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GT40 1.5JZ
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1,210 Posts
Discussion Starter · #1 ·
How important is the flying lead??? To my understand, only two wires are used in that harness.... light blue and brown.

Can someone do me a favor, disconnect that harness, and drive around in the supra. I'm curious to see if you get similar results. Mine has never been connected, due to the fact that my harnesses don't match up. I've got an '88 shell with a new '89 harness that has a 1JZ harness grafted onto it.

I have this problem where my car keeps cutting out, when I tried to drive it hard. This problem has been here since I've had the car. Everytime I downshift and hit the gas hard, the car will accelerate for a second, then the engine would cut out for a split sec, then it would come back on with alot of power. This problem makes it hard to get out of the hole properly... and it's bothering me. My harness btw, was made by M.U.
 

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HMOOB VWJ NYOB MINNESOTA
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1,352 Posts
lower your fuel pressure about 5psi and go try you car out
 

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GT40 1.5JZ
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1,210 Posts
Discussion Starter · #3 ·
I have the stock fpr....

I have to install my HKS one still... can it really be the fuel pressure??? I had a walbro, stock, and now mkiv pump in there with the same problem... but I'll give it a shot....

thanks
 

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Akai Suisei - 赤い彗星
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10,376 Posts
Mine wasn't plugged in for a few months after my swap do to a wrong connector on the harness. When it was fixed, I didn't notice anything had changed... Not saying nothing happened, but I just didn't notice...
 

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GT40 1.5JZ
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1,210 Posts
Discussion Starter · #6 · (Edited)
OneJoeZee said:
Mine wasn't plugged in for a few months after my swap do to a wrong connector on the harness. When it was fixed, I didn't notice anything had changed... Not saying nothing happened, but I just didn't notice...
I connected mine 2 weeks ago and I didn't notice anything...
 

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Not so boring anymore
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7,085 Posts
i've had mine disconnected before, notice no chanage..
 

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Your Neighborhood Pikey
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3,341 Posts
The flying lead goes to the IAC valve on the manifold, for idle control. If you had a power fc, they would not be connected at all. This isn't your problem.
 

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GT40 1.5JZ
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1,210 Posts
Discussion Starter · #9 ·
HamsMKIII said:
The flying lead goes to the IAC valve on the manifold, for idle control. If you had a power fc, they would not be connected at all. This isn't your problem.
care to take a stab and what is? I'm just lost and don't know where to look anymore... I'm going to try that fuel pressure thing a couple of weeks.
 

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Your Neighborhood Pikey
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3,341 Posts
How long does it cut out? Does your CEL come on when this occurs? Are you bypassing fuel cut in any way? What boost are you running? Mods? These things I need to know.

- Chris
 

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GT40 1.5JZ
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1,210 Posts
Discussion Starter · #11 ·
HamsMKIII said:
How long does it cut out? Does your CEL come on when this occurs? Are you bypassing fuel cut in any way? What boost are you running? Mods? These things I need to know.

- Chris
no CEL
no codes whatsoever


The cut out varies.... normally less than a second, like 3/4th of a second.


I've had this problem even when I was running stock, with only two mods, bypassed FUEL DAMPNER and a walbro. I had the 370's in there with a resistor (had 550's prior).

I put the 550's back in, then my walbro crapped out. In went the stocker, and then the mkiv(current)

Currently, I have an eMAN blue, 2JZ map, 550's, resistor, gt40, no dampner, stock fpr, mkiv pump.
 

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Your Neighborhood Pikey
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3,341 Posts
perf0rmance said:
no CEL
no codes whatsoever


The cut out varies.... normally less than a second, like 3/4th of a second.


I've had this problem even when I was running stock, with only two mods, bypassed FUEL DAMPNER and a walbro. I had the 370's in there with a resistor (had 550's prior).

I put the 550's back in, then my walbro crapped out. In went the stocker, and then the mkiv(current)

Currently, I have an eMAN blue, 2JZ map, 550's, resistor, gt40, no dampner, stock fpr, mkiv pump.
The damper is designed to maintain fuel pressure for quick bursts. Your problem is starting to sound more like a fuel issue. I would check your fuel pressure and watch your A/F's. I bet your fuel pressure is bottoming out when this happens and makes your car go lean.
 
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