Dodge Repair/asd relay will not keep voltage to coil: '93 dakota 5.2L
QUESTION: 1993 dodge dakota 5.2 auto air 4whl drive Asd relay will only stay on for a second then shuts off power to coil. replaced computer...crank sensor...cam sensor...ingnition switch..o2 sensor..... asd relay . have allready fixed three red & white striped wire conection by PDC. Fuel pump does energize and I have fuel pressure.
ANSWER: Hi Robin,
I don't have the wiring diagrams for the '90's truck line so am at a disadvantage in analyzing the circuits.
I suspect there is on-board diagnostic capability which is accessible by the ignition switch:"on-off-on-off-on and leave on" doing that in 5 seconds or less elapsed time.
Then watch the check engine light which should remain 'on' to see it begin to flash, pause, flash, etc. Count the number of flashes before each pause. Then repeat the process to be sure of an accurate set of flash counts. Tell me what they are and we'll go from there.
Red/white wires are often associated with 12v carrying wires. Do you happen to know if that is the case for your truck and have you checked out the presence of 12v at the far ends of the damaged wires? I am wondering why the fuel pump seems to remain pressurized even though the ASD relay won't. The normal operation of the ASD relay, by the way, and also the fuel pump is that when you turn the key to run the ASD closes but only for a second until you start cranking over engine at which point it will close again and continue that way as long as the engine is turning over or running. Same for the fuel pump.
So maybe there is nothing wrong with the ASD and a fault code will give us another possibility. For example, does that engine have an egr valve (exhaust gas recirculation). If so check that out to be sure that the valve stem is moving freely and that internal spring-action causes it to close to a dead stop. If not, spray some WD-40 on the stem where it enters the body of the valve and work the stme back and forth via the slot in the stem, using the tip of a screwdriver to move it.
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QUESTION: Thanks Roland...been busy tearing my hair out...ha! I do not have codes from key because of checking the 60 wire PCM. I do have OBD 1 information that came back....43-spark/ignition control circuit problem.......42-asd relay problem.......21-oxygen sensor shorted to voltage or to high. I can remember in past problems; ex no spark from coil I did have constant voltage to the feed for the coil.That time the coil was bad.This is whats strange why I don't have constant feed now. The computer must see something thats not right.... Oh if it would just speak english ...right! I do have continuity to both wires that feed the coil.Also I noticed when I have a test light on what is supposed to be the hot wire for the coil and fuel injectors an try to start the engine it will turn the light on but not feed the coil driver. EGR valve is good. Also have continuity to throttle sensor and idle air control motor and MAP sensor. Your ball.
You could try one test to isolate the problem: simply remove the ASD relay and jump from the rear to the front pin of the socket so that the spark coil will get power as will the fuel pump and the injectors. Do this just long enough to try and start the engine then disconnect it. If it starts then I would suspect one of the rotational sensors is not getting a signal through to the PCM which is required by the PCM for it to close the ASD.
Each sensor has three wires: a 8V or so supply orange, a black/light blue ground, and a siganl wire. Measure the voltage between the signal and the ground wire while you turn the crank by hand using the socket on pulley bolt. The signal should vary between 5v and 0.3v as you rotate. If you get that, then verify that you 'see' that also at the pcm pins for those wires.
If it doesn't start then verify whether there is or isn't spark and that there is fuel pressure and that there is pulsing on the coil driver wire(s) and injector driver wires.
Are those OBD-I codes current?
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