jordadms07

Kinda new here been lurking around for some time, but I finally have something I can't find information on. I have a 95 sc300 stock ge with a 5 speed swap done with a w58 still auto ecu.

The problem is the car has felt sluggish since I purchased it being my 3rd 300 it just didn't feel right. Upon further inspection I saw that the injector 1 was not clipped in. So I plugged it in and made no difference in how it ran. Thought the injector could be bad. Turned the car off and heard a slight humming noise Coming from the area of the injectors. then smelt fuel. Unplugged that injector and the noise stopped. So at first I thought it could be a stuck injector well that would make sense except the ignition war turned off and keys removed no chance it was in the on position. So anybody have an idea as to what may cause that injector to stay with a constant spray even with the ignition off?

I pulled the coil wire and fuel pump fuse and spun the engine over to get any excess fuel out, then checked for gas in the oil with no smell or noticeable ga. Then reconnected everything and fired it back up with that injector unplugged and burnt the fuel out that remained to make sure it didn't do any further damage or wash it out. But any help would be greatly appreciated.

Vrank

iTrader: (4)

it doesnt spray fuel, but if it's stuck open in any way, then as long as there's fuel in the rail and pressure (which is still there when the key is turned off), then fuel will pass until it doesnt have any available to pass. The funny thing is the noise with the key off. You should not have power to the injectors at key off. They only get power via am2 when the key is switched on. So it's possible you have a faulty ignition switch if they're powered when the key is off. You should definitely check to make sure you have no power to the injector when the key is off. Another thing though is possibly a bad ecu. And this is why. Not sure if you know how an injector works, but basically when you switch the key on power goes to injector. it goes through the injector into the ecu. The injector only opens when the ecu says it needs to and it does this by supplying a momentary ground based on how much fuel it deems necessary at a given load point. For instance, idle it might only hold that injector circuit to ground for .8 ms. At wide open throttle at it's highest load, it might hold it open for 4 ms (these are made up figures for example only) So, picture it, key on running, each injector channel at the ecu has 12v input into it and only makes action when it is given a ground path. Maybe something has gone wrong inside the ecu and is somehow feeding bak voltage into the number 1 injector. Ecus go bad pretty often on these. My ex's factory 5 spd 92 had intermittent ecu issues that drove me nuts til it just stopped working altogether.

So cliff notes, check the injector plug for power at key off and key on. The black/orange stripe wire (should be that color, could be black/white stripe though) is your 12v switched power coming in. This will be the same color for all the injectors in the same pin location on the clip. The other wire is the signal wire for lack of a better term and will be a different color wire on each injector going into the ecu. with key on and unplugged from the injector, it should be cold on that side. if it has power you have a problem.

For 1jz guys, you have to make sure to unplug the corresponding injector's clip as well since they pair the injector channels on those, batch over sequential. I learned that one the hard way years ago. a for sure wtf moment where i scratched my head for a while.

jordadms07

okay so as you stated I turned the key on (not running) and I have a constant 12v on both sides. This would say ecu I believe and I already ordered an ecu the other night because that's what process of elimination brought me to that. New ecu should be here Friday and I'm going to see what that does. Thanks for the help I just am not a fan of electrical work

Ali SC3

iTrader: (10)

I was going to say ecu, most likely a failed capacitor shorted that injector driver, it happens alot on the sc400 actually but it can happen on both ecu's. I would open it up to confirm or if you already ordered the new one just try that one out.