Author Topic: coil testing  (Read 832 times)

0 Members and 1 Guest are viewing this topic.

Offline cookjer24

  • RCC Rookie
  • **
  • Posts: 266
  • Gender: Male
coil testing
« on: February 21, 2013, 01:05:36 PM »
any one tell me what the ohms should be and how to test the coil to see if its bad :o
1977 plymouth trailduster sport 8" lift 33" tires 4.11 dana 60's 360 727-203

1993 dodge shadow es 2.5 turbo (sleeper) work car

Offline mopar65pa

  • DODGE TRUCK PARTS COLLECTOR
  • RCC Addict
  • ********
  • Posts: 48204
  • Gender: Male
  • I NEVER CLAIMED TO BE ANYTHING BUT KNUTTS!
Re: coil testing
« Reply #1 on: February 21, 2013, 01:26:06 PM »
 ;)
I'd rather push a DODGE than drive a chevy or a ford!!!!!!
78 D200 Crew Cab
99 Volvo S70
77 400/727 RC
79 360/727 RC
89 318/727 RC
80 318/435 TD
89 CTD D250
90 CTD W250
73 Charger SE 400/727 
02 883R Harley
85 Merc 300TD
Quote
Ted Nugent called and he wants your shirt back! http://www.youtube.com/watch?v=HFduVeNEWSA

Offline cookjer24

  • RCC Rookie
  • **
  • Posts: 266
  • Gender: Male
Re: coil testing
« Reply #2 on: February 21, 2013, 01:29:51 PM »
thanks
1977 plymouth trailduster sport 8" lift 33" tires 4.11 dana 60's 360 727-203

1993 dodge shadow es 2.5 turbo (sleeper) work car

Offline mopar65pa

  • DODGE TRUCK PARTS COLLECTOR
  • RCC Addict
  • ********
  • Posts: 48204
  • Gender: Male
  • I NEVER CLAIMED TO BE ANYTHING BUT KNUTTS!
Re: coil testing
« Reply #3 on: February 21, 2013, 01:31:56 PM »
I'd rather push a DODGE than drive a chevy or a ford!!!!!!
78 D200 Crew Cab
99 Volvo S70
77 400/727 RC
79 360/727 RC
89 318/727 RC
80 318/435 TD
89 CTD D250
90 CTD W250
73 Charger SE 400/727 
02 883R Harley
85 Merc 300TD
Quote
Ted Nugent called and he wants your shirt back! http://www.youtube.com/watch?v=HFduVeNEWSA

Offline cookjer24

  • RCC Rookie
  • **
  • Posts: 266
  • Gender: Male
Re: coil testing
« Reply #4 on: February 21, 2013, 02:46:15 PM »
ok tried 3 different coils and no go have 12 volts at both terminals of coil when key is on so i'm thinking its a bad ecm becouse don't they controll the on off trigering of the coil.
1977 plymouth trailduster sport 8" lift 33" tires 4.11 dana 60's 360 727-203

1993 dodge shadow es 2.5 turbo (sleeper) work car

Offline moparmaiden

  • Full Member
  • ****
  • Posts: 1340
  • Gender: Female
  • I love Lee Michaels...,Do you know what I mean?
Re: coil testing
« Reply #5 on: February 21, 2013, 07:53:15 PM »
ok tried 3 different coils and no go have 12 volts at both terminals of coil when key is on so i'm thinking its a bad ecm becouse don't they controll the on off trigering of the coil.
Yes they do, and they are known for going bad.
78 Ramcharger 440
72 Rallye Charger 440
69 Polara CHP car 440
68 Coronet street legal drag car 440
75 power wagon 360(currently apart)
72 plymouth satellite 318 (future Petty stock car clone)

Offline hoov100

  • Jr. Member
  • ***
  • Posts: 524
  • Gender: Male
Re: coil testing
« Reply #6 on: February 21, 2013, 08:11:13 PM »
Check the dizzy and also check to see if the dizzy is grounding the coil.

