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Spitfire '74 Spitfire won't run

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Smoke

Freshman Member
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My '74 Spitfire quit running when I left the bank. I had already driven about fifty worryfree miles.
It was idling fine but when I pulled onto the road it quit running. I turned the key and it started but quit immediately - did this three more times.
I finally parked it and called AAA.
Clogged fuel filter?
Carb?
Electrical?
Anyone got any idea?
Thanks,
Ron Wasmuth
Florida
 
is it getting fuel?
spark? :wall:



check/clean battery terminals
fuel filter
<span style="font-style: italic">hidden shut off switch?DPO</span>
 
I'd start with the filter, folowed by the fuel pump...

Oh wait a minute, does that thing have one of the ballast resistors? The start circuit shorts out the resistor, the run position puts it in line. Try replacintg the resistor with a peice of wire, it will be ok for a short time. even up to 10 miles or so, just to get you home.

Could also be a bad ignition switch, does everything else work in the "run" position?

All those ok then go to the fuel system.

FWIW
 
Ron-
Everyone is giving you good things to check. When you get right down to it you need: Fuel, Spark, and Compression. Without anyone of them you will be thumbing a ride.
Good luck, you will track it down I know it!
Elliot
 
71MKIV said:
Oh wait a minute, does that thing have one of the ballast resistors? The start circuit shorts out the resistor, the run position puts it in line. Try replacintg the resistor with a peice of wire, it will be ok for a short time. even up to 10 miles or so, just to get you home.
Click to expand...
:iagree: I believe a 74 would have the ballast wire incorporated in the wiring harness, and the described failure is very typical of a failed ballast wire.

But don't be tempted to just leave the bypass wire forever. The excess current will eventually damage the points and/or coil. In my case, I got maybe 500 miles before the points quit working.
 
Consider this a "third" for the ballast resistor being at fault.
 
Oh, and if you are unsuccessful in finding a lack of spark or fuel, and this is a relatively original and unmolested 1974 Spitfire, it might be time to suspect the Smiths module that controls the seat belt interlock, an endearing and immensely troublesome bit of wizardry found ONLY on 1974 model year US cars!

Meanwhile, I'm pretty sure Randall is right about the ballast resistor actually being built into the wiring harness. I've not seen one of those wires fry, but I'm sure it can happen. It's also possible that the coil itself is dying/dead - especially if it's the incorrect coil for a ballast-resisted circuit (if it hasn't already been bypassed). Easy enough to substitute a known good coil to check!
 
Hmm, I thought the seat belt module only blocked the starter from operating, not the ignition. But I don't have a diagram for a 74 Spit handy, so I could be mistaken.
 
First Triumph I had was a 74 Spit, and yes the ballast wire is built right into the harness. And yes, the devilish Smiths module underneath the dash near the battery box can be troublesome, though I don't recall having it misbehave enough to effect how the car ran.
 
Wow! Thanks to all.
I was thinking along the fuel line but a lot of you think maybe the ballast - I never gave that a thought.
Again thanks to all.
Ron
 
Okay - most of you hit the nail on the head. I checked the easy stuff first and the ballast wire last. That seems to be the problen since I placed a jumper from the + on the coil to the top fuse and she fired right up and ran great.
Now here's another question since you guys seem to know your stuff.
The ballast wire runs to a 3 prong plug (thru the harness). Without undressing the harness does the other side run to term. 3 on the ignition sw.?
I massume it is a standard 12v. ballast also.
Thanks,
Ron
 
That looks like one of the ones I used - I have a '74 and '75 diagram but they don't show connectors. From that I assume it goes to the sw. and I can wire a new one as such.
 
Believe so, based on what wiring diagrams I could scrounge on the net:
Diagrams

The one I looked at for a 75 even shows the ballast wire as "pink-white" which my failing memory thinks was what I had in the 74 harness.

Randy
 
It's faded but both my diagrams show pink/white and I believe it is.
By the way, randy, i have family in Mountain Home and We just attended the Pow-Wow in Fredericksburg in May.
Got to see what I can accomplish with this car.
 
Definitely to the 'run' terminal on the ignition switch, tho I can't say offhand if that is terminal 3 or not.

A standard ballast will work fine, eg
this one at Summit Racing or likely you can source one at your FLAPS.

Hmm, did a quick Google for a Lucas resistor. Guess what I found
 
Smoke said:
By the way, randy, i have family in Mountain Home and We just attended the Pow-Wow in Fredericksburg in May.
Got to see what I can accomplish with this car.
Click to expand...

Haven't been through Mountain Home but have enjoyed Fredericksburg a few times. Hill Country is a nice diversion from the flat Houston scenery.

Good luck with the Spitfire!

Randy
 
Thanks Randall... I forgot that MM posted my article.

If you want to retain the pinkish resistor wire, I think you can buy it by the meter from britishwiring.com However, it would be a lot easier to buy an external resistor like Randall suggested and wire it in place of the pinkish wire (white wire from ignition switch to resistor, other side of resistor connected to coil (+)).
 
Thanks again to all of you for your help.
I will hopefully get her running again soon - gonna buy two balasts!
 
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