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Category: Dodge
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1998 ram 1500: fire to the coil...fuses ok, replace computer {

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Working on a 1998 ram 1500 5.9. I have no fire to the coil. All fuses ok, replace computer { that was expensive} did this twice. checkd for any fuse links none found. no burnt wires that i can see. When you turn the key to start position with a test light on the coil wire you can see it light up for a second then fire goes away again. Turn key back off then over to start and same result. If you crank the motor you can see the light come on at test light but as soon as you let go of the switch fire goes away. I have a 99 ram 1500 that has fire at coil when the key is in the on possition. Its a six cly. but wiring looks the same. I assume this one should also be hot with the key on. Any help with this one? Steve
have you checked the asd (auto shutdown) relay? it controls power to the coil and should be located in the underhood fuse box
Customer: replied 9 years ago.
Yes I have replaced every fuse and relay under the hood with the other dodge I have, with the correct amps.
did you swap crankshaft and camshaft sensors as well? if there are no engine speed signals then the computer will not ground the asd relay
Customer: replied 9 years ago.
I do not find a crank or cam sensor on this vehicle. Do they have either
cam sensor is the pick up inside of the distributor......crankshaft sensor is mounted on the bellhousing of the transmission and reads off the flywheel teeth....its got a pigtail connector and has a brace with two bolts holding it to the transmission
Customer: replied 9 years ago.
So if one of these parts is shorted could it cause the know fire to coil wire> The original problem with this happed when the battery was replaced. Ran good prior to that. Just had a dead bat. and replaced it now have this problem
yes its possible....however before you replace them....1. when you turn the key on to the run position does the check engine light illuminate? 2. does the odometer work and read actual mileage or possibly show a "no bus" message?
Customer: replied 9 years ago.
Befor changing the computer we had no fuel pump no fire to coil and the fuel guage did not work. After replacing the computer the fuel pump worked and all the gauges worked. But still no fire to coil. The milage works and ch engine lite is comming on with key in on position...
lets try something....lets see if you can manually pull codes from the check engine light....hop in the truck and tuen the key to the run position and then back off three times in a row within five seconds and then turn the key to the run position and see if the light starts to flash a code...count the flashes and post the code here
Customer: replied 9 years ago.
This truck is back at my shop. But I tried that with the old and new computer. I could not get the truck to do a self diagnostic. I thought with chrysler you had to push the trip button and hold it while you turn the key off and on three times though. Did I do that wrong? I did this several times..
hmmm....usually just doing the key will do it...three times within five seconds....
Customer: replied 9 years ago.
This is a wierd one. My dad and I are partners in this shop. He has been an auto tech for 35+ years and I of course all my life. I am 36. Usually we can figure things out between us in a short time. This one has us both scratching. We have tried everything of logic. Except replacing the expensive cam and crank sensors. Is there a way to test those yet..? I will try the KOKO again in the morning..
ok....keep me posted......i use a snap on vantage pro to look at the signal integrity on a gives you a sample of a good signal
Customer: replied 9 years ago.
Thank you very much for your time. I appriciate it much.. We are a small shop actually mobile mechanics. So we do not have the scopes or high tech equipment to really do intense auto electric work. But we can usually figure it out without it. Thanks again. If you think of any other ideas please contact me...[email protected]
will do
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