TR4/4A TR4 suddenly shuts down

[mcmillal]

Good morning, I love these cars, but they can sometimes drive you crazy. My recently rebuilt TR4 was running fantastic and I've been thoroughly enjoying buzzing around in it. Well, Friday night, I'm pulling into the grocery store and as I roll into a parking spot, she dies. Hmmm? I try to restart her, but no luck. The car turns over but will not start. I noticed a lot of fuel spilling out of the rear carb. I get the car towed home and start trying to analyze the problem. I correct the fuel problem but the car just will not fire up again. Now, the battery is old, but I was getting 11.86v at the coil. I do not however see any spark at the plug. I have a Pertronix unit installed which was functioning perfectly. I'm thinking it's the coil it the old battery.

Thoughts?

........ Cheers, Alex

 

[poolboy]

You can't leave the ignition ON for very long if the engine is not running when you have a Pertronix.. If you did during the ordeal, the Pertronix might be dead.

 

[TR3driver]

I agree, most likely culprit. You could try checking the coil voltage while cranking, tho. If it's dropping down below 8 volts, the battery might be the issue.

Here are some old Pertronix troubleshooting steps
https://drive.google.com/open?id=0B2H2NJt34OffNmE2Njk1YjYtNGQxMC00ZDU1LWI3YzQtZmUxYWZiM2JiZWVi

 

[mcmillal]

Thanks Folks. Although there's a chance the Pertronix may be shot now, but what was the original problem. I was driving the car around with no problem or hint of something about to happen when the car died. What would have initially caused the car to die?

 

[TR3driver]

The fuel spilling from the rear carb seems a likely culprit. A chunk of something (perhaps from the inside of one of the fuel lines) got jammed in the float valve and the fuel level in the bowl went way too high. You saw it spilling out, but it was also spilling into the intake manifold.

 

[mcmillal]

Would that cause the engine to just die? Even after I fixed the float issue, the car would not start. I will check the coil for spark today and possibly replace the Pertronix with the points again.

 

[poolboy]

Flooded engine, yes. If it were just one carb flooding, it could put 2 of your cylinders completely out of action and with some sort of crossover tube in the intake manifold which I believe exist in the TR4 intake, the remaining 2 cylinders could also flood out.
Anyway, fix the flooding carb and see if you can restore spark..there's really no alternative.

 

[TR3driver]

You said it died as you rolled into the parking lot, which I assume means your foot was off the throttle. It doesn't take much to get it to die with your foot off.

It might possibly still have run on two cylinders at that point, but it's really tricky to get them started on just two. Takes a lot of throttle, but not too much. I once got given a little German car because the owner couldn't get it started; but it ran on two (and I even managed to limp home with it that way).

Anyway, like Ken said, it doesn't much matter on how you got to where you are, the question is how to move on. There are lots of more esoteric possible explanations, but no matter what, it isn't going to run without spark. The Pertronix is a known weak spot; unlike things like the coil, camshaft drive, distributor drive and so on.

As a friend of mine says "A test is worth a thousand theories."

Since it's quick and easy, you could try installing a "known good" rotor (the one you took out at the last tune-up), just in case you've got a rotor failure. Or try testing for spark right at the top of the coil. But I still think the Pertronix is the most likely cause of your "no spark" (and may possibly even be why the engine died). My first step would be to put back points & condenser.

 

[mcmillal]

That's the plan, revert back to points & condenser tonight. I am going to test for spark at the top of the coil too. I'll let you know how it works out.

 

[Geo Hahn]

...I get the car towed home and start trying to analyze the problem. I correct the fuel problem but the car just will not fire up again...

What was the fuel problem (stuck valve, sunk float)? You might also mention it this has SUs or ZSs - though you have now moved on to ignition issues.

Yes, I can confirm that a flooded carb will kill the engine and feels about the same as a starved engine when it does.

 

[tinman58]

I got tired of petronix. I had my old dist. rebuilt and curved for my TR3 engine with the extra horspower parts. Advanced dist. did the work and he recommended to go back to points also. WhenI installed the dizzy there was a noticable increase in power. Most likely from the new power curve, but I will stay with points.

