Need help with troubleshooting ignition/coil
Thread Starter
Instructor
Joined: May 2004
Posts: 247
Likes: 0
From: Baton Rouge LA
Need help with troubleshooting ignition/coil
Read another thread that sounded familiar, but thought I would ask anyway. Started having issues with car dying. Runs fine down the highway, but then when I slow down to stop for a light/stop sign, car dies. Turns over, but doesn't fire. Let it sit for 15 minutes and fires up like normal. Talking to friends we thought vapor lock or possibly coil overheating and opening up? How could I troubleshoot? Friend suggested pulling the plug wire next time it dies and see if I have spark. If not, then ignition problem. From the forum, I figured it's either ignition module or coil, but betting on coil. Before I go spend the $80 on a coil to see if it fixes the problem, would be nice to do some kind of troubleshooting.
Any help appreciated.
Any help appreciated.
Intermediate
Joined: Oct 2005
Posts: 29
Likes: 0
From: Brussels
I'm not qualified in any way to answer this, but it sounds like the same problem I had (maybe it was my post you saw?) and it was the contact points in the (old mechanical) distributor that were at fault.
In the end I just needed to dismantle the distributor and clean the contacts with some sandpaper. Made a huge difference to how the car ran. The timing was also out, when this was fixed it was like having a new car
In the end I just needed to dismantle the distributor and clean the contacts with some sandpaper. Made a huge difference to how the car ran. The timing was also out, when this was fixed it was like having a new car
Race Director
Joined: Mar 2001
Posts: 11,322
Likes: 1
From: Living in the Hartland
If you happen to be refering to my post about my Firebird with a chevy eng, it is not the coil. I took the coil out of my vette and ran the bird with it and it still died on me. Not sure if the pick up would cause these symptom but am going to swap out the whole dist to see if changes anything.
Le Mans Master
Joined: Sep 2001
Posts: 7,739
Likes: 630
From: Unreconstructed, South Carolina
Originally Posted by Custum73
This is not an original ignition system. It now has a Mallory coil and distributor.
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Le Mans Master
Joined: Sep 2001
Posts: 7,739
Likes: 630
From: Unreconstructed, South Carolina
Originally Posted by Custum73
Mallory ProMaster Coil 28720
Mallory Unilite Electronic Distributor 3864501
Points Ballast Resistor
Mallory Unilite Electronic Distributor 3864501
Points Ballast Resistor
However, Unilite is optical ... replace its module.
Then again, that remote box could be bad.
Dunno if that coil is supposed to run with a ballast resistor when triggered by NON-points dist?
Suggest you review all instructions for all components. If you don't have them, they're probably available via download thru Mr Gasket site.
Thread Starter
Instructor
Joined: May 2004
Posts: 247
Likes: 0
From: Baton Rouge LA
The following info was sent to me from mr gasket. any merit to it? I'll give it a shot tonight.
"The 28720 is actually a points type coil with just about .75 ohms of resistance. If your Corvettre still has the loom resistor wire or you are running a ballast resistor or both, low voltage to the coil (+) could be the issue when everything is hot. Fire it up and let it idle for about a minuit or so and check the voltage going into the coil (+) terminal with it idling. If the voltage is down around 6 or 7 volts, low voltage is the issue. If you are running a ballast resistor check the voltage coming into it from the ignition switch side. If the loom resistor wire is in place and working you will see about 9 to 9.5 volts. Take out the ballast resistor. If you still see 13+ volts then try moving the distributor red wire to the ignition switch end of the ballast rtesistor. This should solve the issue with the hot stalling problem. "
"The 28720 is actually a points type coil with just about .75 ohms of resistance. If your Corvettre still has the loom resistor wire or you are running a ballast resistor or both, low voltage to the coil (+) could be the issue when everything is hot. Fire it up and let it idle for about a minuit or so and check the voltage going into the coil (+) terminal with it idling. If the voltage is down around 6 or 7 volts, low voltage is the issue. If you are running a ballast resistor check the voltage coming into it from the ignition switch side. If the loom resistor wire is in place and working you will see about 9 to 9.5 volts. Take out the ballast resistor. If you still see 13+ volts then try moving the distributor red wire to the ignition switch end of the ballast rtesistor. This should solve the issue with the hot stalling problem. "
Le Mans Master
Joined: Sep 2001
Posts: 7,739
Likes: 630
From: Unreconstructed, South Carolina
Originally Posted by jackson
Dunno if that coil is supposed to run with a ballast resistor when triggered by NON-points dist?
Suggest you review all instructions for all components..
Suggest you review all instructions for all components..
Originally Posted by mrgasket
If your Corvettre still has the loom resistor wire or you are running a ballast resistor or both, low voltage to the coil (+) could be the issue when everything is hot...
Last edited by jackson; Oct 20, 2005 at 09:53 PM.
