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Engine 93 Cobra loses spark>>>>

  • Thread starter Thread starter Monkeybutt2000
  • Start date Start date Sep 20, 2020
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Monkeybutt2000

Mustang Master
Aug 11, 2019
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Lafayette,IN
Sep 20, 2020
#1
  • Sep 20, 2020
  • #1
Owner (very close friend) has been battling this issue for over a year. Car will start and run for about 20secs,then die. With the key in the ON position, you pull a plug wire and put a plug in, it will NOT spark. You cycle the key back to OFF, the car will start,or throw spark at said plug EVERY time. If you pull the plug from the TFI module,and plug it back in, it will start or throw spark as well. There are no aftermarket electrical items hooked up to the car. We have tried two different ecu's, two different coils, and two different distributors. All three of these items were from my running,driving car so we know these parts are good. If you hook a dvm to the coil,and turn the car over,you can watch the voltage drop. We pulled codes as well, but IMO they wouldn't cause this issue. I can post those later if necessary. So,where do we begin?
 
M

Monkeybutt2000

Mustang Master
Aug 11, 2019
1,387
849
133
Lafayette,IN
Sep 20, 2020
#2
  • Sep 20, 2020
  • #2
 

General karthief

wonder how much it would cost to ship you a pair
5 Year Member
Aug 25, 2016
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polk county florida
Sep 20, 2020
#3
  • Sep 20, 2020
  • #3
Have you checked the. Ignition switch?
 
M

Monkeybutt2000

Mustang Master
Aug 11, 2019
1,387
849
133
Lafayette,IN
Sep 20, 2020
#4
  • Sep 20, 2020
  • #4
General karthief said:
Have you checked the. Ignition switch?
Click to expand...
Already replaced.forgot about that.
 

HemiRick

I'd be looking at jacking under the house
Jun 28, 2020
723
272
73
Memphis TN
Sep 21, 2020
#5
  • Sep 21, 2020
  • #5
Have you checked fuel pressure?
 
M

Monkeybutt2000

Mustang Master
Aug 11, 2019
1,387
849
133
Lafayette,IN
Sep 21, 2020
#6
  • Sep 21, 2020
  • #6
HemiRick said:
Have you checked fuel pressure?
Click to expand...
Yes,we have fuel pressure.
 

General karthief

wonder how much it would cost to ship you a pair
5 Year Member
Aug 25, 2016
27,875
10,543
203
polk county florida
Sep 21, 2020
#7
  • Sep 21, 2020
  • #7
Would the fuseable link in the ignition wire in the harness up by the master cylinder effect power to the coil?
 

Mustang5L5

That is…until I whipped out my Bissell
Mod Dude
Feb 18, 2001
43,225
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Massachusetts
Sep 21, 2020
#8
  • Sep 21, 2020
  • #8
When you lose spark, do you also lose fuel injector pulse? Can you test with a noid light?

If not, I would troubleshoot the ECU relay, or just try swapping it if it's easier since you have a car to "borrow" one from. Not 100% sure this is a valid reason for your issues, but one thing to check out. It would be good to know if you are just losing spark, or losing injector pulse as well at the same time.
 
M

Monkeybutt2000

Mustang Master
Aug 11, 2019
1,387
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133
Lafayette,IN
Sep 21, 2020
#9
  • Sep 21, 2020
  • #9
General karthief said:
Would the fuseable link in the ignition wire in the harness up by the master cylinder effect power to the coil?
Click to expand...
I believe once a fusible link blows,that's it. Car wouldn't start. I may be wrong.
 
Last edited: Sep 21, 2020
M

Monkeybutt2000

Mustang Master
Aug 11, 2019
1,387
849
133
Lafayette,IN
Sep 21, 2020
#10
  • Sep 21, 2020
  • #10
Mustang5L5 said:
When you lose spark, do you also lose fuel injector pulse? Can you test with a noid light?

If not, I would troubleshoot the ECU relay, or just try swapping it if it's easier since you have a car to "borrow" one from. Not 100% sure this is a valid reason for your issues, but one thing to check out. It would be good to know if you are just losing spark, or losing injector pulse as well at the same time.
Click to expand...
Gonna pick up a noid light,won't hurt to have it around. EEC relay was replaced with a parts store unit.
 

