Is there a way to determine if the ECU is NA or Turbo (already identified it as an S4)? I cracked it open hoping to see a chip or some other identifying marker, but no such luck (the original sticker is gone).

 

well... how about some pictures of the inards of an NA s4 ecu and a turbo s4?

 

There should be a sticker right on the casing with a number on it

ECU Part Numbers (this is the version # that's on the ECU itself)

84-85

GSL-SE

N304 18 880A
86-87
NA
N326 18 880, N3Y6 18 880
87
Turbo
N332 18 880
88
NA
N327 18 880
88
Turbo
N333 18 880
88
Convertible
N338 18 880
89
NA California
N350 18 880
89
NA Fed.
N351 18 880
89
Conv. CA
N352 18 880
89
Conv. Fed.
N353 18 880
89
Turbo
N370 18 880

NOTE - If there's an "R" at the end, it's a remanufactured ECU. They also change the last 3 digits to "881". Example - '89 Turbo Reman. - N370 18 881R. A remanufactured ECU isn't necessarily bad; it DOES mean the ECU was replaced.

 

he doesnt have the sticker on it

I'll get a pic of the insides of a NA this weekend if it isnt too late.

 

Thanks, it'll be greatly appreciated.

 

I got all the pics, do you have an email where i can send them so you dont lose any detail?

 

here's some pics of the innards... any identification available from these?

 

what are the numbers on the two stickers on the chips in the top picture. Those are the fuel and timing maps, but your image is too blurry to see what they are.

and I can confirm that it is a S4 ECU as you say.

 

very top chip: 079753-0277
bottom chip: 079753-0287

 

Although, if you can't find out what kind it is, well, just run it to see what happens =]

There were more S4's than S5's anyway, im sure its a nonturbo S4...most likly.

 

I still have those pics?

 

just go ahead and host/post them. I like to allow people the benefit of seeing what others are talking about.

I suppose it may not be 100% necessary if Ice Mark can Identify the ECU from those numbers.

 

will do

 

N327 (non turbo 1987.5 and 1988)

 

Thanks Icemark.

 

Who can I send my N351 ecu to to get the fuel and timing maps changed? I don't want to spent the dollars on a Haltech and I'm not sure I want to get a Pocketlogger setup but atleast for now, whats the best route for getting my stock ecu tuned? (can I buy the parts and solder it myself?)

It's a racecar only that istn't streetable and turns 6200-8400rpms, never less.

 

You can't. Nobody does any chip change for the S5 non turbos.

Replace it/upgrade it with a Rtek or Megasquirt or other ECU if you want to change maps.

 

https://www.rx7club.com/rtek-forum-168/thumbs-up-s5-na-2-0-a-668832/

 

sorry to pull this thread out of the wood work. i ran into this problem today. i have the same ecu in my tII swap. would this have caused a problem? it has ran fine with it so far, i opened it to see if i could find out what one it was just like this guy. my sticker was also completely unreadable.

same:
very top chip: 079753-0277
bottom chip: 079753-0287


thanks in advance

 

its not a TII ecu

you need a TII ecu, get a n332 or n333

 

Again (as above in this thread) that is a N327 ECU used in a non turbo 1987.5 RX-7 and a non turbo 1988 RX-7.

 

when in doubt, it's probably an s4 n/a

 

yeah, they only made about 200,000 non turbo S4 models... the odds are that it will be a Non turbo S4.

 

im just wondering how i didn't blow the thing up yet. i have ran it at 9 psi for quite a while. just dumb luck i guess?

 

I ran one once at 12 psi on my TII with a walbro and stock 550s and the AFRs seemed pretty good and their was no fuel cut since it is an NA ecu.

The biggest problem I was looking at was improper ignition timing, which will eventually kill the engine.