I have a brand new loom for a Link ECU (it has no engine electrical connectors)which I am going to use when I reshell the ST205 (project starting soon I hope) I want to use as many new parts as possible for this so the signals etc are as good as they can be (I remember Datajon commenting that there may be some sugnal degridation with nr 20yr old wiring) I know that the link only uses the essential sensors but I`m going to have to buy a load of end connectors...I think that these will be expensive from the dealers or are they not too bad?

I it best to solder them on or crimp them on?

Anyone else built a loom that can offer any advice?

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ST205

Crimped is better.

As for how I'g go about it, I wrote most my thoughs in resonce to Diceman's similar question a while ago

For what you're suggesting

Are you planning to use stock sensors or new custom omes?

If reusing stock thenI think most of the connector "pins" are removable. With a (fair) bit of searching on RS you'll probably find new ones pretty cheap that you can plug into the old housings

I have a suspicion that you won't be able to buy new connectors and crimps from Mr T. You might get bare connetor housings to replace damaged ones but the general consensus seems to be if wire replacement is required you fit a new loom

Buying a good local auto spark lunch and beers might be a good investment for a bit of knowledge harvesting

I can't remember where Don's take wiring monkey lives but he seems a helpful guy

Two main problems with old wiring:

1. The insulation going brittle & becoming prone to cracks when moved (especially the bits that get hot over the engine)

2. Degradation of connectors with age / corrosion.

Toyota seem to use good quality connectors and as long as they are not physically damaged and the seals are intact give little trouble. I have far more problems with new aftermarket connectors after 2 years than OEM after 20.

There is no significant degradation of signals along old wire. Worst case is a bit of oxide along the outside of the copper strands. Any problems will come from the connections.

IMO if the wiring loom is in good condition, I would stick with it and make up an adaptor at the ECU end, or cut the wires from the standard ECU plugs and splice to ECU loom with butt crimps or solder + sleeve (adhesive lined heatshrink)
The standard engine loom carries many wires which have nothing to do with the ECU, such as all the fusebox wiring. Replacing all this would be a mamoth task.

p.s.
If you do use crimp connectors, use the correct proffesional grade tool for them. For connector pins these usually cost a lot of money (in the £100s). If not crimped properly, they WILL be unreliable in a damp automotive environment.

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If at first you don't suck seed, try drier grain.

Reusing the old loom would save alot of hastle....maybe I`ll just remove the old electrical tape and plastic guards and fit new ones.

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ST205

Apparently these are the pibs used on Evos (which look very similar to GT4 pins & plugs) http://www.newark.com/te-connectivity-a ... tt=85C1211

Pin removal tool:- http://www.bmotorsports.com/shop/produc ... ts_id/1083

I also purchased a ratchet crimping tool with proper die set for my new ECU but I am buggered if I can find the part now! IIRC it was from digi-key.

If you buy any pins I wouldn't mind buying 100 with you!

The ST205 loom is much easier than ST185 as engien & body are seperate. ST185 and parts are integrated

Ideally I woudl like to amend the STd ST185 by replacing all ECU/sensor wires for engine but the liklihood is I couldn't afford the man to do it.

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JP
GT4DC Treasurer

Grey St185 RC
Silver BMW E46 M3
Multicolour yawn Honda VFR400
Silver Honda Civic Type-R

check my project thread on how to de-pin the connector plugs. Crimp is my choice, but I may be moving to solder sleeves for easy application.
Tyco/Raychem and a whole bunch of other companies are going to be your best friends soon. Enjoy going through the catalogues. They are lots of fun!

Also check out honda wire tucks. The really competant guys use good materials and equipment with fantastic results:
http://honda-tech.com/showthread.php?t=1693934

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GT Four Adovansu

"I want to enjoy the powerful and nimble agility behavior."

I really need to chase up my tame wiring man to see how my loom is progressing for the track toy build. He has said that crimped is better than solder as the solder is prone to fracture due to vibration. This is much more likely to be a problem with a competition car than road spec.

