90 motor, tranny, ecu into a 91

[Got Rice Galant]

Ok. I wrecked my 1990 fwd laser. A buddy of mine just painted his 91 fwd talon and the motor's now junk. His tranny also has a bad 2nd gear grind. My motor and tranny are fine so I decided to pick his up for $1500. Brand new paint job, lowering springs, big 16G, front mount etc.

Everything I keep comming up with says I can swap my ecu (chipped for 550's and 2g maf) from my 90 to his 91 and only have to swap pins 6 and 14. However, I am putting my 90 motor and tranny in also. Can I still run my 90 ignition components or do i have swap to the 91?

My searches also came up with I have to swap my shifter cable's and bracket. Do I have to swap the bracket on the tranny? I have both complete so whatever the easiest way please let me know.

Thank you very much for your time.
Pete

 

[19Eclipse90]

Swap everything from the base of the shifter in cab to the bracket on the transmission. If you swap the pins on the ECU, I believe you can run 91 coil as long as you run the 91 harness as well.

 

[Rex2342]

If your using the 90 ecu I believe you'll also need to swap the guage cluster from your 90 so the tach will work. I may be wrong though. I haven't read much about swapping 90 parts into the 91. Usually it's the other way around. The 91 ignition components are also slightly different. The plug for the 91 power transistor is different and there will be some issues with the noise filter also. 90's have a seperat filter where as 91's are part of the coilpack itself. The easiest way to do it would be to use all the 91 components and just get another eprom ecu. Do you really have a working 90 eprom??? If so you'll be able to sell it for top dollar and it should be more than enough to cover the cost of the 91 eprom.

 

[Got Rice Galant]

Do you really have a working 90 eprom??? If so you'll be able to sell it for top dollar and it should be more than enough to cover the cost of the 91 eprom.

Thats a great idea. I could always just run 450's and the stock 91 ecu until the 90 eprom sells. Thanks for the idea. I might just do that.

 

[pitbull419]

If your using the 90 ecu I believe you'll also need to swap the guage cluster from your 90 so the tach will work.

\

Yes the tach signal wire is different.As is the ground wire.
It would be easiest to just use the 91 ecu and ignition componets.
If that really is a 90 eprom some people would kill for that ecu.
Here is how you can be sure.
http://www.dsmlink.com/faq-eprom.html
Lets just say some people would frown upon you, if you mess up a perfectly working 90eprom.

 

[oldman]

Yes the tach signal wire is different.As is the ground wire.
It would be easiest to just use the 91 ecu and ignition componets.

You guys are getting confused. To use the 90' eprom in the 91' chassis, all that needs to be done is swapping pin 6 and 14 while still using 91' harness and ignition components. It's when going the other way around, 91' ECU in a 90' that creates problems with the tach signal, even then, there are already simple fixes out there without having to swap everything over.

http://www.dsmchips.com/1990ecu.html

19Eclipse90 had it exactly right.

 

[pitbull419]

Umm....He will still be using the 90 ignition componets.
Hes not just putting in his ecu hes putting in his entire engine/ignition setup in.
Now if he switches to the 91 setup all he has to do is switch the pins and brackets.
Which is why I said it would be easiest to use the 91 ignition componets.

Correct me if im wrong.

 

[oldman]

Umm....He will still be using the 90 ignition componets.
Now if he switches to the 91 setup all he has to do is switch the pins and brackets.

Why can't he just use the 91' ignition components that are already in the car and simply swap ECU and motor over?

 

[pitbull419]

That is what he is asking.
If he should use his 90 componets or the 91 componets.
Thats why I said to use the 91 componets.

 

[oldman]

That is what he is asking.
If he should use his 90 componets or the 91 componets.
Thats why I said to use the 91 componets.

Then I mis-understood, I thought you were implying he couldn't use his 90' Eprom with his 91' ignition components, I would never give up the 90' eprom especially if it's already chipped for his current injectors when all it takes is to swap pin 6 and 14.

If your using the 90 ecu I believe you'll also need to swap the guage cluster from your 90 so the tach will work. (untrue)

Yes the tach signal wire is different.As is the ground wire.
It would be easiest to just use the 91 ecu and ignition componets.
If that really is a 90 eprom some people would kill for that ecu.

 

[pitbull419]

Never.I would never give up a 90eprom chipped for 550's to run a 91 ecu with 450's.
I was telling him to use his 90 eprom,91 harness and 91 ignition componets.
Switch pins 6 and 14.Swap all the shifter stuff and be good to go.

If your using the 90 ecu I believe you'll also need to swap the guage cluster from your 90 so the tach will work.

Oldman your correct this is untrue.
I was in no way going along with this.
I was stating that your 90 and 91 ignition componets use a different tach signal
Its your ignition componets and gauge cluster years that determin if your tach will work coorect.

