1G 90 vs 91 DSM's

[codeofdastreets]

Hey I was just curious of what the difference between the 1990 and the 1991 DSM are?

 

[steve]

Some of you guys are screwing this up, 91's could also have the early trans with the 22 spline output shaft...

Only the first month of 91 builds.

 

[350war]

My '91 has an oil cooler. I thought they put the oil cooler on all turbo cars. Or is it a different style oil coolers on the '90?

 

[codeofdastreets]

That's funny because I've never come across a 90 that had one and believe me I've searched every yard I could find for one. Maybe it's an East/West thing for eproms or something.

Anyway, codeofdastreets, it is possible to use the 91-94 ecu in the 90. Heres a few articles about the wring differences.

http://www.dsmtuners.com/forums/art...4-ecu-swap-into-1990-dsm-ignition-wiring.html
DSMChips.com | DSM ECU Chips Enchanced by Keydiver
http://www.dsmtuners.com/forums/bolt-tech/213438-91-t-body-cas-90-a.html

I appreate it thanks.

 

[steve]

My '91 has an oil cooler. I thought they put the oil cooler on all turbo cars. Or is it a different style oil coolers on the '90?

Yes they all have (had) oil coolers, on the 90 it's an air cooler and on the later cars it's a water cooler.

Speaking of oil, the 90 and most of the 91 cars have straight cut gears in the oil pump. The 90's also have a different oil pressure regulator in the head.

 

[350war]

Got it. Post #8 kinda threw me.

 

[93 GSX TURBO]

Is this why on some 90´s and 91´s the fuel and rpm gauges wont work?

The ECU issue.

 

[roughidle]

My 90 does not have abs....

 

[steve]

Is this why on some 90´s and 91´s the fuel and rpm gauges wont work?

The ECU issue.

Tachometer, maybe. If the car has a 91+ ECU in it without a tach converter or swapping the power transistor, or swapping the tach and the rest of the ignition can cause it but so can a missing 90 noise filter.

Fuel gauge no.

 

[willydsm]

I have 90 TSi. The ECU in it did not work right, I have a 91 EPROM in it now and had to swap pins 6 and 14. Works great other than the tach but I have an aftermarket tach so that really doesn't matter to me.

Mine also does not have ABS, I really don't care for ABS anyways. TB on a 91+ have more vac ports 3 or 4 on top note sure, and a 90 only has 2.

Also used to have a 91 Eclipse GS turbo FWD, seemed a little faster in the top end, AWD deff launches better. I have been told FWD have a taller 5th gear and the n/a 2.0 is even taller than the turbo.

 

[DSMopar]

Only the first month of 91 builds.

Oh? And what month was that? My finding is most 91's have 22 splines... possibly only the late ones had 23

 

[steve]

Oh? And what month was that? My finding is most 91's have 22 splines... possibly only the late ones had 23

CAPS says that on manual AWD cars the 22 spline transfer case, MD739053, was used from 1989.03.1 to 1990.06.3 and from 1990.07.1 to 1994.05.1 the 23 spline MD785205 was used.

Production of 1991 model AWD cars started 1990.06.2 so the first couple of weeks they got 22 spline transfer cases.

 

[codeofdastreets]

CAPS says that on manual AWD cars the 22 spline transfer case, MD739053, was used from 1989.03.1 to 1990.06.3 and from 1990.07.1 to 1994.05.1 the 23 spline MD785205 was used.

Production of 1991 model AWD cars started 1990.06.2 so the first couple of weeks they got 22 spline transfer cases.

Ok now let's say I have a 90 GSX but break a tranny or transfercase at the track. Lucky I have a 91 tranny and tranfercase on the side. How would I make this work in my 90 GSX? Would have the get a 91 driveshaft?

 

[steve]

Output shaft on the transmission has to match. The drive shaft fits.

To swap you have to open the trans, take off the VCU, swap the output shaft to a 23 spline, reinstall VCU, close up the trans and fill it.

 

[Rex2342]

CAPS says that on manual AWD cars the 22 spline transfer case, MD739053, was used from 1989.03.1 to 1990.06.3 and from 1990.07.1 to 1994.05.1 the 23 spline MD785205 was used.

