What could cause coil not to ground?

Mitchocalypse · 05-09-2014, 09:09 AM

Basically I'm getting no spark. I have done a lot of electrical testing and gone through the whole system quite thoroughly and think I have narrowed the no-spark issue down to one thing.

Apparently if you have everything hooked up and jumper the ground pin on any coil plug, and test voltage with a multimeter (one lead on pin/paper clip/whatever you are using to jumper the ground at the plug, and one lead to a ground/chassis) you should see fluctuating voltage. So basically 12v-0v-12v-0v-12v-0v as the igniter grounds the coil. I'm seeing very good voltage at the plug (16v, 13 when cranking) but it never grounds.

I haven't actually tested my coils but I'm convinced they aren't the problem because they rarely fail and they were Working fine the last time I used them. So as far as I'm concerned, once the coil starts grounding I should see spark.

Problem- I don't have a heck of a lot of time to work on this car, only really Saturdays and Friday nights so I want to make the most of that time and have just a solid list of things to check so I'm not just dicking around for hours trying to BS myself into thinking I know what the problem could be.

So I got a list of things going here and I just want to know if there's anything else I can add. So far I've got:

-Make sure igniter is grounded (this is my #1 suspect)
-check ecu is grounded properly
-check ground on coil harness
-check engine to chassis ground
-make sure crank sensors are working properly (no clue what proper functioning voltage and amperage fluctuations are but I can get a running car to compare to)
-test using stock ecu (to eliminate the ecu as a potential problem)
-test without twin power (again, shouldn't be the problem since power is still going to coils)

Is there anything else I can add to the list?

Garfinkles Motor Works · 05-09-2014, 08:32 PM

Coils DO fail , swap the low volt wire plug from one of the other coils and see if the failure follows the low volt plug. If it is the leading coil that is bad try to find a leading coil for a second gen,they are less money and give a higher output .

Mitchocalypse · 05-09-2014, 08:59 PM

Quote:

Originally Posted by Garfinkles Motor Works

Coils DO fail , swap the low volt wire plug from one of the other coils and see if the failure follows the low volt plug. If it is the leading coil that is bad try to find a leading coil for a second gen,they are less money and give a higher output .

Oh I might not have been clear in the OP but non of the coils are working. None of them are grounding. They were working good when pulled and one I actually replaced with one from fritz Flynn.. Not sure which one but I doubt he sold me a dud

05-09-2014, 09:09 AM	#1
Mitchocalypse Rotary Fanatic Join Date: Jun 2012 Location: Edmonton, AB Posts: 179 Rep Power: 13	What could cause coil not to ground? Basically I'm getting no spark. I have done a lot of electrical testing and gone through the whole system quite thoroughly and think I have narrowed the no-spark issue down to one thing. Apparently if you have everything hooked up and jumper the ground pin on any coil plug, and test voltage with a multimeter (one lead on pin/paper clip/whatever you are using to jumper the ground at the plug, and one lead to a ground/chassis) you should see fluctuating voltage. So basically 12v-0v-12v-0v-12v-0v as the igniter grounds the coil. I'm seeing very good voltage at the plug (16v, 13 when cranking) but it never grounds. I haven't actually tested my coils but I'm convinced they aren't the problem because they rarely fail and they were Working fine the last time I used them. So as far as I'm concerned, once the coil starts grounding I should see spark. Problem- I don't have a heck of a lot of time to work on this car, only really Saturdays and Friday nights so I want to make the most of that time and have just a solid list of things to check so I'm not just dicking around for hours trying to BS myself into thinking I know what the problem could be. So I got a list of things going here and I just want to know if there's anything else I can add. So far I've got: -Make sure igniter is grounded (this is my #1 suspect) -check ecu is grounded properly -check ground on coil harness -check engine to chassis ground -make sure crank sensors are working properly (no clue what proper functioning voltage and amperage fluctuations are but I can get a running car to compare to) -test using stock ecu (to eliminate the ecu as a potential problem) -test without twin power (again, shouldn't be the problem since power is still going to coils) Is there anything else I can add to the list? __________________

05-09-2014, 08:32 PM	#2
Garfinkles Motor Works RCC Contributor Join Date: Mar 2008 Posts: 535 Rep Power: 18	Coils DO fail , swap the low volt wire plug from one of the other coils and see if the failure follows the low volt plug. If it is the leading coil that is bad try to find a leading coil for a second gen,they are less money and give a higher output .