Hey guys,
I just finished my 13B swap into a 1990 B-2200 pickup. I started with a S4 6 port motor, ported with Pineapple Racing's templates on the fuel and exhaust. Running Racing Beats Holley, intake manifold, header, and 2 1/2" pipe all the way back with Magnaflow strait through muffs. Motor starts and idles fine once I tuned the idle mixture, but I am not making any power down the road. It is responding likes it's running lean. Does anyone have experience with this? Have any idea what jet sizes I should start to tune from?

 

What kind of carb you are runing? Double pumper or vacumm secondary? How much cfm 390, 425, 600 , 650, 750, 1000?

 

What kind of fuel pump are you running?

How much fuel pressure?

Where are the floats set? (The fuel level should just barely dribble out of the sight plugs)

First things first.

 

I picked this carb up used. But it was originally purchased from racing bead for a stock S4 second gen. The carb has vacuum secondaries, fuel pressure is set at 6psi, and I did not adjust the floats. When you say it should dribble out of the sight plugs, Do you mean the little rubber cap connected to an arm, which opens at idle? I know racing beat machines a few different things in the carb. I looked up the carbs number on Holley’s website and it started off as a Model 4160, with 450cfm. When I took the bowl off the jets in it now are 122-59.
My big problem is that the truck is missing all power, even at 5 and 6 grand. It is breaking up with light to mid throttle, and is missing any really power on the floor. I figure it has to be either the ignition or the carb. I am running two MSD 6A's and a first gen distributor. I don't have a vac lines connected to my distributor, and were told by a more experienced rotary friend of mine that it was not necessary. And my Leading timing is set to 15degs.

 

Ignition timing for no-vacuum advance distributor used with performance carbs:
Hold idle speed up to about 3500-4000 rpm, and then set leading advance to 24 deg BTDC. This method has worked great on my road racer for 2 decades now.

There is a big screw in the side of each Holley float bowl, maybe 3/8" dia. Remove this screw, and adjust float level until fuel just dribbles out the bottom of the hole, then put the big screw back in.

 

If you are not going to use the vacumm advance, just set your total advance to 23 degrees BTC on the leading & 16 degrees BTC on the trailing. Set the fuel pressure before you trying to adjust the fuel bowl level.To adjust the fuel level firts park your B2200 on level ground.you must loose the locking bolt on top of the adjusting nut. Do not try to move the nut without loosening the bolt. Eres Boricua?

 

Alright thanks guys, the truck is starting to repond the way it should, i still need to go alittle bigger in the jets and lock the timing in, but i think thats going to happen after the brake in.

 

How do you know you need bigger jets? Are you using a new school wide band O2 sensor , old school reading the spark plugs or just a feeling based on the seat of your pants ?

 

Well my largest problem was my timing; I had the leading set at 15degs BTC. I turned it back to 25degs and made a world of difference. I just assumed I needed bigger jets because my carb was set up for a stock 13b, and I have a decent street port done. The motor still acts like it is a little lean, Hold the motor at around 3 grand in neutral and it starts to bog after half a second. My plugs look ok but I have not done allot of driving so far, only about 150 miles. My intention it to pick up, and install a wide band for fine tuning. Does anyone know what fuel numbers I should be looking for once I have the wide band installed?

 

You say it acts a little lean, but the truth is that it is extremely difficult to tell what lean spots "feel" like, vs rich vs timing etc. Even a long time pro can't always tell by feel. And you don't need broken in plugs to tell by color. You need the color of the plugs at the instant you are tuning for, the instant you think you are lean, or rich, etc. Some people drive the car up to the rpm and throttle level they are tuning for and then turn the key off, coast to a stop, then inspect the plugs.

Say you are tuning to see what wide open throttle at 6000 rpms-ish is like. You drive at WOT, cut the ignition at 6000 rpm or so, coast to a stop, and pull the plugs.

or if the car bogs weird, re-create what makes it bog, cut the ignition while it's doing it, coast, pull plugs, etc.

It's better then guessing, but a wideband is tons better.

 

i agree! the P port had a spot that we actually all agreed was lean, and it turned out it was a huge rich spot once the WB was on it. if you're way lean or way rich it feels the same, but if you're a little lean vs a little rich that is easier to tell

anyways. AFR numbers, this is a general guide, some combo's are happier at different AFR's...

idle; what ever is best, usually this is around 12-12.5. if it runs ok leaner, go leaner.

1200-3000 part throttle, factory is 14:7:1 here, for best economy you can go slightly leaner, a little richer just uses more fuel, you don't want to be richer than mid 13's...

full throttle; generally na's like 12 to maybe 13.5:1, ive seen leaner and richer.