ST165: '88 vs. '89 ECU difference?

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Aleks

New member
Hi all,

I was wondering if anyone tried switching '88 and '89 st165 ECU's. They have different part numbers, 89661-20360 and 89661-20361 correspondingly. I've read that in the -20361 ('89) version, maps for cold driveability had been improved, but aside from that, no hardware changes had been implemented. That is, I can use a '89 ecu in a '88 alltrac and vice versa with no compatibility issues. Is this true?

Mucho thanks :)

Aleks
 
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Rider

New member
This aint gonna help you too much since my car is a JDM GT4, but I have used an 87 ecu in my 88 with no trouble at all.

I would say for sure that there will be no trouble with doing what you propose, they are the same engine afterall...
 
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Aleks

New member
Rider: you guys are lucky out there, getting jdm cars! :) About the ECU, Toyota catalog shows only one part number for jdm st165 computers across all years, 89661-20270. So in your case you definitely can't go wrong using a different year ECU...

Rick: have you actually tried '89 ECU in your alltrac, in the end? I remember you were interested in this too, and there was a post in the old forum, regarding a technical service bulletin on st165 that addressed cold driveability issues. I recall now that one of the board members actually got a newer ECU from Toyota, but don't remember if there were any real advantages reported.

Thanks guys!

Aleks
'88 st165
 
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Rick89GTS

New member
Aleks, I wish I had an extra 89 ECU to try! I know FlyinBryan has an 89 ST165 and I don't believe he has this problem.

I recall the post but don't recall which member it was. I think he was a Toyota tech and I recall him saying that it solved his problem.

Seems silly that Toyota wouldn't think of doing that though - I mean, how many other turbo cars go through this?
 
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spoolin_gt

New member
i also wanted to ask....

i got an ecu thicker than usual..and has 2 circuit boards on it.....which gen is it from??
 
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Aleks

New member
Allrighty, I decided to try and got me an '89 ECU (89661-20361 p/n)! It works fine with the '88 wiring and sensors. In fact, Toyota lists the -20361 unit as the only replacement part for both years.
I haven't driven it much yet, but first impressions are good. Have to wait for a real chilly morning for a good test though, which are not that frequent here in Southern Cali :)

Rick, I remember that Toyota tech guy's post too, but couldn't find it, since it went with the old forum...

Spoolin_gt, do you a part number for thar ECU you have? Then we could try to see for what model it is...

Thanks everyone for suggestions!

Aleks
'88 st165
 
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Rick89GTS

New member
Aleks":1ql09puz said:
....I decided to try and got me an '89 ECU (89661-20361 p/n)! It works fine with the '88 wiring and sensors. In fact, Toyota lists the -20361 unit as the only replacement part for both years....
Click to expand...

Aleks, did you buy it from the dealership? If so, how much?
 
A

Aleks

New member
Rick, I got a used ECU from a dismantler in Tewksbury, MA (Penney's Auto). The price was US$120 shipped. New from a dealer, it would've cost ~$700 plus $100 core (even at online discount like Jay Marks). I found my ECU via www.car-parts.com, and it appears that there are quite a few st165 ECU's out there for sale, mostly '88s, but '89s also can be found. Good luck to you if you decide to try a '89 ECU too :)

Aleks
'88 st165
 
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Rick89GTS

New member
Old post but I managed to find myself an '89 ECU, part no. 89661-20361. Will give 'er a try and see if the cold driveability is any better.
 
88gt4DE

88gt4DE

Active member
That is an updated ecu for cold driveability problems ( which mine has ) I had never been able to find that part # 89661-20361. Its from an old toyota tsb from 2/89 . Good find man !!! Let me know if you find another !!!
 
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Rick89GTS

New member
Yes, they seem to be quite rare. I picked it up a few years ago and forgot to put it in b/c my 165 was off the road at the time. I actually think I got it from a seller from this site. They do pop up on Ebay once in a while, but most are 88's. I saw an 89 in a junkyard once years ago and regret not grabbing it. Good luck on your search!
 
88gt4DE

88gt4DE

Active member
Ehhh its not an emergency but if I stay with the 165 ecu Id like to try that one. My current one has the fried idle motor resistors which I plan to fix at some point. Your more likely to find it up yer way then I am down here with temp differences being colder where you are. To date I have never seen one in a junkyard anywhere ...
 
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Rick89GTS

New member
Popular Machanics, March 1990:

Note:
89 ECU has grey connectors vs 88 ECU has yellow connectors
 

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