t2d2

iTrader: (8)

Well, after another week+ of limited testing, I'm not so sure the '95 ECU is making any difference with the cold start-up. It could be from disconnecting the cold start injector's wiring, I suppose, but I didn't notice any change for the worse from that at the time.

So, I put the '94 ECU back in and have a low mileage CSI on the way to try out at some point.

t2d2

iTrader: (8)

I confirmed today that the O/D is still working with the O/D OFF light flashing when the '95 ECU is installed in the '94. If I end up sticking with the '95 ECU (went back to it because my "new" cold start injector didn't work, so needed the 95's non-dependence on it; didn't want to change CSIs again right away), I'll just pull the O/D warning light unless someone has suggestions how to silence whatever it thinks is amiss.

Ali SC3

iTrader: (10)

the blinking is actually telling you there is a transmission code, if you jump the diagnostic port it will blink out the code and then you can see what its complaining about. blinking o/d doesn't usually mean the o/d wont work.

t2d2

iTrader: (8)

I did that when I checked/confirmed that the accompanying CEL was just for EGR, and either the O/D light wasn't blinking a code or I wasn't paying attention for it. I'll have to check again for that specifically. I assume it will be one of:

67 - OD direct clutch speed sensor signal malfunction
68 - Short circuit in kick-down switch

67 is the commonly reported one for O/D OFF flashing, but only when there's an actual problem causing O/D to not work, such as a loose connector. 68 seems more likely in my case, since the '95 ECU wouldn't be making use of the kick-down switch, per the explanations on pg 1. But, would the gauge cluster know that? I would have thought it receives notice from the ECU whether there's a problem in that regard, and the ECU wouldn't see a problem because it doesn't get the kick-down input in the first place. Just thinking out loud...

t2d2

iTrader: (8)

Ah... So, it is throwing O/D codes, afterall: 38 and 46. 38 doesn't exist according to the list I'm looking at, but 46 is something I didn't even consider.

46 - Open or short circuit in no. 4 solenoid valve

I have the 4th solenoid bypass in place, which is known to throw error codes on OBDII. Maybe it's actually a '95+ issue? I wired mine up on a toggle, so it'll be worth another test of clearing the codes, turning off the solenoid bypass, and seeing if the O/D OFF light blinks.

t2d2

iTrader: (8)

Hmm, I pulled EFI the fuse for ~5 min to reset, re-enabled the 4th solenoid, and the same two codes (38 and 46) flash. That was unexpected. I figured at most the unknown #38 would still be there. I wonder if that means it's an issue on this particular ECU, or maybe the EFI reset didn't occur despite waiting much longer than necessary?

t2d2

iTrader: (8)

I noticed something interesting today in browsing the RockAuto clearance email: There are two different cold start injectors.

STANDARD MOTOR PRODUCTS CJ20 - TO 1/94
STANDARD MOTOR PRODUCTS CJ21

http://www.rockauto.com/en/catalog/l...art+valve,6032

My '94 is a late '93 build date...

To recap, I ran the '95 ECU as a start-up experiment, then switched back to the '94 ECU after putting in a low mileage (96k) cold start injector along with the manifold porting project. The "new" CSI didn't seem to work, however, so I went back to the '95 ECU until taking things apart to put the old CSI back on, as the '95 ECU doesn't need the CSI.

I'm not sure what year the "new" CSI/plenum came from. I'm wondering now if it's the CJ21 equivalent. It never occurred to me to look for a specific version of the CSI, as I had never run across dual part numbers before (always #23260-59045). Looking at the RockAuto pictures, I can't see any differences. Any guesses what might have changed?

Ali SC3

iTrader: (10)

old bump but was looking up stuff for the 95 sc400 being sequential and you can see in this manual they did it early on the LS in preparation for obd2.
see page 40 at the top
http://www.mr2.com/files/mr2/techinf...e95LS1uz-1.pdf

I think it was the same for the sc400 also because if you look up part numbers for sc400 ecu's, 95 has its own year cause it is the older maf and sequential injection.
96-97 had the newer maf and sequential injection, and 92-94 had the older maf and batch fire injection.

Kahn amazingly put this all in one place:
https://www.clublexus.com/forums/per...s-by-year.html

The reason the 95 ecu will still run a 92-94 car is cause the way the harness is designed, in 95 they reused the original 4 injector wires from 92-94 and added 4 more to companion cylinders.
So as you discovered, the 4 original signals are still being duplicated to the 8 injectors through the batch fire harness, so its like you are just not using the extra 4 injector signals.
I think you would even get a similar amount of fuel injected the way its wired, but the o2 should be able to take care of it, which is why your car mostly runs the same on either ecu.

Its kind of similar the way the old 1j's were wired in batch and running them off 2j sequential ecu's and stuff, but lets not get into all of that here =)

t2d2

iTrader: (8)

I forgot this was even my thread when I got the reply notification.

That's pretty clever how they wired the additional injector signals for backward compatibility.

Ali SC3

iTrader: (10)

It was a while ago, it is either that or they just made a different ecu for 95 that is still batch fire but has other differences. I think I would have to get my hands on an original 95 car to say for sure anymore lol.