beefhole

iTrader: (29)

And we begin!

The car fires up within 3 seconds of cranking EVERY TIME I ever tried starting it for the past 3 weeks. I do not have to tap the gas, hold the throttle or anything so... I must have done something right!

It will idle steady between 750-1000 rpm depending on where I adjust the stop screw. I like to have it set around 900.

I run a Haltech E6k, have no emissions and everything you can think of is blocked off. My gauge is telling me I am not pulling any vacuum at idle I am also very rich (low 11's). However, if I TAP the throttle I will pull 10-15 inches immediately and I will lean out between 12-13. Same for driving. I can drive with very little pedal and the car will have 15 inches of vacuum and be in the 12-13 range again. My brakes are very stiff, i'd imagine because the booster is not receiving vacuum. I can still stop but I have to concentrate and press very hard.

Now, I haven't had much time to diagnose and I will need to pressure test for a leak somewhere if there is one. But can anyone give an idea of why my car acts this way? I figured a leak would affect the vacuum and still read 0 even if I hit the gas no?

Now I'm thinking of something else also... I can adjust my idle with the stop screw and if I undo it all the way the car will die. What if I adjust my idle with my throttle cable? Maybe it would have vacuum. Plus with the Haltech I can zero the TPS. Is that a proper way to do things or would I be "ignoring" the problem?

Comments, questions, "you're retarded", anyone anything?

clokker

iTrader: (2)

Don't overlook the obvious...the booster line check valve.

In theory, this valve allows the booster to store enough vacuum for a couple of stops even without a vacuum source present.
If you're still running the original booster vac line with the integrated check valve, it'd be easy and cheap to get a new valve at the parts store and see if it helps.

beefhole

iTrader: (29)

At this point I won't rule that out as far the booster goes. Is there a way to test this valve though before I go to my local auto parts store and the people look at me like I have 2 heads?

clokker

iTrader: (2)

Well, you can remove the hose and blow through it.
You should be able to blow from the booster side to the engine side but not vice-versa.

Unfortunately this doesn't tell you if the valve will hold a vacuum.
A generic check valve (doesn't have to be internal to the hose- in fact, most aren't) shouldn't cost more than $5 or so (I'd guess even cheaper) and any clerk who doesn't know what one is should be shot...you have my permission, aim for the torso.

beefhole

iTrader: (29)

Hah, sounds good. I think I rember seeing a spare in my box'o'parts, it was green and white, plus it had that arrow on it. I do see the valve too on the line and it has the marking for 'E ->' or something like that.

Any other ideas besides my brakes as far as the other issues?

clokker

iTrader: (2)

Not offhand.
Not really a rotary expert.

clokker

iTrader: (2)

That sounds more like one of the check valves from the solenoid rack.
I think you'll find it's too small to work in your booster hose.

Rextasee

i think your booster is internally vac leaking... just changed mine for the 2nd time w/a new one (dont go used) which had the same problems and now its fine. got more power and my brakes are cherry now. s4/s5 na/boostn?

beefhole

iTrader: (29)

I didn't get a chance to pressure check yet, keep getting home after dark

I just want to pressure check with all my lines hooked up and then I can narrow down 1 by 1. I know it's a vacuum leak somewhere.

scrip7

iTrader: (6)

If you have a leaking brake booster diaphragm you can pinch the vacuum line closed going to the booster with needlenose pliers with the engine idling the idle speed will slow down. If the booster is good, you should see no change. Also check the other booster vacuum line on the other end of the metal pipe. The hose that connects from the pipe to the engine on the passenger side. Often this hose cracks on the back side where you can't see it. It can cause low vacuum readings and a stiff brake pedal.

KhanArtisT

iTrader: (2)

Good idea, don't pinch the hose though, stick a bolt in it.

First of all, if the vacuum gauge reads 0 at idle, you have a problem with your gauge or the source because the engine cannot idle at 0 vacuum. It should read 11-18 roughly at idle and max out the gauge under deceleration.

Secondly, you should get a second vacuum gauge from a parts store and check it for yourself. Even if you were pulling low vacuum at idle (-10), you should still get a couple good pumps from the brakes after a short drive since the vacuum you pull on deceleration would fill up the booster and the check valve would seal it.

beefhole

iTrader: (29)

I can check vac/pressure off the haltech map sensor too no (laptop hooked up)?

When I first let my rebuild idle I blocked off the UIM vac source for the brake booster, and I still had this problem. I don't know for sure, but I'm thinking I have a leak somewhere else. I suspect the BOV. I will hopefully check tonight.

HAILERS2

Your boost gauge is picking off the *vacuum* from a source prior to the throttle plates. Not all nipples on the throttle body go to sources after the throttle plates. Some are connected to ports Prior to the throttle plates.............that explains the zip vacuum at idle. If the boost guage was connected to a nipple that gets its source after the throttle plates, then you'd have vacuum when idling.

As for the brake booster vacuum line, you need to explain in detail where the hose for the brake booster is attached to the engine/throttle body/intake manifold/wherever else.

beefhole

iTrader: (29)

My boost gauge is connected to one of the 3 nipples on the front of the UIM. I was unaware of any nipples to even connect to on the TB. I thought this to be correct but I will check again.

