need electrical help

[Sparky33]

ok here's the background on this car. bought it for 400 bucks and it didn't run. it wasn't getting any fuel so i threw in a walbro i had lying around and now it has fuel. so i get it started but it runs poor. come to find out, the wiring harness is brittle as can be. so i go and buy a harness that was a little better than mine to rob the connectors off of it. the car ran like crap with codes for mass air flow signal and iat. so i replace the maf pigtail. same issue. so i find out i have no continuity between the pigtail and the ecu for the ks and iat wires. i run temporary wires and now the car runs normal again. now i go out the next day and the car wont start lol. now i have no spark. the cps wires are shot so i throw a pigtail on that and great now i have spark and the car runs again. now i come home today, and want to change the nasty fouled plugs that have been in the car, so i get that all done, car starts up runs normal. so i shut it off and go eat dinner. when i come back the car wont start again i have no check engine light displaying when i turn the key on either. so i ground pin 19 on the ecu and the light comes on so the bulb is good. now i go to the diag port and i have no power at b+. so from here i am having a bit of trouble. b+ is a black and red wire that goes to the isc valve vsv's and fuel pump relay. i have continuity at black and red at the isc valve and fuel pump relay, haven't checked vsv;s but im going to assume i do. so that's where i'm at with the wiring on this car, so if anyone has experienced anything like this or even better some of you veteran guys that are good with electrical could help me out id be very appreciative.

thanks in advance

Jimmy

 

[hvyman]

Why not just get a good harness to start with I stead of going around in circles trying to fix your current one.

 

[Sparky33]

thanks for the suggestion, i am looking for one but i also would like to figure this out. guess i just like to fix things.

 

[planemos]

Just don't give up so easy. If you do it yourself then have the right tools to do it and take your time. Otherwise, ya, there are options of buying new.

 

[Sparky33]

im not giving up just looking for a few suggestions im pretty good with electrical just seeing if anyone has some insight. and there isnt an option to buy new, i dont beleive there are any new harnesses available, also the cost of a new harness is more than i paid for the car, so im not really considering that.

 

[hvyman]

Could pull the harness. Take it apart and ohm each wire individually and fix any problem areas.

 

[Sparky33]

yeah i could, i may be thinking its an ecu problem as well just because i have no cel on at all.

 

[jetjock]

http://www.cygnusx1.net/Supra/Library/TEWD/MK3/manual.aspx?S=Main&P=47

Assuming the EFI fuse is good no + B likely means no Main Relay.

 

[Sparky33]

ah good call think that could be my reason for check engine light as well?

 

[jetjock]

The main relay is what supplies +B and +B1 to the ECU. Without them the system will be dead. It works like this:

1) IGSW goes high
2) M-REL goes high
3) The main relay supplies +B and +B1
4) The box wakes up.

Course, you'll need the associated grounds too...

 

[Sparky33]

right thanks for the input man ill grab my relay testers tomorrow at work and see what i have going on at the main relay and let you know how it goes.

 

[Sparky33]

so i figured it out for some reason i lost the ignition switch signal to the ecu. thanks for the help everyone.