Mcy17

Hi, I am obviously new to posting on the forum but have read for quite a while. I have an 86 Toyota Pickup 22R with a Weber 32/36 carb with electric choke. The cat is cut off and it has a straight pipe to stock exhaust. My issue is when I am driving the truck and press the throttle halfway, it seems sluggish. This is right before the secondary opens. At 3/4 to full throttle the truck has great power. At 1/4 throttle the truck cruises fine, its just close to half throttle it gets sluggish and seems to jerk the truck slightly as if its missing. Ive tried adjusting the carb using Weber's instructions. I had to timing set just about a month ago at a shop so it shouldn't be a problem. Any help would be great. Thanks

dhall50

Are you using the two part adapter? Mine had a vacuum leak that was leaning my engine and causing similar symptoms. With the truck running I sprayed carb cleaner around the base of the carb a few times. If you have a vacuum leak the engine will stumble. It took a few tries to find the leak. Once fixed it runs much better even though i still might mess with the jets.

Mcy17

Thanks for the reply. I have checked for a leak and found none so far. I checked my vacuum line to distributor as well. It runs fine like and has great power at full throttle but at half throttle it gets sluggish and sort of misses like its got restricted fuel flow. If you let off the throttle a little it stops immediately. It occurs at half throttle right before the other butterfly opens on carb. I can feel the notch in the gas pedal.

xxxtreme22r

where do you have your idle jet and idle screw settings at? fuel pressure regulated? if how? factory or electric fuel pump?

Mcy17

Ahhh as a matter of fact it is the factory fuel pump but no regulator. See I bought the as is so I havent changed anything. I appreciate the reply and more information would help a ton.

xxxtreme22r

most problems with webers on these trucks are due to the fact the factory fuel pump puts out maybe 7psi and if you hook up a gauge to it you can see it fluctuate really bad. The webers are designed to run at 3.5-4psi. Also is the fuel return line blocked off as it should be? In order for me to provide more help, I need to know how far out your idle speed screw is and your idle mixture screw is.

Mcy17

The factory fuel pump has the 3 lines on it. The input, output, and return. The output is going straight to one side of the tee on the carb and other side of the tee is blocked off. I ran across a Mallory Bypass-Style Fuel Pressure Regulator. Will this work? Also the idle speed screw is about 2 turns in after touching the arm and the Idle Mixture screw is 1 and 1/8 turn on. This is after I adjusted it using the instructions from the Weber paper that came with the carb.

xxxtreme22r

the other side of the tee is just another way to hook the line to the carb. There is 3 connection on the fuel pump itself. one of those is the return back to the tank. it should be blocked off. I would not use a bypass style regulator. It fluctuates the pressure too much. On mine I used a Holley. I swear by these regulators. Have used them on alot of vehicles. Never once had a problem with them.

The setting on the idle mix screw sounds about right. Are you sure you set this screw with the idle speed screw no more than 1 turn in from contact? This is very important that the butterflies on the carb will mask lean/rich condition if it's turned in too far. Has to do with where the air meter is in relationship to the butterfly/throttle position.

Where do you have your timing set? 0 degrees?

Mcy17

I got the Mallory regulator for free and I have it set to approx. 3-4 psi. I readjusted the idle mixture and idle speed screw. It helped some but it still lacks power and runs sluggish at half throttle. The timing is set to 0 degrees with the vacuum line off. I will go readjust right now and make SURE that idle speed screw is no more than one turn on from contact and let you know. Otherwise, it may be the bypass style regulator not working. I plugged the return port on the fuel pump and used to line for the regulator. Ill be back in a minute.

Mcy17

I readjusted and tried it again and its the same. On a flat road, casually driving, barely giving it gas im in 3rd gear. I go to half throttle and it starts running sluggish, i let off the gas about a 1/4 of the way, it picks up speed so smoothly and drives fine. This is a problem because when im going slow and start to go up a hill while cruising I go to half throttle and it slows down so I have to mash it down more in order to get the power I needed to go up the incline. Maybe the regulator isnt regulating?

Mcy17

Well, just for more information, I found out a vital piece. The instructions on the fuel pressure regulator did NOT say at all which way by turning the screw increases or decreases pressure. So, me not knowing, and without a damn gauge, I installed the regulator and turned the screw ALL the way IN, then backed it out 1 turn. It BARELY made a difference. So I went back under the hood and turned the screw IN 1/2 turn. It ran the same. Still had the problem. So then I come inside and look around. I finally found a set of instructions for the regulator that were detailed. It clearly stated, unlike my instructions, "Clockwise increases pressure." So now in the morning im going to readjust the screw on the regulator and see if it improves, if so, Im snagging a $25 dollar Holley 1-4psi fuel pressure regulator I found at Oriellys. Tell me what you thing xxxtreme and thanks for all your help. Hope it fixes the problem, we shall find out in the morning xD. Oh and sorry all my posts are so long. I just love to be detailed and thorough.

xxxtreme22r

so the regulator was on there from the start? or you tried putting the regulator on to fix it? where is the vacuum advance hooked up to the distributor? front connection closest to the radiator or the back on closes to the head? Also where is that advance hose hooked up on the other end carburetor or the intake manifold etc? the holley you want is the 12-500, 12-501, 12-804. one is chrome one is billet one is satin. 1-4psi.

Mcy17

No i got a regulator and put it on. The vacuum advanced is hooked closest to the radiator.