FYI FORD MustangSteve's Ford Mustang Forum / No spark at the plugs

**Posted by Steve69** 8/18/2024 4:42 PM

Hey Guys,

Was going to go to a car show on Saturday and my engine wouldn’t fire. It had sat for a couple of weeks prior and ran fine to parking it in the garage. Usually I disconnect the negative side of battery cable for safety reasons and forgot about doing that.

I have a hyfire ignition box that’s probably 15 years old. Had power going to it for full power and ignition power. When I checked the power output from ignition box positive side of coil nothing. So I believe maybe the box is bad. I bypassed the ignition box and connected the ready to run distributor directly to the coil. Ignition hot and distributor red to positive side of coil. Yellow on distributor on negative side of coil and black to ground. I now have 12 volts at the positive side of the coil but still no spark at the coil to fire the distributor cap. The coil is a blaster 2 which is new. The distributor is new and blueprint distributor that is a Petronix. Any other tests I can do to determine if the coil or distributor is bad? I’m stumped.

Thanks!

Steve69

Last edited by Steve69 (8/18/2024 4:43 PM)

**Posted by Nos681** 8/18/2024 7:55 PM

Do you have or can make a drawing of this setup?

I am not familiar with the Hy Fire, Pertronix, or the Ready to run components.

This might aid troubleshooting the problem.

Last edited by Nos681 (8/18/2024 7:56 PM)

**Posted by Raymond_B** 8/18/2024 8:47 PM

Steve69 wrote:
Hey Guys,

Was going to go to a car show on Saturday and my engine wouldn’t fire. It had sat for a couple of weeks prior and ran fine to parking it in the garage. Usually I disconnect the negative side of battery cable for safety reasons and forgot about doing that.

I have a hyfire ignition box that’s probably 15 years old. Had power going to it for full power and ignition power. When I checked the power output from ignition box positive side of coil nothing. So I believe maybe the box is bad. I bypassed the ignition box and connected the ready to run distributor directly to the coil. Ignition hot and distributor red to positive side of coil. Yellow on distributor on negative side of coil and black to ground. I now have 12 volts at the positive side of the coil but still no spark at the coil to fire the distributor cap. The coil is a blaster 2 which is new. The distributor is new and blueprint distributor that is a Petronix. Any other tests I can do to determine if the coil or distributor is bad? I’m stumped.

Thanks!

Steve69

I'd pop the dist cap and turn the engine over before tearing in to your wiring.

**Posted by BobE** 8/19/2024 6:37 AM

As Nos681 stated, a wiring diagram would help.
From what you posted, if you have 12v at the coil, my first guess would be that the Pentronix is not provided the 'make & break' process to 'fire' the coil, or the hyfire ignition box.

**Posted by MS** 8/19/2024 7:03 AM

Sounds like the “New Pertronix Blues”. Been hearing of lots or early fails.

**Posted by Steve69** 8/19/2024 7:55 AM

MS wrote:
Sounds like the “New Pertronix Blues”. Been hearing of lots or early fails.

That’s what I’m thinking to. I believe that’s what BP is using. After doing some research the ignition box is checking out ok. Down to the coil or distributor. I’m leaning towards distributor. It is under warranty though BP for the engine. We’ll see how much hassle it is to get it replaced.

Thanks Steve69

**Posted by GPatrick** 8/19/2024 8:00 AM

With a Hyfire or other spark box you will not see 12 volts at the coil so the lack of 12 volts when the engine is not running is not a valid test of the box. High voltage to the coil will only be delivered when the ignition fires. You should confirm that you do have 12 volts coming from the ignition switch.

To verify your coil and spark box, conduct the basic white wire test as described in the instructions -
CHECKING FOR SPARK If triggering the ignition with the White wire:

1 Make sure the ignition switch is in the "Off" position.
2. Remove the coil wire from the distributor cap and set the terminal approximately 1/2" from ground.
3. Disconnect the White wire from the distributor's points or ignition amplifier.
4. Turn the ignition to the On position. Do not crank the engine.
5. Tap the White wire to ground several times. Each time you pull the wire from ground, a spark should jump from the coil wire to ground (the LED should also blink). If spark is present, the ignition is working properly. If there is no spark skip to step 6.

