6G Celicas Forums

Oh, and I also noticed that in the fuel trims, the computer has to move the fuel mixture up by around 7.5 percent. The engine stumbles at times, especially at idle, despite changing out the cap, rotor, plugs, wires, and thermostat after changing the coolant. I think this is all the more reason to get the computer when I get my check.

I just noticed something regarding the P0141 code I get that may point to my need for another ECU. I got the OBD dongle and used it with scantool and the code is saying that it is related to an O2 sensor heater malfunction, but the O2 sensors in my car DON'T HAVE A HEATER. They are the 2 wire type, and not the 4 wire that has one, so I have a suspicion that the computer expects them to be there, and they aren't, and that's why the code is being thrown despite getting the Denso sensor.

I'm not sure if mine has the TVIS, but it would be nice to see in real time what my sensors and whatnot are all doing, that way I can not only have info on the engine it's made for, but also if the ecu is defective or not.

I found some pinout PDFs from shop manuals that might help in this:

5SFE

7AFE

I also want to get the plugs off the donor's wiring harness when I go to the wrecking yard to get the ECU to compare to mine so I can see if the previous owner did re-pin my plugs and re-pin them back if necessary.

You asked, and here they are (Sorry I had to use imgur):

The engine:

http://imgur.com/a/t7Bv5

The ECU from the top (I did a search on the ECU's black numbers, and it came out of a '97. Does anyone recognize the numbers written in blue?):

http://imgur.com/MqoLsrh

The bottom of the ECU (Does anyone recognize the yellow numbers?):

http://imgur.com/6OMr2xL

The guts from the top (does anyone recognize if the internals are original?):

http://imgur.com/a/DNRDs

The guts from the bottom (does anyone recognize if the internals are original?):

http://imgur.com/eOtTTBG

And the plug:

http://imgur.com/WVU2THA

The previous owner had the original 5sfe throw a connecting rod when I first got the vehicle and I had to replace it with another 5sfe. I did not know about the mismatch with the numbers on the ECU at that time.

I did some looking at the wiring schematics of one out of 7afe m/t, 7afe a/t, and the 5sfe m/t I have, and the 5sfe m/t and 7afe a/t ECUs appear to have similar wiring diagrams, but the 7afe m/t has a different plug layout compared to my 5sfe. Something is telling me that someone got into this ECU or refurbished it at some time and mismatched the cover or something. I found some numbers written on it as well.

The salvage yard looks to be my option. I have a pull n save lot close to where I live that might have one where I can get it for about $40.

Yeah, me too. I am wondering if this is a modded ecu, perhaps. This ecu mismatch could be causing my check engine light obviously, despite changing the o2 sensor to a new oem denso. What's weird is this is now the ONLY check engine light I have, but it's like an itch I can't scratch and I can't get rid of it.

Oh good, that's a relief, no having to change sensors or the like.

Hello all, I found a surprise in my 1996 Celica: It has an ECU for a 7afe manual transmission engine, however, mine is a 5sfe manual. The engine runs well, but gas mileage is not as good as it is supposed to despite replacing the cap, rotor, plugs, wires, and I get a P0141 code despite replacing the O2 sensor with an OEM Denso and checking the wiring connection between the sensor and the computer. The cables don't appear to be all spliced up, either.

Why would someone do this, and what would I have to do to replace it with the original (if this would fix the gas mileage and sensor issues)?