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Man this is frustrating!

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TRclassic3

TRclassic3

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As those know that have read my previous posts, this all started with an attempt to get my idle under control (idle at 1400) I fooled around one day, didn't real change anything that I was aware of, but did not correct the idle and did manage to make the car idle very rough, backfiring from as exhaust an through carb. So today I attacked the problem. Most felt that it was timing related. I have adjusted the timeing multiple times using different methods, the most recent being static timing using a Color Tune. I have also cleaned the carbs, centered the jets, used various methods to try to dial in the carbs, all with little success. I was able to somewhat improve on the smoothness of the idle, although still a bit irregular, and also able to rev the engine in the garage without back firing. However, when I take it out on the road it will backfire again and run like crap under acceleration. I've also changed the rotor and cap. Reminder that I am running Pertronix ignitor.

I don't seem to be able to get one of the carbs leaned out corretly. The piston falls with a nice loud click, but according to the color tune, even with the jet all the way up it's still rich. Interestingly , if i do the test and lift the piston slightly it essentially stays the same, slight increase, but little enough that it wouldn't seem to be the problem. Plugs are well carboned though.

I really have no idea where to go from here. Is it possible that the pertronix is the problem? I feel like I'm fishing here.
 
I don't understand how any electronic ignition could cause such a problem as a high idle, at least not by itself. Certainly timing is one possibility for a cause, but I don't see how the electronic ignition could "override" the timing, i.e., the physical position of the distributor?
 
The pertronix is not new. It was in it when I got the car a year ago. I would guess that it has 3 to 4 K miles on it.
 
Ithink you are right Andy. I jsut don't know what I should be focusing on., Carboration, timing, ignition....???
 
Ed, just curious: are you using the original tachometer to judge that 1400 rpm idle? If so, have you checked it against anything such as an electronic instrument (i.e., diagnostic equipment)? Just thinking that maybe your tach is a bit psychotic. /bcforum/images/%%GRAEMLIN_URL%%/wink.gif
 
Ed - do you have points setup you can install and try? I can send one out if you need to borrow it to diagnose the problem. Or just buy point and condenser set.

I thought about the marks on your pulley and the reason they are off is probably because someone took the pulley apart and didn't put it back in the same holes. There are six 1/4-28 bolts that hold the two pulley halfs to the front hub. The drilled hole should line up opposite the keyway so that it points to 12 o'clock at tdc. Easy to put it together wrong. So someone just made their own marks instead of taking the pulley apart.
 
Sounds like my 60 TR3A. Idle and richness has been a problem for years now. I even foul out plugs and have done everything you've done. I know where the problem is now with the idle. My throttle shafts are worn out. Air that gets sucked in through the gap between the carb body and the shaft. This leans out the mixture and increases the idle. I'd try this test, Get a can of brake cleaner or starting fluid with the extension straw and spray some around the throttle shaft outlets while the engine is running. If the RPMs rise you know the problem. If not, or you may want to do this any way, spray around the intake gaskets and listen to the RPMs. Any increase then that's your problem. You must address this problem first even if the carbs have been recently rebuilt to rectify ANY mixture problems. Bushings can be but in. I've heard of guys counter boring the shaft holes and pressing in shaft seals like on Stromberg carbs. Good luck and be carful when you are spraying. You have that hot exhaust manifold under the carbs.
 
Thanks for the responses. Andy, I am just using the car tach to measure the idle. At this point I would be happy to just get things back the way the were. Even though the idle was high it at least didn't miss and backfire. The way it is now it isn't driveable.
Peter, I do have multiptle sets of new points and condenser(thanks for the offer). I could switch over to check the results. Should I assume from your suggestion that you believe the problem to be ingnition and not timing or carboration? Just had anoter thought. One of the things I had done juest previous to this problem was to pull the plugs, clean and gap to .025. Could this have cause the problem. Geez could it be as simple as plugs?

TR3ATR250, I have cehcked for leaks by spraying the carbs and intake with carb cleaner. No indication of leakage. If it were would the result be lean runnig rather than rich?

again, thanks to all for the help.
 
No idea what the true problems is, just trying to isolate the problem and go from there. When I make a change that doesn't fix the problem, I most always put it back to the state before the change to not introduce another problem.

Since your problem occurred after you poked around inside the distributor with your meter, I would start looking there. Maybe pull the Pertronix and points plate, examine the wires for shorts, cap, etc. Make sure the points plate is rotating properly ...

GOOD LUCK for a fix TODAY!!!
 
TRclassic3 said:
One of the things I had done juest previous to this problem was to pull the plugs, clean and gap to .025. Could this have cause the problem. Geez could it be as simple as plugs?
Click to expand...

Did you drop a plug on the floor when cleaning and gapping?
 
I'm like PeterK, then. Maybe you knocked something loose with your meter probe.

The only thing I can think of is going back to points. You could swap out the plugs if you have any spares.

I'm just grabbing at straws now.
 
Grasping at straws is what I've been doing for 2 days. Swapped out the plugs. Still running rough. Centered jet on front carb. No change. I guess i'm down to swapping in the points, although I cannot imagine what I could have done. There isn't much there, and I made no adjustment. Does seem like the only thing left.
 
The problem might not have anything to do with what you did. Sometimes things will fail at the moment you change something, making you think that the problem was caused by the thing you changed, but the failure is really unrelated.

It's just the inanimate objects' way of being onry.

The Boffins here at HSTRL Soggy Bottom have experimented with this phenomenon.
 
Correct, it would lean it out on the idle side. That's why the RPMs go up. The air is introduced after the metering needle so when you try to adjust the mixture you have to richen it to compensate for the extra air. As the shaft floats around in the carb body it will from time to time shut off the leaking air making the mixture way to rich. I've forgotten all that happens on the higher rpm ranges and I know I have an article around here explain it. But I'll never find it when I need to. We recently moved and can't find anything now. Keep this posted and on the first page and maybe change the title to define your problem more closely and you'll find someone who will get you the right answer. Larry
 
I'd suspect the carbs as the culprit. Everytime I've had a similar issue with fluctuating idle/rich/lean problems(solex's, su's etc) it has been throtle shaft issues allowing air to seep past at different rotation intervals.
Luckily SU's are inexpensive to rebuild.
 
A quick way to check if it's the carbs is while driving and the engine at full temp pull the choke and see if there is any differance in pefromance.
 
Good Morning & or Hopefully It will be for Yourself?

I`m not a Guru @ setting the Carbs at all but Sounds like you may have a "Vacuum Leak" somewhere: Using some "Ether" or "Carb Cleaner" spray Everywhere! The Carb Shafts being out of Alignment or slightly bent is a Typ Problem: Spray the Exhaust Manifold; Spray everything that has a "Gasket" attached to It! Should this Not show a Vacuum Leak; Call the "GHOSTBUSTERS"!! There is an Exc. Carb Re-Builder in LI NY: "JOE CURTO", whom I`m sure your probably familiar with? He advertises Everywhere, Hemmings etc etc: What you may also do is contact My "Brit Mech": He`s Outstanding & Extremely Helpful: He`s a Tech writer for "Moss Motors": His Ph. # is: 570-424-6379; His Name is "Don Lawson"; Ref. Myself, "Russ Chura": He`s Located in NE PA:

Good Luck & Don`t Quit; There is a Solution;

Regards, Russ
 
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