Vac line Q....

[rwtf]

Alright, s14 sr20, my boost gauge is only reading a -10 or so vac, from what I've read it should be 20....

There is only 3 vac sources being used...

First is of course the FPR
Second is the BOV on its own line under the TB
Third goes from the WG then Ts to the boost guage then goes to the second spot under the TB.

Is this right? I know the 1st and 2nd are but the 3rd I'm not sure about....

It idles kinda rough and backfires a shit ton under boost.:naw:

[jr_ss]

The vacuum sources are lines that come from the middle of the intake manifold. If you are using the ports on the throttle body, they only see boost reference.

[rwtf]

not sure what you mean....

[jr_ss]

Alright, there are two ports on the actual throttle body itself. They only see boost because they are before the throttle plate. There are 3 metal hardlines running from under the IM towards the throttle body. One is for your IACV the other small lines are vac sources to be used for whatever you see fit.

[rwtf]

yeah, the other two are what i'm talking about...

[jr_ss]

Do you have any open lines? There is also one for the PCV and one for the brake booster, but those are located on the back and side of the IM. What type of BOV are you running? Is it vented to atmosphere or plumbed back into the intake tract after the MAF/before the tubo?

[91ka24]

You shouldn't run your boost gauge inline with your wg. Boost gauges need to see there reading from the intake manifold directly. So on your tb there are 2 vac ports, 1 needs to run to a t fitting, then off of the t, one lines goes to the fpr, the other port goes to your boost gauge.then the 2nd nipple on the tb needs to run to your bov. Now go get a brass fitting with a barb and drill a hole on the under side of your hot pipe,thread in the brass fitting, then run a vac line straight from that brass fitting to your wg. If you even run a boost controller just t it in between that fitting and your wg.

[rwtf]

alright i'll post a pic of how its setup atm...

[Mikester]

So on your tb there are 2 vac ports, 1 needs to run to a t fitting, then off of the t, one lines goes to the fpr, the other port goes to your boost gauge.

Miguel?

Anyway, although it can be done; it's never a good idea to tee anything off the FPR source; except maybe in a short-term pinch. Don't get me wrong- I drove like that for longer than I'd like to admit in Japan & never had any problems. However, I was lucky and quite frankly I didn't know any better 'till later in life. If I WERE to have developed a vac/boost leak there, the results could very likely have been catastrophic. The FPR needs to be able to add pressure as the boost goes up... If it's tee'd & there is a leak at/in anything connected to it; shit leans out real quick and bad stuff happens in the combustion chambers...

[jr_ss]

You shouldn't run your boost gauge inline with your wg. Boost gauges need to see there reading from the intake manifold directly. So on your tb there are 2 vac ports, 1 needs to run to a t fitting, then off of the t, one lines goes to the fpr, the other port goes to your boost gauge.then the 2nd nipple on the tb needs to run to your bov. Now go get a brass fitting with a barb and drill a hole on the under side of your hot pipe,thread in the brass fitting, then run a vac line straight from that brass fitting to your wg. If you even run a boost controller just t it in between that fitting and your wg.

The ports on the S14 SR throttle body are not vac sources. They are drilled right at the throttle plate. They must be after the throttle plate to see vacuum.

Never T off on your FPR line. That should remain on its on line at all times.

The wastegate only needs a boost reference, so it does not need vacuum. (Use one of the throttle body ports).

Like I said previously, those metal hardlines that run from underneath the upper manifold are vacuum sources. The FPR should have its own source on the side of the IM. Use the two below for your BOV, boost gauge, or whatever vacuum needs you have.

[rwtf]

Well the reason why i'm asking is because i'm reading like -7in/hg vac and it should be -20 or so.... also it breaks up under boost at 4k then stops wanting to go and backfires like a mofo.:-/

[Mikester]

Make SURE your FPR is plumbed to the intake properly; then look elsewhere. Sounds like you have a leak somewhere.

[rwtf]

yeah its on its own vac source on the inside part of the intake.

[rwtf]

Here is my vac line setup....

http://img14.imageshack.us/img14/3961/img0016vac.jpg

[jr_ss]

Wastegate doesn't need vacuum. As stated, there are two nipples on the throttle body you can use for that.

Have you done a leak down or comp test? Was the car running fine then lost vac at idle? Typically, vac at idle tells you how healthy your motor is. With you only pulling -10in/hg it leads me to believe you have a large vac/boost leak somewhere. Take a spray bottle with some soapy water with the car running and hit your couplers or gasket areas.

Put your hand over the BOV discharge area at idle. If you feel air being pushed out, there is part of your issue. What is mech timing set at? How about idle rpm? Is it at 750?

[rwtf]

oh okay.

when I first crank it its jumps to 2k idle then slowly goes down to around 1k, and has a rough idle, which leads to me to think vac leak also, I remember the same crap on my KAs.

