Split second stall when accelerating hard

[Nucleo]

Hi all,
this car is giving me a headache! ..

2004 Vectra sri 120 1.9 cdti.


from my other thread:
http://www.vectra-c.com/forum/showth...nd-broken-Pipe

I have bypassed the vacuume sump at the rear of the engine and my vac pipes now go from the solenoid straight into the vac pump.

Since doing that, my performance has been crazy good since breaking the original vacuume sump pipe.

I do have a problem tho. when accelerating hard, usually in first, The engine will cut out for a split second. The car jolts like crazy, I get a split second stall and everything then comes back on.

I have a sneaky suspicion it could be the pipe I joined straight onto the vac pump as it was a silicone 5mm pipe (type recommended in the vac/boost pipe thread) as I didn't use any heatshrink to wrap the connecting ends.

could it be that the pressure from some hard acceleration is causing a quick expansion of the silicone and 'popping' to give an all of a sudden drop in pressure within the vac pump? causing the turbo to have a fit and stall the engine?

i dont seem to get the issue when accelerating in 2nd onwards. Any ideas?

I hope it is just the connection, going to get it heat wrapped anyway when I get some more but I just hope there isnt something else wrong with this damn car!

[Nucleo]

does anyone have an idea? going to be heatshrinking the pipes this weekend with some luck.

[Casey]

Im thinking that maybe the vac reservoir is used to smooth out the vacume rather like a capacitor does in an electrical circuit so now you are subjecting your turbo to the raw un filtered vac its picking up and dropping out slightly. Just a guess on my part but cant see any other use for the vac reservoir. It must do something otherwise they wouldnt have bothered with it and its associated pipework.

[Nucleo]

Updating this in case anyone wondered. When fitting the battery I didn't tighten the junctions properly. They had full contact but the other junction off the main head was too loose. The extra vibration from accelerating hard must have been enough to cause the stall ! Well, we live and learn