Injector Pulse Issue! Any Tech's?
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Injector Pulse Issue! Any Tech's?
08 Mercury Mountaineer, 4.0 V6
I started this new thread because I have determined the issue just don't know where to go from here.
#2 cylinder misfire. Have tested everything that I'm aware of and the results are NO PULSE OR RANDOM PULSE AT THE #2 INJECTOR! I have power (+) but no pulse or random pulse (-) at the injector. I traced the pulse (-) wire to the PCM and have continuity thru the wire to the injector harness but no pulse. New Cam sensor and it was doing this before the replacement!
Starts up runs well until it gets warm then the pulse goes intermittent. Always #2 cylinder.
What does the Cam sensor read? Are there magnets on the cam that the Cam sensor reads then tells the PCM to pulse the injector? Could the camshaft be the issue? Is there a way to determine if the Cam sensor is sending the signal to the PCM for #2 pulse?
I want to be sure all other possibilities are exhausted before I think about replacing the PCM!!
I started this new thread because I have determined the issue just don't know where to go from here.
#2 cylinder misfire. Have tested everything that I'm aware of and the results are NO PULSE OR RANDOM PULSE AT THE #2 INJECTOR! I have power (+) but no pulse or random pulse (-) at the injector. I traced the pulse (-) wire to the PCM and have continuity thru the wire to the injector harness but no pulse. New Cam sensor and it was doing this before the replacement!
Starts up runs well until it gets warm then the pulse goes intermittent. Always #2 cylinder.
What does the Cam sensor read? Are there magnets on the cam that the Cam sensor reads then tells the PCM to pulse the injector? Could the camshaft be the issue? Is there a way to determine if the Cam sensor is sending the signal to the PCM for #2 pulse?
I want to be sure all other possibilities are exhausted before I think about replacing the PCM!!
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I replaced the crankshaft sensor yesterday then took a 50 mile test drive. Much better but still stumbles occasionally when RPM's are below 1200. During this test drive the stumble at 40-50mph in overdrive was gone. This is really pissing me off and I can't seem to get much advice! I was thinking PCM problem but the problem gets a little better each time I replace something.
I have read a few posts about possible bad ground to PCM, how/where is the PCM grounded.
I have read a few posts about possible bad ground to PCM, how/where is the PCM grounded.
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Joined: Jun 2009
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From: Cedar Rapids, IA
So going way back to your first post in this thread, since the injector pulse issue seems to only be present when the engine is warm, that points to something electrical rather than something like an issue with the camshaft. It sure seems like the issue would have to be either the CMP sensor, or the wiring between the CMP and the PCM, the PCM, the wiring between the PCM and the injectors.
If you haven't already, you might want to trace the wiring harnesses looking for sharp bends or pinches and disconnect every connector in the circuit and carefully inspect the terminals for signs of corrosion, malformation, or terminals that are loose or pushed in. You're looking for anything that could cause a poor connection as things heat up and expand.
-Rod
If you haven't already, you might want to trace the wiring harnesses looking for sharp bends or pinches and disconnect every connector in the circuit and carefully inspect the terminals for signs of corrosion, malformation, or terminals that are loose or pushed in. You're looking for anything that could cause a poor connection as things heat up and expand.
-Rod
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Originally this problem did occur when the engine was warm but I had just taken possession of the SUV. As I drove it more and more the symptoms changed and I was replacing sensors/parts then retesting. Now, I realize, it would have been much more productive if the test period was longer in-between remedies. I have since posted several updates on other threads and adjusted the symptoms. This problem was all but gone while driving it to/from work last week. I was so happy, even though my diagnosis was not a stuck injector, I thought maybe the injector cleaner is working and the problem is going away. NOT SO!
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Yesterday I changed the the coolant and thermostat. I started the SUV and the misfire was as bad as it had been. I wanted to get it to full temp to check/top off the coolant level so I let it run. I noticed that something was intermittently causing a large draw of power on the engine (seemed to anyway, possibly because of the misfire) so I started shaking wires and checking connectors. When I unplugged the Electric Fan Clutch connector the load went away. I will test the fan clutch today! Also, I moved the #1 injector connector and another improvement. The connector was definitely an issue so I bought a replacement and installed it. The connector may have been self inflicted with me using the noid light several times but it's good now!After all that it was 06:30 pm and I was going on 3 hours sleep so I called it a night.
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