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Distibutor Question

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jerrybny

jerrybny

Jedi Knight
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Ok problem of the day on my 73 TR6. I can't get my idle down below 1600rpm. In troubleshooting I noticed that when I pull of the vacuum line on the distributor it makes no difference. I have a feeling my vacuum retard isn't working. It usually speeds up when you remove it and slows back down. Where should I start? Thanks
 
I guess that be possible but I have the idle screws backed all the way out and its still at about 1600 rpm
 
Got an air leak somewhere?
Also do a static timing check.
 
The retard not working would certainly explain the high idle.

Although it's better to use instruments (vacuum gauge, Mityvac), you can get a good idea by putting your finger over the end of the tube to see if there is vacuum being supplied. It's not very strong, but if the tube wants to grab your finger at all, there is probably enough that it should work.

I'd also check that the plate inside the distributor can be moved by hand (compressing the retard capsule).

If the plate is free, and there is vacuum being supplied, the module must be bad. If so, you have to decide whether to tune without it, or get a new one (or try having yours rebuilt).

If you try to tune without it, and can't get the idle down, most likely the throttles are being propped open by the bowl vent valves. I'm not sure exactly what they look like on a 73 TR6, but on my 73? Stag carbs, there is an adjustment screw and a spring metal clip that it bears on. I had to pull the clip off and bend it to get enough adjustment. Apparently on later carbs, though, it was just a screw (Photo courtesy Nelson & Buckeye Triumphs).
 
I would go looking for a vacuum leak somewhere causing the high idle.
It might be related to the distributor retard system but it might be something else leaking.
Try disconnecting each vacuum pipe and plugging them at the source with the engine running until you find the culprit (dist retard, brake booster, charcoal cannister line)
 
I'm better with TR4s than 6s, but on my TR4 over last weekend I had exactly that problem. But the problem was the choke cable. I fixed it and the RPMs dropped by 300.

Other than that, or a stuck accelerator pedal or linkage, I can't imagine anything "sudden" on the vacuum line could do that. Timing way off might.

I would not focus on that vacuum line until you rule out other things. On my TR4, at least, the vacuum won't make any difference at low idle speeds or slightly above. Someone once explained why, but in many years of TR ownership, I've not had the vacuum mean much in basic tuning and setting RPMs at idle.

Good luck and let us know. thx
 
To all those that said to check other things that the vacuum retard give yourselfs a pat on the back. It appears that the rear carb's chock was hung up which was causing the high idle.
Once thanks for the advice. :savewave:
 
a little off subject but when I set the timing on my 71tr6, set the static timing, with out vacuum line, and reved up the engine, no advance, took the distributor apart and found that the weights were frozen, cleaned every thing, oiled it, cleaned and greased the tach gear and all is well, so check to see if the mechanical advance is working

Hondo
 
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