ECU Technical Question 91 240sx

[mickeyd420]

I cant get a awnser can anybody check this out and make some sense out of it..

zerothread?id=338943

BTW im mickeyd420

[r3v_v3ng3]

the only difference that i see on the chart is on the REG. one is a C and the other an F but i don't know what the reg means.

[mickeyd420]

does anybody have any input on that difference?

[Vegascorbin]

As far as I can tell the "F" and "C" refer to Federal and Califonia emissions.

Back in the day Califonia had their own set of emission standards for cars that were more strict than the federal.

California cars had differant settings to meet the different standard.

[mickeyd420]

so would that effect my car running proprely?

[r3v_v3ng3]

hmm. maybe. i know CA emissions is more strict and maybe have more emissions/sensors compare to a federal vehicle

[Goldeneagle]

The 28 ECU is for a 91-94 base model 240sx with manual transmission.
Modified by Goldeneagle at 11:49 PM 7/1/2008

[Goldeneagle]

As far as I can tell the "F" and "C" refer to Federal and Califonia emissions.

Back in the day Califonia had their own set of emission standards for cars that were more strict than the federal.

California cars had differant settings to meet the different standard.

Assuming you are correct on the "F" and "C" what would the "M" and "U" refer to?

[Vegascorbin]

Sorry for the slow response.all of the "M" listings show Mexico for a Nissan Part number. I would assume they were only foir use in Mexico.

All of the "U" listings I looked at were OBD2. I am guessing that it refers to a "Universal" ECU that is smart enough to know if it is manual or automatic.

Not an expert but educated guess work

[twistedsymphony]

As others have stated F and C are Federal and California

U = universal emissions... (which started with OBDII in 1996) meaning not federal or California but universal (at least for America)

no idea what M stands for but Mexico is a pretty good guess IMO...

even "universal" ecus are different from Manual and Automatic...

ecus can differ on the following aspect-Chassis style (hatch has different ecu than coupe)-year range (89-90, 91-94, 95, 96, 97-98)-transmission (MT or AT)-emissions (F, C, U)

I would highly recommend replacing your ECU with another of the same number, you can get away with swapping them but you might need to make some changes for it to work properly.

Swapping a federal ecu into a California car you might run the risk of the ECU not understanding the more restrictive emissions systems on the intake and exhaust and as a result it doesn't run properly.

alternatively the sensors ranges might be different and the ECU can't interpret them properly.

the O2 sensor and MAF are sometimes slightly different depending on the ECU too.

[Vegascorbin]

Good answer.

Thanks

[mickeyd420]

so i should only replace the ecu on my car with the number ecu it came with witch would be ecu #30... i found a number 28 ... so i should not get it?