Yay first post! Been lurking for a bit and first off want to say thanks for the great info on this site.

Now, on to my issue. I bought my first RX-7 a few weeks ago and have been loving it so far, except for a slight hesitation issue. Might come back to that later, but in my troubleshooting/fixing of things I did something bad I think. Car is an 89 TII with a JDM S5 swap.

I was adjusting timing and got everything in spec, idle was a little high during the test but I thought I would try it out and see what happens. Adjusted the CAS and tightened it down, went driving around the block a few times and it seemed pretty much the same as before. On my last little bit of test drive I was in second gear and punched it about 90% throttle, and it was running fine. Pushed the pedal to the floor and all of the sudden the car immediately bogged down and lost all power. It didnt backfire or make any scary noises, just bogged completely and wanted to die if I didnt give it a ton of gas. It sounded like an entire rotor was not giving power, like a piston engine running short on cylinders.

It limped back to the house where it died. Tried for a long time to get it started and finally got it to run but it was no where near idling and required constant gas to stay running. Same one-rotor thing going on, really rough and the motor was shaking bad. Also, it wouldnt generate any boost, gauge would go to <1psi and stop there. Vacuum also seemed less than normal. I checked for loose couplers and vacuum leaks but didnt find anything, and something causing this much of an issue would be pretty freakin obvious I think.

Anyways, just curious what I could have done and if anyone could offer suggestions on what to check out. I ran a test light on the plug wires and one wire in particular seemed really sporadic with spark, I believe it was L2. The trailing plugs looked to be firing fine.

Thanks in advance for the help, I really could use some about now

 

In most cases the used turbo motors from japan are begging for a rebuild asap. First off, sounds like a fuel issue possibly. Check your fuel system, injectors for cleaning etc etc. You might be on the verge of flooding, you'll know when its turning over but not firing. If you don't already know about this procedure here it's.

Pull the egi fuse (red, engine bay fuse box), turn the key and hold it for 5-10 seconds, put the egi fuse back in and start the car.

 

I did this a few times and it didnt help to get it started, although I did eventually get it started and running (albeit poorly). Now that it starts and runs the missing and skipping of the engine has me really worried. I guess it could maybe need a rebuild, although the motor has under 55,000 miles on it and compression checked out fine. Im going to do another compression check and see what comes up now that it has issues.

 

I hooked a timing light to each plug wire and it looks like both L1 and T1 are randomly missing spark. L2 and T2 and firing like you would expect, but the rotor 1 plugs are missing fires and kinda sporadic.

I pulled all 4 plugs and they had lots of carbon build up, but they always did on this car so nothing out of the ordinary there. I cleaned them up and put em back in, took the car for a short drive and pulled them again, they werent wet or carboned up after a short trip.

 

so you did a compression check AFTER this occured?? and it came out fine?

 

Do a quick&dirty compression test...
REMOVE EGI fuse in engine bay.
Remove top two TRAILING spark plugs.
Hit the starter for 5 seconds.

Do all the PSSST's sound the same?


-Ted

 

My 12A did this when an igniter went bad, I would go to a junk yard and pick up another leading coilpack with igniter.

 

Haven't done a true compression test yet but just ran the down n' dirty method and it sounded good. All the compressions sounded uniform and strong.

One thing I noticed was the rotor 1 trailing plug was wet with gas and had NO new carbon deposits, whereas the rotor 2 plug was dry and had new carbon since I cleaned them earlier. This corresponds to the L1 and T1 wires having sporadic spark and what not...

Like I said I am new to rotaries, but would anything cause one rotor to lose spark? The leading and trailing plugs share a coil each so it doesnt add up to me.

BTW thanks for the help so far, hopefully I can get to the bottom of this quick.

 

Going to get new plugs and HT wires tomorrow just to be safe, I dont think it is the issue though. Any ideas please let me know