Random cut out, advice on where to start looking please.

The back of the ignition switch, which has the electrical part is notorious for causing these problems. I had this type of problem and just changed the back electrical part - you don't need to remove much to do it, from memory - just the covers on the steering column to get to the back side of the ignition switch, if memory serves me correctly. If you buy a replacement, I think there are some slight differences in the electrical plug from memory. So it is probably a good idea to have a look at your own, before you lay out the money. I think there are a few threads on this forum about it, which should provide you with the info you need.

cheers, Tim.

Thanks Tim, yeah that's my gut feeling. I've just had to rebuild the light switch stalk on a Datsun 240z as all the current runs through it for the lights. The terminals were a bit dirty but not that bad looking, but clearly enough such that I got no lights at all. Similar story with the heater switch on my 69 Econoline van and also did a similar job on a Lamborghini Urraco ignition switch. So I guess stop one is to pull the cowl and take a look at the switch with a view to swapping or trying to dismantle and clean.

Grounding is a big deal, make sure your ground strap mounts are clean and not installed over painted components including the one from the chassis to the rear of the transmission. There is also a ground location under the dash (see photo) which will make your gauges act up if not clean. This could also contribute to you cutting out issue?

The terminal nuts on the back of the amp meter are notorious for loosening. Might be worth your time to check them

Larry

Thanks, yes if I'm reading this right the entire ignition system runs through the ammeter... right ?   Do you know what constitures an early and late car in the diagrams from PanteraPlace ?  Mine is a 73 build 74 model

When you say “cut out “ does the engine quit entirely or just stumble and run rough?  The amp meter flickering should not affect the engine.  You can bypass it by hooking the two heavy wires together- just tape them up well so they don’t touch anything else.  See if this changes anything - it should not.  Next look for loose or corroded connections, the ignition switch, or possibly a bad coil.

Dont forget the connector between the ignition switch and the main harness.  I eliminated it completely, soldered the wires together and cleaned the ignition switch contacts. Also added a relay. All has been good for years.

@ufo-low posted:

When you say “cut out “ does the engine quit entirely or just stumble and run rough?  The amp meter flickering should not affect the engine.  You can bypass it by hooking the two heavy wires together- just tape them up well so they don’t touch anything else.  See if this changes anything - it should not.  Next look for loose or corroded connections, the ignition switch, or possibly a bad coil.

Yeah so it just flat dies with zero warning. I'm sort of half thinking it could also be a carb idle thing ...

So investigation today update:
1) ignition switch cleaned up and put back together as per the PanteraPlace tutorial. Before and after. The black was actually grease through I can't imagine it helps with conduction.

l

2) tinned the ends of the wires where they connect to the loom connector block which seemed in good condition.

3) cleaned up the battery ground - wasn't too bad, but now it's shiney

4) swapped in a new Amp meter I had on the shelf to get a comparison - less wiggle on the needle, no wiggle when there are no systems switched on. The more is switched on the more wiggle - I think it's jsut a fact of Pantera life... and I think we all know that.  Banjo connections on the red wire looked to have suffered from heat...

5) went for a drive, 10 miles maybe, all seemed ok, but died once at idle at the lights - perhaps it's more of a carb idle thing... as it fires right up. idle is highish anway so it's not slowing down too much and dying, it just cuts out randomly...

I might wire in an experimental hot wire directly from the battery to the coil via a simple switch - do I need a ballest resistor ? I need to check which coil I have in there. It could be a Pertronics Flamethower 3 as the car came with spares and there was an empty box for one.

...I'am going with a Bad Coil*, Intermittent Failure. And, if you are running a Holley Carb, check for incorrect 'Idle Screw' setting, and Make sure the 'Idle MIXTURE' Screws a NOT Screwed in TOO FAR!! They should be OUT from closed-off, a Minimum of 1-1/2 Turns or More. Sure! With the Accelerator Pump SHOT, it WILL 'Fire Right UP'! But it will NOT Idle, for a Holley Carb.

* Test this, borrow a known Good Coil and Try it out on the Road.

Good-Luck with It!

MJ

I had a situation where my car (Jensen) would die occasionally, randomly at idle.

I finally figured out it was an intermittent electronic distributor.  What was happening was if the engine was going at higher RPMs it would power through the cut out and keep running. At idle the engine with die occasionally.

I’m not saying it’s your distributor, it might be an intermittent coil like Marlon suggests, or wiring.

Good luck tracking down the problem.

Rocky

thanks, folks, yes really annoying as there is no pattern yet. As far as I'm aware this engine build has less then a 1000 miles and it had new carb, distributor and coil, maybe more stuff - of course, new stuff on old wiring is not the best and this car looks to have had very few electrics upgrades in general. I'll pull the front cover and take a look at the ignition end of the engine - I've only had the car for 10 days!

Hi Lee, Yes you are correct that the whole electrical system (minus the starter motor circuit) goes thru the ammeter and therefore makes it a single point of failure. My gut feeling is that the rev levels that make a difference is down to vibration and some levels of vibration the circuit "likes" and others it doesn't. To me, most of this points to a loose connection somewhere on the distributor feed circuit, and most probably between the battery and up to and including the ignition switch. Possibly the engine ground strap too, or the main battery negative lead. If it was a bad coil only, the ammeter would not be hugely affected.

