'82 Carbreutor Jetting
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From: Houston
'82 Carbreutor Jetting
I posted this in the Windsor smallblock section but I am crossposting it here as I did not get a reply and figure people here might be able to answer.
For the most part what jet sizing should a 302 V8 with a 2bbl carb from '82 be? If I wanted to go up one or two sizes to correct my stumble from idle which sizes would be recommended.
What happened is this, I adjusted the accelerator pump back during summer up to the highest setting which was the next setting and it correct 90% of the rpm drop when stepping on the accelerator pedal from a stand still. But with cold weather here even with the engine hot there is a rpm drop as bad as it used to be in summer before I moved the accelerator pump up one notch.
What I did noticed how ever is with the choke closed both cold and hot the engine ran great and had great acceleration with zero rpm drop. I am starting to think maybe the jetting needs to be upped one or two sizes. This is a rebuilt engine and that could be why I need to up one or two sizes. I also dont think I should adjust the mixture screws out more for this cold weather cause I cant remember but I think I am already at 5 turns out from bottom and dont want to go more than that.
For the most part what jet sizing should a 302 V8 with a 2bbl carb from '82 be? If I wanted to go up one or two sizes to correct my stumble from idle which sizes would be recommended.
What happened is this, I adjusted the accelerator pump back during summer up to the highest setting which was the next setting and it correct 90% of the rpm drop when stepping on the accelerator pedal from a stand still. But with cold weather here even with the engine hot there is a rpm drop as bad as it used to be in summer before I moved the accelerator pump up one notch.
What I did noticed how ever is with the choke closed both cold and hot the engine ran great and had great acceleration with zero rpm drop. I am starting to think maybe the jetting needs to be upped one or two sizes. This is a rebuilt engine and that could be why I need to up one or two sizes. I also dont think I should adjust the mixture screws out more for this cold weather cause I cant remember but I think I am already at 5 turns out from bottom and dont want to go more than that.
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From: Virginia
Changing the main jets will not fix your problem. They add fuel through the main venturi, and at idle and when you step on it, there is no fuel being added by the main venturi, that is what the accel pump is for. It has to be there till the engine starts pulling enough air through the engine to make the main venturi start working.
Have you ever rebuilt the carb? The accel pump diaphragms can get old and stiff, especially when running the alcohol fuels. Cleaning the carb can also make the accel pump work better if the check valves in the carb are old and sluggish. Ford usually used a rubber flap for one of the accel check valves.
Have you ever rebuilt the carb? The accel pump diaphragms can get old and stiff, especially when running the alcohol fuels. Cleaning the carb can also make the accel pump work better if the check valves in the carb are old and sluggish. Ford usually used a rubber flap for one of the accel check valves.
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Lead Driver
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From: Houston
Changing the main jets will not fix your problem. They add fuel through the main venturi, and at idle and when you step on it, there is no fuel being added by the main venturi, that is what the accel pump is for. It has to be there till the engine starts pulling enough air through the engine to make the main venturi start working.
Have you ever rebuilt the carb? The accel pump diaphragms can get old and stiff, especially when running the alcohol fuels. Cleaning the carb can also make the accel pump work better if the check valves in the carb are old and sluggish. Ford usually used a rubber flap for one of the accel check valves.
Have you ever rebuilt the carb? The accel pump diaphragms can get old and stiff, especially when running the alcohol fuels. Cleaning the carb can also make the accel pump work better if the check valves in the carb are old and sluggish. Ford usually used a rubber flap for one of the accel check valves.
Now on the thing about the accelerator pump, the pump itself has had the diaphragm replaced three times so far, this is the third one on there. The first two started leaking and this one is the last one and it seemed like it might be leaking a little when I did the adjustment during the summer to the accelerator pump. hasnt yet though. If I set the idle mixture down to 3 turns the truck lacks power and it did the hesitation more than it did when I turned it out and ran a richer idle mixture. This is why I am thinking if I up the size of the jets one or two sizes I can lean out the idle mixture and it should work fine seeing as enriching the idle circuits removed more of the hesitation.
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From: Houston
I already checked timing, vacuum leaks, even set fuel mixture via vacuum and still have this hesitation in some form or another either very bad or almost not noticeable but still there. The accelerator pump adjustment to the next level did help out for the most part and made a huge difference. But its still there and have to be careful if the choke opens and the engine is not warm enough it will stumble enough that if a car is coming fast you dont want to pull out and try to beat them like you would if the engine was fully warmed up
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From: Houston
I for some reason keep thinking its in the fuel system and not an emission system. There is no converter anymore, that was hacked off a year and a half ago and the truck was straight piped with a thrust glasspack and a turn down exhaust tip. The hesitation was there before and after the cat was removed and the exhaust was changed. So I am not sure if emission system could be causing it, I will how ever take a look into the EGR but I dont think its functional but it is hooked up correctly last time I checked.
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Just a thought EGR will mess with the combustion mix . If not coming at the proper time , problems .
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From: Houston
I had one stick open on my Mercury, when I came to a stop at a red light the engine just stalled out, and not running rough I never felt the engine drop dead. I hit the throttle with the light turned green and nothing thats when I saw the tach was reading 0.
But I will give it a go. If I can correct the cold weather bringing this out more I might upgrade to an aftermarket 2bbl carb, like a 500 CFM Holley 2bbl. Might improve performance till the engine needs to be overhauled and I swap in a oem style 4bbl intake.
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From: Houston
When I set the idle mixture using a vacuum gauge I am estimating cause my old gauge sits below 0 inches by a good two inches and I was in the green on this old gauge reading 18 inches of vacuum so I am estimating I was around 20 to 22 inches of vacuum which is a rough estimate.
I really need to put a new gauge on my black friday list of tools to buy.
Tomorrow at work appears to be a dead slow day for me so I will pull the vacuum hose at the EGR valve and see if theres vacuum there at idle. If there isnt then I will pull the EGR valve off to check for leaks. But the engine runs too smooth and Ive never seen an EGR valve open at idle actually idle dead smooth. The tach looks like a picture in this case. But there is always a first time for everything.
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From: Tennessee
I bought an 84 Camaro for $300 in 92 . The guy put a bunch of parts and 3 carbs on it before he sold it . He was Pi$$ed When he saw me the next day driving it . EGR valve had a piece of carbon holding it open ..... He had the vac already off it , so ruled it out .
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From: Houston
Thats why I am thinking to check it, if it doesnt work or if it does work I need to rule out the valve being held open just a little. Maybe not enough to cause it to run like **** or surge up and down but just enough to cause my problem.