Its quite a big job (read expensive!) to make up a new loom so I'd probably stick with modifying the stock loom unless you are building a Four for the track.

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Don
GT4DC Chairman
1994 Toyota Celica GT-Four ST205WRC JDM 269bhp @ 0.9bar
1994 Toyota Celica GT-Four Special GT 590bhp @ 1.8bar
1989 Van Diemen RF88/89 Formula Ford 1600
2008 Nissan Patrol GU 3.0L ZD30DDTi 154bhp

I have heard the same regarding crimping vs soldering. A couple of pro solderers have been happy soldering with correct materials and procedure but the average guy will end up making the wire brittle and prone to fracture.

I have also heard of people sealing the crimp join with a glue a well as heat shrink to keep moisture out and reduce corrosion at the join. It must be a good crimp though.

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JP
GT4DC Treasurer

Grey St185 RC
Silver BMW E46 M3
Multicolour yawn Honda VFR400
Silver Honda Civic Type-R

The heat from soldering does indeed make the copper brittle. I've heard that oxygen free cable (OFC) was brought about to reduce this effect although I haven't heard it from a source I trust.
On the other hand, crimp connections are far more susceptable to poor connection due to damp/corrosion.
IMO for joint where there is a lot of movement close to the joint then use crimps. If the wire can be supported close to the joint so there is no movement at the joint then solder.
For wire to wire splices I tend to solder and use adhesive lined shrink sleeving as this ends up fairly stiff and supports the joint over the brittle part.

On our electric vehicles we get far more failure of crimp joints due to corrosion than solder joints due to movement. Similar environment to automotive but less high frequency vibration.

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If at first you don't suck seed, try drier grain.

Classic failure of solder joint where movement is present:



Classic failure of crimp joint due to corrosion/poor connection leading to heat and accelerated corrosion. (blue wire early stages - crimp plastic has heated & shrunk & lost crimp tool marks)




Classic failure of screw terminal joint for same reasons as crimp:

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If at first you don't suck seed, try drier grain.

Would there be any benifit in using the new wires but soldering the old connections + a bit of wire to the new loom?

I`m good at soldering. would use shrink wrap material as well

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ST205

This may help
http://www.ih8mud.com/tech/WireHarnessRepairParts.php

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Vice Chairman
1990 White UK Celica ST185 - Project DTM
1997 Cream BMW R1200C (as seen in James Bond "Tomorrow Never Dies")
2005 Jaguar X-type 3.0 Sovereign AWD Automatic
Blood Bikes - https://www.freewheelers.org.uk/

Unless the old loom is in poor condition, you will get better reliability splicing at the ecu end of the wires as the environment is much less harsh inside the cabin (damp/dirt/heat/vibration)

For solder splices on wires I use RS 366-2825 These end up quite stiff once shrunk and provide good support for the brittle part of the joint. Don't use too close to a connector or it will end up fatiguing the wire at the connector.

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If at first you don't suck seed, try drier grain.

Hi,

i have a connector specific manual (with part numbers) from toyota on my PC if you are interested in i can sent you the pdf's.

in hope that i'am allowed to drop also a question, as i also will build my own specific engine loom i'am searching a 1x connector system for the battery wire in the engine bay (my battery is in the boot), that have no problems to be fused at 120A

greetz

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KEEP COOL UNDER PRESSURE

street legal?.....perhaps in tschibuti

Anderson power:

http://uk.rs-online.com/web/c/connector ... wer/?sra=p

We use these on our electric vehicles and are the only connectors we have tried that give us very little problem.
If you don't have access to the very expensive crimp tool you can solder with a blowtorch (we do) - ensure all flux is cleaned from mating faces after.
Avoid putting the connector where the wire will move, e.g. 'in line' between body & engine.

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If at first you don't suck seed, try drier grain.