Hello All -

1980 SA, been running very well up until the last few weeks. Seemingly random power loss - about 50% I'd say - and when coming to a stop and letting the engine come back to idle, it dies. I can keep the engine going by getting on the throttle and keeping the RPM up at about 1500 - 2000 at a stop light, but to get moving again a LOT of RPM needed and very gentle with the clutch. Any "normal" load on the engine and it dies again. Have limped back home a few times in this mode. When running in this less-than-ideal mode, the exhaust note sounds like a low, somewhat muffled, growl. In fact, that's how I know it's gone into this mode when driving down the freeway, suddenly it sounds different. The first time or two this happened, I shut it down, let it rest 10-15 min, and it fired up fine and ran perfectly. Now it seems more persistent. Car will restart, but shortly thereafter goes back into this degraded mode.

Might be something as simple as new spark plugs - it's been a few years since changing those. But open to any other ideas. I've perused other threads addressing similar issues, but none seem quite like what I'm experiencing. TIA - PJ

 

I think you have igniters instead of points in the 1980 ignition, yes? To me it sounds like a failing igniter for the leading spark.

I had a similar problem with my 1983 which has electronic ignition and it did turn out to be a failing leading igniter. You can swap the leading and trailing igniters and see if the problem goes away.

 

Great idea - will do that, thanks!

 

Yes, this sounds like failing ignitors for sure. Its a bit of a pain to swap in an SA due to the ignitors being in a box. I had this issue and then after fixing it, the circuit in the ignition box burned out and I then did a the TFIDFIS linked in my signature. Good luck.

 

@t_g_farrell Thanks!

OK, admittedly a rookie at this stuff.

Found both igniters, wire connections, etc. So you're saying just swapping connections between the two igniters should do the trick? That's my first thought, move connection from igniter "A" over to "B", and from "B" over to "A". If that's not the way to go, then was thinking I could physically remove igniter "A" and put in place of "B", and vice versa, keep the wiring going to the same place (if that makes sense) but have the actual igniters swapped positions.

Pics attached: igniters attached to the back side of gold-colored box, was thinking just remove that box / assembly to access the igniters, once I have access do the swap.

Further question - if a bad igniter is the problem, swapping may help with troubleshooting but am I not just moving the problem unit from one place other another, and that igniter replacement is the way to go for truly correcting the problem?



Thanks for the help.

 

To answer your last question first, this is mostly for diagnosis. If the leading igniter is bad and you move it to the trailing position, then yes you are moving a bad igniter from leading to trailing. But the leading ignition spark does most of the work and the trailing is there to help clean up any unburned fuel oxygen mix. The engine can run well on just the leading spark.

You should physically swap the igniters, you want both the inputs and the outputs to be swapped. It's a great idea to add some heat conducting compound to the back side of the igniters. If the engine performs consistently and powerfully after the swap then you can either find a used j105 igniter (not the j109, that's for later cars) or check out Tim's ignition modification that uses readily available igniters and coils in place of the OEM ones.

 

I thought you can just swap the wires, leaving the ignitors where they are. Aren't the 2 connectors the only interface with the systems circuitry and it does not matter which one is mounted where? We are just swapping the other ignitor over to the leading plugs to see if it runs better off the other ignitor.

If this has no effect, I was wondering about the condition inside the gas tank. Sometimes suction from the fuel pump draws fuel along with excess crud around the pickup tube, choking off the flow of fuel. After shutting the car off, the crud dissipates and falls away only to be sucked back up again after driving it more.

 

I had that same thought (fuel), I'll get the fuel filter and fuel tank checked as part of the troubleshooting. Thanks for the suggestions.

 

Understood, thanks for the explanation.

 

I'm pretty sure you have to swap the ignitors so that the leading works. The 80 ignition disables trailing on certain conditions and it would probably not work right anyway because it would be getting the leading dizzy signal but would still be connected to the trailing coil circuit I think. I haven't had the OEM ignition for a long time so a bit fuzzy on it. Physical swap should work but as mentioned add heat paste as well.

 

I had easy access to a spare box from an 80 and some time, so I took off the cover and found that you're right, you do need to reposition the ignitor. In addition to the external wire connection, the back side of the ignitor plugs into a receptacle under the circuit board.

So yea, the box will need to come off the fender but still, not a major job.

 

OK great info - thanks very much!

 

You don't need to take the cover off, just remove the 2 screws on the back side holding both ignitors and pop them off.

