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[69tr]

I am still pondering the OD problem. I will work on that again tomorrow.

On another test drive today I noticed a misfire at between 2500 and 3000 rpm. It happens at random intervals while maintaining a fairly constant speed. I am going along just fine and it just sputters once and everything is fine until the next time. Sometimes it is barely noticeable and sometimes it is REAL noticeable.

The carburetors do not have any adjustment except idle speed.

While the car was down, I adjusted the valves, removed and sealed the tank, and replaced the fuel filter.

It has the petronix ignition. I am using a mid grade gas. The engine does not seem to ping. I am not sure about the timing. When I time it by the book it has no power. I think it is a timing problem.

Do I need to keep adjusting the timing and test driving or does someone have another idea?

Another problem is the idle speed. It idles at about 900 rpm most of the time but at times it seems that the linkage does not return fully. I have taken the linkage loose at the carbs and I still does this. I even took the linkage loose between the carbs and the front carb seems to be the problem. Anyone else have this problem?

Thanks in advance for any help, Pete

 

[3798j]

I can recall being stumped by the same mysterious miss on my TR4A. My belief is that I cured it when I realized the Pertronix was'nt receiving full battery voltage. Check your grounds (I even cleaned dirty long neglected battery terminals). I know it sounds almost too basic, but it cured that difficult (intermitant) miss.

 

[pjsmetana]

Could be a loose plug wire as well. I would recheck all the ignition wires from the battery to the plugs.

 

[Brosky]

I would follow the same paths suggested here by me and the others. Process of elimination.

High Speed Miss thread

 

[69tr]

Doing some checking this afternoon. While checking the timing I saw that the timing mark would move. I checked with the vacuum hose loose, plugged and connected. Does this mean dizzy bushings or maybe a distributor? What else would cause this. Please tell me it is something simple and inexpensive.

 

[MDCanaday]

Grab the rotor and wiggle it,if it likes to move more than 1/64 of an inch the bushings are shot and you must re-build.....
MD(mad dog)

 

[pjsmetana]

While checking the timing I saw that the timing mark would move.

What do you mean by this? Like, it would advance under acceleration, or just be sporadic?

 

[69tr]

Pete, with the engine idling the timing mark would advance. It would advance sporadically. The engine was idling about 1000 rpm.

MD, do you mean move the rotor back and forth or try to turn it?

If the distributor must be rebuilt will it need to be done professionally?

 

[pjsmetana]

Check the vacuum tube off the carb that leads to the distributor for leaks.

And I think MD means Shake it all over in every direction. If any direction is loose as described then its got issues.

 

[poolboy]

I bet your distributor could benefit from a reconditioning and a "recurve" back to original specs. Ths guy does great work, has a fast turnaround and his price is modest considering the results. NFI
https://www.advanceddistributors.com/
Also using a vacuum gauge can be more helpful than a timing light in engines that have many miles on them. This is due to stretching of the timing chain, wear in the sprockets as well as the gears that turn the dizzy shaft, not to mention damper slipage.
Here's a link:
https://automotivemileposts.com/garage/v2n8.html

 

[TR6BILL]

I had my distributor rebuilt 2 times and this same problem always occurred. I finally had it rebuilt by Advanced Distributors (very reasonable pricing, by the way) and all these problems disappeared. I think you have a dizzy problem.

 

[TonyPanchot]

did you pull the coil off and make sure it is clean (mounting bracket) and well grounded this was my problem