With the cleaning job on the ign switch, has the fluctuations on the ammeter stopped? If so, I'd say you have a separate lesser problem with the carb settings.

Thanks Phil, all major connections so far look good, and certainly the ignition switched need a clean, but I would not think it would start immediatly again if there was small issue such as a loose wire to the distributor, but I've been there in the past so I need to pull the bulk head cover and have a look in there.

As I go through these issues, I'm finding the car is pretty sorted so quite unlikely for there to be an obvious loose wire, whereas reading around the Holley carb setup and a lean idle it seems can cause issues particularly with a performance cam which my car has.

I had a similar problem and it turned out to be the ballast resistor connections. (I no longer use a system that requires a resistor. Good riddance )

Remember George Holley’s famous quote recorded by Henry Ford on his victrolla, when they were working together on the first Model A, integrating George’s iron pot carburetor.

“Henry if I told you once, I’ve told you a thousand times! 95% of ‘carburetor problems’ are caused by ignition!”

😎

@piney posted:

I had a similar problem and it turned out to be the ballast resistor connections. (I no longer use a system that requires a resistor. Good riddance )

Thanks, yes I was thinking it could be connected. I've found my wiring in the engine bay now. Looks a bit messy and actually awkward to get to. It might be sensible to relocate the coil to be beyond the swirl tank out in the engine bay. I prefere to be able to get to these things easily. Even with the bulkhead cover off (I've not done that yet) it looks still tricky to get to. I know a coil out back might look offensive to some but a non running Pantera is more offensive to me . Also I'll wire in an experimental clean 12v feed to the coil which looks to be a Flamethrower III to a matching Flamethrower III new distributor.

Car looks to have a ground strap already from the gearbox to chassis strenghtener point, but I'll pull it and give it a clean.

Also I see the regulator in there is an original Motorcraft one and it looks old, that's ok, but the connectors and such as probably in need of a clean.

I've located the single mixture screw on the carb so when next testing I'll tweak it richer just a little.

...if you have a Holley carb, there are 2 Mixture Screws, one on each side of the Primary 'Block'. After setting these as described, The 'Final' adjustment is made, with the Engine running, adjusting both screws Simultaneously. Turning each in until the Engine Starts to Stumble, then screw back-out for a smooth idle. One will Affect the Other, this is why the 2 must be Adjusted Together. Should You get that far.

I will add, I have found Loose connections at the AMP gauge AND at the Multiple Ground Connections at the Stud, located UNDER the dash at the Drivers' (left) 'A' pillar. Both gave me the same problem of a Mystery Engine 'Stumble', Cut-Out.

Marlin

Thanks yeah I found the AMP meter connections to be sound though one showed signs of being hot. I might just run with the meter removed and the cables terminals just joined for now. I know the system is charging (red idiot light works as expected).

I think for sure the next thing after I've been through the ignition wiring in the engine is to check the idle mixtures. There is mention of performance engines needing a richer mixture in their tune up

https://www.holley.com/blog/po...e_mixture_and_speed/

I had a 95 5.0 Mustang that did a similar thing. Driving and then die and actually start again. It turned out to be the distributor pickup.

Lee, if you install an insulated jumper across the amp gauge terminals, the alternator voltage will be split, with one portion going across the meter and a second portion across the jumper. The meter deflection will also be lessened so the needle swings will be half or less, in proportion to the surface area of the jumper vs the meter..

For my jumper, instead of wire & crimped ends, I used a piece of 0.060"x 3/16" wide brass shim stock with two holes punched & shrink-wrap-insulated. The gauge readings are now inaccurate, but they were so jerky before, accuracy was 'relative' at best. The meter still indicates + or - readings so health of the alt can be seen  Mod done in 1987- no problems yet.

Thanks, yes I'll add the solid jumper, then at least I know the connection is good.

@bosswrench thoughts on my jumper ? I made it from 3/8" strip of 1/16th brass and some insulation in the obvious area. I have some fresh rubber terminal covers coming. I think in the future I may well replace this with a Voltmeter anyway - the one from Hall.

Lee, yours looks like mine except nicer! A voltmeter is about the same as the stock ammeter- not much info to be had, except that the alternator is making power.

ha ha thanks, yeah I was even thinking just put a couple of USB charging points in a chrome 52 mm gauge as it would be more useful...

Lee,

Did you get any of the old parts with your new car?????

IF so, you could put the old distributor back in place along with the original coil.  You may actually notice a HP increase!!!  Presuming these old pieces are original Ford parts....... Just saying.

Too many swap in too many new parts all at once and then can't figure out why things don't work as well as they did before all the new parts!!!

Good luck!
Steve

DuraSpark II has been working in thousands of station wagons world wide......

Thanks Steve, my investigations have not got that far yet and my feeling is that the issue is not ignition, but I'll keep on working through it. Winter now so not much can be done out there as it's cold and too wet to do any road testing.