No Voltage at coil 93 W250 5.9L
#1
No Voltage at coil 93 W250 5.9L
Update... It is running again. I replaced the coil. I'm not sure if it was the coil or just the coil wasn't grounded to the frame. I did check the resistance from the + to the coil output and it was around 9K ohms, which is better than the old coil, so IDK. LOL.
Update... I see the coil does have about 9V when I am cranking it over; the ECM doesn't let the coil just sit there if you turn on the truck? I guess now I will do the usual stuff and check cap, rotor, etc... I will post if I get it started.
I'm having a heck of a time figuring out where the ASW is located or even if the pickup has one. I don't know if I'm just old, but I can't find anything searching google or bing or youtube. So what is the first place to look when you don't have 12V at the coil. I checked with the ignition on, and there is just a trace amount of voltage (0.2V). I checked the duck foot with a voltage meter and it is good. I traced the wire to the coil that is supposed to have 12V back to a solder joint up on the intake manifold and no voltage there either. Is there a fuse anywhere I need to look for? The last time it did start I had to crank it for more than the few seconds it usually takes to start. Thanks in advance... Rob W
Other info: The wire in question is dark green with an orange stripe. With the key on, I don't have any voltage to it. I noticed also that this wire goes to all the injectors too, and maybe some other areas. I do also see a wire that goes to the front drivers side fender; looks like the brain maybe? LOL. I'm tempted to separate the wire for voltage and run a direct wire to the + of the battery and see what happens, though all those other items wouldn't have voltage either. I did try starting fluid to see if it would fire, but nothing happened, so I am assuming no spark. How could there be if the coil doesn't have any voltage anyways.
I do not think this has a ballast resistor. I traced the dark green with orange back to a relay; replaced it, but still no voltage to coil. There are two wire (other than the 12V red) that go to this relay. Both seem to have the same voltage, which wouldn't activate the relay. Any idea where these two wire go? I would think one would have to be a ground... is there a neutral/park switch that might be the issue?
Update... I see the coil does have about 9V when I am cranking it over; the ECM doesn't let the coil just sit there if you turn on the truck? I guess now I will do the usual stuff and check cap, rotor, etc... I will post if I get it started.
I'm having a heck of a time figuring out where the ASW is located or even if the pickup has one. I don't know if I'm just old, but I can't find anything searching google or bing or youtube. So what is the first place to look when you don't have 12V at the coil. I checked with the ignition on, and there is just a trace amount of voltage (0.2V). I checked the duck foot with a voltage meter and it is good. I traced the wire to the coil that is supposed to have 12V back to a solder joint up on the intake manifold and no voltage there either. Is there a fuse anywhere I need to look for? The last time it did start I had to crank it for more than the few seconds it usually takes to start. Thanks in advance... Rob W
Other info: The wire in question is dark green with an orange stripe. With the key on, I don't have any voltage to it. I noticed also that this wire goes to all the injectors too, and maybe some other areas. I do also see a wire that goes to the front drivers side fender; looks like the brain maybe? LOL. I'm tempted to separate the wire for voltage and run a direct wire to the + of the battery and see what happens, though all those other items wouldn't have voltage either. I did try starting fluid to see if it would fire, but nothing happened, so I am assuming no spark. How could there be if the coil doesn't have any voltage anyways.
I do not think this has a ballast resistor. I traced the dark green with orange back to a relay; replaced it, but still no voltage to coil. There are two wire (other than the 12V red) that go to this relay. Both seem to have the same voltage, which wouldn't activate the relay. Any idea where these two wire go? I would think one would have to be a ground... is there a neutral/park switch that might be the issue?
Last edited by rwaltemate; 03-07-2023 at 09:09 PM.
#2
there is only power to the coil for a couple seconds then the computer will shut the asd relay off so trying to test it with a multi meter may not be possible unless you are the Flash. it would be best to try testing for power at the coil wires with a test light so you can see if power is being delivered before the computer turns it off.
#3
Is it possible to bypass the Automatic shut down? I assume the thiner yellow blue wire that goes to the engine control module needs to be grounded to get power everywhere, though I saw on my voltmeter that yellow blue and larger blue were the same voltage. I would cut the yellow and blue wire, and ground the relay if I did anything. I don't want to ground out the ECM. LOL
#4
#5
#6
What condition is the battery in? 9 volts to the coil should be the same at the battery during cranking seems a bit low. Have you tried checking for codes? Seems the asd relay is working since you have voltage cranking. Your problem may be the crank or cam sensors.
https://www.allpar.com/threads/the-1...ost-1085223107
https://www.allpar.com/threads/the-1...ost-1085223107
#7
I will check the codes. Had the battery on the charger overnight, but will check the date, and if I can find my battery tester, then I will give it a test. Pulled #1 spark plug and grounded it and no spark while cranking.
Thanks for the link; I am going to see what I can find next. Thanks all.
Thanks for the link; I am going to see what I can find next. Thanks all.
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#8
The battery isn't great, so I put the 40 amp shop charger on it (the wheeled one with a timer). Code 12 and 55 is all. Still no spark. I guess I will go ahead with a new coil next as I don't have a computer to plug a 1993 into if there deeper codes I could get too. Might get a new battery too; or steel the one out of the chevelle. LOL
The cap and rotor did have corrosion on it. At least I know it isn't that! Small victory is better than none.
The cap and rotor did have corrosion on it. At least I know it isn't that! Small victory is better than none.
Last edited by rwaltemate; 03-07-2023 at 07:42 PM.
#9
Not sure I am doing this correctly, but to test the coil there is a primary and secondary resistance. Primary is between 0.97 and 1.18, and the secondary is between 11,300 and 15,300. If I take my multi-meter and go from the + of the coil to where the wire goes from the top of the coil to distributer I get 12,940, and if I go from the + to ground I get an open circuit. Am I doing this correctly?