 

[groupdeville]

So...given that the Pertronix ignition units are a bit fragile, what is the experience of the group with points-triggered electronic ignitions having an external box as an alternative to Pertronix or points-and-condenser? Thinking here of Crane, Piranha, MSD, etc. Thanks!

 

[TR3driver]

I ran a MSD 6A triggered by points on my TR3A for a lot of years. No trouble with the points, tho they do need to be reset every few years as the rubbing block wears. Had lots of problems with the MSD, finally decided it wasn't suitable for a car that sees lots of road miles. I've lost count, but at least 4 of them have failed in service for me (on various vehicles). Once, I sent it back and they repaired it for a reasonable price; but the next time they said it couldn't be repaired. After that, I started replacing them with something else.

I also had to modify the TR3A distributor cap, as the increased spark current burned out the center contact; and switch to colder plugs.

BTW, it is supposedly possible to use a Pertronix module to trigger an external box. The greatly reduced load would, I think, eliminate concerns over the Pertronix module overheating. But I haven't tried it yet.

Crane also offers a couple of optical pickup ignitions that can be fitted to the TR2-6. I ran an XR3000 for a few years after the last MSD box died. Had a really tough time getting it set up properly, but it worked well enough after that. Except for the time the ground wire got some corrosion and it quit in the rain on my way home from work. Not sure why, but the engine never seemed quite as crisp with the XR3000 as it did with fresh points. It ran well enough, but switching back to points was like a fresh tune-up. If I was going the Crane route again, I'd try the XR700 instead. (The 3000 is capacitive discharge and I suspect may not put out as much spark duration. The 700 is inductive, like points and Pertronix.)

 

[groupdeville]

Thank you! Sounds like you've tried most of the available units. Crane and the MSD-6A were the units I've been wondering about. Currently running a Pertronix (courtesy of my car's previous owner) but not crazy about the idea of it suddenly taking a dump while on the road.

Also noted a tip somewhere on this site about having to provide adequate slack in the Pertonix wires where they enter the distributor cap, and then fixing the wires in position with small wire ties after the slack has been provided. Gotta do that sometime soon!

 

[poolboy]

Here's an example:

 

[TR3driver]

Ken's photo reminds me, that ground wire visible to the upper left is still important with a Pertronix module. On a TR4 (with vacuum advance), that wire is forced to flex every time you change the throttle position, so sometimes the wire can break internally and be intermittent. Not a common problem, but it's happened to me (although not with a Pertronix).

To check it, remove the screw that holds the wire to the body, then check the resistance while gently tugging and flexing the wire.

 

[TexasKnucklehead]

Kens photo appears to be the Petronix, using a magnet/cylinder inside a plastic shell that slides under the rotor.

This picture is my Crane unit, with a "window"/cylinder cut for the sensor, and an external control box.

I had Petronix on my TR6, and presently a Crane on my TR3, as well as points on both. I can say there are advantages/disadvantages to any method. But, I can also say that I carry a complete ignition fitted with points in my car as insurance.

 

[DougF]

I once had the Pertronix leads arc through insulation and short out the system, something I never would have believed had I not seen it happen. Pertronix carries a warranty on the unit, I believe one year.

 

[glemon]

I have certainly heard enough issues with Pertronix to know they aren't bulletproof, but I am on my third or fourth car I have installed a unit on, about twenty years of use with no failures or issues. Not a bad track record.

I think the latest ones are ok with the ignition being left on. But I don't think mine is new enough to have that feature, so I am careful with it.

 

[tdskip]

So...given that the Pertronix ignition units are a bit fragile, what is the experience of the group with points-triggered electronic ignitions having an external box as an alternative to Pertronix or points-and-condenser? Thinking here of Crane, Piranha, MSD, etc. Thanks!

I'd, cooperatively, not agree with that. All of my LBC have then, never had one fail over lots of use in touring events etc. Install it properly, with the right coil, don't leave the ignition on, and you are done. Ditto for their distributors.