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2.9l injector misfire


Fordracing88

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Good afternoon so I’m looking for help on a problem I’m having with a misfire in cylinder 3. There is spark, good fuel pressure, the cylinder has good compression and when you pull the plug after vehicle has been running the plug is completely dry. I was wondering if it could be the ecu causing just that one injector not to fire? With the truck running when I place a test light in each side of the injector plug it has power but I haven’t seen it pulse so that’s why I think it might be the ecu since there is power on both sides. Please let me know what you think or any ideas
 


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It's not the ECU if other injectors on that side are firing. They are batch fired so one "side" of the engine fires, then the other. So if you are seeing pulses at other injectors in that bank but not at that one, it's almost certainly a wiring issue - broken, cracked, chewed threw, grounded out, etc
 

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It's not the ECU if other injectors on that side are firing. They are batch fired so one "side" of the engine fires, then the other. So if you are seeing pulses at other injectors in that bank but not at that one, it's almost certainly a wiring issue - broken, cracked, chewed threw, grounded out, etc
X2
 

RonD

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+1 ^^^^^

2.9l used Batch fire which means, on a V6, 3 injectors share the same pulse, they open at the same time, usually the 2 end ones on 1 side and 1 center one on the other, then on the next engine rotation the other 3 open

So with this type of setup the lower intake is filled with air/fuel mix(like a carb) and each intake valve sucks in what it needs
But because of the injector placement a cylinder can certainly get a lean mix if its injector fails or gets clogged up

Did you check other injectors with your test light to see if they pulsed?
Injectors are only grounded for milliseconds, so it ground pulse can be very hard to see on a standard 12v test light, thats why NOID lights are used, they can show the ground pulse easily

If you disable spark on cold engine
And then crank it over a few times
Then pull out a few spark plugs to check the tips they should be wet with fuel because of Choke Mode
If cylinder in question is not as wet, or dry then yes, I would say its injector is clogged or has failed

Cranking vacuum is only 2-3" so you won't get much air-fuel sucked over from adjacent cylinder with working injector

Ford injectors should read about 15 ohms, 11-19 ohms
 
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Fordracing88

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Okay thank you guys I’ll try some of this tomorrow and see where I’m at, every time I’ve ran the truck and checked the plug it was dry so I’m assuming your right with the wiring harness, I have a spare one I’m going to try
 


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