Suck my vacuum

[davelittlewood]

I've had the TVR for 5 years now.

It has always had the 'shunting' to a greater or lesser extent so I decided to try to sort it out once and for all (or at least until I got hacked off with it and put in an MBE system)

I started by doing lots of reading (mostly on here) and then getting the bits I might need for diagnosis (Rover Gauge, oscilloscope [not quite sure what I'd use this for but I wanted one, so there] , was about to buy a vacuum gauge etc etc).

2 days ago I decided I'd try to run without the vacuum advance connected so I pulled the vac pipe off and then looked for a suitable bung to go over the stub pipe on the plenum. It was then that I spotted a small rubber pipe with a screw in the end of it on the vacuum advance pod.

All this time I've had the pipe connected but with the atmosphere side stopped off!!

I put the vacuum pipes back on and pulled the bung off the atmo side of the diaphragm and took it for a spin.

Different car!!

I can now drive at 30 MPH in 4th gear and it pulls smoothly.

If the vacuum advance is disabled, should the timing be altered to compensate?

My guess is that some of the guys who have serviced it and set the timing have noticed the bung and adjusted the timing slightly and others have not, which is why some times the shunting has been worse then at other times (it has been good for a year, bad for a year etc).

[davelittlewood]

Maybe I've just sealed the system a bit better so it's not pulling in any air through the pipes (the connector on one end was't very snug).

Anyhow, it seems to run better know so until something else packs up I'm going to stop playing with it.