Who's on first? I said it "does" matter - not that it "doesn't".

At least it does if there was a CA and a Federal model ECU in the same year.

I don't know about the '90/'91 models, but as an example on the '89s there was a Federal and CA ECU. One difference (don't know if there was more than one) was that the '89 CA models had an EGR signal circuit which the Federal models don't incorporate. The '90/'91 models had no EGR, though (at least not the Federal models).

So - if there's both a Federal and CA model for his truck, there may be a difference in the ECU units which would effect performance.

I'm on the lookout for a reasonably priced FSM set for the '90/'91s so I can see if the pinouts are the same for the '89 ECUs with the exception of the EGR circuit. If so, the '90/'91 ECU and distributor can be used on the '89 if you snip the EGR harness wire and you could eliminate the EGR system altogether on the '89 without concern for a performance change.

Frank

who is... dam frank <img src="/forums/images/graemlins/scared.gif" alt="" />, sorry i misread the post <img src="/forums/images/graemlins/drunk.gif" alt="" />, my bad <img src="/forums/images/graemlins/kewl.gif" alt="" />. your batting record is still a perfect 1000 <img src="/forums/images/graemlins/lol.gif" alt="" />. btw, the ecu ive got is out of a 90'cali... dunno if its compatable with a 91', it should be as the major differences were between 89/90' and from what i understand there wernt many changes between the 90/91' models. mitsu service should be able to tell a simple yes or no. as for them not being able to tell you by running the vin if its cali or federal... its bs. sound like theyre just being lazy. when they did it for me, they took down the numbers and researched it. it did take them a little while, about an hour if memory serves for her to get back to me on it. if youd like call the same mitsu dealer that i use... ken garff mitsubishi in slc, their number is 1-800-451-4760 ext.4 (for parts, gotta ask to get transfered to service). theyve been great to me, so you shouldotta call them up and tell them where you are and how you were refered by a slc native because of their superior customer service... buttering them up always helps in the end result <img src="/forums/images/graemlins/cheers.gif" alt="" />.

I believe the '90 and '91 ECUs are interchangeable - the ad I posted says the same ECU is used '90 through '93, but I can't verify that (yet - CAPS CD on the way <img src="/forums/images/graemlins/kewl.gif" alt="" />). IF there were CA and Federal models for those years, it would be necessary to stick to the correct designation.

Frank

[hijack]


I think know where a 90/91 set of manuals can be found.

[/hijack]

Talk to me, Mark - I'm listening. <img src="/forums/images/graemlins/wink.gif" alt="" />

Frank

According to car-part.com, there is a difference in ECUs in 1989 for Cal and Fed models. But for 1990-1991, all montys used the same ECU. <img src="/forums/images/graemlins/kewl.gif" alt="" /> If you go with a used one, you might want to do what I did: Test it in the car first, if it works, pull it back out and order the three electrolytic capacitors it needs. I do not have the special soldering tools to install circuit board components, so I took the ECU and the 3 caps to a local computor repair shop, for $10 they removed the old caps and soldered in the new ones. That was about 2 years ago and the ECU has worked fine.

That would suggest that the only difference in '89 was the EGR circuit. I'll bet the harness was the same in the '90/'91 models as the '89 Federal models and the ECUs can be swapped year/year in the Federal models as long as you change the distributor.

I still want to check the pinouts and all of the sensors for cross-reference, though.

Frank

Well, it just goes to show you it's not what YOU (I!) know, but WHO you know. I'm glad I know you guys.

Grass13, your mitsubishi number was most helpful. Thanks! That guy(Allen) took 2 seconds to tell me I have a Federal model.

Now, should I try your california ecm? I haven't heard from Toby. What do you think Frank? <img src="/forums/images/graemlins/confused.gif" alt="" />

Thanks again! I'm at my ropes end here and hanging on by a thread here.

You need a '90/'91 and trust the info that IdahoJack gave you that there was no difference for CA.

According to the ad, '90-'93 will work, but I wouldn't trust that unless you have the part #s verified... I notice that car-part.com lists the '92-'94 in a separate group.

If you can't get one from someone on the forum, call a local junk yard or try calling the dealers on car-part.com that don't have a price listed and see what they want for one. There are 5 with no listed price:

car-part

Make sure you get a guarantee that it's a working unit.

Frank

IdahoJack had some good advice too. I'm just hopeless with soldering though. <img src="/forums/images/graemlins/frown.gif" alt="" /> I'll see if someone will sell me a '90-'91. <img src="/forums/images/graemlins/cheers.gif" alt="" /> Toby or Grass??? bluebirdacrefarm@yahoo.com