OK, I am feeling out the new car and have driven it for a little bit now and I have a couple questions. First, I have an air fuel mixture gauge. It is one of the electric digital sweep models. It sweeps a full 3/4 of a circle from the left to the right. The first quarter is lean, the second quarter is stoick(sp) and the last is rich. Engine is a built 2.5 liter running DelLorto 45's. Car starts right up when cold with a little bit of a fluctuating idle but always stays running. Upon Start-up the AFM reads full rich. It stays this way for most of the warm up but then it goes to just off rich and a little stoick. If you start driving just as it is getting into the stoick from rich it will go most of the way to lean if you get on it good. At this point the temp is still not all the way up and is around 140. Once the car is completly warmed up running at 180 degrees (never gets any higher because of front cooler) the AFM reads right in the middle of stoick at idle and while crusing down the freeway at a constant speed, not on power but not off. Here is the troubling part. The moment you tip in on the throttle the AFM pretty much pegs at full lean AND, if you pay attention, you can feel the drop in power. Now the car still goes like stink but this big sweep to lean is troubling me. It appears to me, based on the gauge sweep, that there is no way to set the car up to idle in stoick and stay in stoick when in full throttle. I am sure you engine/carb guys have figured out that I do not know much about engines from the above but can someone throw a little help in my direction. My friend/mechanic is a 60 mile drive away and has told me in the past that the AFM is just for reference but has also told me that you should not feel the slight loss of power when you tip into the throttle. Can I fix this or do I need to bite the bullet and go back to my friend or wore yet, a mechanic and pay $$$.

My first thoughts:

1. You have a narrow band AFM, which is not that helpful. If it were my car, I would definitely remove it and, optionally, replace it with a wide band AFM like the LC1.

2. You might have to adjust your acceleration pump volume to squirt a little more fuel when you step on the throttle. Was there an elevation change from the previous owners location to yours?

Yea you need more enrichment on your Acceleration jets.

When you hold it to the floor and pull for a good bit you should see 12.5 : 1 or so. that's where your power will be.

word

get a bigger squirt!

Here are some pics of the spark plugs that were in the car for a little bit. there are 4 pics.

#2

#3

#4

Additionally, O2 sensors need to be up to temp. I did OK, with a narrow band, but not until I got one that was self heating. What jets (idle and main), air correctors, and vents are in your carbs?

You need to be tuning the main jets not the idles if you are lean at full throttle...

Let us know.

-Aaron

the problem with plug tuning is they kinda tell an average.
unfortunately by the time you idle down and pull into the garage or pits to pull them, that average includes a lot of different throttle positions and coasting.

If you were to do a full power run and then turn the ignition off on the track or road, and let off the throttle and coast to the side of the track and pull the plugs on the actual track, then the plugs may tell you wide open throttle.

but you are not going to find a situation where the plugs can tell you throttle tip in

only a wide band is going to be able to show you that.

set your floats and then use other's experience to jet your carbs and you will be close without a wide band. Or get on a dyno to go from there.