Injector question


#1

What codes will u get if u unplug 1 electrical connector for the fuel injector on a V6 motor? The computer does not know it is unplugged. The spark plug is still firing. There is no “excess” unburned fuel in exhaust since none is injected in that cylinder. Will you be in a lean situation since u have extra air in exhaust now?


#2

You will see codes in the P02xx categories. P0200 is a general injector circuit malfunction. Others pinpoint specific cylinders and problems with the electrical circuit firing the injector. The ECU reads the voltage at each terminal across the coil that opens the injector. Open or short circuit throws a code.

So, yes, the computer does indeed know that the injector is unplugged.


#3

The computer will seee that there is no current going to that injector coil.
I don’t know what the code number is, but it’s called something like “circuit fault #x injector”.
p.s. how much more effort is it to write “you”. “u” hurts my eyes.


#4

Also you will get a P030X because the computer does not see the X cylinder contributing a torque pulse to the rotation.


#5
Also you will get a P030X because the computer does not see the X cylinder contributing a torque pulse to the rotation.

Never heard of the an ECM checking for that before. Is there a sensor for it?


#6

Yes indeed, the ECM can detect a dead cylinder and report it by number, regardless of why it’s dead…


#7

P03xx as stated above ex p0301 is cyl #1 P0300 is random misfire.

Steve


#8

“Never heard of the an ECM checking for that before. Is there a sensor for it”

Yes, the crankshaft position sensor. Its resolution is fine enough to determine variations in torque pulsation. High speed ECU’s with good software are wonderful things.


#9

Never heard of the an ECM checking for that before. Is there a sensor for it?

Misfire codes have been around since 1996, it’s nothing new.


#10

Pardon my curiosity, but was there a specific failure that prompted the question?


#11

I stand corrected and learned something thanks guys!


#12

@Mountainbike, I too would like to know why @Cavell is asking this question. I fear he might be considering manually disabling a cylinder or two hoping for better fuel economy.


#13

I’ll go slightly off topic

I’ve seen many misfire codes caused by rodent damage to the injector wires. That would be the closest thing to an unplugged injector

A misfire is a misfire, whether it be due to a bad plug, injector, low compression, wiring, etc.


#14

I had misfire code. And I needed to drive 20 miles to store to buy new coil. I did not want to drive with excess fuel being dumped into cat. I was at rock auto website. They have current stock and close out stock all the time. They happen to have a maf for my car for $13 and no core charge. Reg price is 85 plus 40 for core. My Taurus is flex fuel so it has no Fpr. It varies power to pump to tweak fuel pressure. No map sensor either. So my rich issue is almost certainly maf related. Or not. But $13 is pretty darn cheap.


#15

I see. You were getting no spark, and you still had to use the car, so you wanted to stop the gas flow to that same cylinder until you got the spark problem fixed. Makes sense to me. Besides the cat problem you mentioned already, unburned gasoline can wash the cylinder walls of their needed oil protection and can cause damager there over time too.

There are other things that can cause a rich mixture besides a faulty MAF, but for $13, certainly worth giving a try. Best of luck.


#16

New coil fixed misfire. But I still get code for rich condition. Motor has slight chuggle during cruise. Previous owner had trans rebuilt. New struts. Cv axles, alt, and so on. I know he maintained it. I did not check codes after trip to store. I cleared them.


#17

rich condition, and slight chugging or surging at cruise is almost certainly a leaking fuel injector.

a simple way to check to see which one is leaking is to pull the plugs out and turn the key so that the fuel pump starts,whichever cylinder has gas shooting out of the plug hole is the cylinder with the bad injector.