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1993 gm 3800 left bank disconnecting of plug wire and injection connector does not change idle, appears left bank is not working.. Compression good...

Noid test is good... havnt checked fuel pressure

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Did you test for spark? I would check spark and fuel pressure. OK, here's a little bit of working theory that'll help you to see the ‘why’ of the Noid light test.

Whether you're testing a No Start Condition or a Misfire Condition, you'll need to know if the cause of the problem is a lack of fuel. When your GM 3.8L (Buick, Chevrolet, Oldsmobile, Pontiac) does not start, it will be either because of a lack of fuel or spark. The same thing goes for when your GM 3.8L equipped car or mini-van is misfiring... that specific engine cylinder isn't contributing to engine power because it either lacks fuel or spark.

Now, since the above two conditions (No Start and Misfire) can be caused by any number of things... one of the things that has to be eliminated, from this list of possibles, is the fuel injector not getting power or the injector pulse signal (On/Off switching signal) from the vehicle's Computer.

This is where the fuel injector Noid light test comes in handy, because you're able to visually see if both of these signals are present or not. If no flashes, then now you know that you have to verify that the connector is getting power (12 Volts) and the injector pulse signal.

One thing to keep in mind, is that the fuel injector Noid light test does not test for a BAD fuel injector. But, is the first step in verifying if the fuel injector is BAD or not. For the fuel injector test tutorial.

Posted on May 07, 2017

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Sounds like the power splice to bank one is lost. By injection tester, do you mean a noid light?

Do you understand how the fuel injection circuit works? When the ignition key is in the on position, all of the injectors will have constant battery voltage applied to them. Bank 2 (#'s 5,6,7,8) is good- they are all pulsing. The same power wire is spliced to all 8 injectors. The other wire at each injector is the ground wire, and each ground wire goes separately into the engine computer to be internally grounded for a split second. That is the pulse of the injector, and is when it sprays fuel into the cylinder.

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