5.0L (1979-1995) Mustang Technical discussions on 5.0 Liter Mustangs within. This does not include the 5.0 from the 2011 Mustang GT. That information is in the 2005-1011 section.

302 ignition failure, this is a good one for you guys

Old 12-03-2011, 07:19 PM
  #1  
lxonlifesupport
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Default 302 ignition failure, this is a good one for you guys

hello everyone. im new to the forum but not new to mustangs. ive got an odd one for you here.

firstly, ive got no check engine light, and havent attempted to pull any codes on the car.

heres how it started, driving and the mustang dies, doesnt stutter, doesnt groan, dies. like someone pulled the plug. get the car back to the shop(i do collision work) and find i have no spark from the coil whatsoever, power to both wires with ignition on. First thought, coil, swapped, nothing. I replace my msd distributor, with the same unit.... car will fire but wont run really...TACH IS BOUNCING ALL OVER THE PLACE. very odd.

i have a digital 6 box but dont use it for the most part. i hook up the digital 6, fire the car and immediately find idle. AND THE TACH IS WORKING PERFECTLY--- work over my timing a little, go for a drive, and it wont drive well at all. timing is all over the place and to get it driveable i have to retard the timing to a ridiculous extent. car still wont drive right but got me home where its warm and im not losing my mind. also starts horrendously once its warm.

my thinking is that when the distributor let loose it ruined my icm/ecm...does this car have a separate icm? how do i test this, what codes should i be looking for...etc...one of you out there knows this...help me out please
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Old 12-04-2011, 10:32 PM
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projectresto83
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Run a KOEO/KOER tests

the only computer is in the passenger kick panel

remove the spout connector and see if the timing stays at the base timing.

just if you want to start from scratch...
http://sbftech.com/index.php?topic=588.0


What are your mods? I would suggest getting rid of that MSD dizzy for a stocker but that depends on what all you have done....
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Old 12-10-2011, 12:37 PM
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Trollin
 
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Okay, I would either diagnose or just replace your distributor.

In your distributor there is a hall effect sensor, those are common to fail on these cars causing a no spark no start condition. The hall effect sensor basically tells your ignition module to fire.

Check for battery voltage on the Red/Light Green wire at both the ignition module and the distributor. This should be hot when the key is in the run position and is fed from fuse 18 in the Central Junction Box (Engine bay fuse pannel)

If OK, check the Profile Ignition Pickup (PIP) output from the distributor on the Dark Blue wire that goes to the ignition module. If using a lab scope, this would be a battery voltage square wave. IF using a voltmeter, bump the engine over while observing the meter, the meter will toggle from 0 volts to battery voltage. The other PIP wire is Gray/Orange that goes to pin 56 of the PCM for injector pulse and should read the same as the DB wire.

If that doesnt fix your problem there is probably an open/short in that circuit.
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Old 12-10-2011, 01:11 PM
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projectresto83
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Originally Posted by Trollin
Okay, I would either diagnose or just replace your distributor.

In your distributor there is a hall effect sensor, those are common to fail on these cars causing a no spark no start condition. The hall effect sensor basically tells your ignition module to fire.

Check for battery voltage on the Red/Light Green wire at both the ignition module and the distributor. This should be hot when the key is in the run position and is fed from fuse 18 in the Central Junction Box (Engine bay fuse pannel)

If OK, check the Profile Ignition Pickup (PIP) output from the distributor on the Dark Blue wire that goes to the ignition module. If using a lab scope, this would be a battery voltage square wave. IF using a voltmeter, bump the engine over while observing the meter, the meter will toggle from 0 volts to battery voltage. The other PIP wire is Gray/Orange that goes to pin 56 of the PCM for injector pulse and should read the same as the DB wire.

If that doesnt fix your problem there is probably an open/short in that circuit.

There isn't a fuse box under the hood of a foxbody.....that started in 94
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Old 12-11-2011, 07:29 AM
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My bad, I own a 95 mustang so whereever the CJB is on the foxbody fuse 18.
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Old 12-11-2011, 07:51 AM
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projectresto83
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Also, the fox doesn't have a remote ignition module like the 94/95 does so it doesn't have the dark blue wire (PIP output) because the TFI module (ignition module) is attached to the distributor. The ignition is not ran by a fuse either. The wiring does have a fusible link though but that powers the whole ignition system.

OP follow the link I posted and Trollin, read it to learn some foxbody knowledge
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Old 12-11-2011, 08:30 AM
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eb2gt
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hey Project, does this exist in years back (like 87-88-89) ??
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Old 12-11-2011, 09:54 AM
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projectresto83
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yes, 87-93 the ignition system is set up the same. Maybe a few minor differences but its the same setup
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