Offline phillip637

  • RCC Rookie
  • **
  • Posts: 407
  • phillip
Re: coil testing
« Reply #7 on: February 21, 2013, 08:14:52 PM »
The ECM grounds to the firewall where it bolts up. Poor grounding there can cause it to fail. What I've done in the past is sand the firewall where it bolts down to bare metal to make sure it had a good ground. After that mine has lasted ever since. I went threw a good handful of the at one point
1985 Ramcharger 4WD 318 cammed 4bbl headers 727 auto
1989 Ramcharger LE 4WD 318TBI/727
2000 Dakota 3.9l magnum automatic 2wd

Offline moparmaiden

  • Full Member
  • ****
  • Posts: 1340
  • Gender: Female
  • I love Lee Michaels...,Do you know what I mean?
Re: coil testing
« Reply #8 on: February 22, 2013, 12:50:40 AM »
The ECM grounds to the firewall where it bolts up. Poor grounding there can cause it to fail. What I've done in the past is sand the firewall where it bolts down to bare metal to make sure it had a good ground. After that mine has lasted ever since. I went threw a good handful of the at one point
He's right, it may not be grounded. Didnt think of that :P
78 Ramcharger 440
72 Rallye Charger 440
69 Polara CHP car 440
68 Coronet street legal drag car 440
75 power wagon 360(currently apart)
72 plymouth satellite 318 (future Petty stock car clone)

Offline cookjer24

  • RCC Rookie
  • **
  • Posts: 266
  • Gender: Male
Re: coil testing
« Reply #9 on: February 22, 2013, 10:24:56 AM »
its grounded made sure of that. pretty sure it is stock from the factory back in 78 so its time for a new one.
1977 plymouth trailduster sport 8" lift 33" tires 4.11 dana 60's 360 727-203

1993 dodge shadow es 2.5 turbo (sleeper) work car

Offline KThaxton

  • The Criticizer
  • Global Moderator
  • RCC Addict
  • *****
  • Posts: 26569
  • Gender: Male
  • Have leafs, wheel travel.
Re: coil testing
« Reply #10 on: February 22, 2013, 11:41:08 AM »
Check the dizzy and also check to see if the dizzy is grounding the coil.

What do you mean? The dizzy doesn't ground the coil, and if you mean that it shouldn't be grounding the coil, how could that logically happen?
STOP PLATE TECTONICS!

You're absolutely correct, Kendall. My mistake  ;D

Offline phillip637

  • RCC Rookie
  • **
  • Posts: 407
  • phillip
Re: coil testing
« Reply #11 on: February 22, 2013, 05:26:21 PM »
its grounded made sure of that. pretty sure it is stock from the factory back in 78 so its time for a new one.

Yea I'd go get another one. They should be in stock at your local parts store. And even if that's not the problem it's never a bad idea to have a spare one around.
1985 Ramcharger 4WD 318 cammed 4bbl headers 727 auto
1989 Ramcharger LE 4WD 318TBI/727
2000 Dakota 3.9l magnum automatic 2wd

Offline mopar65pa

  • DODGE TRUCK PARTS COLLECTOR
  • RCC Addict
  • ********
  • Posts: 48204
  • Gender: Male
  • I NEVER CLAIMED TO BE ANYTHING BUT KNUTTS!
Re: coil testing
« Reply #12 on: February 22, 2013, 06:00:53 PM »
Yea I'd go get another one. They should be in stock at your local parts store. And even if that's not the problem it's never a bad idea to have a spare one around.

X2.
I'd rather push a DODGE than drive a chevy or a ford!!!!!!
78 D200 Crew Cab
99 Volvo S70
77 400/727 RC
79 360/727 RC
89 318/727 RC
80 318/435 TD
89 CTD D250
90 CTD W250
73 Charger SE 400/727 
02 883R Harley
85 Merc 300TD
Quote
Ted Nugent called and he wants your shirt back! http://www.youtube.com/watch?v=HFduVeNEWSA

Offline hoov100

  • Jr. Member
  • ***
  • Posts: 524
  • Gender: Male
Re: coil testing
« Reply #13 on: February 23, 2013, 01:35:06 PM »
What do you mean? The dizzy doesn't ground the coil, and if you mean that it shouldn't be grounding the coil, how could that logically happen?

