You don't have to worry about the the heat shiel on the exhaust manifold. I have run mine for years without that piping even in place. As for the vacuum lines, just plug it off so you don't create a leak.

 

I was looking under the hood yesterday and found that the vacuum line attatched to the flapper doesnt even attatch to anything on the other end. Im not even sure where it is supposed to attatch to. lol. I also took a look at the code the CEL was throwing and it showed up as a code 34. Im pretty sure that has something to do with my vacuum leak I am convinced I have somewhere. I plan on running all new vacuum lines when I upgrade to the holley TBI as soon as the new butterfly plates come in. Any suggestions where to buy tubing and connectors?

 

The hose should have ran up to a t on the back side of the TB, mine was easier to reach from the pass side with the cleaner removed. You can get vacuum line at any parts store.

code 34 points to the vacuum on the MAP. First make sure the hose is connected to the MAP and to the port on the TB thats in front but points to the drivers front corner. Nothing should the teed off this line as it should only serve the MAP sensor. Also make sure the electrical plug it plugged in good and tight. If both are good you might have a bad MAP.



Good luck with the high dollar holley, I went the cheapo route and put a 4.3 TB on a bored out 2.8 intake.

 

I will have to take some pics of the vacuum lines and show you guys to see if they are even hooked up right. I acquired my blazer for free and the owners before me did an engine swap in their garage. Im pretty sure some things are not right, especially after finding duct tape holding some things together. lol.

The holley only cost me $20 (the cost of new butterfly plates). The person who is giving the TBI to me messed up the butterfly plates and no longer has a use for it. I gladly took it for free.

Oh, ad just for clarification, is the MAP the piece that has 2 vacuum connectors on the bottom and resides on the intake above the TBI inside the air filter?

 

this is my MAP, yours should be the same and in the same spot (just not with a chrome breather). Should be only one vac line and notice where it runs and doesn't tee.


Good find on the holley. If you go to www.autozone.com and regsiter your truck they have the simple haynes manual online for free and it has vac diagrams.

 

Oh ok. I know for a fact there isnt a tee on my vac line to the map. I know that the electrical connector on the other hand is held on by duct tape. Someone in the owners history must have broken the plastic tab that holds it on. Thanks for all the help. Im going to register at the site now. I have a haynes manual but im not really certain how to read the vac diagram. Maybe the autozone version will be the "vac diagram for dummies" type. lol.