Starts then won't start.... - MustangForums.com


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.

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Old 08-10-2010, 11:43 PM   #1  
gsl969
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Default Starts then won't start....

I have a 1993 5.0 GT. I'm able to start it up 2 or 3 times without any problems. After I shut it off and on, that's when it won't start back up again. It'll crank but it won't start. I've been able to drive it pretty far (LA to San Diego) without any problems but one day I drove it only 15 miles, shut it down, and couldn't start it back up again. This seems to happen randomly and I can't figure out why. Car is still stock.
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Old 08-11-2010, 07:41 AM   #2  
9redfox3
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Cranks OK, but No Start Checklist for Fuel Injected Mustangs

A word about this checklist before you start: it is arranged in a specific order to put the most likely failure items first. That will save you time, energy and money. Start at the top of the list and work your way down. Jumping around will possibly cause you to miss just what you need to see to find and fix the problem. Donít skip any steps because the next step depends on the last step working correctly.

Revised 19-Jun-2009 to clarify ignition switch & coil power states.

All text applies to all models unless stated otherwise.

Note: 94-95 specific changes are in red

1.) Remove push on connector (small red/blue wire) from starter solenoid and turn ignition switch to the Run position. Place car in neutral or Park and set the parking brake. Remove the coil wire from distributor & and hold it 3/8Ē away from the engine block. Jumper the screw to the big bolt on the starter solenoid that has the battery wire connected to it. You should get a nice fat blue spark.
Most of the items are electrical in nature, so a test light, or even better, a voltmeter, is helpful to be sure they have power to them.

No spark, possible failed items in order of their probability:
A.) MSD or Crane ignition box if so equipped
B.) PIP sensor in distributor. The PIP sensor supplies the timing pulse to trigger the TFI and injectors. A failing PIP sensor will sometimes let the engine start if the SPOUT is removed. See paragraph 5A - a noid light will tell if the pip is working by flashing when the engine is cranking.
C.) TFI module: use a test light to check the TFI module. Place one lead of the test light on the red/green wire on the ignition coil connector and the other lead on the dark green/yellow wire on the ignition coil connector. If the TFI is working properly, the test light will flash when the engine is cranked using the ignition switch.
D.) Coil
E.) No ECC or computer power - ECC or computer relay failure
86-93 models only: ECC relay next to computer - look for 12 volts at the fuel injector red wires
94-95 models only: EEC or PCM power relay in the constant control relay module. Look for 12 volts at the fuel injector red wires.
F.) No ECC or computer power - fuse or fuse link failure
86-93 models only: Fuse links in wiring harness - look for 12 volts at the fuel injector red wires. All the fuse links live in a bundle up near the starter solenoid.
94-95 models only: 20 amp EEC fuse in the engine compartment fuse box. Look for 12 volts at the fuel injector red wires.
G.) Ignition switch - look for 12 volts at the ignition coil red/lt green wire. No 12 volts, blown fuse link or faulty ignition switch. Remove the plastic from around the ignition switch and look for 12 volts on the red/green wire with the switch in the Run position. No 12 volts and the ignition switch is faulty. If 12 volts is present in the Run position at the ignition switch but not at the coil, then the fuse or fuse link is blown.
Note: fuses or fuse links blow for a reason. Donít replace either a fuse or fuse link with one with a larger rating than stock. Doing so invites an electrical fire.
Ignition fuse links may be replaced with an inline fuse holder and 5 amp fuse for troubleshooting purposes.
94-95 models only: Check inside fuse panel for fuse #18 blown Ė 20 amp fuse
H.) Missing or loose computer power ground. The computer has its own dedicated power ground that comes off the ground pigtail on the battery ground wire. Due to it's proximity to the battery, it may become corroded by acid fumes from the battery. It is a black cylinder about 2 1/2" long by 1" diameter with a black/lt green wire. You'll find it up next to the starter solenoid where the wire goes into the wiring harness
I.) Computer.
J.) Bad or missing secondary power ground. It is located between the back of the intake manifold and the driver's side firewall. It supplies ground for the alternator, A/C compressor clutch and other electrical accessories such as the gauges.
K.) Engine fires briefly, but dies immediately when the key is released to the Run position. Crank the engine & when it fires off, pull the small push on connector (red wire) off the starter relay (Looks like it is stuck on a screw). Hold the switch in the crank position: if it continues to run there is a problem with either the ignition switch or TFI module. Check for 12 volts at the red/green wire on the coil with the switch in the Run position. Good 12 volts, then replace the TFI. No 12 volts, replace the ignition switch.
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Old 08-11-2010, 06:13 PM   #3  
19stang88
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could be the tfi module. the samething happened to me
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Old 08-11-2010, 10:30 PM   #4  
gsl969
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I still wasn't getting any sparks so I'm replacing my distributor to see if that helps. I originally bought the MSD but that sucked so now I'm going with the Mallory and hopefully that would help.

On the clutch pedal switch, there's 2 wires that connect together and one wire that's separated. Which wire goes where? Does the single wire go to the starter relay and does the 2 wires go to the computer and transmission? I think my wires got clipped when they tried installing my alarm.
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Old 08-12-2010, 12:12 AM   #5  
19stang88
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just buy a normal oem dizzy. Im betting it is the TFI module or PIP. just get the tfi tested at a auto part store.
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Old 08-16-2010, 11:17 AM   #6  
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whats the pip im having the same prob and i have already replaced the tfi the fuel pump , fuel pump relay , ecc relay ,
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Old 08-16-2010, 11:21 AM   #7  
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im getting fire it will run on either
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Old 09-23-2011, 04:13 AM   #8  
gsl969
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replaced eec relay, fuel pump relay, msd distributor, msd coil, everythin is grouded well, clutch pedal switch. checked the fuel injectors and im getting 12v.
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Old 11-30-2011, 08:05 PM   #9  
gsl969
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I was wondering about the distributor that has a control module attached to it. Has anyone ever tried rigging it up to the SN95 distributor with the 6AL ignition box?

Anybody know anyone in Long Beach that can check out my wiring? I've taken it to a few shops and they don't even wanna mess w/ my car.
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