Hi. I have a 1998 wrangler with the 4.0 and 5 speed and am having issues with power to coil and injectors. Tested the control side of the Asd relay and all checks out. And also have 12 on the hot side of relay. When key is turned I am only getting .2 volts to coil. From the diagrams I have seen it shows the asd relay output also going to field on the alt. I am getting a good 12 volts to there for 2-3seconds when key is tuned like it should I’m at a loss
Asd power issues
Tmoore1998
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Hi. I have a 1998 wrangler with the 4.0 and 5 speed and am having issues with power to coil and injectors. Tested the control side of the Asd relay and all checks out. And also have 12 on the hot side of relay. When key is turned I am only getting .2 volts to coil. From the diagrams I have seen it shows the asd relay output also going to field on the alt. I am getting a good 12 volts to there for 2-3seconds when key is tuned like it should I’m at a loss
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My 98 had a problem with grounds, a added 3 ground wires, 12 ga, and problems went away. 1 was to the relay box.
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Ok I will check and clean all grounds I am looking for a wiring diagram that shows where the 12v constant power comes from for injectors and coil if anyone can help find one
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What is the overall problem? Is it that the engine will not start?
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Yes engine cranks won’t start don’t have 12v at injectors or coil only getting .2 Volts
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OK that helps.
The diagram you found is not for 1998 as you describe it. There are free year specific FSMs in pdf on the net. The ASD is not connected to the alternator field wire in 1998.
It is normal for the ASD relay (& fuel pump relay) to only stay energized for 2-3 seconds after the key is turned on unless the PCM sees a crank sensor signal. So unless you are cranking the engine or it is running the relay will not have output to the injectors or coil after than time.
The path for 12v from the energized ASD relay for 1998 is through fuse 21, also in the PDC, then to the coil & injectors as well as the O2 sensor heaters. So check fuse 21.
If that fuse is good here is how to check this circuit. Use the diagrams of the relay socket terminals below to check the input & output or the ASD relay.
Pull the relay. Check terminal 1 for 12v power (from fuse 6). If nothing check fuse 6.
Next make a short jumper wire & jump from terminal 1 over to terminal 2 (see the red circled #s). That should send 12v power to fuse 21, then to the coil & injectors. If yes, see if the engine starts.
Report findings for more info if needed.
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The diagram you found is not for 1998 as you describe it. There are free year specific FSMs in pdf on the net. The ASD is not connected to the alternator field wire in 1998.
It is normal for the ASD relay (& fuel pump relay) to only stay energized for 2-3 seconds after the key is turned on unless the PCM sees a crank sensor signal. So unless you are cranking the engine or it is running the relay will not have output to the injectors or coil after than time.
The path for 12v from the energized ASD relay for 1998 is through fuse 21, also in the PDC, then to the coil & injectors as well as the O2 sensor heaters. So check fuse 21.
If that fuse is good here is how to check this circuit. Use the diagrams of the relay socket terminals below to check the input & output or the ASD relay.
Pull the relay. Check terminal 1 for 12v power (from fuse 6). If nothing check fuse 6.
Next make a short jumper wire & jump from terminal 1 over to terminal 2 (see the red circled #s). That should send 12v power to fuse 21, then to the coil & injectors. If yes, see if the engine starts.
Report findings for more info if needed.
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