So, I recently purchased a 1986 RX-7 GXL with a 13bt swap. Guy said the car needed an "upgraded ecu", which meant that it still had the stock 13b ecu. I assume that the reason he thought this was because it had a bouncing idle, and sometimes would just stall after running for a while, because the idle bounced too low. After a long time, the idle would even out, but I decided to replace the ecu anyway, just to be safe, as it was also getting terrible gas mileage, something along the lines of 5 miles to the gallon. I assume it was running very rich, as it also stank of feul while running. I just installed the new ecu the other day, and the bouncing idle is still there. In fact, now my speedo has just stopped working, or works erraticlly. I have not driven it long enough to detirmine if the gas mileage has improved, and now when I start it a thick, white, smoke comes out of the exhaust. I hope that the smoke is just condensation, however it seems thicker and more volumous than the condensation smoke that would be produced before the ecu swap. Any ideas on whats wrong. I was talking to someone, and he was mentioning the coils, so maybe its that? Any help would be greatly appriciated.
Thanks

 

the smoke sounds like you have bad seals! sounds like time to rebuild

 

If it was burning oil the smoke would have a blueish tint, no?

 

yes it would but on a rotory motor it will be a thick white smoke on start up does that sound like you?????

 

bad seals wouldnt cause a speedo problem though would they?

 

bad seals would not cause that. check to make sure your seals are good. at least that way you wont be wasting your time with a computer b/c that'll be the last thing on your mind.

as far as the whole computer situation goes, how easily/hard does the car start. how does it run also?? you might have the wrong computer in there. i purchased what i thought was the correct computer for my car when i did my swap... turns out it was crap and my 7 did start and run, but it was freakin horrible. timing was off and mpg was bad too.

 

With the exception of the bouncing idle, the car runs ok, no clicking or knocking. Car starts relitivly easily, I never have to pump the gas or anything. Sometimes however I do hear a grinding noise when i turn the key, even with the clutch all the way in, but I usually play with the shifter and it goes right away. As for the computer, I have a 13bt, and I bought a turbo II ecu, so it should be correct right? There must be something I'm missing. Thanks for all the help.

 

On another note, is there a way to tell a s4 ecu from an s5 ecu. Could these problems be caused by the fact that I need a turbo s5 ecu, and I am running an s4?

 

you need to stick with the same series. do you know what year motor is in there and what wiring/electrical he used. the number on the ecu will tell you what series it is

 

Honestly, the entire electrical system of the car is shot. It works fine, its just very thrown together. Tons of wire caps, and tape, and exposed leads. I worry that it's something more serious than the ecu, like one unconnected wire. I just had the ecu out the other night, wish id written down the number. Any specific number or combination of numbers I should be looking for to tell if the ecu is s4 or s5. I know that the guy who did the swap said that the motor was an s5
Thanks

 

well, if he said it was an S5 i'd got with that. but the whole wiring being thrown together can be a big issue. also here are the numbers for an s5 and s4. a wrong computer could be the cause, but i'd take a good look at your wiring to be sure.

s5 TII ecu N370,

S4 TII ecu N332, N333