• Hi Guest!
    If you appreciate British Car Forum and our 25 years of supporting British car enthusiasts with technical and anicdotal information, collected from our thousands of great members, please support us with a low-cost subscription. You can become a supporting member for less than the dues of most car clubs.
    There are some perks with a member upgrade!
    **Upgrade Now**
    (PS: Subscribers don't see this gawd-aweful banner
Tips
Tips

Spitfire Back to the '74 Spit

Share this page

S

Smoke

Freshman Member
Offline
I was on he the end of December. my Spit quit running. ('74 Spit Won't Run) Several of you seemed to think the problem was the balast wire and I tended to agree with that as I jumped from the coilto the run terminal on the switch and it ran. I did not leave the jumper on as I did not want to cause any damage.
I've driven the car (hoping to double check) with no more problems until today.
Same thing. Car won't run. It starts, but won't run. I jumped again from coil to run terminal, this time with a ballast resistor in the circuit. The car won't run. Tried jumping without resistor. car won't run.
Got 14 volts, spark, fuel is fine all the way, points look good.
Does anyone have any more ideas where I can look?
Thanks,
Smoke
 
Pull a plug, and see if it's wet, if it's not then smack the float bowl with a stick, hammer handle will do.

Could be your float is getting stuck.

If the plug is wet, then it's not firing with compression in the cylinder, which tells me coil, since none of the cylinders fire, if it was just one not home, then it's the plug that went south. I have seen, not very often, coils that partially failed, they would give you some spark if you jumped to ground, but nothing under compression.

keep us informed
 
Same thing. Car won't run. It starts, but won't run. I jumped again from coil to run terminal, this time with a ballast resistor in the circuit. The car won't run. Tried jumping without resistor. car won't run.
Okay. I tried it again after the car had sat for about 15 minutes and it will start and run with a jumper from the coil to the run terminal on the switch.
Still kinda sounds like the ballast wire but it's confusing me as it would not run earlier with a new ballast resistor in the circuit.
Am I missing something?
Thanks,
 
Okay. I checked the plugs. They are dry and look great.
I did not try the tapping on the carb but did put some oil in the damper and the car now runs with no jumper.
Don't know how long it will run but beginning to think problem is either float or ballast.
I'm not an auto mechanic so I don't know. I can work on them. replace parts and fix things but I cannot diagnose.
Any idea where to go from here?
Thanks,
 
Oil in the damper is probably not going to be a cure.

If the progression to a stall is "soft" it probably points to some kind of fuel starvation - something that can easily be caused by a seeming inconsequential bit of dirt. Here's some places I'd look.

Stuck or sticking float as above would be good start.

Pull the line at the carb' and check pump action (cold engine please and be careful about sparks.) The pump diaphragm could be worn/leaking, the pump valving could be leaking and/or the pump's internal filter might be blocked if fuel flow is poor.

A pesky one can be a partially blocked fuel line. You think you have gas at the carb', but the engine quickly starves when running. Disconnect the line coming into the pump. Gas should be flowing freely under gravity. If it just trickles/weeps then the line is partially blocked. Check at the in-line filter (I'm guessing here that there's one in the engine bay between the end of the line from the gas tank and the pump.) If still in doubt, blow air through the line back to the gas tank (don't blow through any in-line filter as it will probably destroy it.) If there was a blockage you should see a change in the gravity fuel rate. If so, you'll need to clean out the gas tank and the lines.

Good luck.
 
Lemme back up and think a bit.

I just went back a reread your post more carefully and I noticed that you are running your jumper to the run terminal on the switch. Nice and conscientous (SP) but....

Which means there is still one thing in the circuit that you aren't eliminating.

the switch. The position of the switch that gets the most abuse.

try jumpering from the battery plus to the switch side of the resistor.

Now when you try to start, the switch will give you full voltage on the coil for starting, and your jumper from the battery will energize the coil. Warning here, it will continue to run until you either disconnect the jumper or you run out of gas.

It could be something as simple as figuring out that if you turn the key a degree or two more or less it will run, as you hit a point in the switch that still works. Make sure that the switch isn't falling off the tumbler, I've had that happen on mine. Maybe the switch can rotate on the tumbler assy by just enough that it doesn't make contact consistently.

Go over this possibitlity before you start trying to spray gas all over. I hate that, it stinks.
 
71MKIV said:
try jumpering from the battery plus to the switch side of the resistor.
Click to expand...
I agree, but I would go more radical than that. Jumper directly from the battery hot terminal to the coil. If that makes it keep running, you <span style="font-weight: bold">know</span> the problem is somewhere along the wires to the switch, or the switch itself; and can proceed from there to narrow it down. A short term test (say no more than 20 minutes) with no ballast won't hurt anything.
 
Smoke,
I'm no expert all I can give you is what I experienced. My 79 did the same thing until I rebuilt the carb, the carb was not the problem however. I have the dreaded water choke and due to some corrosion, it was stuck. Motor started and ran ok till warm, then it just wouldn't stay fired up.

For what it's worth.
 
Thanks for all the ideas.This is driving me nucking futs!
I will start looking at the things you all pointed out.
I managed to get hold of the old owner and he said he had a problem with the switch one time long ago and was never able to find the problem. I do have a second switch I bought from RustyRoanoke on ebay so I may substitute that one and try again.
I won't give up!!!!!!!!!!!!!
 
One more idea, it's always harder to troubleshoot over the Internet. If you contact your local club, there's a good chance someone local would be willing to help you out.

Last Spit owner I helped out had so many problems that it was hard to know where to start. Loose connections, carbs horribly out of adjustment, wires twisted together and taped, others bare and dangling loose ... biggest mystery was how it ran before! Worst part is that it was apparently a professional that left most of it that way (his immediate problem was that the mounting threads on the switch were stripped).

Not that I'm saying your car is like that, but sometimes it helps to have a fresh pair of eyes look at the problem.

Also, if your car has the anti-runon valve, you might try disconnecting it. If it was somehow getting power when it shouldn't, that could cause the engine to start and promptly die. A clogged carbon canister might do it, too.
 
Have to see if I can find a local club.
Sounds like it could be one (or more) of several thing. Wow!
 
Aloha Smoke,

The '74 Spit may (probably?) have the same seatbelt-starter interlock setup as the '74 TR6. The 74 has a Seat Belt Module that won't let the car start unless the seat belt is fastened for any seat that has someone in it. A starter relay is in the circuit to do this.
Does your starter work and it just won't fire? I bypassed the seatbelt control module and replaced the starter relay with a $6 headlight relay from Checkers. I also had a bad connection where the ignition pigtail plugs into the wiring harness. A good cleaning fixed that.
I can't get to a photo now, but if you have a '74 Spitfire wiring diagram, look for a starter relay. Good Luck!

Jeff
2xTR6
 
Back
Top