82 22R, Half Throttle Hesitation....

10468 Views 8 Replies 6 Participants Last post by jamesn, Mar 4, 2008

Lromine

Discussion Starter · Feb 25, 2008

Please help, anyone!!!!
I have an 82 4X4 that I friggin LOVE... This is the best truck I have ever had, and I have had lots of them included brand new one... So, if anyone can help, that would be awesome...
About 1 yr ago, I took the truck apart down to the frame to paint it and do all the usual offroad stuff to it. Before I took it apart, it ran great after I did MOST of the vacuum lines, snaked out the EGR components, and replaced the timing chain...

Now that I am ready to use it, it now has developed a hesitation at 1/4 to 1/2 throttle. If I mash it, it seems to rev out just fine.... I did a quick tune up on it; air/ fuel filter, cleaned the cap and rotor (Also replaced prior to dismatle)... It seems to be getting fuel if I look in the carb window.... I am about to try to clean the Vacuum modulator, but I am not too optomistic that clening this will fix my issue. I am really thinking that the carb may need a once over since while it was sitting I ran the fuel level down to next to nothing and only started it a few times to move it.... Any thoughts???? FYI, I'm in CA....

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qsd-dan

· #2 · Feb 26, 2008

Have you checked your vacuum advance diaphragms for leaks? Usually it's the inner diaphragm (the one closest to the motor) that goes bad first. Both should have perfect vacuum indefinitely.

Yeah, the carb may need to be rebuilt. It' always a good idea to do it if you have recently purchased the truck, or if it hasn't been rebuilt in several years. The new formulation of fuel really takes it toll on the rubber parts and gaskets.

http://www.bluebassdesign.com/boonin/carb_faq/

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remushair

· #3 · Feb 27, 2008

I'm having a similar issue after replacing the all timing compnents, fuel pump and filter. It ran fine for quite some time afterwards then randomly started running like ass. Runs and starts great any weather, but as soon as the temp gauge starts to show any warmth in the engine, it sputters and trys to die until I mash the throttle. It doesn't like to stay at asteady speed either... at first I thought it was my AAP diaphram, but it's not leaking and I have fuel in my sight glass. I was told that because my truck has sat for long periods of time off and on (2-5 months) that I could have a lot of varnish build up in the carb. But the vacuum advance could very well be a problem. Also I need to adjust my hot valve lash and recheck my timing as well as fix a minor exhaust leak.

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remushair

· #4 · Feb 27, 2008

it also idles fine at any temp once the engine warms up. But push the gas partially and sputter putter, floor it, backfire boom, tire squeeling, tire smoke, acceleration. That's about how it happens.

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fourwd1

· #5 · Feb 28, 2008

The gaskets in the carbs dry out with old age, especially after sitting unused for a while. A good rebuild may help in all these cases. Don't scrimp on a rebuild kit. Expect to pay at least $50. If they don't ask for the number on the carb tag, go elsewhere.

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myyota

· #6 · Feb 28, 2008

Check your vacuum lines and make sure they are hooked up corectly, also check your vacuum advance, if its bad it can cause problems, and let me tell you this, if its bad and you have to buy a new one its a very expensive part, i tried every parts store in my area and no one could get it so i had to order it from the dealer, and it was 200 dollars, talk about sticker shock ?.

were in california are you located ?.

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remushair

· #7 · Feb 28, 2008

I think I figured my problem out. My choke works, but my secondary throttle plate is at about a 45 degree tilt at idle, but when I rev the engine, the throttle plate closes instead of opening. I held it open with my finger and revved it again and no hesitation. I'm getting a carb rebuild kit and am going to make sure the linkages are all hooked up correctly.

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Lromine

Discussion Starter · #8 · Mar 3, 2008

Back on the road

Well,
After all of your great posts, I simply went down the Kragen and bought some berryman's fuel system cleaner. Filled it up with 91 and the cleaner and within 2 miles it seems to run fine now. I guess that there was some varnish in the carb. Nonetheless, I am going to buy a rebuild kit and do the dead. Besides, it's been awhile since I've rebuilt a carb and it should be fun.
That being said, I have anohter question for you guys; My fast idle has never worked. Well, actually it has worked a couple of times in the past 2 years. However, I am guessing that diaphram is fine because the fast idel does work when I turn on the air conditioning. So, I am thinkning the TSTV valve?????????? Any suggestions??? By the way, to the guy that asked, I'm in San Diego but I have a weekend place in Ocotillo and this is where I use the rig....

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jamesn

· #9 · Mar 4, 2008

remushair said:
I think I figured my problem out. My choke works, but my secondary throttle plate is at about a 45 degree tilt at idle, but when I rev the engine, the throttle plate closes instead of opening. I held it open with my finger and revved it again and no hesitation. I'm getting a carb rebuild kit and am going to make sure the linkages are all hooked up correctly.

if i remember correctly, the secondary throttle blade only opens under load. revving the engine in neutral will not do it. it has to be driven. the B12 is some good stuff. i would use a shot of marvel mystery oil too for good measure. MMO is super cheap so use it strong. you will not hurt anything. be careful with the B12 chemtool though. follow label instructions.

also, try some FP60 on your truck. you only add an ounce to 5 gallons. its available at LCDinc.com and its some really neat stuff. you will get an extra 2-3 mpg out of it and it will clean the entire fuel system and combustion chambers as well. i use it on my acuras and hondas and they really seem to like it.

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