When doing 5speed swap, has anyone swapped ECU's too?
 

Hey all,

I recently did a 5spd swap (VE auto --> VE5), so all the electronics are from the VE Auto. Everything is cool (love the feel), except when coming to a stop, the engine will jump a couple hundred rpm's right before the car comes to a complete stop. (just like it does in an Automatic car)

Do you think swapping in a VE5 ECU would take care of this? Would the car still start and all being that the engine bay wiring harness is from the VE Auto?

Thanks all :)

if your having new problems with the car then it shouldn't be an ECU problem you shouldn't have to swap the ecu unless you did an engine swap if youve been having this problem before then i doubt its the ECU either way whatever was causing the problem before the swap is still gonna be the source of the problem now

also if your gonna swap ECU's why not just get a performance one you did all that work on the transmission and your gonna run the car with an inferior ECU whats up with that?

Explain to all of us why the stock ecu is inferior for just doing a 5 speed swap?

it doesn't control the VI? :gotme:

I didn't see in the original post that he swapped the ve-5 intake over also?

That's correct, the intake manifold is NOT from the VE-5.

I wasn't thinking he did, but that is the only difference ,besides the trans control ability, that I am aware of between the 2.

so do u have to swap ECU or no?

i've ran a 5spd on an automatic ECU since february. car is a GXE therefore factory auto. all auto wiring still in place, just obviously the shifter controls and tranny controls have nowhere to hook to now.

ecu must be showing trouble codes for tranny right?

:rotz: no.... it isn't..... why would it?
find the ECU diagnostic trouble code #s for tranny errors and i'll turn the moon into cheese for ya.

ps i hope you don't like cheese :lol:

You mean besides error code 54?

http://boredmder.com/pics/maxima.org/J30-error-54.png

It's a stretch, but I think it counts. Now where's my cheese moon? :wall:

ruh-roh.
is that on a VE or VG? if it's a VE then i ain't touchin' no dairy.... if that's for a VG then i need to find a cow...

Either or...:shiner:

http://pages.cthome.net/bbachinsky/nissan_ecm_codes.htm

oh... weird. the FSM stops at code 51 on the list in the EC section.


ANYWAYS....

the ECU doesn't care that the TRANNY is gone... it might care that the TCU is gone if i chose to remove the TCU.

But without the TCM, you have no trans control. Indirect, but related.

And my image above is from the FSM so :gotme:

what page? perhaps they list that code apart from the others? EDIT: found it... it was like 3 pages after where i first looked. i found it on pg EC42

but anyways, what i meant was that the a/t spec ECU doesn't actually care if the auto tranny is physically present, it just cares about being able to talk to the TCM. Now, the TCM itself is gonna throw a fit if it can't find it's beloved tranny, but the ECU just cares about that communication link. Take out the TCM and then the ECU might throw a 54. But it will never throw a 54 just by doing a 5spd swap alone.

Same page as all of the other codes that are listed, EC/EF-200.

i think u better off swapping ECU from 5sp as well...better results maybe?

when swapping from auto to manual you have to swap your ECU to a manual so you wont have any CEL i did a 5spd swap like 2yrs ago and im still on my auto ECU since my 5spd ECU got messed up

no need to swap from auto ECU to manual ECU. i've been using my auto ECU after my swap since '04. obviously no CEL since our 3rd gens usually doesn't like to shoot a CEL but would have to pull the codes by doing the self diagnostic test from the ECU. but if the problem came about after the tranny swap just swap the ECU with the 5spd ECU and see what happens. someone on here commented about this a while back to swap the auto ECU with the 5spd ECU because of something to do with air/fuel mixture or something of that matter. i may be wrong.

4th gen = OBDII with transmission codes
3rd gen = proprietary software with apparently 1 possible trans code.

the manual ECU behaves a little differently with respect to the IACV and A/C being on and whether or not the car is in neutral. tho this could be due to the way i wired my clutch start switch and neutral/reverse sensor. i can start my car w/o pushing the clutch, but only if it's in neutral. So since both the shifter and clutch position are hooked in parallel, if I put it in gear and lift off the clutch enough to not be able to start the car (but not enough to actually start engaging the clutch disc) the idle will shoot up to 1200rpm and if I push the clutch again it'll go back down to 750. That's because it thinks I have an automatic, and that I moved it from N or P into R/D/2/L, and is attempting to compensate for TC drag.

a year ago, my heater core blew and wet my computer.... it was done. I got another computer from a " so called nissan specific junkyard" .. when i plugged it in .. my car ran all outta wack ... i pulled the codes w/ the Consult 2 ( i was working at the dealer at the time.. lucky me ) and the ECU part number was for a manual trans car. We discovered at the job that the pin outs are different between auto and manual. To top it all off .. I have a California spec car which also has a different Ecu ..BE AWARE OF THIS !!!.

At this time I am converting my VE auto to VE5. After doing extensive homework,the ECU should not trip a code from doing this swap. Trans has nothing to do with engine control. If u swap to VE 5 Ecu .. u must swap the harness and intake manifold. The so long as u keep the trans computer plugged in and " fool the shift lock module thinking that u are in park or neutral .. u should be ok ... As for the jumping issue ... hmmm.... I agree that being that u had this issue before the swap .. cant be trans related. I am thinking ya might have a bad AAC valve

I was not having this issue before the 5speed swap...

sorry about that ... must of confused it w/ one of the post .... Does it happen all the time ? ... I kinda wonder is i`ll have the same issue.

Yes it does happen all the time..

the jumping issue is probably the automatic ECU trying to 'compensate' for nonexistant torque converter drag, kinda like mine does with the A/C. My friend's 89SE stock 5spd doesn't do that i don't think.

well this is weird.... today I was coming home from taking matt to work, coasted down the neck of the circle in 2nd, put it back in 1st to get up into the yard.... clutched into neutral just before the car stopped moving and the rpm surged up to 1500rpm in neutral before slowly dying back down to idle....

so maybe i'm part of the club after all... but it could also be vacuum lines or something else... could be coincidence that people who swap trannies might accidentally break a vac line and not notice it until later.

Possible..

i would have had this problem but didn't...

caped i think you was right the first time.
the auto ecu compensatin for the load.
when my ve tranny was on its way out.
i could put it in drive and it not move the engine would rev to 1000-1200rpms.
then go down.
then once the tranny went in car it caught the ecu off gaurd. lol.

ve-5 must feels nice...real nice!

Oh I know you have vacuum leaks...

yeeeeah...... how many did we break? yet one more task to complete once i get paid... i think i'm gonna fix all that, and run it for a bit, and then i'll put in the manual ECU and report back if anything actually changes in terms of how it behaves.

becuz if u got the dough why not upgrade to a performance part if your already replacing the part:hide:

sure you will have better performance with a JWT ecu, or the like

but it's not a necessity... it's a separate mod entirely. ballpark figure i'd say 95% of the 5spd 3rd genners (stock 5spd and swappers combined) on this forum are running a stock ECU... if not more. and more than half of the swappers probably left the a/t ECU in.

I ran a VE auto ECU in my VE manual transmission car for about 1/2 a day.

It ran fine, but no Variable Intake function. I don't recall the rpms jumping like the OP stated.

It did not throw a CEL, but I didn't check the ECU manually for codes.