Hello friends, To start I recently bought my Bone stock Cali spec 1993 RX7 in September and have recently pulled it out of winter storage. I drove the car around my neighborhood before putting it away and it drove fine. Over the winter I have replaced the fuel filter, plugs, plug wires and intake filter. I recently drained my coolant and went to fire the car up and run distilled water to do a flush and the car is misfiring horribly. The car fired up easily but hunts around at idle and when rev'd at all will backfire. I immediately shut it off and made sure that the plugs and wires were installed correctly and they were. There was no check engine light but code 16 was stored the fuel smells good and shouldn't be bad as its fairly new. I have used the search feature and have to figure out how to test the tps and map sensor. If anyone could point me in the right direction I would greatly appreciate it.

 

Describe to us how you installed the plug wires, and how you know they are installed correctly.

 

Thanks for your quick response! Coil pack marked T1 to front rotor upper plug, Coil marked T2 to rear rotor Upper Plug. As far as the Coil in the middle upper wire went to Front rotor lower plug, Lower wire went to rear rotor lower plug. I hope that was clear enough I’ll include pictures as well.

 

That is correct. Did you get a positive click on all the plugs? Make sure the wires are pushed all the way into the coil?
I am only asking because it sounds like an ignition issue.

 

Yes my first idea was I had done something wrong so I’ve gone over them a few times and everything is firmly installed. Do you know if there’s a way to test the coils? I can’t imagine they’ve gone bad but I’m not sure where to start.

 

did the vacuum line on the map sensor didn't get knocked off?

 

I checked that as well it’s still hooked up and lines have been replaced with silicone.

 

I'd do a smoke check to make sure there's no vacuum leak. If no leaks found then you'd know it should be ignition related.

 

I agree with double-checking the plugs and wire routing.

Also I’m not seeing a Code 16 listed, but Codes 15 and 17 are both O2 sensor related. Maybe worth re-checking that too.

 

I can confidently say plugs and plug wires are in the right spot. I just triple checked the code and it is indeed code 16 which from my research is an egr fault due to this being a California car. I did have this code before the misfire so Im 99% sure it’s not the cause.

 

what are the chances you have a bad spark plug? like new out of the box, its just bad? also could be possible an injector died.... the timing is odd of course but strange things happen

 

We went through this recently on here and after trying myriad things, finally switched out the gas.

Same problem with my car early this year.

Gas ages less well these days due to ethanol content.

Double check the leads into the coils (i.e. harness connections) and the leads from the coils to the plugs.

 

Here is USDM coil hook-up.

(Note JDM 1996 and later coil position is changed, so leads routing is different.).

The FSM will tell you how to test your coils.

Also check if you battery terminals connections are tight

Did you have the battery disconnected while in storage?



Page g-20 of 1994 USDM FSM.

 

Do USDM cars do "Limp Mode". Could the code 16 trigger limp mode?

The Spiirit R we are working on now is showing three emissions related solenoid related codes, and it is "limp moding" like crazy.

 

I think the gas issue is overblown, if the tank was mostly empty and they only recently filled it back up.
Shouldn't be an issue if the gas is less than, say, six months old. Unless JDM gas lasts longer. Haha.

The fuel in the lines might be much, much older, so maybe he should just let the car run until the old fuel has been sufficiently adulterated by fresh fuel. I don't know how quickly the fuel in the lines gets circulated, though.

OP should probably go ahead and make sure all of the plugs are actually firing (and in the right order).

Disable the fuel system, remove the plugs, ground them to the chassis with the wires attached, and take a slowmo video while cranking the car.

The leading plugs fire together, so it doesn't matter which one is attached to which. A trailing plug firing in the opposite order will be, let' s just say worse than having no trailing plugs at all.

I spend hours and hours trying to diagnose ignition issues this way when I bought my car, only for it to turn out to be a loose ground.

 

Thank you all for your help and suggestions. The gas in the car was 3 months old and half full and I assumed it was fine. I filled the other half with fresh gas and cleaned a few grounds and cleaned the map and tps sensor connections and applied dialectic grease. I also removed every fuse and relay a few times to clean up the connections. The car now runs great and I put 30 miles on it. I’m honestly not quite sure what the issue was but something I did must have fixed it. Thanks again for all the ideas!

 

Almost wish you had just tried one thing at a time, so we'd know for sure what it was. Hahaha.

(Probably the fuel.)

 

Quite often it may be several things, with one thing finally setting off trouble.

So you never quite know.

But it would be a good idea to keep an eye on things, in case there is an underlying cause ready to act up again.

For instance, when a JDM goes into limp mode, the ecu might reset when you turn it off.

The limp mode will go away until the next time the ecu does a self check cycle.

Or it could be an intermittant fault, that the ecu misses sometimes.

A wonky OMP can cause that.

The ecu really does not like a wonky OMP..

All this happened with my car, until a corner shop mechanic hooked up the leads wrong and put paid to the motor.

 

Yes I’m pretty sure it wasn’t in limp mode just because it seemed to want to rev honestly the misfire could’ve been a sticky injector or clogged injector that broke free. Oh well time will tell I’ll do preventive maintenance as I go.