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I recently bought a 1979 rx7 sa and am fairly new to all this rotary stuff but love driving the car. About a week ago though it stopped wanting to idle and became really hard to start when warm. Right now the car won't start at all even if it's cold it cranks and the engine shakes really bad I though might have had a broken motor mount but I checked that and it looked fine. I cleaned the carb and that didnt change it I thought it might be my Apex seals so I did a compression test and my numbers look ok. Also once I do get it running it won't rev past certain point and bogs down and backfires a ridiculous amount. Do I have a blown Apex seal or is it something else.
sounds like might be:
1) fuel issue. Have you changed the fuel filter? Easy, cheep - mounted in front of rear driver wheel. These should be changed annually
or
2) ignition. Have you confirmed plugs are clean and getting spark?
You could remove the plugs, remove the fuel pump fuse, crank it with the throttle open. If every 6th swoosh it soounds different, then it's a bad apex seal.
And you could of used the search function here and got your answer immediately.
I have changed my fuel filter and spark plugs it didn't make a difference I also thought it was a fuel issue at first. I will listen for the blown seal today hopefully I can figure it out
I cracked the engine over with all the plugs out I took a video cause I'm not sure it's hard for me to tell I think it sounds fine also all my plugs which are brand new where completely fouled I also tested for spark and that seems fine everything I've read about how it's driving and running points me to Apex seals idk thanks for the help
Compression sounds good. All the swooshes sound strong and the same. All seals seem good.
If you've got a Haynes manual, you might check the points like J9 mentioned.
Or even simpler, put a little engine oil into the spark plugs holes or just pour a little down the carb if you don't have a squeeze bottle/syringe. Crank the engine over by hand with a 19mm socket on a ratchet from the front pulley to get the oil spread around. Could probably just crank it with the starter, but it's gonna make a hell of a mess in the engine bay. Hook everything back up and see if it'll start or even sputter.
Below 50F my engine misses on start up, as it warms up is gets better. At 20F it is time to break out the methanol andpour 1/4 cup down the carburator.
BTW, what did the plugs look like? Red insulator points to fuel starvation. Black all over means excess fuel and oil. Also with the plugs out it is a good time the verify that they are firing.
Last edited by midnight mechanic; 04-14-20 at 10:31 AM.
I got it to start up it was the engine shakes like and crazy and it runs for 5 seconds then it just dies I checked my spark plugs aswell and they are covered in fuel. I just put oil in the carb and turned the engine over by hand and then it fired right up. Not sure exactly how to check my ignition points they are a bit rusty but when I picked it up it drove 200 miles just fine and now it won't idle l.
You need to either change those points with new ones OR convert the car over to electronic ignition. If both rotors compression sound like the vid you posted, you will be fine.
I hope you reset the idle speed and mixture back to how it was before you cleaned it.
If the idle speed isn't turned out the same amount of turns it was before disassembly, especially if it's turned out fewer turns than it was, it definitely won't help it to stay idling.
Have you checked for spark on each of the plugs? Ground them somewhere you can see them from the driver's seat and then crank for each plug. Be careful setting them near where air and gas comes out of the spark plug holes in the engine. Strut tower studs and some vice grips work for me. If a plug doesn't work, swap a known working plug for the nonworking one and test again. That'll tell you if the wire is bad or the plug is. Check for spark before you mess with points any.
I don't have points myself, but I can tell that's definitely not ideal. Rust isn't great in that area, but the problem is likely the rust might be preventing the points from working properly.
This reminds me of an issue I actually recently (and hopefully) solved on my 83.
The car had been running ok since I had bought it, but started running really good after I changed the dizzy cap and rotor alongside plugs and wires. But recently, it would not hot start; I checked my compression and it came back perfectly to spec. I swapped my original coils, and the car started hot perfectly. It also happened to solve the odd screeching I was getting when cranking a hot motor and solved the crazy misfiring while the motor is cold. I haven't peeked under my distributor cap since I swapped it out, but I don't think it was very rusty. I can pull my cap off and take a peek, I know my car had been sitting outside (in the rust belt) for over 15 years, so my points could be fairly rusty.
TLDR; check your coils and wires as well. Would hate to see you rebuild the distributor only for it still have issues.
I checked for spark all the spark plugs work but I was unable to get spark through the trailing wires on both rotors. The coil is brand new I replaced it about a week ago. Not sure what to replace other than that.
I've got 85 ignition in my 79. Shooting in the dark here. Are the plug wires coming from the distributor going to the right coils since you replaced the coil(s)? L for Leading on the distributor should go to the coil farthest to the front of the car.
I had my coil wires backwards like that and it would fire to life for a few seconds and then die.
Don't forget condensers, while you're there. Not much more expensive, and it's good practice. You don't want bad condensers shortening the life of your new points.
04-12-20, 05:58 PM
