This is topic Pinout Repair in forum Spec Miata Garage at Spec Miata Community.


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Posted by iambhooper (Member # 25235) on :
 
My car expereinced electrical problems off and on during the Goblins Go, and I plan to swing by and look for the culprit, this evening.

As I suspect it's loose wiring in the harness, at the ECU plug, are there any good threads/site's on pinout repair? What have you guy's done in the past?

Thanks!
hoop
 
Posted by Bob Thornton - Race Engineering (Member # 1864) on :
 
Be patient, it takes a lot of time and its no fun.
you will find it just keep looking.
 
Posted by Randy Thieme (Member # 15193) on :
 
I had problems with my harness connector to the ECU earlier this year. Had unwittingly swapped in an ECU whose prongs had been twisted on purpose. Those prongs enlarged the holes in the harness connector so it no longer worked with a ECU with normal, straight pins. Friend recommended an auto-electrician who knew how to diagnose and fix the connector. (It's actually possible to disassemble the connector but I'd only recommended a professional to fix it.) Try to find an old-school technician who fixes things rather than just replacing them.
 
Posted by pat slattery (Member # 1254) on :
 
quote:
Originally posted by Randy Thieme:
I had problems with my harness connector to the ECU earlier this year. Had unwittingly swapped in an ECU whose prongs had been twisted on purpose. Those prongs enlarged the holes in the harness connector so it no longer worked with a ECU with normal, straight pins. Friend recommended an auto-electrician who knew how to diagnose and fix the connector. (It's actually possible to disassemble the connector but I'd only recommended a professional to fix it.) Try to find an old-school technician who fixes things rather than just replacing them.

Why would someone twist the prongs on purpose

Pat
 
Posted by iambhooper (Member # 25235) on :
 
I've never needed to look, does the ECU harness disconect from the dash and engine harness's?

It would be nice to pull it out and get it on the bench w/o unpluging every thing on the engine.

Thanks!
hoop
 
Posted by Randy Thieme (Member # 15193) on :
 
quote:
Originally posted by pat slattery:
[QUOTE]Why would someone twist the prongs on purpose

Pat

Apparantly it's sometimes done as a fix to a loose connection. Twist the pin and it wedges in tighter. Works as long as the same ECU and harness are together but becomes a problem when swapping ECU's. Once that happens only solutions are to either twist the pins in the original ECU or fix the harness.
 
Posted by Willie the Tard (Member # 2319) on :
 
quote:
Originally posted by iambhooper:
I've never needed to look, does the ECU harness disconect from the dash and engine harness's?

It would be nice to pull it out and get it on the bench w/o unpluging every thing on the engine.

Thanks!
hoop

the ECU plug is part of the front harness and does not diconnect from it. it does disconnect front the dash, engine (the one from the alt to battery), FI (the one on the engine) and the rear harnesses.
 
Posted by iambhooper (Member # 25235) on :
 
Yep, I went to the shop and took a look at it. Apparently the repair I made to it (in order to get the car running and on the trailer to VIR for the Goblins Go) was at fault.

My soldering held up [Big Grin] , as the wire I added was still intact to both the harness and the pin. However, the pin was a bit loose in the module and therefore in ECU. [banghead] It pulled out fairly easy.

So I plan to go by Graybar and see if I can get a replacement female pinout (any better idea's?) and repair that. I'm also thinking of applying some hot glue on the back side of the module (where the wire's go in) to "hold" everything in a bit better.

hoop
 
Posted by Randy Thieme (Member # 15193) on :
 
quote:
Originally posted by iambhooper:
So I plan to go by Graybar and see if I can get a replacement female pinout (any better idea's?) ...

hoop

PM me your street address and I'll send you one snail mail for free. Just tell me if its a large one from near the sides or a smaller one from the middle.
 
Posted by iambhooper (Member # 25235) on :
 
UPDATE...

FYI, GM actually has pinout's avialable that are similar enough to the larger one's. I got several of those and "fixed" the wire in need.

But it can't just be that simple, can it? [Big Grin] After repairing that wire, and applying some dialectic grease to the module, I cranked the car and checked the harness. If I moved a group of wire's the car would stall and die. I looked at the module wire by wire (zip tieing all the hvac wire's out of the way), but couldn't find anything that stuck out as a problem.

So, I cranked the car again and tried to repeat the process.... damn if the car wouldn't stall! At this point, I'm flabergasted... maybe it's time to pull the harness out of the parts car and replace this one?!

hoop
 
Posted by Sacslider (Member # 619) on :
 
I have had to replace two entire harnesses in two different cars when the problems could not be readily identified. Both had intermitant problems that could not be duplicated consistantly. Replacing the harnesses fixed both. Seems that the 20ish year old wiring in the 1.6's is slowly starting to decay and cause issues. Not good since the are a bitch to change.
 
Posted by iambhooper (Member # 25235) on :
 
yeah I'm not looking forward to that, especially now that it's starting to get cold (part's car is outside), and subbing one 20 yo harness for another.

but, i'm not paying $1500 for a new one!

hoop
 
Posted by iambhooper (Member # 25235) on :
 
Update... I made a decision to not remove 2 harness's (one each from part's car and race car) and install one. I just felt that would take the better part of an entire weekend.

I decided to cut the harness's and solder in the ECU plug's out of the part's car (the wiring and plug's appear to be in much better condition). Which bring's me to a question... In IT ECU's are open and I can relocate them, can I add wire to the harness to allow the ECU to move (if I need to swap it)?

Also, and I will do a search on this, what are the diffence's in the ECU's? 2383, 2384, 2385? Any? I seem to have several extra's.

Thanks!
hoop
 
Posted by iambhooper (Member # 25235) on :
 
Question... on ECU connector #2, there's a couple of wires that "merge" into a grey/red shieldedand orange shielded wire.

I can't seem to figure out where the sheilded wire's go to. Also, as I am soldering the new connector into the harness, is there anything special I should do with the shielded wire's?

Thanks!
hoop
 
Posted by Kent Carter (Member # 2245) on :
 
quote:
Originally posted by iambhooper:
Question... on ECU connector #2, there's a couple of wires that "merge" into a grey/red shieldedand orange shielded wire.

I can't seem to figure out where the sheilded wire's go to. Also, as I am soldering the new connector into the harness, is there anything special I should do with the shielded wire's?

Thanks!
hoop

I'm pretty certain that the shields are tied together, but 'float' on the ECU side. By 'float' I mean that they do not touch metal at all on the ECU side, but are grounded on the other side (O2 and CAS). This prevents a ground loop from being formed.