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Discussion Starter · #1 ·
Can anyone test a PCM.

Injector not getting signal to spray fuel, so I went through diagnostics. End result, I purchased a new PCM. However, still having problem. I have double checked / triple checked connectors and sensors. Starting to wonder if the new PCM is bad also but I don't want to throw another $200 away.

I can get engine to run by "manually" touching ground from battery to stick pin I put in the ground wire to the injector.
 

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Have you checked your bank angle sensor?

I don't know of any way to check a PCM. I bought a new one for an 07 Rancher I was working on that wasn't getting fire and it ended up being a bad fuel injection relay.
 

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Discussion Starter · #3 ·
I tried to jumper it out by shorting out the two outer pins. After hours of searching, that's all I could find. If you know another way to check it, please let me know.

Last night I pulled on more wires, plugged an unplugged, and attached a second ground to the frame just to make sure it was good.

Originally I was not getting a ground on one side of the injector. Then, for a while I was getting ground but no 12 volts on the injector, fuel pump, ignition coil. Now I am getting both ground and power to the injector. However, it it only spraying a small amount of fuel (not enough to keep it running).

I can jumper the fuel relay AND connect the battery (positive & neg) to the injector and it sprays good so I am thinking the fuel pump and injector is good.

Any ideas?
 

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Have another machine you can use to test parts?

My fuel injection relay would click, but wasn't making a good connection.

Run a jumper from battery + to the red and black wire on the coil, and see what it does.
 

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Discussion Starter · #6 ·
Tried to jumper + from battery to coil, nothing. Measured voltage at injector while turning engine over and getting all kinds of readings from 0 volts to 10.2 volts. Thought the battery might not be providing enough voltage while cranking, so I connected ATV battery to car battery. Same thing.

Started Over, Checked voltage at fuel pump - getting 12 volts for a few seconds. Unplugged fuel line at injector. When turn key on, fuel comes out for a few seconds then stops. With fuel line off, turned engine over and fuel comes out while engine turning over.

Since voltage at injector was fluctuating, I jumpered the black/red wire at the injector to the black/red wire feeding the fuel relay. Now I am getting good voltage at positive side of injector.

To check the injector, I took it out. When I turn the key on, it pressurizes the system. I can ground the opposite terminal (using a pin stick in the ground wire) on the injector with a jumper wire and fuel sprays out good.

But, if I leave the injector out of the throttle body (leave it plugged) and turn the engine over, not much if any fuel comes out. Best I can figure, the "ground" side of the injector is not working. (which was the original problem and the reason I bought the new PCM)

(I can actually put the injector back in, turn the engine over and touch a ground jumper to a pin I stuck through the ground side of the injector and the engine will run for a few seconds).

While I am trying all of this, I do have the breather box off and in most cases the sensor on the box is unplugged. I am assuming it is a MAF and would think the engine would run without it.

Another note: I keeping swapping the PCM's from the original one to the new one, getting pretty much the same result with both.
 

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I would imagine you will need the MAF sensor to be plugged into to trick the PCM into sending the right air fuel ratio. may be why your not getting the fuel you need to run.

also, ,your voltage is wacky. have you tested your stator and pulse coil?
 

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I would imagine you will need the MAF sensor to be plugged into to trick the PCM into sending the right air fuel ratio. may be why your not getting the fuel you need to run.

also, ,your voltage is wacky. have you tested your stator and pulse coil?
It will run without the MAF. Just throws an error code.
 
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