Spitting back through throttle body!?!

I’ve just got my vhpd back in my S1. The engine has had all new ancillaries, lots of new gaskets, leads, plugs etc.

I also had my local engine builder (who has a good reputation) to fit Vernier bullies and set the timing. The timing I requested was (as per Dave Andrews website / “Lift at TDC” method) Inlet .125" Exhaust .110".

It’s a standard engine with a 190 ECU.

I got it to fire and idle ok but on throttle blips it spits back through the throttle bodies on Cylinder 1.

I don’t know why this is but I imagined it could be that the timing on that cylinder isn’t right and the inlet valve is open when it shouldn’t be?

(Other info, the fuel pressure regulator isn’t connected and I wondered if it could be over fuelling but still, even if the it had too little or too much fuel, it shouldn’t be blowing it out of the induction).

(Incidentally the vacuum pipe attached to the FPR goes to the vacuum spigots on the throttle bodies near the block and then where? Is it to the MAF sensor on the roll over hoop stays? On the parts diagram it says “to the vacuum reservoir”…)

Has anyone else ever seen this? I’m thinking that I need to revisit the timing but wanted to canvas opinion.

Your thoughts are welcome!

Many thanks
Simon

Timing can’t be off on just one cylinder, usually spitting back (at least on carbs) is a lean condition. You might want to look for leaks in your inlet manifold gasket around #1. Also, re-connect your fuel regulator to manifold vacuum source. I can’t help you with the vacuum line routing as I run an Emerald and have done away with the reservoir and map sensor.

Good luck!

Are you sure that the vacuum pipes are actually going somewhere and not open and more probably are not split ? - Many cases of the small pipes on the throttle bodies being split …