View Full Version : TR6 TR6 - Idle Issues

09-23-2004, 12:31 AM
Am encountering an idling issue with my '75 TR6. The car starts without issue and idles well until it warms up. At this point, the revs drop and the car coughs and splutters sometimes dying.

For reference, the vacuum advance system and EGR system has been removed from my vehicle by a previous owner and all of the vacuum spouts plugged on the carbs. (The rocker cover has a tube that runs from the rocker cover to the manifold.)

I have checked the plug gaps, replaced the fuel and air filters (Longflo air filters) but the problem still exists. Since the air filter change, the spark plugs are exhibiting signs of a rich mixture. (Black plugs.)

Any help would be greatly appreciated!

09-23-2004, 09:31 PM
Just a guess, but I think you need to run a hose from the rocker cover to the carbs with a plastic split coupler because as I see it you are pulling your oil spray out of the rocker cover right into the manifold and that is what,s making your plugs foul. Is your brake servo coming from somewhere else on the manifold?

09-23-2004, 10:37 PM
Sucking from the manifold to the valve cover is a big no-no.
There is way too much vacumn coming from the mandifold for this purpose. You should be using the manifold vacumn strickly for you brake servo, that is if the pollution apparatus has been removed. Either dump the valve cover gasses into the atomosphere by hanging a hose down to the underside of the car (I didn't say that) or go to the vacumn outlets from the carbs. I run mine through an oil separator back to the carbs, and let the oil drip back into the sump. You need some vacumn on the valve cover, but not THAT much.


09-25-2004, 03:28 PM
Thank you trrdster2000 & tr6bill for your feedback. The break servo vaccuum line is feeding the manifold, however there is a second pipe on the manifold that connects to the valve cover. Should I connect the valve cover lines back into the carbs? If so, should I simply plug the second manifold inlet? Thanks again.

09-29-2004, 01:15 AM
As a follow up, the brake servo now feeds the manifold. The valve cover now feeds both carbs and the second vacuum inlet to the manifold has been plugged. (This I believe was used as an EGR return.) The plugs have been cleaned, th carbs synced and everything runs 100% better. The only issue that I need to troubleshoot now, is that the card idles at around 1300rpm. (There are no evident vaccum leaks.)

10-17-2004, 03:52 AM

What does the oil separator look like and how does it drip back to the sump?