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The auto ECU works for faster top speed! but.....

1164 Views 22 Replies 12 Participants Last post by  RedSVTFlareside
hi, I just installed an automatic ECU from a 1990 into my manual 1990 240sx! I took her out for a spin, and I was thrilled to see my needle creep well past the 115mph limit! I was going about 125ish conservitively! :thumbsup The rev limiter was more like a quick pulsation instead of the sudden death! It also seems to be just a little higher than before too! OK, the engine seems to run great, but now the Check engine light comes on every time i turn on the engine! :tears

What now? I want to get rid of that CEL, it's so annoying! FYI my car is a California car!

thank you!
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swap that badboy out when it's time for smog. i've never heard of an auto ecu causing a cel on an original manual car. i can't see the maps being different.

stumped me on this one. +1 for you.
Try checking the codes?
I'll check the codes tomorrow! a good place to start eh? :thumbsup
definitley check the codes... maybe you did some damage beating on your car with the new ECU in, you obviously hit rev limit lol
my 1990 dosent have diagnostic capabilities. so i cant hook up a scanner. the light is suposto come on when you start the car but it should turn off after about 4 seconds. i dont think my light is even working
SOHC's don't have a CEL as far as I remember.
I think California models got them.....
lol this is hilarious. whats happening is the auto ecu is looking for the certain sensors that the automatic tranny has that arnt on your 5 speed harness. which is why you get a cell. i could be wrong tho
just take out your cluster, and pull out the bulb if you cant figure it out in time for a smog check..:D
dopeassjackson said:
my 1990 dosent have diagnostic capabilities. so i cant hook up a scanner. the light is suposto come on when you start the car but it should turn off after about 4 seconds. i dont think my light is even working
Wrong. Pull out the ECU and turn the screw. The LED will flash and your penis will grow. Just like magic, except better.
LOL! you guys are all crazy!!! :rotflmao

OK, this morning the CEL didn't come on at all! I was so happy!

.....but at lunch time I took the car out to check up on my datsun 240z and on my way back I rolled the speedo past its limit again. The CEL came on! When I got home later today, I pulled the codes and it was a *32, or an "EGR function" code. I'm going to check it out more at lunch time tomorrow! I cleared it and I will check the EGR at lunch break! Any suggestions on a sure fire way to test this bad boy? is it a waste if time to clean it? and reinstall with a new gasket? If it is worn I will just buy a new one! But I also want to get a Dual cam motor installed! and I am poor!:heyhey

My theory for the first CEL is that the computer was wondering why I have less rotating mass because of my U/D pulley & lack of fan clutch, and I have a JW pop charger, 2.25" strait through exhaust with a magnaflow round, I think the ECU might have been fooled the first time! but the second time I may have pushed the EGR too far! I have no proof because I never got the code the first time. It cleared itself though!:thumbsup

So the Automatic ECU is a bolt on that works! I am proof of this!!!!:yummy anyone who is unsure about it, here is your answer! But don't do it, I want to kill any of your dual cam s13 or s14s on the open road with my $500 turd!:heyhey
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the code is more than likely something to do with the fact that the ecu doesn't reconize the 5 speed and teh sensors are different. I swapped one into my car.. 93 auto ecu. runs great, idles fine. no speed limiter. and i haven't tested for a rev limiter.. i never will lol.. anyway. i'm sure it is throwing a code about the tranny
ZeroBladeImpact said:
the code is more than likely something to do with the fact that the ecu doesn't reconize the 5 speed and teh sensors are different. I swapped one into my car.. 93 auto ecu. runs great, idles fine. no speed limiter. and i haven't tested for a rev limiter.. i never will lol.. anyway. i'm sure it is throwing a code about the tranny
well from what i what i understand it cant read 4th or 5th gear after a certain rpm which is why it just keeps going past 115.
Check engine light only comes on when something is wrong with your emissions. it wouldnt come on because of a new ecu .
People, don't make assumptions like "it must be because there is some sensor it isn't reading." If you don't know the answer, don't throw stuff out like this because NO the auto ECU does not throw a code because it's looking for a sensor that isn't there. EGR has nothing to do with the fact that he doesn't have an auto. Many of us run the auto ECU with NO problems.
Moving along, just remove your EGR :).
hmm...

I have an auto KA24DE ECU that isn't doing my SR any good. I could get rid of it. anyone want to buy it?
datboibrad said:
well from what i what i understand it cant read 4th or 5th gear after a certain rpm which is why it just keeps going past 115.
???? It is a EGR code!!!! :12dunno
So my EGR is not up to snuff, and it can't handle the high RPM load for such a long time, It needs to be serviced or the weak link replaced!

anywhooo, thanks for the input, EVERYONE!!!!
RedSVTFlareside said:
hmm...

I have an auto KA24DE ECU that isn't doing my SR any good. I could get rid of it. anyone want to buy it?
thats from numberous reasons. most noteable would be the ignition then the fuel maps. but supposedly the DE ecu can correct up to 370's.
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