Production of 1991 model AWD cars started 1990.06.2 so the first couple of weeks they got 22 spline transfer cases.

Ok now let's say I have a 90 GSX but break a tranny or transfercase at the track. Lucky I have a 91 tranny and tranfercase on the side. How would I make this work in my 90 GSX? Would have the get a 91 driveshaft?

If you swap both the transfer case and trans to a 23 spline it'll be fine. If I remember right when I did mine I just had to switch the shifter brackets over from the 90 to the new trans. Everything else bolted up fine. However if you only have the transfer case you'll have to swap the output shaft on the trans to the 23 spline or it won't bolt up.

 

[brandon1239]

I've had two 90's and they both had EPROM ECU's. just picked up a new 90' the other day and hopefully that has one too. hopefully ahah

 

[DSMopar]

CAPS says that on manual AWD cars the 22 spline transfer case, MD739053, was used from 1989.03.1 to 1990.06.3 and from 1990.07.1 to 1994.05.1 the 23 spline MD785205 was used.

Production of 1991 model AWD cars started 1990.06.2 so the first couple of weeks they got 22 spline transfer cases.

Mines an August build and it had a 22 spline early gear-set trans in it. It was removed at 106k miles and the VINs match, it's never been out of the car.

 

[codeofdastreets]

I"ll be checking my ecu today, hopefully it a eprom..

 

[steve]

Mines an august build and it had a 22 spline early gear-set trans in it. It was removed at 106k miles and the vins match, its never been out of the car.

They must have been out of the right trans that day.

 

[Morphius]

CAPS says that on manual AWD cars the 22 spline transfer case, MD739053, was used from 1989.03.1 to 1990.06.3 and from 1990.07.1 to 1994.05.1 the 23 spline MD785205 was used.

Production of 1991 model AWD cars started 1990.06.2 so the first couple of weeks they got 22 spline transfer cases.

What does caps list for ABS components for a 90?

I've got quite a few 90 cars and none have ABS and I have yet to see a 90 with ABS. (Doesn't mean it's not possible) Like others here, I'd swear they didn't. Like I read it in the VFAQ or other acceptable source.

 

[steve]

What does caps list for ABS components for a 90?

I've got quite a few 90 cars and none have ABS and I have yet to see a 90 with ABS. (Doesn't mean it's not possible) Like others here, I'd swear they didn't. Like I read it in the VFAQ or other acceptable source.

I guess not. Never had a reason to look but ABS isn't in the service manual or the 1G technical manual and CAPS lists the earliest ABS modulator as 1990.06.2.

I though I had seen a car with both the electric cruise control which were used on 90's and ABS but after 20 years it's not surprising to mix up a few facts.

 

[codeofdastreets]

Well there"s one more 1990 DSM that don"t have a EPROM ECU .. Gotta swap it to a EPROM ..

 

[DSMopar]

They must have been out of the right trans that day.

No, they probably still had 22 splines...

CAPS isn't the DSM bible...

 

[steve]

CAPS isn't the DSM bible...

, no it's just what every dealer uses as the absolute reference for what parts go in what car. It may not be perfect but it is as close to the bible as we get.

 

[DSMopar]

, no it's just what every dealer uses as the absolute reference for what parts go in what car. It may not be perfect but it is as close to the bible as we get.

It's just a parts reference, point is it's obviously not right. And if you have a 91, there's like a 50% chance it being 22 spline...

 

[steve]

It's just a parts reference, point is it's obviously not right. And if you have a 91, there's like a 50% chance it being 22 spline...

Right now your argument is ignore what the manufacture says and listen to you instead. So then, where exactly are you pulling this 50% number from. Your car as proof?

I've talked to the guys who worked the line back when these cars were built at factory MOD about inventory management, since there does seem to be a bit of randomness when you look at parts distribution. JIT scheduling was still pretty new and it wasn't unusual for a boat to be late from Japan. When given the choice between shutting down the production line or using a different part that fit, what do you think they did?