I am now getting a code 42-Fuel pump relay control ckt, Auto shutdown relay control ckt, No ASD relay output voltage at PCM, Fuel level sending unit volts out of range, Fuel level unit No change over miles.

Now, I am even more confused. Changed the wiring. Even put the old ECM back in with the new wiring, nothing.

 

Got an analog meter hooked up the problem injector and found that the voltage is bouncing anywhere from 13.9 to 16.5. All other injectors stay at a steady 13.9 volts. I put a separate wiring harness from injector to ECM, no change.

 

found the source of the bouncing voltage to be coming from the alternator. Does anyone have an analog ohm meter and could check to see if the bouncing voltage reading is a common occurrence? Or has anyone else seen this?

 

Disregard the last three posts!

The only thing I need to know now is what component tells the ECM when and how long to fire the injectors. The ECM is telling #5 injector to stay open far too long.

 

The pcm gets input from the crankshaft position sensor and cam sensor in the distributer. That tells the computer when the cylinder is up. Then the pcm will fire spark and the injectors. The period at which the injector is open is called duel time. There is no way for you to adjust it's duel time.

If it was open to long it wouldn't be missing, just rich. A sticky/bad injector can do that. How do you know it is open to long? I still say you have a wire problem. And sounds like the wiring harness you are swapping to is not the correct harness.

And an ohm meter only reads the ohms/ resistance of wires/objects. A volt meter reads voltage. A multimeter reads them all.
Remember the injectors are running to fast for a meter to read correctly. While reading that one injector with higher voltage tells you that the injector has to less resistance in it, it is bad.

 

Well what is happening is the signal to each injector at idle is normally around 0.03VDC. Check your own truck's injector plug and you will see that the green and orange wire is sorce voltage and the signal wire will be around 0.03VDC at idle. Well the #5 injector signal, directly from the ECM, is around 0.14VDC at idle. This causes the dwell time of the injector to be what it would at WOT. Only it isn't at WOT.
I have removed the Exhaust manifold LB to repair a broken bolt and can see fuel drip off of that port at idle. I'm getting good compression and have excellant spark, and I've replaced the injector as well. The only thing I can come up with, that is abnormal, is the higher voltage at the signal for that injector.

 

Turns out to be the ECM. I bought a new one from the parts store and installed it. now the engine works great. A word to those with a code 27 issue. If it isn't the injector that has failed, and you have the possibility of it being a wiring issue or an ECM. Then never under any circumstances make a jumper wire from the ECM to the problem injector. this causes a very high voltage flow to that injector only, and will cause the delicate resistors inside your ECM to let their smoke out. The last owner had done this when I got it. He had replaced the ECM with a junkyard ECM but the issue was still ongoing. When I changed the ECM with a junkyard part I couldn't understand why that many ECMs had the exact same issue. Then if you study a wiring diagram for the injection system it shows that the injectors share a common voltage source. The odds and the evens share their own splices. When you remove voltage from all of those other injectors and put it all into one, for some reason it causes a voltage reading like 16VDC, which is way over even charge voltage. It blew out a total of three ECMs before i realized the mistake.
Also if you are wanting to get an A/C delete belt for your 92-93 3.9L with factory air, the belt the parts store will give you will require you to buy a new tensioner that was designed for a non-A/C engine. mine that they gave me was 2" to small. The proper one I ended up with is a Dayco owned brand called Drive Rite and the P/N:900K7. this one fit with the right amount of slack for the tensioner.

 

i have a 96 dakota with a 3.9l v6 and i have misfire on all cylinders and a system too lean on bank one i have replaced all plugs wires cap and rotor and both o2 sensers and a new timing chain can any one help

 

could be a bad crank position sensor.

 

Have you run you codes through the check engine light? That's the best place to start. If it just started doing this, I would suspect a cruddy fuel system. Wouldn't hurt to put a can of Sea Foam in your tank and see if it clears up.