Will not start after changing spark plugs

Tiny
RUSS1961
  • MEMBER
  • 1999 CHRYSLER LHS
  • 3.5L
  • V6
  • 2WD
  • 300,000 MILES
The car will crank but will not start after I changed the spark plugs. It ran good beforehand. All I did was remove coils to very top the spark plugs. Replaced plugs, put coils back on, and plugged them in. Now it won't start at all. I have changed spark plugs in hundreds of vehicles and never had this problem. Someone, please help.
Wednesday, December 4th, 2019 AT 2:12 PM

12 Replies

Tiny
SCGRANTURISMO
  • MECHANIC
  • 4,897 POSTS
Hello,

This could be a couple of different things here. First off could you please check Fuse N in the Power Distribution Center PDC], or the Under hood Fuse Box in your vehicle. In the diagrams down below I have included a diagram with the location of the PDC, a diagram with the location of Fuse N, and finally the wiring diagrams for your vehicle's Engine Management circuits and a guide for how to find short to grounds in an automotive electrical circuit. Please go through these guides and get back to us with the status of Fuse N, and we will go from there.

Thanks,
Alex
2CarPros
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Thursday, December 5th, 2019 AT 1:13 AM
Tiny
RUSS1961
  • MEMBER
  • 7 POSTS
Thank you for all the information. I checked fuse N, and it is good.
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Thursday, December 5th, 2019 AT 1:41 PM
Tiny
RUSS1961
  • MEMBER
  • 7 POSTS
Any idea about what I can check next? All the fuses seem to be good.
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Saturday, December 7th, 2019 AT 3:53 AM
Tiny
SCGRANTURISMO
  • MECHANIC
  • 4,897 POSTS
Hello again,

Sorry for taking so long to get back to you. Okay, so fuse N is good, so next can you please check the Auto Shut Down [ASD] relay for us. It is located in PDC. Here is a link below explaining how to test a relay, if needed:

https://www.2carpros.com/articles/how-to-check-an-electrical-relay-and-wiring-control-circuit

Please check the relay and get back to us with how everything turns out.

Thanks,
Alex
2CarPros
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Saturday, December 7th, 2019 AT 7:14 PM
Tiny
RUSS1961
  • MEMBER
  • 7 POSTS
I just checked the auto shutdown relay with the help if my neighbor and it does click.
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Sunday, December 8th, 2019 AT 12:42 PM
Tiny
SCGRANTURISMO
  • MECHANIC
  • 4,897 POSTS
Hello again,

Okay, so the next thing that we want to check is the Crankshaft Position Sensor [CKP]. In the diagrams down below I have included a description along with a diagram of the CKP location of your vehicle. Here is a link explaining how to remove and install a CKP in a vehicle:

https://www.2carpros.com/articles/crankshaft-angle-sensor-replacement

Please go through these guides and get back to us with what you are able to find out.

Thanks,
Alex
2CarPros
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Sunday, December 8th, 2019 AT 2:21 PM
Tiny
RUSS1961
  • MEMBER
  • 7 POSTS
Sorry it took me so long. I checked the crankshaft position sensor the way it said on that link you supplied for me and it seems to be working correctly. Also, I just wanted to add, before I changed the spark plugs the alarm would always sound whenever I would disconnect and reconnect the battery, but now it doesn't. Does that mean anything?
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Thursday, December 12th, 2019 AT 12:02 PM
Tiny
SCGRANTURISMO
  • MECHANIC
  • 4,897 POSTS
Hello again,

Hmm, can you take a voltage reading for me across the battery terminals. Please get back to us with that reading and we can go from there.

Thanks,
Alex
2CarPros
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Thursday, December 12th, 2019 AT 3:49 PM
Tiny
RUSS1961
  • MEMBER
  • 7 POSTS
Okay. I just checked the voltage on the battery and it reads 11.99 volts.
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Friday, December 13th, 2019 AT 10:27 AM
Tiny
SCGRANTURISMO
  • MECHANIC
  • 4,897 POSTS
Hello again,

Okay, your vehicle's battery has been run down by the cranking without starting of the engine. If the battery was on the verge of failing before the no start, I would recommend replacing it at this point. If it was a good strong battery before the no start, then I would recommend getting a good recharge on it. Auto parts stores, like AutoZone, offer a free battery charging service that usually only takes a couple of hours if you do not have access to a battery charger yourself. You will need to have a fully charged battery to proceed. Please get back to us when your vehicle's battery is fully charged and we can go from there.

Thanks,
Alex
2CarPros
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Friday, December 13th, 2019 AT 3:54 PM
Tiny
RUSS1961
  • MEMBER
  • 7 POSTS
Okay. Approximately an hour after charging the battery to a full charge, I checked the voltage and it was 12.55 volts.
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Saturday, December 14th, 2019 AT 12:52 PM
Tiny
SCGRANTURISMO
  • MECHANIC
  • 4,897 POSTS
Hello again,

Okay, it's fully charged. So, next let's check the Camshaft Position Sensor[CMP]. In the diagrams down below I have included a guide explaining the CMP operation, complete with diagrams showing it's location. Please inspect the electrical connector and wires for damage and replace the CMP. Get back to us with how everything turns out, please.

Thanks,
Alex
2CarPros
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Saturday, December 14th, 2019 AT 1:00 PM

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