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  #1  
Old October 8th, 2021, 14:57
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Ignition Coil?

When a coil go bad, does the engine shut down without a warning?
My XJ stopped yesterday as sudden as if the ignition is turned off. I was at about 45 MPH. I cannot get it to restart.

I threw parts at it, parts I had on the self, Crankshaft, and Camshaft sensors, but I do not have a coil. I also tried a known good PCM. Checked ignition and wire connectivity. Every thing look good except it have no spark. It have plenty of power to the coil and plenty of fuel but no spark.

What other things should I look at? I have a PC based manual but it do not give coil testing procedures.
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1996 XJ; 4.0L; AW4; NP231; SYE; D30 and D44; ECTED; 4.10 gears; 30X9.5 -15 BFG/AT/KO; 3" lift; Rusty's LCA; JKS ADJ UCA; Kevins ADJ Track bar; Drawtite Front Receiver; Dual Electric Fans; Dual Battaries.
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Old October 8th, 2021, 15:15
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Re: Ignition Coil?

The last time that happened to me the shaft in the distributor had gotten so loose the rotor shattered on one of the distributor cap contacts.
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  #3  
Old October 8th, 2021, 15:35
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Re: Ignition Coil?

Quote:
Originally Posted by 8Mud View Post
The last time that happened to me the shaft in the distributor had gotten so loose the rotor shattered on one of the distributor cap contacts.
I did check that when I was in the distributor to replace the sensor in there. it did feel good and rotated when I cranked the engine.
My 1994 XJ broke the roll pin in the distributor once.
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1996 XJ; 4.0L; AW4; NP231; SYE; D30 and D44; ECTED; 4.10 gears; 30X9.5 -15 BFG/AT/KO; 3" lift; Rusty's LCA; JKS ADJ UCA; Kevins ADJ Track bar; Drawtite Front Receiver; Dual Electric Fans; Dual Battaries.
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  #4  
Old October 8th, 2021, 19:11
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Re: Ignition Coil?

How did you check for spark?

You can use an ohm meter to test the coil. The primary circuit should have a resistance reading of about 1 ohm. The secondary should be somewhere between 11,000 and 15,000 ohms. Also check each circuit to ground. That should be infinite (open).
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  #5  
Old October 8th, 2021, 20:38
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Re: Ignition Coil?

Quote:
Originally Posted by techno1154 View Post
When a coil go bad, does the engine shut down without a warning?
Yes. That is exactly how mine failed.

However, fuel was still being delivered. I was on the freeway when it happened and had just climbed a pass. The raw fuel being dumped on the hot cat didn't work out particularly well for the cat.
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  #6  
Old October 9th, 2021, 09:29
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Re: Ignition Coil?

Quote:
Originally Posted by Saudade View Post
How did you check for spark?

You can use an ohm meter to test the coil. The primary circuit should have a resistance reading of about 1 ohm. The secondary should be somewhere between 11,000 and 15,000 ohms. Also check each circuit to ground. That should be infinite (open).
Between the primary/s it is 1.6 ohms. Primaries to secondary is open.

Quote:
Originally Posted by Anak View Post
Yes. That is exactly how mine failed.

However, fuel was still being delivered. I was on the freeway when it happened and had just climbed a pass. The raw fuel being dumped on the hot cat didn't work out particularly well for the cat.
Was yours also the coil?

This is the first time troubleshooting electrical on a computer controlled vehicle. There are no codes to read. The manual reference a DRB scan tool. This is not readily available. One test referenced in the manual is to check for positive voltage at the coil connector while turning over the engine with the starter. While doing so, the voltage dropped to less than 1 volt. May be a PCM issue. however, a known good PCM does exactly the same thing.

I am going to the local store to get a coil especially because I do not have one in my spares inventory.
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1996 XJ; 4.0L; AW4; NP231; SYE; D30 and D44; ECTED; 4.10 gears; 30X9.5 -15 BFG/AT/KO; 3" lift; Rusty's LCA; JKS ADJ UCA; Kevins ADJ Track bar; Drawtite Front Receiver; Dual Electric Fans; Dual Battaries.
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  #7  
Old October 9th, 2021, 10:38
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Re: Ignition Coil?

The coil plus comes from the ASD relay. The coil negative goes to the PCM and is triggered to ground.
Disconnect the coil, test the plus while cranking, if the voltage drops significantly you have an issue upstream from the coil. If it drops significantly connected on the plus side while cranking, you likely have a partial short in the coil.
Did you test the plus, minus, and high voltage side of the coil to ground?
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  #8  
Old October 9th, 2021, 13:34
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Re: Ignition Coil?

