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I installed a Weber on my '87 YJ with a 4.2 258 last Sunday and it is not idling too well. I have a FPR on it. It is deisling when shut off and it jumps up and down during idle. I resealed it in the middle of the week, thinking that was the problem and the seal is much better now. When i spray carb cleaner on the gaskets it does not change the idle speed. I'm thinking either it's the jet sizes or maybe it is a vacuum issue. I was curious, what am i supposed to do with the two thick hoses that are part of the pulse air system that used to go into the bottom of the stock air filter? one of them seems to have a vaccuum and the other does not. For now I put the two together, but i'm not sure if this is correct. Any ideas? Thanks.

Donny

1987 YJ 258 I6, 5 Speed, TFI Upgrade, MSD 6A, TFX Exhaust, Smitty Sure Steps, Weber to install when it gets a bit warmer
1999 Cherokee Sport, Stock
 

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The dieseling problem is probably from the curb idle speed being adjusted too high. (throttle stop screw) If it is adjusted too high, because it won't idle any lower, try to determine if it is too rich or lean. Simply put the choke on slowley, and it it revs up, you are too lean. If you are sure you don't have any vacuum leaks, and the ignition is correct, you can change the idle fuel jets. You should have moved your dist. vacuum port over to a ported signal. This retards the idle timing, and allows sower idle speeds. Sometimes you can swap the idle fuel jet with the secondary idle fuel jet. The secondary idle fuel jet dosn't do very much. It controlls the smoothness of the secondaries.

As far as the air injection system, looping the check valves will work fine. You don't want to hook them up anymore, they may cause backfiring. The upstream tube was only used during warmups, and the dowmstream air was turned on after the engine is warm. Leaving them hooked up, without any computer controll, may cause a backfire under rapid decell. Plug them both, or loop them together. The vacuum you feel from them just comes from the exhaust pulses, and dosn't have anything to do with the intake.

 

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LEVE brought up a good point above that may effect your idleing problems. Make sure you don't have a manifold vacuum signal going to your egr valve. This will create a massive lean misfire at idle.

 
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as for the pulse-air tubes-
i dis-connected mine from my carter and installed little filters in each- like purolator off shelf at pep boys. then shoved the hoses against the firewall and mounted with plumbers tape/screws. i have to do a smog check once a year and i "dummy" them back up under my air filter canister. i believe they both suck air from the clean filtered air and shove into the exhaust to result a cleaner or dilluted exhaust. my pulse air valves were going bad and "pukeing" crap back into my carb!/wwwthreads_images/icons/smile.gif

steve
 
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