Weak spark of the coil

[Georgia306]

History: driving the other day one of the 2 hard coolant lines on top of the lower intake manifold blew. This made all my coolant go all over the place and blow a head gasket. All of that is fixed now but my car won’t start. I have been following the wont start checklist but I fall somewhere in the middle, I have spark but not strong enough to do anything this is what I have done.
Check for spark- I have a very weak spark at the coil but not at the plugs … coil is new
I have also loosened the timing hold down and turning the distributor makes the fuel pump turn on
Check for fuel – I have 12v signal at the injectors and fuel pump has power
CODES- doing a KOEO test I get no codes at all?? Does this mean the computer is bad?
The thing that confuses me is the weak spark of the coil… you can barely see the spark of the plug gapped 54

 

[Mustang5L5]

You get no codes? Not even 11s?

 

[Georgia306]

I am going to recheck now, but I think when I turn the key to the on position the check engine light illuminates but when the KOEO check starts it goes off and doesn’t come back on.

 

[Georgia306]

Yea i got nothing. When the test starts the fuel pump kicks on and then you can hear a loud click and it stops. If the computer is bad would i still get a weak spark?

 

[jrichker]

At this point, considering your symptoms with blowing coolant, do three things:

1.) Clean the distributor cap, rotor and spark plug wiring with WD40. There may still be some moisture in the cap and under the wires. That would cause a spark leakage, reducing the spark at the plug.

2.) The TFI or the TFI wiring connector may be defective. Check and clean the TFI wiring connector using non flammable brake parts cleaner or elecrical contact cleaner. Do the test light or light bulb test across the ignition coil as described in the Cranks OK but no start checklist. 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.

3.) Check for 12 volts on the red/geen wire on the ignition coil with the ignition switch in the run position. Less than 11.5 volts is a wiring or ignition switch problem.

 

[Georgia306]

Well found that the TFI was bad, i have got good spark now. Just one more question dose anyone know how to ajust the valves the right way? i have read about 5 diferent ways. Stock e7 heads and rockers 92 5.0 H.O

 

[jrichker]

Well found that the TFI was bad, i have got good spark now. Just one more question dose anyone know how to ajust the valves the right way? i have read about 5 diferent ways. Stock e7 heads and rockers 92 5.0 H.O

This is the recommeded method, it may take a little more time and effort, but it will be correctly done.

Michael Yount’s valve adjustment proceedure

Here's an easy way to determine this. Start with the #1 cylinder. Rotate the engine with a ratchet on the crank bolt clockwise. Watch the #1 pushrods. First the exhaust pushrod will rise and fall signaling what would be the exhaust valve opening and closing if the rocker were on. As it closes the intake pushrod will rise -- keep rotating clockwise until the intake pushrod falls and is level with the exhaust pushrod - both at the same height. Both lifters are now on the base circle of the cam - both valves would be closed if the rockers were on.

Now, install both rockers. Tighten the bolts with one hand while rocking the rocker with the other hand - continue until you reach the point where you can't 'rock' the rocker any more because there's no gap on the valve stem end or the pushrod end. You are at zero lash - i.e. - no gaps. Stop tightening just as you reach this point.

Now, put your torque wrench on the bolt and tighten it to 18-20 ft-lbs while counting the number of turns it takes to reach the torque. You should hit the torque within 1/4 to 1 turn of the bolt. If it takes more than 1 turn, use a shim to raise the rocker -- each .030" shim will reduce the number of turns to torque by about 1/4 turn. If you reach the torque in less than a 1/4 turn, or you have trouble reaching zero lash even at full torque, then you'll either need longer pushrods, or to CAREFULLY remove some material from the bottom of the rocker fulcrum. Using the procedure described above, you will work through the remaining 7 pairs of rockers. If you follow the firing order, it will minimize the manual cranking you have to do to get the lifters on the base circle of the cam prior to installation of the next pair.

When I first went through mine, 13 of them took no shims; 3 of them took 1 .030" shim. Upon cranking it up, one or two of them sounded a bit noisier than I thought was right, so with the engine hot, I pulled the upper off, and the valve covers, and went through the installation procedure again. That time, 11 of them took no shims; 4 of them took one .030", and one of them took 1 .060" shim. And they were very quiet running.

Courtesy of Michael Yount - K'ville,TN

 

[Georgia306]

Nice thank you.

Chris