I've got a 2L pinto running on the standard weber carb, which originally had a pipe connecting the carb to the airbox. Seeing as I don't have an airbox any more I just blocked up this connection, but the engine idles really erratically, could this be the cause? If so, what do I have to connect it to, do I drill a hole in the air filter base plate to connect it to? Sorry I can't be a bit more specific but I don't know much at all about engines!

Cheers,

Pete

It's more likely to be air getting in after the carb. Have you got a vacuum advance or have you taken any bits off the manifold and not blocked the holes? If it's running weak it could explain the reluctance to start in the other post.

Think the pipe you are refering to is for the preheat system , used to go to a little temperature sensing valve then to a flap that allowed warm air into carb when air temperature was low to stop carb icing up. blanking off pipe should have no effect in warm weather . Does your distributor have points? could be closed up causing incorrect timing . Also try spraying around your carb base and inlet manifold with WD 40 with the engine running, if you have an air leak the idle will even out if you spray onto the source of leak.May aso be worth checking valve clearances as tight valves will sometimes cause erratic idle. also check idle mixture . Screw in idle screw and count number of turns , turn out until smoothest idle is achieved , should get you somewhere near . if that fails take out idle jet and clean H.T.H.

sounds a lot like mine, when the pipe was removed from the frying pan. just make sure it is entirely sealed, give it a bit of sikaflex to be sure.

if not, then chase the other suggestions.
hth
tom

Thanks for the tips, I'm back at uni again tomorrow so won't get chance to look at the car, but will have a go when I'm back next. The connection comes from the manifold thinking about it, so maybe I haven't sealed it up properly. I'll also have a look to see if there are any other holes I've missed!

Pete

Edit: I also have a return feed to the tank even though it's carb fuelled (I installed it incase I upgrade to injection at some point), I'll try disconneting that too.

[Edited on 8/5/05 by scoobyis2cool]