Let me rephrase that :D

Make sure the dizzy is getting 1.5 volts and make sure the ignition module is grounding the coil.

Offline KThaxton

  • The Criticizer
  • Global Moderator
  • RCC Addict
  • *****
  • Posts: 26569
  • Gender: Male
  • Have leafs, wheel travel.
Re: coil testing
« Reply #14 on: February 24, 2013, 12:51:33 AM »
Let me rephrase that :D

Make sure the dizzy is getting 1.5 volts and make sure the ignition module is grounding the coil.

Where is the dizzy getting 1.5 volts from?

The distributor does not "get" any voltage (except the cap and rotor end). The magnetic pickup generates a very low voltage pulse signal to tell the module to fire the coil.
STOP PLATE TECTONICS!

You're absolutely correct, Kendall. My mistake  ;D

Offline SickDog

  • RCC Rookie
  • **
  • Posts: 399
  • Gender: Male
  • ramblin bumbling extradonaire
Re: coil testing
« Reply #15 on: February 24, 2013, 02:32:40 AM »
ok tried 3 different coils and no go have 12 volts at both terminals of coil when key is on so i'm thinking its a bad ecm becouse don't they controll the on off trigering of the coil.

i think what the OP is saying is that the ECM is failing to provide the grounding cycle for the coil. are these known coils that your are testing with?

however you will get voltage on both posts if the primary winding is ok. there is an ohm spec for the seconadary to primary windings so check that too.

if the coil tests good hook up your test light in series after the coil. like this:

Power wire -> Coil -> Test Light -> ECM.

crank the engine and watch for a flashing test light. if it flashes with no spark induced, the coil is no good and the electronics are ok. if is doesnt flash, the electronics are suspect and need further testing.

either the sensor in the dist. is bad or the ECM is bad. it is possible to test the output signal from the dist. if that tests good, its the ECM.

its a process of elimination because testing the ecm circuits is impractical

Let me rephrase that :D

Make sure the dizzy is getting 1.5 volts and make sure the ignition module is grounding the coil.

the ecm controls the ground to the coil via a transistor thus eliminating points and a condensor. the dist. has a sensor that generates a reference timing signal for the ecm to do its magic.


85 W150 Sno Commander; 318/727/NP208D, CAD D44 and 9.25; 8 in lift; for now.......

Offline cookjer24

  • RCC Rookie
  • **
  • Posts: 266
  • Gender: Male
Re: coil testing
« Reply #16 on: February 24, 2013, 04:28:47 PM »
going to replace both of the components that way i will have a spare pickup or vise versa. there all cheap anyway.
1977 plymouth trailduster sport 8" lift 33" tires 4.11 dana 60's 360 727-203

1993 dodge shadow es 2.5 turbo (sleeper) work car

Offline hoov100

  • Jr. Member
  • ***
  • Posts: 524
  • Gender: Male
Re: coil testing
« Reply #17 on: February 24, 2013, 06:10:55 PM »
Where is the dizzy getting 1.5 volts from?

The distributor does not "get" any voltage (except the cap and rotor end). The magnetic pickup generates a very low voltage pulse signal to tell the module to fire the coil.

So then why does my dizzy have 1.5v to the pickup when the ignition is on?


« Last Edit: February 24, 2013, 06:17:04 PM by hoov100 »

Offline SickDog

  • RCC Rookie
  • **
  • Posts: 399
  • Gender: Male
  • ramblin bumbling extradonaire
Re: coil testing
« Reply #18 on: February 24, 2013, 09:16:04 PM »
most likely reference signal for the sensor.

a quick look at a diagram will answer all these questions
85 W150 Sno Commander; 318/727/NP208D, CAD D44 and 9.25; 8 in lift; for now.......

 

email