Mustang5L5

That is…until I whipped out my Bissell
Mod Dude
Feb 18, 2001
43,225
17,909
224
Massachusetts
Sep 21, 2020
#11
  • Sep 21, 2020
  • #11
Monkeybutt2000 said:
I believe once a fusible link blows,that's it. Car wouldn't start. I may be wrong.
Click to expand...

you are correct, it’s blown and needs to be replaced.
 

nickyb

I gotta say i never painted my nuts, Never Ever
15 Year Member
Apr 3, 2009
2,979
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nevada
Sep 22, 2020
#12
  • Sep 22, 2020
  • #12
To me it doesn't seem like a part because you have replaced with known good ones.I believe it's a wire or wire connector.start with coil connector/wires.
 
M

Monkeybutt2000

Mustang Master
Aug 11, 2019
1,387
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133
Lafayette,IN
Sep 22, 2020
#13
  • Sep 22, 2020
  • #13
nickyb said:
To me it doesn't seem like a part because you have replaced with known good ones.I believe it's a wire or wire connector.start with coil connector/wires.
Click to expand...
I'm with you here, tracking it down is the hard part.
 

Mustang5L5

That is…until I whipped out my Bissell
Mod Dude
Feb 18, 2001
43,225
17,909
224
Massachusetts
Sep 22, 2020
#14
  • Sep 22, 2020
  • #14
If I solve it, can I have the cobra?

Seriously, I am curious if you lose injector pulse and spark at the same time. Could potentially narrow down where in the wiring the issue might lie.
 
M

Monkeybutt2000

Mustang Master
Aug 11, 2019
1,387
849
133
Lafayette,IN
Sep 22, 2020
#15
  • Sep 22, 2020
  • #15
Mustang5L5 said:
If I solve it, can I have the cobra?

Seriously, I am curious if you lose injector pulse and spark at the same time. Could potentially narrow down where in the wiring the issue might lie.
Click to expand...
LOL,well that's not for me to decide. Hopefully get a noid light next few days.
 
Reactions: nickyb
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chriscash96

Member
Mar 6, 2022
7
3
13
Washington
Mar 28, 2022
#16
  • Mar 28, 2022
  • #16
Hey I know this thread is a little old, Ive been working on a the exact same issue and just wondered did you ever figure out the problem? Thanks.
 
M

Monkeybutt2000

Mustang Master
Aug 11, 2019
1,387
849
133
Lafayette,IN
Mar 29, 2022
#17
  • Mar 29, 2022
  • #17
chriscash96 said:
Hey I know this thread is a little old, Ive been working on a the exact same issue and just wondered did you ever figure out the problem? Thanks.
Click to expand...
Not that I'm aware of. He sold his house and moved to Mississippi.
 
M

Monkeybutt2000

Mustang Master
Aug 11, 2019
1,387
849
133
Lafayette,IN
Apr 24, 2022
#18
  • Apr 24, 2022
  • #18
An end to this thread. Buddy finally got the issue sorted out. He took the Cobra to Anderson Ford for a supercharger install and Holley termi X. They claimed the dizz wasn't seated all the way and made the computer shut the car down. He apparently had an oil pump drive shaft for a 351C.
 
Reactions: Boostedpimp and Cheapskate207
M

Monkeybutt2000

Mustang Master
Aug 11, 2019
1,387
849
133
Lafayette,IN
Apr 26, 2022
#19
  • Apr 26, 2022
  • #19
So,gang,I'd like to touch on this and hear some thoughts. The shop said it was the wrong oil pump shaft,which it was. However,how would the dizz not being seated all the way make the car shutoff? It has no way of knowing the installed height of the dizz. They claimed because the dizz was not locked down the timing was jumping back and forth causing the ecu to shut the car off.
 

General karthief

wonder how much it would cost to ship you a pair
5 Year Member
Aug 25, 2016
27,875
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polk county florida
Apr 26, 2022
#20
  • Apr 26, 2022
  • #20
My thoughts, since the 351 shaft does not fit into the 5.0 distributor hole it was riding on the end and slipping causing the distributor to stop/start turning and shut the car off.
My question is if it don't fit the distributor and fits the oil pump is the oil pump wrong?
Just thinking out loud.
 
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