Wiring should be similar to the bottom of page 8 - https://documents.holley.com/690.pdf
Since your system has run for years it must have been wired correctly.

Steve is probably on track with the Petronix and the white wire tap test will help prove that.

**Posted by TKOPerformance** 8/19/2024 10:32 AM

I'd just bypass the box and see if it throws a spark. You can just run a jumper from the + side of the coil to the starter solenoid BATT side. In years past we used to run MSD, Crane, etc. and I always wired them such that I could unplug and bypass them quickly if one failed. That got my K5 home one time from a field outside Allentown, PA.

Coils are easy enough to test, and IME rarely fail. Check resistance between + and - to test the primary winding, and between the + or - and the output terminal for the secondary winding. Specs should be available for your particular coil for resistance.

If it won't fire with the box bypassed and the coil checks good the Ignitor is bad.

**Posted by BobE** 8/19/2024 2:47 PM

Ignition Coil Tests:
Coil + to -: should be about 1-2 ohms
Coil + to Center (Hi Voltage): should be about 8,000-10,000 ohms.
These values are nominal, and if close, the coil is likely good.

Another thing you can try;
Disconnet the '+' wire and the '-' wire from the coil.
Connect an inductive timing light on the hi-voltage lead.
Apply +12v to the '+' side of the coil.
Quickly 'ground' and release the '-' side of the coil, if the timing light flashs, the coil is good.
What you're doing is the same thing that points, or electronic ignitions are dong.

**Posted by Rufus68** 8/20/2024 3:13 AM

...and here's a guy bench firing a coil

**Posted by Steve69** 8/22/2024 11:09 AM

Thanks for all the Great Information guys! BP engines did sent me a new distributor. I received it yesterday. Not bad for 2 days after I call them. Im going to do your tests above. like I had said I did bypass the ignition box with no fire at the coil.

Thanks Steve69

Last edited by Steve69 (8/22/2024 11:31 AM)

**Posted by Ron68** 8/22/2024 2:03 PM

I have the MSD box and MSD distributor. I had a no fire situation. I did the troubleshooting to verify the box was good, but no fire. It turned out to be the coil in the distributor was bad. I had to pull the dist. and remove the drive gear to get the thing apart to install the new coil. That was 10 years ago, and no issues since I did that.

**Posted by Steve69** 8/23/2024 11:53 AM

Ron68 wrote:
I have the MSD box and MSD distributor. I had a no fire situation. I did the troubleshooting to verify the box was good, but no fire. It turned out to be the coil in the distributor was bad. I had to pull the dist. and remove the drive gear to get the thing apart to install the new coil. That was 10 years ago, and no issues since I did that.

Thats probably what I have going on too. Im going to check the coil this weekend and test the box one more time.

Thanks
Steve69

**Posted by Steve69** 9/03/2024 6:38 PM

I tested my hyfire box and had an arc at the coil wire. Ignition box is ok. I then ordered a replacement distributor and installed that. I started it and ran for 5 seconds and wouldn’t start. I also noticed slow cranking. No spark. I’m like WTF! So I retraced my steps. I installed a new $300 powermaster starter in July. It started cold and hot really well. I was getting heat soak in old starter. The powermaster cranked great when it was warm. After installing the new starter I let the car sit for 2 weeks. Then I had the no spark. I charged up the battery and had 13.5 volts and was cranking slow no spark. Yesterday I said screw it Im installing the old starter back on. I Start the car and it fires and runs Immediately and Runs great! I set the timing and adjusted the idle mixture with new distributor. I’m wondering if the power master stater solenoid was sending some power back through the stater relay wire? I really don’t know what would have caused it not to fire the ignition. It was cranking over fast after it sat for two weeks with no spark. Really strange! Im sending the powermaster starter back to summit and buying a 1993 5.0 stater from O’reillys. Ill put a heat cover over it. It has a lifetime warranty and can pick one up at any O’reillys if I have issues. I never in a million years would of thought the new starter would of caused the no spark at the ignition.