 

[oldman]

It's all good, it was just simple misunderstanding, I just wanted clarify it for OP.

 

[Got Rice Galant]

You guys are awesome. Thanks for the input. I do want to eventually get a new dsm chip as mine doesn't have the stutter box (only a stage 1) and would also like to convert the stock boost gauge to a knock gauge so maybe I will sell my 90 eprom with the chip and just try to find an eprom 91-94. I don't plan on turning the boost up until next year. The roads are already getting too cold for a fwd to hook. I'll wait till after winter.

Ignition components I need to swap over to my motor:
Coil
Ignition module under the coil
Cas
Throttle body

Anything else?

As for the tranny, can I just swap the bracket on the tranny that holds the sifter cables to a 91?

 

[oldman]

As for the tranny, can I just swap the bracket on the tranny that holds the sifter cables to a 91?

Already answered, that also include the cable itself.

Swap everything from the base of the shifter in cab to the bracket on the tranny.

In addition, you will also need to swap the transfer case due to spline count, 23 on 91' vs 22 on 90'.

 

[Got Rice Galant]

I understand that was the answer I got. I was asking if there was any other way around it. I was under the assumption that there was an easier way than swapping everything from the 90.

 

[oldman]

I understand that was the answer I got. I was asking if there was any other way around it. I was under the assumption that there was an easier way than swapping everything from the 90.

There is another way but it's not necessarily easier, you have to knock out the roll pin that holds the main shifter bracket to the shaft that goes into the transmission from both trannies and swap the main brackets as well as both secondary brackets, I can tell you now those roll pins on older trannies are next to impossible to remove.

 

[Got Rice Galant]

Well thank you. I appreciate all the information.

I'm going to disregard your post about the transfer case as both cars are fwd. . Just pickin on ya.

Thanks again.
Pete

 

[oldman]

I'm going to disregard your post about the transfer case as both cars are fwd. . Just pickin on ya.

Doh!!!!

 

[Got Rice Galant]

I tried searching here and ebay for a 90 eprom and only found a few. $250-$300. Seems a bit high for a used ecu. I really hate people who price their stuff to high so how much do you think i should ask for the 90 eprom already chipped for 550's?
I was thinking $200 for the ecu or $350 for the ecu and injectors.
Let me know if you think its too high or too low. Thanks.
Pete

 

[Rex2342]

If all you have to do is swap the pins then keep the 90eprom (or sell it to me Like I said before I wasn't sure about swapping a 90 ecu to a 91. I've done it in reverse but never the way your doing it. If oldman says you can just swap the pins and use the 91 ignition components just do that. It would be the easiest and cheapest way to do it. A 90 eprom is a rare piece so hang on to it if you can. I've seen them sell for as much as $450-$500!!!! Since your is already setup for you I would keep it na d make it work.

 

[pitbull419]

Use the 91 ignition componets, 90 eprom,switch the pins and swap brackets/cables.Then your good to go. That is the easiest and best way to do it.Its not often that the easiest is also the best way.

IMPORTANT: While you have the 90 eprom out you should get new caps installed.You wouldnt want leaking caps to ruin a good 90 eprom.Chances are if you have not changed them they have not been changed.

 

[Got Rice Galant]

Its technically not set up for me as i want to get rid of the 550's and I want to get a different chip. I'm just going to run the stock 91 ecu with the 450's and the ported 14b thru the winter and start getting everything i need before summer hits. I want to go with a 50 trim and 680's.

So how much do you guys think I should sell the 90 eprom with the dsm chip and the 550 injectors for? Thanks.
Pete

 

[amiturbo]

Did you end up doing this? Because i'm doing the samething really but i'm converting my 90 motor to 91 components, turns out you need the tb,tps,cas,fuel rail (it's angled differently then the 90),ignition module,coil......as well as you have to cut an engine to interior plug harness from a 90 and put it on the 91+ harness ### it won't just plug <-----i'm in the process of this because i was told to get a 92 harness before i got the car and it turned out to be a 90 and i trusted they knew what they were talking about. And seriously just stick with the 90 eeprom youll be happy you did.

 

[steelzeus]

You may want to check this out real quick. 1990 vs 91-94 ECU - DSMtalk Forums

 

[steve]

You may want to check this out real quick. 1990 vs 91-94 ECU - DSMtalk Forums

That thread isn't any more special than the dozens I've posted here. DSMTalk stevep = DSMTuners steve.

Bottom line recap since this is an old thread:

Get rid of as much 90 unique crap as you can on the engine except for the oil cooler.
90 or 91+ ECU doesn't matter as long as you swap the two pins in a 91+ car. There are advantages to the 91+ software, use it if you have a 90 EPROM. No gauge cluster issues with a 90 ECU in a 91+ car.
90 transmissions need 90 linkages or extra work, I'd sell the 90 trans and fix the later one.