[rwtf]

What are some common vac leaks on a s14 sr20?

Also whats the best way to find them? Can i use brake cleaner?

[Mikester]

^^If it has boost and/or vacuum pressure going to/thru it, give it a look. "Common" leak areas depend on the current setup & the current owner ;)

[rwtf]

Well I sprayed MAF cleaner all over my Vac lines and what not and no change in idle, but I do notice it get rougher(if thats a word) when the motor warms up, it will read like -7 in.hg but If I rev it up a tad its hesitant then the vac will go to -10 then slowly go back to -7.

wtf is going on :(

[jr_ss]

Do you have your timing set correctly? It should be 15degrees BTDC.

[rwtf]

I'm not sure. altho I'm certain it is.

[ultimateirving]

I'm not sure. altho I'm certain it is.

This made me lol...


Sounds like a boost leak is ur issue with it breaking up. And I also had an issue with my boost gauge being t'd from the wrong spot it would only read -10 vac.. Then I figured out I had a bonehead extra vac line and after I removed it my gauge would read the normal -18 to. -20 vac..

[rwtf]

I checked all my vac lines, see my pic with crappy ms paint, thats exactly how its setup. And It has a kinda of a rough idle.

[ultimateirving]

When was the last time you boost leak tested it young man?

[rwtf]

Well Ive been doing some research and got what I need to make a tester, also got new vac line i'm going to run.

so the way ive seen to boost leak is make a fitting on the turbo inlet and basicly pressurize the whole system with a Aircompressor.

So do I need to unhook anything and plug it?

[rwtf]

bump :/


msglength

[cotbu]

Block off anything that will allow air into the crank case or valve cover.
You should pressurize the intercooler and pipes 1st, then with a lower pressure check the remaining system. Most common leaks would be BOV and it's flange, any welds, and coupler. spray those with soapy water. If you have leaks repair, then pressurize the rest of the system with about 5-7psi. common leak areas are, fuel injectors insulators, valve cover, brake booster and it's vacuum line and PCV.

I know you said your vac reading is low, but is the idle high?
You may have more problems then just a boost/vac leak. if you pinch the PCV line at idle and the idle lowers and vac increases? Clear indication of a boost/vac leak, but if only the idle decreases well.... you have work to do. Timing could be off, etc.

[Kingtal0n]

One of those vacuum sources is not vacuum source, it is transient throttle source, and only will see vacuum when the throttle is open somewhat. You might already know that, but just in case you overlooked it...

[rwtf]

The idle when first cranking up the car jumps to 2k then slowly creeps down to 1.2k then down to where its suppose to be but the idle is pretty Consistent, I'm going to check my spark plug gap and my timing and run a nipple on the hotpipe for my WG

[rwtf]

BUMP!


fsdfsdgsdfcdgrefg s :(

[ultimateirving]

BUMP!


fsdfsdgsdfcdgrefg s :(

Why are you bumping, you never reported what happened with the boost leak

[rwtf]

I'm about to do a boost leak test tomorrow, and how can I keep from presurizing the crank case? I read that I could take the oil cap off. I just want to do it right the first time.

[dftsilvia]

do you not read other ppl's posts? u are over looking the right info posted in here.
maybe u should try out a thing called reading.
oh and u still dont have your vac lines run right either.

[fufanu180]

When checking for a boost leak I've always used starter fluid to find it. Gotta spray everthing. Couplers, gaskets, seals, the works. Also you definitely need to be sure your timing is set right and your car is idling at 750 at normal running termperature. Maybe your pcv valve? That could be the culprit.

[rwtf]

Alright, I installed a new thermal intake gasket and fixed my vac lines, how I have one for fpr, one for boost gauge, and one for my bov, as for the WG, I drilled a hold in my hot pipe and screwed in a fitting, now my car runs great and i got proper vac.

But now i'm over boosting.... could my fitting be leaking?
http://img197.imageshack.us/img197/8074/2030aw.jpg

[cotbu]

But now i'm over boosting.... could my fitting be leaking?
A boostleak test would confirm this! lol

You might be facing the all debated internal waste gate suck syndrome!
If you have an ebc, it can be tuned out! or you can go external.

[rwtf]

Yeah, I def need to do a boost leak test, also I dont believe the WG is stuck, I can move it a tad by hand, but i'm going to check it with the air compressor. But i'm def glad I got normal vac and its not breaking up under boost.

[cotbu]

Not Stuck! LOL!
The internal Waste gate SUCK syndrome!

Sent from my S3 pumping Darth Stalker v7

[rwtf]

What does that mean lolol.

[jr_ss]

It means they are prone to boost creep...

[rwtf]

by that much? I would see maybe up to 10 psi, but 15?

[rwtf]

found out actuator is messed up, I blew into the hose going to it and makes a whistling noise and there's not actual pressure, it pretty easy to blow into, so i'm gonna get another actuator from a buddy.