st205 into st185 swap faq/ and parts compatibility

CMS-GT4

Active member
No time to summarize, but you may get questions answered now and then.
TO swap the alternator, just change the plug on the harness. Remove the 185 plug, and solder the st205 plug. This is what you will be doing for all the items that require a new plug.

I know its a lot, but I suggest reading the whole thread, and take pics and notes of all your vacuum lines on the 205 engine. It would also be wise to post your pics and progress here as it will help some help you if you have an issue, and it also add to the data of what one has to do to do the swap.
 

aus jd 2703

New member
ok i swapped the plate of the 185 compressor to the 205 compressor so the hard lines will mate up and was just going to cut the wires and put the 205 plug on the 185 loom, also the pressure sensor from the st205 is a different thread to the 185 should i find an adapter or will the 185 sensor work? im planning to run r134a btw
next ill be changing the evaporators around so i can run 185 hardlines but a r134a expansion valve.
does this seem right to u guys? will this work? cheers
 

CMS-GT4

Active member
I ended up just going back to my 185 compressor. I did not seal the 205 compressor well, so it got corroded inside.

BTW: Make sure you go find the download for the 185 and 205 BGBs. I suggest buying a 185 BGB if you can.

Keep the 185 harness, and only swap the plugs, that you need to swap. Learn to read wiring diagrams if already can't.

Which pressure sensor do you mean? On the AC? Or boost? You will need to make some adapters for a couple of vacuum lines.
 

CMS-GT4

Active member
I can not remember from memory. I don't have my car right now, but honestly if your 185 AC works, I would just use it. Remember to put some silicone grease of some sort on the connection plate. I ruined my 205 compressor cause I did not do that.
 

aus jd 2703

New member
ok is it possible to run a st205 engine of a 185 ecu and loom?
what sensors need replacing and can i replace all sensors? the water elbow is got me worried?
just nt sure im informed enough to do the 205 swap so wanna be sure before i jump in over my head
 

CMS-GT4

Active member
The questions you just asked are explained early on in this thread. If you take time, read it and take notes then you can decide if you are over your head. Scotts posts have the most info, and later on they are applied and verified or mods to his plans need to be made. Running a 185 ecu is a waste. It would not work anyway, two different air reading systems. MAP vs MAF.
 

aus jd 2703

New member
Hey has any one figured out a way to wire the ecu and intercooler up so it doesn't throw a code at all?
Also I have an early 1990 3sgte so I don't have te1 and te2 what did u guys do here?
Cheers
 

CMS-GT4

Active member
aus jd 2703":a7gyp5vx said:
Hey has any one figured out a way to wire the ecu and intercooler up so it doesn't throw a code at all

It requires all the 205 connectors. There is something special how the 205 plug is wired to make it work. So if you have a 205 clip, you can pull the wires and make it work, if not you are best doing the code 54 fix.

aus jd 2703":a7gyp5vx said:
Also I have an early 1990 3sgte so I don't have te1 and te2 what did u guys do here?
Cheers

On my notes those are listed as "check connectors." Its been a few years so I do not remember what that means.

Now on the 1990 BGB it looks like the te1 is listed. It is just marked as T but the description is t-e1.
I am not sure about te2 though. You may want to do some research and find out if it is somehow related to OX. Some people in this thread did this on a 90-91 model, so you may want to PM them and post your findings here.

http://www.celicatech.com/imagearchive/ ... /FI/FI.htm

Direct link:
http://www.celicatech.com/imagearchive/ ... I/FI95.htm
 

aus jd 2703

New member
yeh i worked it out looks like ill be stealling 4 or so wires from the 205 loom for the inter cooler, i may also run tvis as my tham was using cold start injector but that wont work as it doesnt go to ground.
leving all the st205 air con stuff unconnected,
this all sound right?
 

CMS-GT4

Active member
If you don't use tvis look at your egr wires. That may be another solution. I would suggest plugging in the ac wires correctly at the ecu even if you do not run an AC. I found the wires unplugged make the car run poorly. I am still trying to figure out why, because this is what keeps me from running my AC at the moment.
 

CMS-GT4

Active member
If no one responds here, I would suggest making a thread on ctech about identifying those pins. There are a few wiring experts over there, and you might find out exactly what you need. I never messed with 90-91 wiring so I am not too much help in that respect. I have a feeling there is something on the 90 harness that is the same thing, it just might be noted different between the years.
 

celicat93

New member
So if you had to do another one of these, having learned all you have and the notes you've taken, how long do you think it would take to do it again? My 185 transmission is in need of major work and I've been considering doing a 205 swap, considering that the 205 transmission is stronger, why not go for the upgrade across the board? Get the extra ponies and the WTA IC, etc. I have to say that the difficulties you've faced are intimidating, but as I look at nearly a $3000 price tag to rebuild my 185 gearbox, it brings me back to this idea again.
 

CMS-GT4

Active member
If I had it to over again, and all the tools and parts I needed, I could do it in a month. Likely less than that, but I am trying to overestimate due to the factor of "life."
 

celicat93

New member
CMS-GT4":2vdm365p said:
If I had it to over again, and all the tools and parts I needed, I could do it in a month. Likely less than that, but I am trying to overestimate due to the factor of "life."

That's always a good factor include. Thanks, that's encouraging!
 

aus jd 2703

New member
hey guys im a lil stuck ive got the engine all wired up but i need some pins so i can create some wires for the intercooler.
now ive checked and the st205 pins are different as the changed the locking mechanism in the plug so thats a no go, so i need to get some pins that fit in a 1990 plug, does nay one have any ideas?
i dont think my wreckers will let me cut the plug off with out taking the whole looms which cost $$ and imo nt worth it.
does any one know where u can buy just the pins?
cheers
 

aus jd 2703

New member
hey guys has any one wired up a ecu and engine that has an exhaust gas temp sensor?
where did you guys run the egt wire to?
i cant work out if it goes to cco or egw but from what ive read it goes to cco.
any ideas or experiences?
 

CMS-GT4

Active member
It is not needed so it will run fine without it. Just cap the bung where it goes or buy a down pipe.
 
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