1jz single. aristo ecu. Runing mad rich. bad ground??

sean2000gt

New Member
May 10, 2011
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ok, had a problem with wiring and ended having a power melt to a gnd and f some stuff up. i've gone through the harness and replaced all damaged wires...i've spent weeks trouble shootin and finally came to my current situation.
How is the aristo ecu grounded?? my ground wires coming from the map, tps, and iat aren't being grounded. i found this out by checking out the signal wire coming from the tps and it was at 2.6v at closed throttle, i'd slowly open and voltage would do somethin like this 2.6-1.8-1.7-1.6-1.7-1.8-2.2-2.5. (going from closed to wide open). so i knew something was screwy. looked last night and saw it should be grounded when closed so i knew it's a ground problem. today i cut the ground wire and made my own chassis gnd and it fixed the signal...so of course i cut the grounds to map, tps, and iat and sent them to chassis...but then the car wouldnt start...the ecu needs to be wired into these wires to start the car....
my current theory is that maybe another ground isn't routed properly and my main ecm ground wire from the ecu isn't even connected to a ground..basically i'm wonderin how the main ecm ground is connected to ground..is there a different ground coming from the ecu that connects to the chassis which serves as the main ground?
this probobaly doesn't make any sense cause i've had so many different leads for a few weeks and this is my latest and pretty sure once i figure out this ground issue i'll have my car back. please help. thanks much
 

hvyman

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Apr 17, 2007
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Not the black w red stipe wires right? Thats b+ 12v and is also the constant power for the ecu.

There is no single ground wire for the isc. It has power and then the ecu grounds the 4 other wires to make the valve open and close.

Ecu grounds are brown or white with black stripe.
 

sean2000gt

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May 10, 2011
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i'm talking about the brown wire thats goes to the map, tps, and iat. these all branch together and i have attached to i believe E1 (ground)...yet when i check voltage this wire has 2.6...when i cut this wire and ran a diy gnd to chassis it would have 0v and the sensors would show the correct voltages...so it's as if e1 isn't acting as a ground...which i why im wondering if that terminal is attached to another ground terminal and uses that...maybe i'm missin another ground and so e1 wont serve as a ground....hope you understand what i'm sayin.
 

hvyman

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Apr 17, 2007
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Its e2 which is ground but you cant just cut it and ground it. Its ground controlled by the ecu.

Wire it up as it should be then search for the problem.

How is the engine running after that. Are there any codes.
 

enslaved87

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Apr 1, 2005
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piss off
hvyman;1719119 said:
Its e2 which is ground but you cant just cut it and ground it. Its ground controlled by the ecu.

Wire it up as it should be then search for the problem.

How is the engine running after that. Are there any codes.

Precisely, think of it like a multimeter/voltmeter - you must have both wires connected to get a reading. The ecu needs both the signal wire AND the ground wire DIRECTLY connected to it for all those sensors.
 

sean2000gt

New Member
May 10, 2011
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ok. i looked up the wiring diagrams for a 2jz and found the e02 is the wire that serves as a ground to the ecu. all the other ecu grounds are grounded through that ecu. so i checked eo2 and it's ground. The other ground wires showed continuity to ground...however the big E2 ecm ground wire isn't showin continuity to ground.
after having power melted to ground i wouldnt be surprised at all if it fried somethin in the ecu..so ecu ordered..hopefully all is well in a few days.