Last edited by Steve69 (9/03/2024 6:48 PM)

**Posted by BobE** 9/05/2024 4:33 AM

The 'S' terminal on the solenoid provides full 12v power to the ignition coil during cranking. There could be a short in the starter that is being back-fed to the coil via the 'S' terminal wire that was causing your problem. Note that once the solenoid is de-powered, the ‘S’ terminal is isolated from the starter's cable.

Last edited by BobE (9/05/2024 5:43 AM)

**Posted by Steve69** 9/05/2024 7:37 AM

BobE wrote:
The 'S' terminal on the solenoid provides full 12v power to the ignition coil during cranking. There could be a short in the starter that is being back-fed to the coil via the 'S' terminal wire that was causing your problem. Note that once the solenoid is de-powered, the ‘S’ terminal is isolated from the starter's cable.

. That’s what I’m thinking too. I was debating on doing my new starter like this. Only have power to the starter while cranking only. Move the larger power wire from full power to cranking power on the external solenoid. Run a small jumper wire.

Last edited by Steve69 (9/05/2024 7:43 AM)

**Posted by Rufus68** 9/05/2024 9:36 AM

The reason an "I" terminal is on the solenoid is for supply full voltage to the coil during cranking. Anything connected to the "S" terminal will be drawing power through the switch. This can't be a good idea for the switch.

**Posted by 50vert** 9/05/2024 3:35 PM

Steve, I think wiring it that way will result in the starter continuing to crank after releasing the key.

**Posted by Nos681** 9/05/2024 3:54 PM

If you wire it with a jumper, full starter current will have to travel through 2 sets of solenoid contacts.
Unnecessary.

The foxbody setup uses the fender mounted solenoid as a “relay…pilot circuit” to energize the starter mounted solenoid that connects full load of starter on the “starter solenoid” only.

The foxbody setup places a small current through the fender mounted solenoid.
That is reason the PMGR starter can be connected directly to the battery (+) positive.

**Posted by RTM** 9/05/2024 3:55 PM

Isn’t that jumper the way you’re suppose to wire up a late model starter? I think that’s what I did on my old 65 fastback.

I need to look into again because I need to wire up the T5 starter.

**Posted by KeithP** 9/05/2024 4:26 PM

I have a PMGR starter and eliminated the solenoid on the fender wall. In my fuse/relay box I have a relay that controls the solenoid on the starter and another relay to control 12v to the coil.

**Posted by 50vert** 9/05/2024 4:59 PM

RTM wrote:
Isn’t that jumper the way you’re suppose to wire up a late model starter? I think that’s what I did on my old 65 fastback.

I need to look into again because I need to wire up the T5 starter.

A Permanent Magnet motor acts like a generator while spinning, The created current is enough to keep the starter engaged.
Like Keith, I'm using a relay instead of the original solenoid. This is how the 95 is wired.

**Posted by Rufus68** 9/05/2024 6:12 PM

50vert wrote:
RTM wrote:
Isn’t that jumper the way you’re suppose to wire up a late model starter? I think that’s what I did on my old 65 fastback.

I need to look into again because I need to wire up the T5 starter.
A Permanent Magnet motor acts like a generator while spinning, The created current is enough to keep the starter engaged.
Like Keith, I'm using a relay instead of the original solenoid. This is how the 95 is wired.

I'm also using a dedicated relay to trigger my PMGR starter. I did it this way after having the issue of the run on starter. As a bonus, the only load the key switch sees (and the old wiring) is the load of the relay, so very small load.

**Posted by Nos681** 9/05/2024 10:09 PM

I believe the BC Broncos picture is a copy of the original Ford Motosports PMGR kit.

PMGR’s were standard about 1991-1992.

The factory ignition switch is not designed to handle the current draw from the “starter mounted solenoid.”
That is why the fender mounted ones were still used in the 90’s.

Last edited by Nos681 (9/06/2024 3:59 AM)

**Posted by Nos681** 9/06/2024 4:19 AM

This is a stock ‘92 starter.
The original Ford starter mounted solenoid had a slip on connector.
Most rebuilt/new starters will have a terminal lug and perhaps an adapter for original wiring connector.

Notice the starter mounted solenoid terminal opposite of the blade terminal is connected via jumper to the starter winding. This is why it is not a good idea to use the ignition switch only.

Late model Mustang ignition switches are designed differently compared to the first generation Mustang.