Ok.. my setup is using the 4th gen lower.. with the 4th gen IACV.. 5th gen TB.. and i got everything on and bolted up.. went to start it up and i have a idle issue.. im thinking it is a possible vacuum leak.. but i am also concerned about the way i have it set up.. i am wondering whether or not it matters having the EVAP and IACV coming from the same vacuum source.. because so far i can not find a vacuum leak.. and thats the only thing i have done different than other swaps.. usually ppl have hooked the IACV up to one vacuum source and the EVAP up to another source.. does it matter if they are on the same source??? thanks in advance for any help/advice.. -Jason

 

what type of ideling are you having. I have the same problem from dek swap that I finished this weekend!

 

Umm...the IACV doesn't use vacuum, it puts air INTO the manifold so that the engine has oxygen to keep it running when the throttle is closed, hence it's name (Idle Air Control Valve). You can't have it pushing air into the same nipple as something else that is trying to get vacuum, it just won't work. There are plenty of nipples on the manifold, why are you using one for two things?

 

thanks for the help. jason and i have been working on this for a while and we aren't thinking very clearly, you know 20 hours of regular work in two days and then staying up late to do the swap. thanks for getting us straightend out.

 

Yeah, try that first and then we can help troubleshoot you from there. All the major things (IACV, EVAP, brake booster, PCV) should have their own nipple on the manifold. Smaller things can share, but try not to use more than 2 on a nipple. I think the only thing I have T'd off are the FPR and something Cali-related on my car, but they are T'd off going to the bottom of the throttlebody (which is how they are setup stock for me...and I say this because I eliminated my vacuum gallery).

 

ok man.. we got everything straight now.. and did what you had told us about the iacv.. (according to the vacuum setup on your website) using the 4th gen iacv we have it going from the midpipe to point #3 on the intake manifold.. point #1 we have running to the brake booster and then a T that EVAP.. #2 is blocked off.. #4 we have running to the PCV.. and #5 broke off so i just blocked it off (and have checked for vacuums leaks - its fine).. we have the VIAS air line going to the midpipe.. also we have the 5th gen tps running on the 5th TB.. i dont know if this is a issue with the swap.. as far as i have researched this doesnt affect anything as long as its working.. i dont know im right on that.. couldnt find anyone saying not to do it.. but all in all this is how we have everything setup.. but something is keeping it from idling steady.. it runs.. and it will sit there and idle but doesnt idle smoothly.. but anything past 1k rpms is great.. it smooths out.. so this makes me think it has a vacuum leak or something.. oh yeah its also running the CEL the codes are.. 0171 and 1105 .. one was a bank one too lean and the other was a 1105 transmission code.. let me know what you think.. i ended up driving it home last night after working on it until 1:30 in the morning.. and still cant get it idling right..

 

How do you have 2 of the 5 blocked off? I thought each was needed to get the vacuum right...?

 

This is what I want to know as well. Things like duct tape, for example, are not good for sealing of vacuum leaks, not even temporarily (ask me how I know )

Also, are you not using EVAP at all? One of the 2 ports you blocked off (typically #4 or #5 is used) should have the EVAP hooked up to it.

 

yes vacuum port #5 broke off and has some tape around it.. and yes i have the evap hooked up.. the brake booster is hooked up to port #1 and the evap T's into the brake booster line.. what i plan on doing is making the whole on port #5 bigger like most ppl do, and then hooking up the IACV there.. then i will have another spot available to hook up the evap directly to the manifold like others have done.. but i was just reading the definitions of the codes on my FSM and one of the culprits for one of the codes is a vacuum leak.. which i still think i have.. dont know.. i have some things to change and redo.. and we will see what happens.. i was just looking for suggestions or a second opinion to make i wasnt doing anything wrong or not thinking clearly.. thanks guys..

 

I definitely wouldn't be T-ing anything into the brake booster, just to be safe. Not saying it isn't possible, but it would definitely have me nervous. I would say you've got some good plans laid out, just get that nipple on #5 and use it instead of T-ing things.

I would say that tape is causing your vacuum leak (and therefore idle issues). I had my lower PCV hose taped up like that for a month or two before I did my swap (because it was too hard to get to and too short to maneuver due to it's location) and although it ran just fine, the idle was crap sometimes.

 

yup, T-ing off the brake booster is a big nono, Speaking from experience

 

alright i will be sure to fix that then guys.. thanks again.. also does it matter if i am using a 5th gen tps.. or do i need to use my 4th gen?

 

switch over to the 4G TPS, and adjust it properly..

 

Yea I noticed that some of my nipples are missing on my 5th UIM but I'm going to drill all of them so I dont have to t anything. I would assume that t-ing really just doesnt give enough vacuum.

 

In some cases, yes. In others, such as some of the stuff using real tiny hoses, it doesn't really need a set amount of vacuum, it just needs to see that there is vacuum period.

 

Gotcha. See all this hoses and vacuums and **** is what confuses me with this swap...I really dont know about the hoses as much. Dont want to f it all up.

 

Yeah, well, from now on I'm advising people to use ONLY brass nipples for their swaps. I used plastic ones at the reccomendation of the guy who made my adapter plates, and today the one I had on the manifold for my IACV snapped in half as I pulled the hose off

 

metal nipples....check

 

I thought that was a given?

 

Ehh, I didn't think so. If you're not a brute like me (haha) you can get away with plastic fittings.

 

the pic i refered to in post #6 is on tatankos website.. but i could not copy it.. wouldnt let me.. so go to his website and you will see it..

 

My bad. I still have no-right-click in the code

 

hey what size nipple did you replace #5 port with?? and also what size nipple does everyone use on the back of the 4th gen IACV adapter plate.. i dont want to be to small and starve it for air at idle..

 

I replaced it with a 1/2" nipple. I've found it to be overkill depending how you setup your IACV, but it's good security. You'll want a 1/2" nipple on the back of the IACV plate then, too, to keep the whole system 1/2".

 

What's this talk about nipple on the back of the plate? I thought #5 went right to the IACV?

 

No no no. It's on the back of the manifold, on the same area the throttlebody bolts to the manifold. I replaced the stock one with a larger plastic 1/2" one and it snapped off when I went to remove a hose from it yesterday.

Unless you're referring to what I just said above. There has to be a nipple on the back of the IACV plate. How else do you think you run a hose from the manifold to the IACV? The IACV doesn't have a nipple stock, just a "port." The IACV plate makes it so that port is "focused" into a nipple that a hose can be attached to.

 

Gotta check because I dont remember seeing a nipple on the IACV plate...I do know the nipple your talking about, #5. I want to remove all the stock nipples and replace them with the metal ones. Should I just cut them off?

 

Replacing them all isn't necessary and in some cases may actually be a bad thing. Why cut all of them off when some don't need to be changed out and as-is are very structurally strong.

Picture of IACV plate w/ nipple (notice it sticking up?):

 

Guess thats true. Good point. Well the #3 has to be drilled so I'll do a metal nipple there. The I guess metal for the 1/2 #5. Yeah my adapter plate is different. It's a full block instead of two seperate plates....I havn't seen that nipple on mine. What do I do if it isnt there?

 

Yours is just one block? In that case do you mean your IACV bolts to that block? You wouldn't need a nipple or anything then at all, not even on the manifold, because you'd have it mounted like stock where it's directly into the airpath rather than mounted remotely.

 

i'll take a pic tomorrow. instead of two different plates, the block bolts to the tb part of the uim. Then the tb goes out the front of that. Off to the side tho, the IACV bolts right to the block.