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5.0EFI Starts fine when cold..wont re-start after use and temp is 170 on the motor

S

SpikeTampa

New member
My 5.0 EFI will start fine first thing when cool, after running and the motor gets warm up to 170 degrees, it wont restart. The engine turns over and over but wont catch. Has plenty of fresh fuel, just replaced distributor cap and rotor.
Any ideas?
Thanks
Spike
 
Re: 5.0EFI Starts fine when cold..wont re-start after use and temp is 170 on the moto

You have spark at the plugs when this occurs ?
 
Re: 5.0EFI Starts fine when cold..wont re-start after use and temp is 170 on the moto

Have spark at the beginning..it starts..didnt spark test when hot and wont start. Whats the best way to test the spark?
 
Re: 5.0EFI Starts fine when cold..wont re-start after use and temp is 170 on the moto

Use an old spark plug connected to one of the plug wires and ground out the plug casing on the intak man. If you have a timing light you can hook it up to the coil output and watch the flash. Then connect it to one of the plug wires at the spark plug and see if the spark is getting to the plug. Check each plug if needed.
 
Re: 5.0EFI Starts fine when cold..wont re-start after use and temp is 170 on the moto

No spark when hot. I used a spark plug tester....
 
Re: 5.0EFI Starts fine when cold..wont re-start after use and temp is 170 on the moto

If it has Thunderbolt Ignition perform the test procedure.

Tests for Thunderbolt Ignition:


W/ignition key on AND BILGE WELL VENTILATED OF GAS FUMES!!!


Check the kill switch first!


#1 - Connect your voltmeter neg. lead to the engine ground and pos. lead to the white/red wire terminal at the dist. It should read 12 volts.

#2 - If 12 volts are present, remove the coil spark wire from the distributor and connect it to a spark gap tester to ground. Remove the white/green lead from the dist. terminal. Turn the ign. key to on and strike the white/green lead to ground. If there is spark, replace the ignition sensor in the dist.

#3 - If there is no spark, substitute a new coil and repeat test #2. Now if you get spark, install a new coil. NO SPARK, replace ign. amp.

#4 - In #2, if there is No voltage present, disconnect the white/red wire and check it again for 12 volts. If 12 volts is present, replace the ignition sensor inside the dist. cap. If no 12 volts present w/it disconnected--ignition amplifier is shot and must be replaced.
 
Re: 5.0EFI Starts fine when cold..wont re-start after use and temp is 170 on the moto

Thank you. Replaced ignition module...works fine.
 
Re: 5.0EFI Starts fine when cold..wont re-start after use and temp is 170 on the moto

You are welcome; glad it runs.
 
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