• 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

General Tech Condenser test?

Share this page

Not to mention temperature.
Last one I had fail was about 1/2 hour after replacement. It caused terrible missing at highway speeds, but only after it warmed up. Eventually the engine would die. After it cooled down on the side of the road, it would fire up fine and function normal - for a few more miles until warmed up.

I switched to electronic ignition after that.
 
NutmegCT said:
The engine is on my ol' M-B, not my TR. Posted here,
Click to expand...

That, along with your post that you have also replaced the coil prompts other questions. Was the MB built with a ballast ignition system or a regular ignition system and do you have the right coil for that system? If you run a ballast coil on a standard ignition system the points will fail quickly with the condenser and coil following a bit later.
 
dklawson said:
That, along with your post that you have also replaced the coil prompts other questions. Was the MB built with a ballast ignition system or a regular ignition system and do you have the right coil for that system? If you run a ballast coil on a standard ignition system the points will fail quickly with the condenser and coil following a bit later.
Click to expand...

Doug - thanks for the follow up. I'm using the correct Bosch coil for the car, plus the correct Beru 8 ohm ballast resistor. It's a $100 M-B Bosch coil, with the correct condenser on the distributor. Can't believe one or the other has failed in less than 100 miles. Jeez.

Tom
 
Ok, so try cross-pollination. They probably won't fit in the original location; but your TR3A should run with the MB condenser and vice-versa. Remove the old one and temporarily wire the other one up at the coil terminal. Ground the body to the coil bracket (or anything that is firmly connected to the engine block), connect the wire to the same coil terminal that has the wire to the points.

Sucks about your trip. Reminds me of flying to Spring, TX a few decades back, planning to drive a newly-acquired TR3 home. My buddy who lived in Spring had gone all through the brakes, fuel, etc. and pronounced it ready to travel ... I made it all of 3 blocks from his house before it died!

In fact, you might double-check for the same problem. The lead from the side of the distributor to the points had broken internally and become intermittent. It is forced to flex every time you step on the gas, so they can sometimes break internally even when the insulation looks OK.

PS, your FLAPS might still have the condenser in stock for a VW bug. It's handy because it comes with a long wire designed to attach to the coil terminal, rather than going inside the dizzy. And same deal, the engine should run fine with it.
 
I may be bucking the crowd here Tom, but can you change to electronic ignition? I know people may be divided on this subject, but it may prove more reliable.
Just a thought.
 
Randall - I did buy a correct new condenser at NAPA. No change. I'm going to try close inspection of the wires and connections at the distributor (inside and outside) tomorrow.

Elliot - I can install a Pertronix type setup, but I'm not even sure if ignition is the problem. One clue to me was that swapping in a new coil and condenser solved the problem - but only for about 15 minutes. Weird.

At least I got the windscreen washer to work!

Thanks.
Tom
 
Are you sure it's not fuel related?
 
fuel related? might be.

Here's what I did today regarding fuel:
checked fuel filter - clean
checked output from pump - strong
checked flow into carb - strong
checked float bowl - full
checked float bowl valve - functioning correctly (not stuck)
removed and cleaned (air pressure) all carb jets

At least with that, no apparent fuel flow problems.

Edit: pulled plugs - all clean, dry and light tan.

Tom (a/k/a Rapidly Going Nuts)
 
Sounds like you pretty much ruled out any fuel problems.
Any wires grounding out on the points/condenser mounting plate?
 
Gliderman8 said:
Sounds like you pretty much ruled out any fuel problems.
Any wires grounding out on the points/condenser mounting plate?
Click to expand...

I'll poke around inside the distributor tomorrow. I tested the vacuum advance today (sucked on the tube and watched the plate move), so that seems ok. When I first got the car last year, it would start and idle, but engine would die when revved. Finally traced the problem to a loose connection inside the dist, the stud which runs through the case and connects to coil wire. When you open the throttle, the vacuum advance would turn the plate. That would disconnect the voltage coming from the coil and kill the engine. Tightened the nut and problem disappeared. It was a slightly different "symptom" but I'll check it again tomorrow.

Thanks.
Tom
 
NutmegCT said:
That would disconnect the voltage coming from the coil and kill the engine.
Click to expand...

We had a similar problem with a VW with electronic ignition. The Hall effect sensor wires were cracked and the conductors inside would separate (open) when the advance would move.

I know you have addressed all the fuel components. However, is there any chance that your tank vent (or vented filler cap) is plugged?
 
Doug - thanks for the suggestion. Haven't checked the tank vents, but as the carb fuel bowl is still full when the engine dies, I don't think it's a fuel problem. Carb jets are all free and clear too.

I'm just about to open the distributor and see what evil lurks inside.

Tom
 
Old saying. If its got spark and got fuel and they both get there at about the same time - its got to run. Something you have is cutting out (obviously). In my case (TR6) it proved to be Crane ignition - since replaced with points, etc. and end of problems for about 4 years now. Sounds to me like it might be heat related. Something is changing when the engine gets warm. Or does this problem occur at other times? A TR6 owned by a friend had a similar problem. Turned out it was a cardboard & foil gasket from the cap of a fuel additive that dropped into the gas tank and would drift over and block the fuel outlet, thus stopping the engine. He managed to fish out the gasket - end of problem. If I were you, I would check all electrical connections - ALL of them. Use a continuity tester and wiggle all wires. Let us know how it comes out. BTW, where are you in CT? I'm in Stamford. I could give you a hand if you need help.
 
Have found two things that may be the culprit(s).

1. Plugs are way too hot. Spec is for a cooler plug. I'm using NGK BP3ES. Spec is more like BP6ES.

2. But more likely,I *think* I found the problem. Won't know for sure until tomorrow when I can check more carefully.

Let's just say "continuity" (or the lack of it) plays a big part ...

Stay tuned.
Tom
 
Cause confirmed, and problem solved!

I decided to check continuity/resistance of all ignition wires. Spark plug #1 - when I pulled the wire sleeve up from the top of the plug, the wire just fell out of the sleeve. The ignition wire set is Beck/Arnley; the wires themselves are screwed onto small threaded studs inside the plug sleeve. Somehow plug #1 wire was completely unscrewed inside the cap; charge was probably just leaping through the gap to spark the plug.

When engine was under load, evidently the spark wasn't strong enough.


Needless to say, I removed all five wires, fixed plug wire #1, and checked all others.


Then drove 20 miles without problem. Nice to feel the ol' Mercedes keeping up with the interstate semi trailer trucks again!

Onward through the fog.
Thanks again for all the help.
Tom
 
MAN - those red herrings and wild geese sure do play heck, don't they? :jester:
 
Red herrings and wild goose chases - all part of the game.

(But how one brand new plug wire could be completely unscrewed inside the sleeve is mystifying, to say the least.)

Yippee!
 
Must feel good to have things working... way to go!
 
I haven't read the whole thread and it seems to have moved on a bit, so forgive me if this has already been stated. Condensers are cheap and commonly replaced when doing an ignition tune up and replacing the points. If your old one's worked fine when you took them off put them in a baggy in your trunk. Easiest way to check a condenser is by swapping out with a known good new or used one.

One of the biggest head scratchers I ever had was a Sprite that started and idled fine but died under power. Turned out to be a bad condenser. Only time I have ever had a problem with one (so didn't suspect it as a problem).

Lastly there is a great book commonly available for less than 10 bucks and everyone should have one. The Lucas electrical fault finding manual shows simple tests with common tools you can perform on the various components and systems. In fact it is what I used when I finally figured out the condenser issue on my Sprite years ago.
 
Back
Top