 

Well, bad news. Swapped the igniters, ran the car, no change. Maybe even a little worse. Started up fine, got it to the freeway very smoothly, allowed myself to think I had this nailed. About 3 minutes into the drive a freeway speeds I could feel the engine surging a bit, pulled off and engine died at idle. Limped it back home in the same condition as before: low power output, weird exhaust sound, have to keep RPMs up at stop signs or it dies. Getting pretty good at coming to a stop using the e-brake and while keeping my foot on the gas.

I have 2 replacement igniters on order (e-bay, but seller says they tested good). Maybe time to change spark plugs? Or look at fuel system?

Here are a few pics of the swap, FWIW:

 

Given your test results so far, I think it's not that you have 2 intermittently bad igniters. Perhaps as others have said it's time to look at fuel, at least while you wait for the igniters you ordered from ebay.

FWIW, you can test the igniters you have. And it is always better to diagnose than to iterate through part changes, certainly less expensive in the long run.

This diagram is specific to your 1980 system with J105's and comes from the factory service manual, which you can get here: https://foxed.ca/rx7manual/manuals/1...80_RX7_FSM.pdf

The basic idea is to switch 12V on and off to the ignitor's input and see if it outputs power to a small 12v incandescent light bulb (instead of the coil). Given your experience I would rule out heat build up as the failure mode and run the test until the igniter gets warm.

And make sure to reinstall them with a thin layer of heat paste on the backside.

 

@Toruki Thanks very much, very helpful. Agreed, don't want to just throw spare parts at the problem, I'll work on the test set up you referenced and see how it goes.

 

Seems like once your car warms up the failure happens. As we stated, could be ignitors. Another culprit can be a failing fuel pump which can get hot and perform poorly. The way to diagnose that is to tap into the fuel line somewhere and attach a pressure gauge and watch it during the failure mode. Some folks run a line to the gauge and tape it to the windshield when doing this. That way there's no danger of fuel being inside the car while running. Before going to that trouble the other thing to do is a flow and pressure test at the carb fuel inlet hose. Should be about 2.5-3 psi and it should flow about 1 gallon in about 5 minutes.

 

Been traveling for a while, finally back in town.

Got back to the car yesterday and installed the replacement igniters. Cautiously optimistic - ran it for over an hour, good and warm, stop-and-go around town and on the freeway. No issues, purred quite nicely. Heat sink compound is proving difficult to find locally, so I have some inbound tmrw from Amazon so will add that when it arrives.

Thanks for the advice thus far, will update with any further issues.

 

Well ****.

Good long run on the freeway this morning, ran around town, parked for lunch. Started right up but shortly thereafter the problem resurfaced - rough running, poor power output, dies at idle.

I pretty certain this is somehow heat-related. Was a cool morning, but car sat in the sun and the day heated up, that's when the trouble returned.

This is with the "new" igniters I got off eBay and backed with a good layer of heat sink paste.

Back to the drawing board.

 

I been had this issue for a long time. I adjusted my idle up a little so I could drive it without it shutting off. Running the A/C will most definitely cause the car to lose a lot of power. My car been like this for at least 2yrs now. Really don’t drive it a lot but will love to. I will be changing out the exhaust system and install EFI system this summer. Before installing the EFI, I’m going to have someone to check my timing. I’m not good at doing this. There’s a couple of guys near me that have a few RX-7s that they work on.

 

I hear you, no talent at fixing cars, small garage at my unit, no tools other than the basics. Am able to do some simple stuff on my own but otherwise it's off to the shop. And finding a shop that will touch a 40+ y/o rotary motor is no simple task. This situation bums me out, car was running so good (after $$$ worth of work to get it up an running), but now it's a persistent problem and I don't trust taking it beyond my immediate neighborhood.

I suppose I'll begin the search for someone who can install a replacement ignition system.

 

You will need to be aware of smog laws if you are in California. Can you actually replace the ignition without failing smog? Anyway, it sounds like your ignition box is failing. This is what I went through back in 2010 and had to come up with a new ignition. Maybe you can source a replacement 80 ignition box from one of the rx-7 used parts recyclers out there.

 

Yes, well aware of the smog laws, it's a nail-biter every time I have to renew but to date have made passed OK. But good point with regards to some kind of replacement ignition, could certainly add another layer to this whole thing.

 

And by "ignition box" are you referring to the bronze metal box (from my pics above) that the igniters attach to?

 

I had the same problem with my Fc I fixed it by simply adjusting the tps sensor you might want to try that.