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Title: HPE VX Engine cuts out when braking Post by: gjanssen on February 06, 2025, 03:43:35 PM Hi all,
After 29 years of sleeping in a garage box a the Lancia has been inspected and admitted to public roads again ! The garage has spent many hours to make everything technically ready. The only problem now is that when I press the brake pedal hard, the engine cuts out. The brake pedal is also not always equally hard. Sometimes I have to pump a bit to be able to put full pressure on the brakes. And as I said, the engine often stops. I suspect there is something wrong with a vacuum hose. Is this easy to test? (https://www.betaboyz.myzen.co.uk/forum/index.php?action-gallery;sa=view&id=566) Kind regards, Gerrit Title: Re: HPE VX Engine cuts out when braking Post by: gjanssen on February 06, 2025, 03:48:51 PM And a nice picture..... :-)
(http://www.betaboyz.myzen.co.uk/forum/gallery/3513_06_02_25_2_36_22.jpeg) Title: Re: HPE VX Engine cuts out when braking Post by: JohnFol on February 08, 2025, 12:30:15 AM Hi Gerrit, I can see you've not had a reply so just giving this a bump.
I'm far from an expert but I had similar on my Spyder. combination of idle set too low and a manifold leak. The way I found the manifold leak was to spray something flammable around the inlet gasket with engine running. If engine picks up, the spray has been sucked in where it shouldn't. Title: Re: HPE VX Engine cuts out when braking Post by: Nigel on February 08, 2025, 11:24:20 PM Hi Gerrit,
Assuming it's running and pulling normal power, perhaps the brake servo is leaking air/vacuum? I say this because applying the brakes is actioning the servo, before that there is no fault apparent. There could well be a leak elsewhere as John has suggested, but that type of leak would not change when the brakes are used. I suggest you try blanking off the pipe to the servo, and driving it. Obviously extreme caution needed as you'll have a very heavy brake pedal, but if it doesn't stall you'll have an answer. Go carefully Nigel Title: Re: HPE VX Engine cuts out when braking Post by: gjanssen on February 20, 2025, 06:47:45 PM Thank you both for your answers!
The problem was a vacuum leak between the master brake cylinder and the servo. Checking cables: no problem. While the engine was idling, disconnecting the vacuum hose from the carburetor resulted in the engine stalling immediately. When the pedal was pressed, a small hissing noice was coming from the servo. Afther that, i noticed one of the 2 bolts, were the master brake sylinder is connected to the servo was not tighten properly and when my son presses the brake, I noticed the master brake cylinder moves one millimeter forward Just after tighten it, problem is solved. |