Quote:
Originally Posted by 8Mud View Post
The coil plus comes from the ASD relay. The coil negative goes to the PCM and is triggered to ground.
Disconnect the coil, test the plus while cranking, if the voltage drops significantly you have an issue upstream from the coil. If it drops significantly connected on the plus side while cranking, you likely have a partial short in the coil.
Did you test the plus, minus, and high voltage side of the coil to ground?
I did test with the coil removed positive to negative, positive to output, positive to coil body. Then I did the same tests with the negative input. The only reading was between the primary (pos and neg) input. Tis was done wit the VOA meter leads attached to the positive in the connector and the negative to the battery.

Yes, I do agree the issue is before the coil. I disconnected all sensors including the injectors and cranked the engine and the voltage dropped to less tan 1 volt when the engine is turning then returned to 12.6 when I released the key. I think I need to start looking at the positive input to the PCM or maybe the wire from the PCM to the coil.
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1996 XJ; 4.0L; AW4; NP231; SYE; D30 and D44; ECTED; 4.10 gears; 30X9.5 -15 BFG/AT/KO; 3" lift; Rusty's LCA; JKS ADJ UCA; Kevins ADJ Track bar; Drawtite Front Receiver; Dual Electric Fans; Dual Battaries.
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  #9  
Old October 9th, 2021, 19:30
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Re: Ignition Coil?

Quote:
Originally Posted by techno1154 View Post


Was yours also the coil?
Yes.
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  #10  
Old October 11th, 2021, 01:12
azzy89 azzy89 is offline
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Ignition Coil?

After reading all of the comments no one mentioned CPS, for craps and giggles try unplugging and cleaning the contacts for the CPS with electronic cleaner, and adding dielectric grease, or if you donít want to go through the trouble, unplug CPS use a multimeter while cranking to see if itís outputting any voltage.


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  #11  
Old October 11th, 2021, 08:25
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Re: Ignition Coil?

Quote:
Originally Posted by azzy89 View Post
After reading all of the comments no one mentioned CPS, for craps and giggles try unplugging and cleaning the contacts for the CPS with electronic cleaner, and adding dielectric grease, or if you donít want to go through the trouble, unplug CPS use a multimeter while cranking to see if itís outputting any voltage.


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He said he changed the CPS in his OP.
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  #12  
Old October 11th, 2021, 09:37
azzy89 azzy89 is offline
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Ignition Coil?

Quote:
Originally Posted by Saudade View Post
He said he changed the CPS in his OP.

Good catch, my bad, still good to check cause all the new CPS s are made in China, unless you wait a year or two for Nick Risley (REM guy) to come up with a solution to that issue. Also good idea to back probe the connector on the harness side to make sure it is actually receiving that signal.


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  #13  
Old October 11th, 2021, 13:28
75SV1 75SV1 is offline
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Re: Ignition Coil?

I had a coil issue with my first '98 XJ. I bought it and it didn't run. I tired to test stuff. I think I did check the coil. Finally, I just put a new coil from NAPA. Then it ran. Had an issue with my present '98, after wheeling. I did have an MDS coil on it. Probably had it for 5 years. It did have a spark when I took one of the grounds off. I replaced the coil and the alternator. Then it ran.
Now on my 2000. I bought it non running. I replaced about everything. Sensors, fuel pump, swapped the coil rail. I tried to check volts and ohms. Then I got some NOID lights to check the injectors. I had replaced the originals with 12 holes. The originals looked bad, rusty and cracked cases. The NOID light would light up after I turned the key, then retracts it. Just a flash. A guy at work said it might be the ignition electrical block. I bought one from NAPA, and after a few tries, it ran.
Also, I had a Gremlin that the coil would a act up intermittently. I took it to a shop, and when I drove it home, it ran great. Next morning, it would not start. Guy down the road, took his multimeter, a few measurements, said coil was bad. Replaced the coil and it ran.
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  #14  
Old October 14th, 2021, 06:12
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Re: Ignition Coil?

Is the coil made by Magnetti/Marelli?
If so, replace it.
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  #15  
Old October 15th, 2021, 15:44
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Re: Ignition Coil?

Quote:
Originally Posted by cruiser54 View Post
Is the coil made by Magnetti/Marelli?
If so, replace it.
I am not sure who made the coil. I did see signs of arching on at least tree pins in connector 100 which have all the engine controls running through it including the coil ground wire. I will try to get a good harness from the Pick and Pull and splice it in.

I will also get a new coil while I am at it. It may take a few weeks because my job is a 100% travel job even though I am at home most weekends. Not having the XJ cost me a 2018 Corolla for my commute. Well, it is better than the XJ on
gas.
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