5 speed swap with an Automatic ECU

[420xsGuy]

so heres the story my friend decided to buy an S14 the guys said it used to be an automatic and they did the swap but he says they left the old ECU in so my question is can that really cause the check engine light to come on? ive looked around and havent found the right answer quite yet. ive read that it will cause a rough start but thats about it havent really found much going to keep looking would like some answers from personak experiences with doing the 5 speed swap.

[future]

Yes, yes it can and will

[420xsGuy]

Yes, yes it can and will

now my next question is will replacing the ECU with one of a 5 speed will that cause the car to be back to normal or is there more to it than just that? thanks

[gist864]

now my next question is will replacing the ECU with one of a 5 speed will that cause the car to be back to normal or is there more to it than just that? thanks

manual ecu with lower harness will

[420xsGuy]

yeah i was talking to my friend also he mention i need to get the switch for the clutch when you press the clutch in to start the car

[xoxide]

^You dont have to get the switch... The only thing different is that you can start your car without pressing in the clutch. I have an auto ECU in my car also... Starts are a little rough (just have to give it a little bit of throttle and then its good to go). And yes it will throw codes... Nothing major to worry about.

[Agamemnon]

yeah i was talking to my friend also he mention i need to get the switch for the clutch when you press the clutch in to start the car

You need to wire in your neutral position switch. If not, you will throw a code.

[420xsGuy]

^ thanks im gonna have to start searching about that good looking out agememnon

[bunny13]

Just thought I would mention, many people that swap 5 speed transmissions into s14s use s13 transmissions. In doing this many leave the crank angle sensor out because they're too lazy to drill a hole in the top of the bell housing and shim it accordingly. This turns on the check engine light but doesn't affect engine operation. It's strictly for diagnostic purposes. Might want to ask what transmission was swapped in.

[FRpilot]

^^^
Doesn't that only apply to obd2 s14s? I thought the stock obd1 s14s manual transmisions have the hole drilled for crank angle sensor but don't have cas there and are basically like s13 obd1 so if you do a mt to at swap on an obd1 s14 using an s13 mt it will make no difference?

[bunny13]

My car is obd1 and has a crank angle position sensor.

[420xsGuy]

Just thought I would mention, many people that swap 5 speed transmissions into s14s use s13 transmissions. In doing this many leave the crank angle sensor out because they're too lazy to drill a hole in the top of the bell housing and shim it accordingly. This turns on the check engine light but doesn't affect engine operation. It's strictly for diagnostic purposes. Might want to ask what transmission was swapped in.

oh yeah yeah my friend mentioned that to me but do you know which code it flashes due to the transmission? that way i can check if the check engine really is cause of the transmission not something else but either way im gonna have to look it up

[Juantwo3]

^You dont have to get the switch... The only thing different is that you can start your car without pressing in the clutch. I have an auto ECU in my car also... Starts are a little rough (just have to give it a little bit of throttle and then its good to go). And yes it will throw codes... Nothing major to worry about.

is this only for s14's???

cuz my s13 coupe starts fine with no problem i swapped it to a 5 speed no CEL or anything.

[420xsGuy]

is this only for s14's???

cuz my s13 coupe starts fine with no problem i swapped it to a 5 speed no CEL or anything.

yeah i believe its only on s14's i read some thread but i forgot where and the details didnt really do much reading since i have a s14

[FRpilot]

My car is obd1 and has a crank angle position sensor.

But is the wire left unplugged and tucked away from the factory. I thought I read something like that because the cas in tranny is strictly for obd2 and Nissan did that to be ready for when obd2 was required.

[Agamemnon]

But is the wire left unplugged and tucked away from the factory. I thought I read something like that because the cas in tranny is strictly for obd2 and Nissan did that to be ready for when obd2 was required.

Negetive. It is wired into the ECU and is not OBD II specific. It doesnt actually have any effect on engine control, but just detects misfires.

[xoxide]

is this only for s14's???

cuz my s13 coupe starts fine with no problem i swapped it to a 5 speed no CEL or anything.
Im not sure, ive never done a 5 speed swap on an S13.

[bunny13]

But is the wire left unplugged and tucked away from the factory. I thought I read something like that because the cas in tranny is strictly for obd2 and Nissan did that to be ready for when obd2 was required.

Nope it was in the transmission and plugged in.

[Jays Performance]

Im not sure, ive never done a 5 speed swap on an S13.

When I did my auto<manual swap I used the auto ECU and it started like normal. I think the only difference is the auto ECU doesn't have a speed limiter because I know I have had it over 128

[nicolai1]

so heres the story my friend decided to buy an S14 the guys said it used to be an automatic and they did the swap but he says they left the old ECU in so my question is can that really cause the check engine light to come on? ive looked around and havent found the right answer quite yet. ive read that it will cause a rough start but thats about it havent really found much going to keep looking would like some answers from personak experiences with doing the 5 speed swap.

i hope you guys do know thats the auto ecu will have a 500 rev higher and it willll go past 116 mph so pass the governer

[36chambers]

Sorry for bumping a sort of old thread, but I am having problems passing smog. I get code 1605 which I believe is the auto ecu code from using the auto ecu and 5 speed swap.

I bought a 5speed manual ecu and the car wont even start with it, which is weird because I thought it suppose to take off code which it did and fix it.

How do you use the auto ecu and have it not throw the 1605 code to pass smog with the a/t ecu?