TR2/3/3A floundering At High RPM

[CJD]

Yep...loosing power at higher RPM is a classic sign of a weak spark. It can be caused by anything that reduces power through the points, a bad coil, or dirty/bad cap and wiring.

 

[sp53]

Sorry for the confusion it is my fault for not being clear. I am jumping around with different stories about different cars. The car with the bad oil rings and electric fuel pump was back in 1980ites. Fast forward to today, and this latest restoration, that is cutting out at 4K.


Yesterday I put a new coil and distributor cap on the car and it ran worse. It actually started cutting out in second gear whereas before the car was not cutting until 3rd gear at 4K

I stopped the test drive and came home and replaced the distributor and condenser and retimed the car. After I replaced the distributor with a new condenser and check the timing, the mark was at TDC with the light. I fiddled with the distributor and put the mark on the advanced side of TDC about a ¼ inch. The car sounded better and the advancement as I reved the engine was quicker and went about ¾ of an inch and came back better.

The car is running better, but at peak performance there is still something not right. At 4K the car still seems to hold back. I have set this distributor up so I can keep advancing it will the knurled dial. I plan to road time it by advancing the timing as I drive the car up hills and such.

The condenser could have easily been the problem. I was trying to move slow and isolate the exact component of the problem problem, but I replaced condenser at the same time as the distributor. This is another old distributor that I rebuilt, but it could probably use a new bushing. the bushing looked very difficult to replace.

The problem does seem to be ignition which I glad about because my first thoughts were the cam shaft had failed again.


This might sound dumb, but if I race the car downhill there is no 4K floundering. I would think it would do it then also unless it was fuel starved. I have not ruled out fuel starvation at high rpm. I need to get under the car and look for that dent in the fuel line just to see how bad it really was or perhaps blow some air back towards the tank.

Thanks steve

 

[sp53]

Ok drove the car last night and the engine power is fixed. the car ran almost perfect. I think the condenser was the problem all along. My high school auto shop teacher made a lasting impression on me that condensers do not become faulty. He even said when they are bad they shot and will not work at all. Well I think either he was wrong or parts have changed. I am now in the replace the condenser club.

steve

 

[CJD]

One time in my life I tuned up a car without changing the condenser...also because a shop teacher swore they never go bad. We were driving up the million dollar highway in Colorado, between Durango and Silverton. That has a 12000 foot pass to cross. The Scout started banging and popping until it finally wouldn't move uphill another inch. Of course this was before cell phones. I had to hitch a ride with a trucker to call a friend who towed us over the pass, and I almost ran into him on the down side several times as my brakes faded. Sure enough, the points burned because the condenser went bad. Maybe we had the same shop instructor?!?

Anyway, good job getting her running again!

 

[bobhustead]

Condensers do fail all at once. They do not ever "partially" work. Bad running is the same thing as not running at all on this point. A condenser that causes bad running has simply failed. I have several stories like John's about condensers. Several years ago I threw a tune-up on my swamp buggy. New condenser. I then disassembled and cleaned the carb twice, to no effect, before going back to the old condenser. Ran great (still does) with the old condenser. BTW, a car will run without a condenser, but poorly and for a pretty short time
Bob

 

[DrEntropy]

Same lesson/experience. If something goes 'sideways', whatever you touched last is usually the first place to look.

 

[charlie74]

An aircraft engineer once said to me “the hands of man” when trying to diagnose a poor oil pressure problem on a turbine. He had just changed the oil filter and had over tightened the housing and cut the gasket on the manifold it sat on. It’s stuck with me since then…

 

[Hamish Racing]

Same lesson/experience. If something goes 'sideways', whatever you touched last is usually the first place to look.

Especially true if you didn’t really need to mess with it in the first place !!!!

 

[Sarastro]

Initially I was puzzled by frequent reports of bad ignition capacitors. In my experience, as a professional electrogeek, it is unusual for capacitors to fail at all, especially ones that are not electrolytics. Indeed, I'm sitting here in my office-cum-laboratory, and there are probably several thousand capacitors within a few feet of me, all working just fine. So, I decided to study the matter. Here is the result:

https://sprite.nonlintec.com/cap_failure/

The cause seems to be poor contact between the case parts and the foil "capsule," that comprises the business part of the capacitor. It results in burning at the contact points, which increases the internal resistance. It doesn't take much to make the capacitor useless in a high-current system such as exists in automotive applications.

In any case, if you want to solve ignition capacitor problems forever, this looks like a good way to go:

TheSamba.com :: VW Classifieds - Polypropylene capacitor condenser ignition points

Classified ads, photos, shows, links, forums, and technical information for the Volkswagen automobile

www.thesamba.com

 

[CJD]

Is there an issue using an electrolytic capacitor?