tr7 rough idle

[stephenjtsims]

Anyone got any advice to give on a tr7 that idles roughly, misses upon gentle throttle opening, misses after a 20 min run especially when pulling away and will just die when idling at the traffic lights. All ignition parts new. Carbs throttle spindles have a tiny amount of play. What am I missing? Any advice gratefully received!

[TimD]

Check for vacuum leaks or possibly the egr valve sticking or leaking. i was having a hard time finding a similar problem and used a spray can of carb cleaner and sprayed around the usual problem areas like the carb rubber mounts and vacuum hoses, the idles will speed up and smooth out as the carb cleaner is sucked in the offending source. My egr valve was leaking through the pintle valve even while the valve was closed at idle. I sprayed the carb cleaner where the pintle shaft runs thru the center of the valves base and my idle increased about 200 rpm and the engine smoothed out. I ended up just removing my egr valve and made
up a plate out of aluminum, cut out a gasket out of gasket paper, drilled out a couple of bolt holes, plugged the vacuum and my problem was solved.


http://s1048.photobucket.com/user/tkdreher/slideshow

[Hasbeen]

Stephen it would be a good idea to put your location in, as it gives us some idea what spec your car is, Eg. SU or Zenith carbs.

Tim's advice is sound, & other possibilities are water in your fuel, in the carb float bowl, or any in line fuel filter.

Also check for a failing fuel pump giving an inadequate supply of fuel. Can you rev it to 5000 through each gear from a standing start?

Don't be surprised if you have a couple of problems simultaneously. How well balanced is the suction through the carbs?

Hasbeen

[stephenjtsims]

well, well, loads of water discovered in the fuel tank. What's the best way of making sure there's none left without removing the tank? I've tried blowing it through with compressed air having removed the pipe to the fuel filter. I made a makeshift seal at the fuel filler end.

[Hasbeen]

Jack up one side of the car, & support safely.

Remove the fuel pickup/fuel gauge sender, from the front center of the tank.

Insert a syphon hose, [I use a 1/2" clear plastic hose, with a few inches of copper pipe in the end to weigh it down].

Syphon out all this will pick up from the low front corner.

Strain some of the old fuel & pour a few liters back into the tank & repeat syphon procedure. This helps get more water & muck out.

There is a fair chance your tank is rusty inside. If it is add some Morey's upper cylinder lubricant to the fuel. I use it not to lubricate my valves, but the fuel tank.

I found it preferentially dissolves [or goes into suspension] in water. It makes any water in the tank oily & yellow, & leaves an oily film on the tank, helping to resist rusting.

Hasbeen