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no spark on my start plugs.... help plz

1K views 8 replies 5 participants last post by  90hatchlx818 
#1 ·
my 90 mustang 5.0 wont start theres no power on the ignition coil wire to the distributor i put a new coil and start plugs and wires.......still no start!
 
#7 ·
Here's a little background information to help you diagnose this no spark condition. In a nutshell, when the system is working properly and you turn the key to crank and start your car

The distributor shaft starts to rotate which causes the PIP (Profile Ignition Pickup) sensor to start generating its crankshaft position signal.

The ignition control module (ICM), upon receiving this PIP signal, starts to ‘open and close’ the ignition coil's primary current. As you might already be aware, it's this action that makes the ignition coil spark.

The Fuel Injection Computer also receives the PIP Signal at the same time that the ignition module does.
Once the engine STARTS, the Fuel Injection Computer takes over the ignition timing.

Try this test to see if the module is bad

http://easyautodiagnostics.com/ford/4.9L-5.0L-5.8L/ignition-module-tests-2
 
#8 · (Edited)
Heres the no spark test steps from sbftech.



1)  Loosen distributor holddown bolt with ½" wrench, remove coil wire from coil, turn ign on, hold the coil wire (with insulated pliers)3/8" away from the coil post, rotate the distributor left-right-left.
a)Spark doesn't arc from the coil to the coil wire=next step
b)Spark arcs from the coil to the coil wire= check condition of distributor cap & rotor and replace.

2) You could also check for spark using one of the spark plugs, grounding it to the frame while activating the starter with the key in IGN ON.

3) Place ignition key in on, with a 12 vdc test light connected to a good ground, probe the (+) terminal at the coil (Red/Lt Green wire)
a)Test light off = usually an ignition switch or 20 ga. fuse link problem
b)Test light on = next step.

4)  Place ignition key in on, with the 12 vdc test light connected to a good ground, probe the (-) terminal at the coil (Tan/Yellow wire)
a)Test light off = replace coil
b)Test light on = next test

5)  Place ignition key in on, with the 12 vdc test light connected to a good ground, probe the (-) terminal at the coil (Tan/Yellow wire), rotate the distributor left-right-left and check test light
a)Test light blinks = replace coil
b)Test light on = next step

6) Ign On, backprobe or disconnect TFI harness and check pin #4 (ICM Power)with a test light.
a)Test light on =next step
b)Test light off =open problem in wiring that needs to be traced & repaired.
""" Pin #4 is the 4th terminal down from the top of the module or the 3rd terminal up from the bottom.Its marked with the asterisks below """
© 1
© 2
© 3
© 4 **
© 5
© 6

7) Up till now the problem is either a TFI module or pip sensor failure. Your options are to either replace the module and check if it starts, or follow a testing procedure to rule out/id the module as the culprit, and replace the pip sensor, TFI module, or both....I usually recommend the latter one for these cases anyway.....
If you suspect the pip sensor as being bad,remove the spout plug(the plug that has to be removed before setting initial timing)then try to start the car.If it starts with the spout plug removed,thats a sure sign the pip sensor is defective.If the no spark condition seems to occur mainly when the engine is hot,thats almost a guarantee the tfi module and/or pip sensor is bad.

Heres another tfi & pip sensor testing link to add to 89foxbodys link.
http://351winsor.com/joel/Ignition_Systems/tfi2.html
 
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