Coils overheat with merely turning key on

Tiny
GAIL ERLICHMAN
  • MEMBER
  • 2001 NISSAN SENTRA
  • 1.8L
  • 4 CYL
  • 4WD
  • AUTOMATIC
  • 120,000 MILES
Started with car would turnover but no start. After hesitation while driving and loss of power while driving.. After changing fuel pump, most sensors and changing out the four coils, and fixing wiring. Please help me resolve this. Much time and many dollars and these cars did have their share of problems. Help
Thursday, September 7th, 2017 AT 11:06 AM

9 Replies

Tiny
STEVE W.
  • MECHANIC
  • 14,514 POSTS
What wiring did you fix? The only reason why the coils would get hot as soon as the key was turned on would be if they are being triggered on all the time. Below is the schematic. Each coil should have battery power to pin 3, Ground to pin 2 and the trigger wire goes to the ECM and only gets a signal when told to fire,

The most likely suspect that would trigger them on all the time would be a failed cam sensor, or bad ECM. If it was a shorted trigger wire it would have to be all of them which means a bad ECM.
You should be able to see the ignition pulses to each coil with a test light on the trigger pin. If they each glow as soon as you turn the key on you have a problem.
Unplug the cam sensor, do they stop and cool down? If yes the sensor is faulty.
Image (Click to make bigger)
Thumb
Was this
answer
helpful?
Yes
No
Thursday, September 7th, 2017 AT 11:18 PM
Tiny
GAIL ERLICHMAN
  • MEMBER
  • 4 POSTS
Do you have the schematics for the ECM or know how to find? I would if you have access, since I do not, if you would send. Thanks. We are preparing for a big storm out here in Florida.
Was this
answer
helpful?
Yes
No
Friday, September 8th, 2017 AT 9:30 AM
Tiny
GAIL ERLICHMAN
  • MEMBER
  • 4 POSTS
Not able to find it, limited time with prepping for major hurricane. Any other suggestions you come up with would be appreciated. I am good with wires and all, so any options rather than replacing ECM if it is fixable? Or any suggestions. Thanks
Was this
answer
helpful?
Yes
No
Friday, September 8th, 2017 AT 9:42 AM
Tiny
STEVE W.
  • MECHANIC
  • 14,514 POSTS
If it is the ECM there is not any repair, just replace. Mainly because there are no schematics available to "the public" and the parts can be hard to source.

I have been watching Irma, stay safe and return when you can. We will be here.
Was this
answer
helpful?
Yes
No
Friday, September 8th, 2017 AT 10:24 AM
Tiny
REDGITTL
  • MEMBER
  • 3 POSTS
I have some resources and maybe they will be able to help find parts if I knew what parts I was looking for. I will still try to access schematics and look for some work around search to find access not easily available to public.
I will not know if I do not try.
Also, where is the ECM relay to ECM located? Thanks for all your help thus far.
If you have any other suggestions, please send them my way. Of course, prepping for storm safety first.
Was this
answer
helpful?
Yes
No
Friday, September 8th, 2017 AT 12:41 PM
Tiny
REDGITTL
  • MEMBER
  • 3 POSTS
What is ASCD Control Unit and where is it located? What does it do?
Was this
answer
helpful?
Yes
No
Friday, September 8th, 2017 AT 5:35 PM
Tiny
STEVE W.
  • MECHANIC
  • 14,514 POSTS
Have you unplugged the cam sensor to make sure it isn't shorted?
With a drop in ECM at around 200 bucks I would simply swap it for a reman or a used unit for testing. But for either of those you still need to be able to program the unit when you install it, unless you can get one that is a drop in.

ASCD is Nissan speak for cruise control. Automatic Speed Control Device. It's a box hidden behind the dash.
Was this
answer
helpful?
Yes
No
+1
Friday, September 8th, 2017 AT 9:55 PM
Tiny
GAIL ERLICHMAN
  • MEMBER
  • 4 POSTS
Got it running, but after 1 minute coil #1 gets red hot and stalls
Was this
answer
helpful?
Yes
No
Saturday, September 23rd, 2017 AT 7:24 AM
Tiny
STEVE W.
  • MECHANIC
  • 14,514 POSTS
What happens if you swap the coil to a different cylinder? Does it still get hot or does the problem stay at cylinder 1?
Was this
answer
helpful?
Yes
No
+1
Sunday, September 24th, 2017 AT 12:03 AM

Please login or register to post a reply.

Related Ignition Coil Replace/Remove Content

Ignition Coil Replacement
VIDEO
Ignition Coil Replacement
In­struc­tional re­pair video
VIEW MORE