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Throttle Body Bypass Procedure

Parts List:
  • (1) 3/8" Barb Fitting
  • (2) 3/8" Vacuum Caps Required Tools:
  • Flathead Screwdriver
  • Needlenose Pliers
  • Rags
  • Patience
  • Maybe a Knife, if you run out of below!
    Okay, I did this install by myself, so its not that difficult. It is a bit of a pain in the #$% to get one of the hoses off, but if you have worked on a Fourth Gen at all you know that nothing is easy to do on these things! All you need to do this mod is a 3/8" barb fitting and two 3/8" vacuum caps. You can find them at your local parts store. Total cost...about $3.00. Please read the note at the end of the page if you have a 96-97 the inlet hose differs from the pictures.

    Okay, first step, pop the hood and this is what you should see!!!:

    Next, disconnect the hose clamp holding the elbow onto the throttle body, & unclip the wire going into the left side of the elbow. Now, you can loosen the clamp on either side of the MAF but, I figured I'd loosen the one on the right side of it, and take the MAF out all together, just so its not around to bang into...considering its such an expensive piece. You'll have to unclip the wire running into the back of it to remove it.

    Now, Remove the clip going into the left front of the throttle body, just to get it out of the way and so you don't damage it.

    This is a pic of the outlet hose, stick a rag under it, squeeze the clamp with needlenose, slide clamp down hose, and slide hose off, be careful to catch the antifreeze that will leak out with the rag, just so it doesn't find its way into the good old optispark!

    Here's a pic of the left side of the throttle body, the fitting to the left of where the electrical connector was...the one with the needlenose on it is the bastard you have to get the hose off of. You really can't get to it very well at all, if you know how to remove the throttle body, you may want to do this it will make this mod a lot easier. Slide the clamp down the hose and try to work the hose off. You can't pull it from underneath and you can't push it down from the good luck. I worked on it for twenty minutes and I finally just sliced the hose down about an inch and it came off...if you want to reattach it for the winter this probably isn't a very good idea, but I ran out of patience!!!

    Here's the two hoses off

    Slide the brass connector on the two hoses

    Slide the clamps back over the ends

    Slide the two vacuum caps over the ends of the throttle body, and reassemble all the air intake equipment. Just slide the two connected hoses down somewhere...just make sure it is away from anything that it could get caught on...belt, fans, or away from Optispark/ shouldn't leak, but if for some reason it does that is the last place you want it to leak on! You are done!

    Special Note to 96-97 LT1 Owners:
    The inlet tube on the passenger side of the engine on at least 96+ is a little different. It still enters the TB in the same place, but instead of turning down and ending, it turns back and runs along next to the fuel rail and then ends(well when I say ends I mean the metal tube ends and the hose connencts there.) I know this because my friend has a 96 and I helped him do his, so I guess for some reason they changed it a little on the later cars. When we did his car I think we took of the TPS-Throttle Position Sensor(see pic above) as well, just to gain access to the hose that I am talking about is a real BI*$% to get to. The TPS is the little P shaped piece on the pass side of the TB, it isn't very tricky, just make sure you take it apart carefully and put it back exactly the way it came out...not sure if you it will fit back in wrong, but it may. There are three torque screws holding it on. Otherwise everything else is the same...Here are some pics that hopefully illustrate it so it is understandable. Email me if you have any questions!

    Okay, here is a far away pic. I drew on where the metal pipe comes from and at the end, where the round ball is approximately where the metal pipe ends and the rubber hose is attached. It then runs into the side of the throttle body. This picture is obviously after the bypass has been completed.

    This pic is of the metal pipe I spoke about above. This is where the rubber hose attaches. This is the 'ball' in the picture above or 'A'

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