I bet this will stump you as it does me..

[skyhigh350]

Hey guys, First off I want to say hi. I'm a member over at mitshu forums, and also on Chevy truck world, fordtruck world, offroadworld, and l13. I have been into the older 350 small block stuff for a long time, but just recently I decided to tackle somethign else. I bought a 90' gsx, and a 91'gsx, in hopes of building one nice car. The 90' has a bad body, however it had a great engine ((bad wiring harness)-got fryed due to a batt short on hood) a 3 inch stainless exhaust, a apexi timer, guage pods, face blue green gauges and a gs interior. The 91' had a terrible leather interior, a blown engine, and a perfect body, sunroof and all options. I swapped engines from the 90' to the 91'. It went well and I also did a timing belt, and a few other mods. I swapped interiors, the 3 inch exhaust and all other aftermarket mods to the 91' It is one sweet car. The 91' ecu wouldnt allow the eninge to run, so I swapped in the 90' ecu.. It works well, however the car will only run for a minute at its best (let me tell you it is fast lol) then it will dy down and load up and barley rev.. It seems like once the ecu goes to take over enigine controls, it will do this. I replaced the fuel pressure regulator, the coil pack (also everything electrical dealing with spark.) The car shows a check engine light for a few seconds while it is in rough run mode. I pulled the vacume off of the egr in hopes that it would be the that, however to no avail, it didnt work.

Does anyone have any informtion regarding this trouble? I have been working on it for about a month now, and once it runs good, I am to sell it to a friend. Two things differant between the 90' and 91, is the ecu, and the TPS (throttle positions sensor)

Thanks in advance..

rob

[niterydr]

So you are attempting to use the 90 ecu with a 91 motor and a 91 harness?

There is a generation split between 1990 and 1991. The 1990 throttle bodies are different, cas/transistor wiring is also different.
www.vfaq.com is your friend on this one .

[skyhigh350]

Thanks for the link. I am using the 90' engine in the 91' eclipse. With the 90' ecu.. I will check the link.

[niterydr]

Alright.
So what did you do about the cas sensor? That is different at times as well.
You'll want to swap on the 91 cas, 91 tb, 91 transistor, and then move a few pins in the ecu.
Go to http://www.dsmchips.com/1990ecu.html for more info on the ecu stuff.
I don't think it is on vfaq anymore, sorry for the bad link.
Your best bet?
Swap in the 1991 ecu (if it is a good ecu, check the caps). And also swap in the 1991 transistor, coil pack assembly, tb, and cas

[skyhigh350]

Thanks again for the help. You seem to know this well. This cas you speak of.. I am lost at that one.


*edit**

I installed the 91' coil pack, and power tr unit.

I do believe the ecu is shot on the 91' because it sends no spark.

[niterydr]

Sends no spark? Yeah it could be a dead ecu.
Then you get to do some wiring my friend, or find another 91+ ecu. (I"d recommend the latter).
CAS=Cam angle sensor. The later the year (1g) the better the sensor. It would be best for you to get a 93-94 sensor if you could.
I've owned 3 dsm's and worked on so many I've lost count, but thanks for the compliment!

[skyhigh350]

Ok thank you. I will proceed to find a 91' ecu, but before that I am going to change the CAS, and also the tb and TPS sensor. Therefore everything on this engine is 91'. I will check out this wiring a bit more to see if it may help my application..

Originally Posted by niterydr

Sends no spark? Yeah it could be a dead ecu.
I've owned 3 dsm's and worked on so many I've lost count, but thanks for the compliment!

Sure thing, I am just getting into this, it's a new thing for me.. If you ever have any v8 questions I be sure to know lol..

[skyhigh350]

Wel after further review of those links..

I have noticed this page.
http://www.ecanfix.com/users/mdhamilton/ecuwiring.html

So i think the only differance with the ecu would be pin 6 and 14.. Is this true? If so all that would be in order is to switch the pins in order to use the 90' ecu.. Of course with a detailed note explaining why I did this taped to the 90' ecu for future owners lol..


edit**
1. Deal with the ecu wiring first. The only difference between the 1990 and the 1991-94 ecu pin outs is pin 6 and 14. Just swap these two pins by cutting and soldering and heat shrinking. (or just pull out the pins)

[skyhigh350]

I changed pin 14 and pin 6.. The car drives too good.. I also switched the vacume lines to the correct position on the throttle body because someone had them backwards.. All I can say is this site rocks, and thanks for all the help! I hope this thread can be used to teach someone else in the same predictment.. Too bad I have to sell this..

[Matt D.]

Kick ass! Glad to hear all is well.

[niterydr]

Originally Posted by skyhigh350

I changed pin 14 and pin 6.. The car drives too good.. I also switched the vacume lines to the correct position on the throttle body because someone had them backwards.. All I can say is this site rocks, and thanks for all the help! I hope this thread can be used to teach someone else in the same predictment.. Too bad I have to sell this..

Glad it worked for you, it is what we are here for .