st205 into st185 swap faq/ and parts compatibility

CMS-GT4

Active member
Slight change of plans, I wll be using my RC box. Can't get to my '92 box, and I need this car on the road. I am planning a gearbox upgrade/clutch flywheel etc... down the road anyway. Won't kill me to use a higher FD for 7 months or so. I am heading to get the car now. Hope to have it running by the end of the week.
 

InitialD93

New member
u better have it running in time for the meet josh... i might actually be able to keep up this year... holy shit ive done alot to my car since the last meet.. i just realized that
 

CMS-GT4

Active member
I hope to have 245's on some 17x9's by the meet. Plus in the range of 270-290hp. So we will see. :evil:
 

CMS-GT4

Active member
Whats your progress K_trac? I should be giving you a call tomorrow to see what you have sorted out.
 

CMS-GT4

Active member
scothaniel":177y6sfa said:
I have posted a little drawing for which pins to change on the ST185 harness.


Where is this drawing posted? It would be a great reference.
 

scothaniel

New member
Sorry for not responding earlier - had a few issues this weekend that kept me busy. I'll PM my phone number, glad to help where ever I can.

The first time I did the swap, I used the 205 harness and tried to swap the 205 fuse box over - big mistake. The bulk of the issues were because I dont have the BGB for the 205, so I dont have all the diagrams for the secondary systems. I spent a lot of hours repinning the dash plugs and working through the fuse box, checking for proper connectivity. It was a mess. I ended up ditching the harness, then later on swapped over just the 205 fuse box in an attempt to free up 2" of space. I need a bigger engine bay!

The second time I used all 185 harnesses only, and re-pinned the 3 connectors for the 205 ECU, then went through the diagrams to make sure all the sensors were getting the proper voltage. Made the changes I listed before and it worked perfectly. So much easier. I made a little diagram that others have used for repinning thiers.

My last 3 harness projects have been more difficult, and have really taught me some valueable lessons - like keeping the wiring as simple as possible. For instance, I spent all weekend troubleshooting some weird s#&% on one harness without any luck. The engine is a 3rd gen 3SGE converted to turbo, the ECU is from a ST205, the harness is from the 3SGE (had to be lengthened and modified) and the car is a 97 Celica ST. I have a major issue with the ECU / ISC valve and troubleshooting has been an absolute nightmare since none of it is stock. A full weeked and the car is no closer to being on the road... very depressing.

When you leave the internals of the harness in tact, its one less thing to worry about, one more thing to rule out when there is a problem.

Just my 2 cents.
 

scothaniel

New member
Oh - and if you guys have a spare 185 engine harness sitting around, let me know. I need to replace the harness in my car since I've butchered it installing a Link Plus EMS ( harness project #3).
 

CMS-GT4

Active member
Yes, I agree. Simple as possible. If it would be easier using the entire 185 harness, and just repinning it, I am up for that. PM me your number when you get the chance. I will be working long days till wednesday, and plan on starting on this wednesday or thursday.
 

CMS-GT4

Active member
Can you wire a 185 harness to work for a 205 engine/ecu? If so... I love you. At least if you tell me all the details.
 

CMS-GT4

Active member
I think I got most of it figured out anyway. I am taking the BGB and these notes to the shop this week and try and get all this right. It seems as if everything should hook up just fine. Little concerned bout the 2nd temp sensor but it may be OK. I am not using an air box so I think I will put it in the strait intake pipe.
 

CMS-GT4

Active member
So I just finished doing my notes for a 92-93 pin conversion to the 3rd gen, and all I can say is wow. It looks like I may only have to move 2 pins. FPR (Fuel Pump relay) and PIM Turbo Pressure sensor.

Everything else matches up.

All I have to switch after is the install is a couple of wires for sensors on the engine end, and it should be good to go.

Now I just got to make sure I have the info figured out for the code 54 intercooler pump since I will have a fmic.

Here is a link to the 90-91 pin swap to 205.

http://img440.imageshack.us/img440/154/ ... mod1rz.jpg
 

k_trac

New member
Thats cool for you! Shit, wish mine was a 92....oh well

Maybe I will end up going this route anyhow, its pretty much the only thing I got left for the swap. Mabye Ill make progress this weekend.

Kep me posted as to what you got!
 

CMS-GT4

Active member
Make that 4 wires, but still not bad. My confusion now is based on that the first diagram does not have any wired moved to the IC ports. So maybe this means that by having no wires they are not bridging a connection and not throwing a code???? :shrug:

Once this thing is running, we will see if I get a code 54 or not.
 

CMS-GT4

Active member
Had to use the '92 motor mounts and power steering pump.

So there is two more items that can not be used for the swap.

I am having a hard time figuring out what the hell wire goes to what. I guess when they drop in the engine, I will try and match up the temp sensors to splice into.

I will keep you all posted. My project may be delayed due to the fmic.
 

k_trac

New member
Ya, motor mounts dont match up....its too bad, I had them on when I was first putting the motor in then after a little tweaking I realized that only the half of the rear mount was compatable.

I did use my gen3 power steering pump however, it just had a different outlet for the high pressure line, which was a little tricky to work on in the car, but i got it all together.

I think I am going to stick with the 205 harness, the whole this is legnthened now, so I just gotta match up the box, may have some time soon. :shrug:

Let me know how its going man!
 

CMS-GT4

Active member
What did you use to addapt the hard lines to the powersteering pump?

That way I don't have to buy a new one. My old one is fragged.
 
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