Sporadic Ignition Failure

Jason70GT · 04-29-2007

HELP!

I have a rather challenging problem and I need help! Here are the circumstances: I have a 1970 Opel GT, 1.9 rebuilt about 250 miles ago. Manual transmission.

When driving I will suddenly loose power...the RPM needle will drop to zero like a rock and I can push the gas pedal to the floor and absolutely no reaction...almost as though the linkage has broken. Just as suddenly the power will come back. It will be fine for a minute or two, then happen again. After several bouts of this many times the engine will shut down completely or misfire.

I have replaced the manual fuel pump with an electric. I have also changed to Pertronix Electronic Egnition. I am about to change the coil to see if that helps at all...but i doubt that's the problem. I have not noticed any particular circumstances where this will occur...with the exception of the fact that it never happens when I first start out. It usually takes 20 minutes or so of driving. I'm wondering if it needs to heat up before failure???

My latest thought is that it is somehow related to the egnition switch. I know they can burn out, but I'm wondering if this burnout can be intermittent until total failure.

Any help you all can provide would be appreciated. I'm pulling out what little hair I have left on my head!

Jason

73Manta72gt · 04-29-2007

wire up a small 12v bulb and connect it to the + side of the coil and mount it on the cowl with tape so you can see if power to the coil disappears while driving. If it does you know you having a wiring/switch probblem.

Jason70GT · 04-29-2007

Is it possible for the coil to be intermittent? I was under the impression it either works or doesn't. I have no problem starting the car...and so assumed the coil is ok.

73Manta72gt · 04-29-2007

the coil can be intermittent and if the light gets brighter then the coil or the points/wiring will be the problem. if the light goes out then your just losing power to the coil.

Lindsay · 04-29-2007

GT owner thought he had a vapor lock problem. GT would cut-out when hot. Changed coil and problem was resolved. Low cost troubleshooting!

73Manta72gt had a great idea for checking with light bulb.

tekenaar · 04-30-2007

Originally Posted by Jason70GT

HELP!

I have a rather challenging problem and I need help! Here are the circumstances: I have a 1970 Opel GT, 1.9 rebuilt about 250 miles ago. Manual transmission.

When driving I will suddenly loose power...the RPM needle will drop to zero like a rock and I can push the gas pedal to the floor and absolutely no reaction...almost as though the linkage has broken. Just as suddenly the power will come back. It will be fine for a minute or two, then happen again. After several bouts of this many times the engine will shut down completely or misfire.

I have replaced the manual fuel pump with an electric. I have also changed to Pertronix Electronic Egnition. I am about to change the coil to see if that helps at all...but i doubt that's the problem. I have not noticed any particular circumstances where this will occur...with the exception of the fact that it never happens when I first start out. It usually takes 20 minutes or so of driving. I'm wondering if it needs to heat up before failure???

My latest thought is that it is somehow related to the egnition switch. I know they can burn out, but I'm wondering if this burnout can be intermittent until total failure.

Any help you all can provide would be appreciated. I'm pulling out what little hair I have left on my head!

Jason

Check the things mentioned in previous posts, but I would add checking the Pertronix red + wire to see that its power source there is not intermittent for some reason . . . uh, you DID connect that to a switched 12V source (comes on with ignition key "ON"), right?! I mean, not just connected to the coil + side!!

OpelJim · 04-30-2007

For me it was the small braided wire in the distributor plate I do believe it is a ground wire for the distributor If that were severed or kinked up it could cause this problem as the distributor plate moves it shorts out or is disconnected from completing a circuit

Another cause was a condensor that was not grounded out against the case of the distributor

JMTC

tekenaar · 04-30-2007

Originally Posted by OpelJim

For me it was the small braided wire in the distributor plate I do believe it is a ground wire for the distributor If that were severed or kinked up it could cause this problem as the distributor plate moves it shorts out or is disconnected from completing a circuit

Another cause was a condensor that was not grounded out against the case of the distributor

JMTC

True, but this ignition is Pertronix triggered . . .

neuropel · 04-30-2007

I had the EXACT problem discussed here on my first GT, and the problem went away when I replaced the coil. Mine would drop ALL power as mentioned, the tach would drop to zero, then it would suddenly come back and all seemed fine. Mine also never acted up until it was warm. I think the coil was getting hot and failing. It's a cheap test to see, and if the car has an old coil you'd be better off replacing it with a decent one anyway. I have had really good luck with the Bosch Red coils - they are a drop in swap (no need to switch out the resistor wire) and provide a good, hot spark. I've also used one with a pertronix with no issues. I hear the pertronix flame throwers work well also, and I think you can get the proper resistance coil to match. They're far cheaper than the bosch red coils and would complement the pertronix you already have (you can get them in chrome as well I think!).

Todd

Paul · 04-30-2007

Originally Posted by neuropel

. (you can get them in chrome as well I think!).
Todd

Yes they come in CHROME

Jason70GT · 04-30-2007

In the most platonic way ever meant...I love you guys! This is great...thanks for the help and I'll let you all know if the coil replacement does it.

Again, THANKS!

OpelJim · 05-01-2007

Originally Posted by tekenaar

True, but this ignition is Pertronix triggered . . .

