Disconnecting vacuum advance

[cmr2payne]

O.K read this in a few posts what does it help and should I do it ???

[joospeed]

it helps nothing and you shouldn't do it.

[sgrimshaw]

It's supposed to help if you're experiencing "rough running" at low revs.

Must admit I disconnected mine, as it seems to have helped.

Simon

[david beer]

Cured my rough running at low revs at partial throttle. I doubt TVR re-engineered the vacuum for a car that weighs a fraction of the Range Rover. MIne was smooth up hill or while accelerating,so reducing the vacuum advance. My opinion only, i only repair car stereos !

[joospeed]

don't understand why it would do that .. unless removing it cured a symptom of a fault and not the cause .. the vacuum advance is the only way the ignition can sense load, so why remove it?

[ian8542]

joospeed said:

don't understand why it would do that .. unless removing it cured a symptom of a fault and not the cause .. the vacuum advance is the only way the ignition can sense load, so why remove it?

I concur. It's like removing the thermostat because the radiator is shafted, to try and "fix" the overheating problem.

[GreenV8S]

If the vac advance unit is faulty, or the slow return valve has got blocked or been fitted back to front, then these problems could be hidden by disconnecting the vac advance. Personally I think the valve is more trouble than its worth and if in doubt it should be the first thing to go, but there's no reason to get rid of the vac advance.

[david beer]

Just to put my side across. My last Griff was a bugger at 30-40mph in fourth gear, took it back and was told "TADTS", pop into third gear.. My new Griff, just the same, hold light throttle and it would "jerk" along. Disconnect the advance and you can poodle along even in fifth. The car has been serviced three times and even set up on a rolling road. So i can not see im hiding a problem ?

[GreenV8S]

Do you find it uses more fuel cruising on part load?

[david beer]

I know where you are coming from Peter ! Im afraid i do not check the mpg, i fill it up, drive some and have to fill it up again ! In my defence, its only my play car, so i would have to wait sometimes two weeks before i filled up. Several people have done it on various threads and maybe if they are taking a look here, they would be able to comment. I know that on my last Rangie i did the "suck" test and found the vac puctured, replaced it and never noticed any increase in mpg, unfortunately, usually around 13-15.