Too rich or too lean?

71T Targa · 08-04-2005, 12:40 PM

If/when I stomp on the gas, my car dies for a second and then takes off. Some times I need to feather the gas to get rolling. Ie. Give it a little, let up, give it a little more. Is this the result of a rich or lean condition?

’71 2.2 T with Webers.

jluetjen · jluetjen's Garage

How about the acceleration pumps?

sammyg2 · 08-04-2005, 02:51 PM

Could be either, more information is needed but I'd say that too lean is more likely.

jluetjen · jluetjen's Garage

If it's too lean, you'll find that the engine momentarily "picks-up" when you close the throttles. This is called "lean surge".

project 911 · project 911's Garage

Joel,

You might check your timing. If I set mine to the specs given in my manual, it falls flat on its face when you punch the gas. I just time mine by ear until the throttle response is crisp.

jluetjen · jluetjen's Garage

project 911; I suspect that your car's dizzy may not be advancing correctly. The factory settings should work great if everything is working correctly. The factory new what they were doing when they came up with those settings. Have you confirmed that your car's distributor is advancing according to spec?

project 911 · project 911's Garage

John,

I had a lot of trouble with two of the original Marelli dizzys, then upgraded to a Bosch, but they all did the same thing as far as timing and throttle response. I imagine the newer Bosch may have a different curve as I think it was for an S model, but I have yet to check it. The car runs great, and 6000 rpm timing still falls in the 30-35 degree zone.

Rex Walter · 08-05-2005, 04:00 AM

Steve,

I think John is correct. After I replaced my dizzy, it took some fiddling to get the advance curve correct again. It's good that you check the total timing, but if you do a search here, you can find the complete curve from idle on up. If you match that at idle, 1000 rpm, 2000 rpm, on up, I think you'll find the car runs great.

phred68 - Check your total timing at 6000 rpm like Steve did.

Good luck - Rex

71T Targa · 07:43 AM

Thanks all, sounds like it might be lean, as I do get what John describes as "lean surge". When I come to a stop, the RPM's will pick up for a bit, and then settle in. The acceleration pumps measured correct when I rebuilt the carbs, and the timing is on at 6K. (Well I don't know if it's 6k, but once the advance stops)