotta go buy a gauge since I loaned mine to a friend, he moved and never returned it.

 

So I got a compression gauge today and I going to test compression Saturday. Do you need to remove all the plugs or one at a time during the test? And disconnect the fuel pump?

 

https://www.rx7club.com/2nd-generati...est-fc-980440/

 

Pull the EGI fuse so the ECU doesn't work thus no fuel delivery or spark.

 

Thank you.

 

Did a compression test today. 135PSI in the front and 50 PSI in the back. Toast I think?

 

Toast.

 

Anybody want to buy a slightly used 87FC with a perfect body with newer paint. Sunroof was replaced last year and many other new parts. Car runs , just like crap because of the back rotor. Getting tired of this.