Electrical problem: IDL2 will not send ground signal?

[di_rosa]

car runs and all, but the tps isn't working cause the IDL2 pin on the flying lead will not send a ground signal to the tps, it sends a voltage signal. i have checked, and the ecu works fine on another 1jz car, and i have checked the tps, same deal. i know the problem is somewhere in the harness, but i don't know what to look for.

i have checked:

all 4 wires have continuity from ecu to tps plug
all 3 grounds (e1, e01, e02) have grounds at the ecu
ecu is good (tested on another car)
two grounds at intake manifold are on and secure

now i know this is the problem as once i ground the wire at the tps, it starts reading correctly.

any help would be greatly appreciated

 

[di_rosa]

ok, more progress update.

did some testing on a friends harness, and it looks like his ecu puts out 12v to the IDL2 flying lead, BUT the harness side is grounded somewhere. and i checked, and i have continuity with some grounds on the harness. so it looks like the efi wiring diagram for the 1jz is missing that. so it looks like the ground isn't coming from the ecu, but from the harness.

but my question is, even if i do ground that wire, won't it create a short circuit when i take a ground and a 12v source and connect them? i don't want to blow my ecu ......or is it going to be like a circuit breaker switch dealy?

aiyah, what to do???

 

[Ken]

just run a replacement wire and route it according to how it's shown on the wiring diagram. also, did you test resistance of the ground wire?

 

[di_rosa]

i tried that, no go. i ran 4 new wires to the tps, and nothing. the wiring diagram is WRONG! there is no ground listed on the wiring diagram, yet there clearly is one on my friends harness. i grounded the IDL2 wire on the flying lead, but left it disconnected, and now it runs ok, and i'm not throwing any codes.

but my original question, if the female part of the flying lead plug puts out 12v on the IDL2 pin, and the male part of the flying lead plug puts out ground on the IDL2 pin, if i connect them, won't it fry my ecu?