General What ECU's with work in my 90 Plymouth Laser RS-T??

[Lx89stang05]

im going to be needing a computer for my 90 laser 5spd and i wanted to know what cars i can get to computer out of. thanks mike

 

[huafist]

im going to be needing a computer for my 90 laser 5spd and i wanted to know what cars i can get to computer out of. thanks mike

If it's turbo, you need an ECU from a 90 model turbo FWD or AWD 5 speed DSM. If it's non-turbo, get a non-turbo 5spd 90 model ECU.
91+ ECUs won't work properly in a 90 model without swapping out the power transistor with a 91 model and altering the tach feed.

 

[Lx89stang05]

If it's turbo, you need an ECU from a 90 model turbo FWD or AWD 5 speed DSM. If it's non-turbo, get a non-turbo 5spd 90 model ECU.
91+ ECUs won't work properly in a 90 model without swapping out the power transistor with a 91 model and altering the tach feed.

it doesnt affect the sensors under the hood??, its just the power transistor?? if it is wheres the power transistor located??

 

[sbiggi]

It will run fine on a 91+ after swapping the two wires on the ecu, but your tach will either freak out or not work properly.

To fix the tach you need the 91+ ignitor and tach. The coils them selves are the same.

The ignitor is located on the back of the head, its the 3"x3" plastic thing.

 

[huafist]

It will run fine on a 91+ after swapping the two wires on the ecu, but your tach will either freak out or not work properly.

To fix the tach you need the 91+ ignitor and tach. The coils them selves are the same.

The ignitor is located on the back of the head, its the 3"x3" plastic thing.

Actually you don't need the tach. If you rewire the PTM ("ignitor"), feed the dash tach the signal from the coilpack, and send the ECU the tach signal from the 1991+ PTM, you're good to go. But yeah, you still have to swap pins 6 & 14 on the ECU harness.

 

[sbiggi]

Actually you don't need the tach. If you rewire the PTM ("ignitor"), feed the dash tach the signal from the coilpack, and send the ECU the tach signal from the 1991+ PTM, you're good to go. But yeah, you still have to swap pins 6 & 14 on the ECU harness.

Didn't work on mine, as soon as I redid the wiring, my tach no longer functioned at all.
Swapped in the tach from a 93 and it works perfect now. I followed some directions on line, but I dont remeber feeding the tach seperatly from the ecu signal.

I guess if you follow these http://www.ecanfix.com/users/mdhamilton/ecuconversion.html
you need to do the tach.

If you do it this way http://www.dsmchips.com/1990ecu.html
Your stock tach will work.

 

[huafist]

Didn't work on mine, as soon as I redid the wiring, my tach no longer functioned at all.
Swapped in the tach from a 93 and it works perfect now. I followed some directions on line, but I dont remeber feeding the tach seperatly from the ecu signal.

I guess if you follow these http://www.ecanfix.com/users/mdhamilton/ecuconversion.html
you need to do the tach.

If you do it this way http://www.dsmchips.com/1990ecu.html
Your stock tach will work.

You have to feed the two signals seperately because, as Jeff O. states in that last link, the signals are inverted between the two.
They'll both get you to the same goal, I'd just rather not replace more parts than I have to.

 

[90blacktsiawd]

If it's turbo, you need an ECU from a 90 model turbo FWD or AWD 5 speed DSM. If it's non-turbo, get a non-turbo 5spd 90 model ECU.
91+ ECUs won't work properly in a 90 model without swapping out the power transistor with a 91 model and altering the tach feed.

He doesn't have to use a 5 speed ecu. An auto one will work since the programming for that won't do anything.

And if your going to be replacing the ecu i suggest you try to find yourself an eprom ecu. Might as well do it now while you have to change it anyways then do it later and pay for another ecu. 90 eproms can be a bi*** to find but they are out there. And just as a precaution you could get the caps replaced in the ecu while it's out incase they decide to leak on you later.

 

[huafist]

He doesn't have to use a 5 speed ecu. An auto one will work since the programming for that won't do anything.

And if your going to be replacing the ecu i suggest you try to find yourself an eprom ecu. Might as well do it now while you have to change it anyways then do it later and pay for another ecu. 90 eproms can be a bi*** to find but they are out there. And just as a precaution you could get the caps replaced in the ecu while it's out incase they decide to leak on you later.

Auto ECUs are programmed for 390cc injectors, and if memory serves the fuel maps are a little different. If you get an A/T EPROM ECU you can get it reprogrammed it for the right injectors, but if it's non-EPROM don't try it.

 

[90blacktsiawd]

Auto ECUs are programmed for 390cc injectors, and if memory serves the fuel maps are a little different. If you get an A/T EPROM ECU you can get it reprogrammed it for the right injectors, but if it's non-EPROM don't try it.

Good call that totally slipped my mind. If you have some sort of fuel control im sure that could be handled. But im thinking about 2g's where they all have 450's.

 

[huafist]

Good call that totally slipped my mind. If you have some sort of fuel control im sure that could be handled. But im thinking about 2g's where they all have 450's.

2G's are the same - the ECUs are identical, right down the part number.

 

[Lx89stang05]

ok guy thanks for the quick post.