Did not look at the posts above my bad

ephillippe · 05-01-2007

Double check your fuse box too, I have a petronix and an MSD setup, about once a month my car would be running smooth but die for no reason, a little pushing on the fuse box would bring it right back. Found out that 2-3 fuses were very loose, really need to replace the box, but I just made some copper shims for the time being, the dieing hasn't come back yet!

04-29-2007	#1 (permalink)
Jason70GT Opeler Join Date: Jul 2004 Location: Carmel, Indiana Posts: 10 Real Name: Jason	Unanswered: Sporadic Ignition Failure HELP! I have a rather challenging problem and I need help! Here are the circumstances: I have a 1970 Opel GT, 1.9 rebuilt about 250 miles ago. Manual transmission. When driving I will suddenly loose power...the RPM needle will drop to zero like a rock and I can push the gas pedal to the floor and absolutely no reaction...almost as though the linkage has broken. Just as suddenly the power will come back. It will be fine for a minute or two, then happen again. After several bouts of this many times the engine will shut down completely or misfire. I have replaced the manual fuel pump with an electric. I have also changed to Pertronix Electronic Egnition. I am about to change the coil to see if that helps at all...but i doubt that's the problem. I have not noticed any particular circumstances where this will occur...with the exception of the fact that it never happens when I first start out. It usually takes 20 minutes or so of driving. I'm wondering if it needs to heat up before failure??? My latest thought is that it is somehow related to the egnition switch. I know they can burn out, but I'm wondering if this burnout can be intermittent until total failure. Any help you all can provide would be appreciated. I'm pulling out what little hair I have left on my head! Jason

04-29-2007	#5 (permalink)
Lindsay Opeler Join Date: Jul 2003 Location: San Diego, CA Posts: 508 Provided Answers: 1	Could be coil GT owner thought he had a vapor lock problem. GT would cut-out when hot. Changed coil and problem was resolved. Low cost troubleshooting! 73Manta72gt had a great idea for checking with light bulb.

04-30-2007	#7 (permalink)
OpelJim Member Join Date: Mar 2002 Location: Fallbrook. CA Posts: 704	this has happened to me For me it was the small braided wire in the distributor plate I do believe it is a ground wire for the distributor If that were severed or kinked up it could cause this problem as the distributor plate moves it shorts out or is disconnected from completing a circuit Another cause was a condensor that was not grounded out against the case of the distributor JMTC

04-30-2007	#9 (permalink)
neuropel Rice Cooker Join Date: May 2002 Location: Spring Church, PA Posts: 1,787	I had the EXACT problem discussed here on my first GT, and the problem went away when I replaced the coil. Mine would drop ALL power as mentioned, the tach would drop to zero, then it would suddenly come back and all seemed fine. Mine also never acted up until it was warm. I think the coil was getting hot and failing. It's a cheap test to see, and if the car has an old coil you'd be better off replacing it with a decent one anyway. I have had really good luck with the Bosch Red coils - they are a drop in swap (no need to switch out the resistor wire) and provide a good, hot spark. I've also used one with a pertronix with no issues. I hear the pertronix flame throwers work well also, and I think you can get the proper resistance coil to match. They're far cheaper than the bosch red coils and would complement the pertronix you already have (you can get them in chrome as well I think!). Todd __________________ "In the end, it's not the years in your life that count. It's the life in your years." -Abraham Lincoln ________________ 1972 GT 2.4L 1974 Manta GT/E 2.2L 1973 Manta Rallye 2.5L

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04-29-2007	#2 (permalink)
73Manta72gt Member Join Date: Nov 2002 Location: Winston-Salem, NC Posts: 341	wire up a small 12v bulb and connect it to the + side of the coil and mount it on the cowl with tape so you can see if power to the coil disappears while driving. If it does you know you having a wiring/switch probblem.

04-29-2007	#3 (permalink)
Jason70GT Opeler Join Date: Jul 2004 Location: Carmel, Indiana Posts: 10 Real Name: Jason	Is it possible for the coil to be intermittent? I was under the impression it either works or doesn't. I have no problem starting the car...and so assumed the coil is ok.

04-29-2007	#4 (permalink)
73Manta72gt Member Join Date: Nov 2002 Location: Winston-Salem, NC Posts: 341	the coil can be intermittent and if the light gets brighter then the coil or the points/wiring will be the problem. if the light goes out then your just losing power to the coil.

04-30-2007	#11 (permalink)
Jason70GT Opeler Join Date: Jul 2004 Location: Carmel, Indiana Posts: 10 Real Name: Jason	In the most platonic way ever meant...I love you guys! This is great...thanks for the help and I'll let you all know if the coil replacement does it. Again, THANKS!

05-01-2007	#13 (permalink)
ephillippe Manta Ray Join Date: Sep 2005 Location: Alameda, CA Posts: 74	Double check your fuse box too, I have a petronix and an MSD setup, about once a month my car would be running smooth but die for no reason, a little pushing on the fuse box would bring it right back. Found out that 2-3 fuses were very loose, really need to replace the box, but I just made some copper shims for the time being, the dieing hasn't come back yet!

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