mgs
[Top] [All Lists]

Re: Run-on in 78 B

To: mgs@autox.team.net
Subject: Re: Run-on in 78 B
From: "John M. Trindle" <jtrindle@tsquare.com>
Date: Mon, 24 Apr 1995 07:21:22 -0400 (EDT)
On Sun, 23 Apr 1995 Mark5757@aol.com wrote:

> I recently bought a 78 MGB.  My previous British cars were all prior to 69
> and didn't have any pollution control equipment.  This car has had the smog
> pump, air rails, converter, etc removed.   After the usual tune up the car
> runs beautifully and gets reasonably good mileage.  My problem is this, the
> car wont shut off unless I stall it out.  There is a run-on valve with a
> small hose that leads from the manilfold to it.  I dont know how to test this
> valve or if it is the cause of the problem.   Any advice will be appreciated.
> 

On the '73, the run-on valve is fused, with an in-line fuse.  The holder 
on my car is just below the regular (4 fuse) fuse block.

It is closed during normal engine operation, and opens when you turn the 
key off.  This introduces a bunch of air into the intake manifold and 
leans the mixture out.

If you can tune your car, I think that means that the run-on valve is 
closed OK.  It may be stuck closed.  I'd apply 12 volts directly to it 
and see if it changes position.

I could be more specific but the run-on valve has been removed (and the 
manifold "plugged", literally, by a spark plug) by the PO.

Apologies if this is not relevent to the '78.

John M. Trindle | jtrindle@tsquare.com | Tidewater Sports Car Club
'73 MGB DSP     | '69 Spitfire E Stock | '88 RX-7 C Stock


<Prev in Thread] Current Thread [Next in Thread>