Chrysler Repair/1990 Dodge Spirit: weak/no spark
QUESTION: I have a 1990 dodge spirit that quit running on me back in november. It is getting fuel but no spark. I replaced plugs,wires, coil, pickup, cap, rotor and asd relay. I have power when i put a test light in the plug that connects to the coil when it turns over. The light is weak however. Also get a very weak spark when i plug a spark plug into the center wire going into the distributor. I get none when i plug a spark plug directly into the spark plug wire. I have got the car to fire only a little if i turn the distributor counter clockwise as almost as far as it will go. I have exhausted all my ideas. Any help would be greatly appreciated. Thanks
ANSWER: Hi Aaron,
Let's try using the built-in diagnostic capability using the ignition key. Turn it; "on-off-on-off-on and leave on" doing that in 5 seconds or less elapsed time. Then watch the check engine light, which remains "on", to see it start to flash, pause, flash, etc. Count the number of flashes before each pause. Then repeat the process to be sure of a repeatable set of flash counts, and let me know what you get. We'll go from there I assume this is a 2.5L engine.
If the voltage to the + post of the coil is not the same as battery voltage there could be some sort of a drain on the output of the asd relay,
Try jumping a wire directly from the battery to the + post of the coil temporarily and see whether that improves the quality of the spark. If you had a voltmeter you could also see what voltage is shown on the gray wire at the + post of the coil while you are cranking it over. I conjecture if the voltage is low on the gray wire at the coil that you may have a short circuit of that ASD voltage source at the heated oxygen sensor which has very fragile wires between its plug and the sensor. The other items connected to the ASD are the fuel injector and the fuel pump which are less likely to have shorts. Let me know what you find.
Please read the PS (below) and respond to it.
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QUESTION: It is a 2.5l. I jumped a wire to the coil and it did make better spark. I also did a diagnostic test and got 1,2,5,5. If i do have bad wires on the oxygen sensor would it be best to replace it. Is the heated oxygen sensor the one located on the exhaust manifold?
The 12 code simply means the battery was disconnected sometime in the recent past, and the 55 code just verifies that the readout is completed. So there is no clue as to the problem in the those codes.
So if the engine will run properly with the jump wore to the coil, that does suggest that something is indeed pulling down the voltage to the coil. Replacing the sensor is a reasonable thing to try.
First, try disconnecting the heated oxygen sensor at the plug, then see of the engine (spark) problem is solved. If so:
Use penetrating oil on the threads overnight before trying to remove it. You might even use a tap (18 x 1.5 x 6E) to clean out the threads before installing the new sensor.
But if you have an ohmmeter, before you remove it you might want to verify that the sensor's 12v wire is indeed shorted to ground. The two white wires between the plug and the tip of the sensor are the ones that carry 12v and the ground for the heater. When unplugged those wires should be 'floating', i.e. show infinite resistance to chassis ground
Use a 22 mm wrench (box end if you are going to remove and throw away the old sensor. Use an open end wrench to install and use anti-seize compound on the threads of the new unit.
Thanks for the rating and nomination. You can do it again for this answer, is you so-choose.