My brake booster is connected to the only large nipple on the top of the UIM. It is on the backside if you are looking at the front of the car. Hope I am explaining OK (an am remembering correctly). I will take a picture when I am home tonight.

HAILERS2

I must have missed it or forgot. What year/series is the engine and is it USA or JDM?

beefhole

iTrader: (29)

Well, the way it is now I don't think it makes a difference. Everything is blocked off. No BAC either. It's S4 plates though with J-spec housings.

I fiddled with the car while I still had some light. I hooked up my laptop and started it up. I noticed my Haltech was reading 15-16 inches of vacuum, but my gauge had 0 as you already know. Something is wrong here. My haltech feeds off of the one nipple on the "side" of the UIM. If you are looking at the car from the passenger fender. So it's getting a good reading there. I disconnected my boost gauge from the front of the UIM (capped the nipple off) and teed into the haltech MAP line. Success! I was pulling good vacuum under very light throttle and when I let off the gas it pulled over 20 then settled again at 16. My gauge and the haltech now read the same. The UIM front nipples must not be a good source for a gauge then?

I still have my BOV hooked up there. Should I move it? I am looking at a diagram I saved that was posted here. It looks like on stock cars, the BOV is fed via the nipple on the side, where I have my gauge and MAP sensor hooked up. Should I tee into that again and run the BOV there, capping all Nipples on the front of the UIM? Perhaps that is another issue to fix.

Finally, my brakes. I was so excited about my gauge "working" I started playing with my haltech settings. I was able to lean out my lower RPM ratios by playing with the fuel maps. Kind of what my goal ultimately was tonight as my idle was very rich. I was able to get it to idle in the mid 12's. However, I am new to this fine tuning so it may all be in vain. Ultimately I will bring the car to be tuned to someone who knows what they are doing.

Anyway I had so much fun playing with the bars on my maps that I ran out of light. I didn't diagnose the brakes still.

I am looking through the manuals I can't seem to find the booster vac source though. It's not under the brakes section??

HAILERS2

Brake booster source is shown in the three jpg attached. For a series four turbo car. NOT series five car.

On the front of the throttle body (not intake manifold) are three nipples one above the other. Two of the three are vacuum sources as long as the black phenolic spacer on the throttle body has not been installed wrong.

On the back of the throttle body are four metal nipples one above the other. The very bottom one is the ONLY one that is vacuum. Some models only have three nipples back there. Still, the bottom one is the only one with vacuum. The others source air from before the throttle plates.

misterstyx69

iTrader: (142)

If you got "brakes"per say and they feel good,But When you Go to Hit them when Rolling,and they Feel like you Have to grab the steering wheel and PUSSSHHH on the brakes,because they just don't want to stop..the Solution is very Simple
you put that Rubber hose From the brake booster to the steel Firewall line On Backwards!
it is not Allowing vaccuum..
Turn it around and it will now give the boster vacuum from the intake to help you stop.
I did that and it took me 3 days to figure out,,The check valve is Located IN that Rubber S shaped line.

KhanArtisT

iTrader: (2)

Yes you need to change BOV reference line. If you want to be sure all you have to do is start the car and feel for vacuum on the port...

Its not that the rest of the vacuum ports aren't "good sources", they have a passageway from the spacer that allows them to draw pre-TB air.

beefhole

iTrader: (29)

No wonder... I think my brake booster feed on the back of the UIM isn't even there!

Thanks guys I will check this all out tonight.

HAILERS2

All those jpgs I attached were of SERIES FOUR TURBO intake manifolds. The series five has it's brake booster nipple .....somewhere else. like on the lower intake manifold??? I think it's on their lower intake manifold and on the rear of that manifold with a "elbow" fitting. That's just a Guess, so it's not a certain thing.

HAILERS2

In the first jpg of a USA series five Turbo engine, number thirteen is the brake booster feed line.

Second jpg is series four brake booster check valve.

It's starting to sound like you have a series five turbo upper intake manifold??? Got me.

beefhole

iTrader: (29)

I must say I am second guessing myself regarding the lower UIM source for the BB. I really don't remember anymore if I capped it off. I think I may have accidentally. I will know for sure tonight.

Hailers, those diagrams/pics are really helpful, thanks.

beefhole

iTrader: (29)

OK, update to those who care!
I have series 4 manifolds. I had the vac source for the BB in the back of the UIM, it was just covered in my harness it was difficult to see (and remember). So.... I hooked up my BB line to that and voila, brakes!

While we are here, still curious about some other sources for vacuum. I have my BOV hooked up to the bottom nipple on the front of the UIM. Is that a good spot? I popped it off the BOV and it was pulling vacuum, I could feel it on my finger.

Also, where should I put my wastegate line?

Thanks guys for your help.

HAILERS

Of the nipples on the front, the top and bottom ones should be vacuum for sure. The middle one.......no as far as vacuum goes. But if boosting, it would show pressure.

ON the back, only the bottom one has vacuum as mentioned in the mans post somewhere above.

I'll let someone else do the wastegate line.