phillup23

Recently found out my 95 sc400 had a 92-94 California ecu. My sc is non-Cali. Just wondering what this could do to my car. Would it tinker with stuff or would it just be okay? Car is having idling problems as of right now. Going to replace ecu with a 95 one. Just wondering if this could be the very culprit for my problem. Or nah. Lol

phillup23

Soooo. Anyone???

t2d2

iTrader: (8)

I think most people try to avoid finding out what effect that would have.

ACCHRM

Thats nothing, I run a gs300 ecu on my sc300. Everythiing works, it just has a lot lights on the dash, cause it wont recognize them

Ali SC3

iTrader: (10)

Simply yes, that is your problem those sc400 ecu's are not compatible. its not like a sc300 at all.
sc400 received quite a few changes in 1995 including becoming an inteference engine and an updated ecu/harness.

95 sc400 uses sequential injection meaning it has 6 wires one for each fuel injector.
92-94 sc400's use batch fire injection meaning there are 3 wires for 6 injectors and 2 fire at a time.

So when you use a 93-94 sc400 ecu on a 95 sc400 harness... you get half the cylinders getting fuel.
let me guess its idling at about 350-400rpms and feels very sluggish like its on 4 cylinders... well that is because it is running on 4 cylinders right now.

Yes you need a 95 ecu. you cannot use a 96 ecu because it is obd2. you specifically need a 1995 Sc400 ecu, non cali preferably.

phillup23

thanks for the info! Well my car ran good when I got it and a few days later had idle loop at 1200-2000. Also accelerated by itself.

Ali SC3

iTrader: (10)

sounds like you are in new territory I would start with the ecu but that high of an idle might say you have another problem also on your hands.

t2d2

iTrader: (8)

Could the CA vs non-CA differences with the sub-cat and any other emissions controls be throwing off the ECU and creating that idle loop?

Ali SC3

iTrader: (10)

usually its just codes for the heaters missing on the o2 sensors and other minor differences none that would cause it to idle like that. what was it doing before the ecu was changed?
that is usually a sign of a iacv issue or tps issue or an air leak.

also I just noticed that you said you just figured out about the ecu, which means you didn't swap it.
SO... There is a very good chance someone not only changed the ecu but the entire harness and motor to the more available 92-94 kind. If that is the case then you would not want to use a 95 ecu. you will want to use the ecu that matches your harness or it won't run right.. so you might have the ecu you want already if that makes sense.

theres no quick way to tell short of pulling the connector off of the ecu and seeing how many injector wires there are. if 4, 5 and 6 are missing you have an old harness and should keep the older ecu.