Alfa Pages

[BigAl]

I checked my fuel pressure and it was at the maximum on idle, I removed the vacuum pipe from the FPR and there was no difference. I connected some vacuum pipe to the FPR and sucked, the pressure dropped as expected by 0.5 bar, so there is not enough vacuum being generated to suck on the FPR diaphragm.
I mentioned this to my Alfa mechanics and they said that there are idle bypass screws on each TB and that 1 on each side should be closed. Can someone explain how and why this is, wouldn’t one cylinder then be running leaner / richer than the other, also how do you make sure the IAC valve isn’t mixing things up, do you make the balance adjustments with the manometer with the IAC disconnected.

Thanks

Alan
_________________
x2 33 16v
pictures http://www.alfa-pages.co.uk/viewtopic.php?t=5203

[BigAl]

I set the TB butterfly stop screws to 1/4 turn "10 thou" it mad no difference to the vacuum produced on the pipe to the FPR.
I disconnected the IAC, no difference to the vacuum produced on the pipe to the FPR.
I checked all the vacuum pipes from the plastic spider.

There is only enough vacuum to just move the skin on the tip of my finger and the pipe will not say there by itself.
When i connected a vacuum pipe to the FPR and monitored the fuel pressure, i needed to suck about the same as when sucking a milkshake through a straw

What else could cause not enough vacuum on the pipe to the FPR, the pipe to the brake master cylinder, which has a 1 way valve?
_________________
x2 33 16v
pictures http://www.alfa-pages.co.uk/viewtopic.php?t=5203

[BigAl]

I tried closing all the mixture screws on the TB's, made no difference.
I opened all the mixture screws on the TB's to 2 turns, made no difference.

The only other vacuum on the car is to the brake master cylinder, there is a 1 way valve, could it be the wrong way round?
_________________
x2 33 16v
pictures http://www.alfa-pages.co.uk/viewtopic.php?t=5203