where should I begin to look for vacuum leaks? This is a new motor with like 6 miles on it. i've finaly gotten it to idle but it's rough and acts like a vacuum leak, I've checked injector seals, and intake manifold for leaks nada, so what next ? where should I go or what should I do ?

 

trace down each of the vacuum lines; test along the length of each line, and at the valve/system it operates, such as the BAC valve, thermovalve, each of the solenoids, the power brake system, cruise control servo, etc.

 

I have a new TII dropped in my car as well. I'm having the same problem. It idles rough and it even dies if its not warmed up.

 

Question, I have installed a front mounted intercooler on the car , so where should the BAC be connected, after the Air Flow Meter , or from the charge pipe on the intercooler ?

 

I have two methods for finding vacuum leaks - a garden hose and a butane refill.




If you use the hose, have it running fairly slowly and, with the engine running, slowly let the water run over pretty much everything. Vacuum hoses, joints in the manifolds, etc. Go slowly, get everything.

With the butane refilll, point and shoot. It's not as volatile as Quick Start so you won't blow yourself to hell if it ignites (hasn't ignited on me yet.) Take your time, work your way around the engine. If the cause of your problem is a vacuum leak, dollars-to-donuts says one of these methods will find it.

 

I did the squirt boddle thing, and the quick start thing , it didnt seem to improve things much. I think it's a combo of problems adding all up to one major issue, it could just be that the motor hasnt seated yet and it needs to seat fully giving both rotors compression front and back, or lines are crossed or it has vacuum leaks.

 

Is there a point where it smooths out? Typically vacuum leaks will only run rough at lower rpm and they smooth out once you get RPM up. Does everything else seem fine? If you can get it to idle smoothly at around 1200 or so I'd put some miles on it and check it again later. Some rebuilds have great compression off the start, other's take some seat time. If it doesn't seem to get better, then i'd start looking into other things. (Timing, etc)

 

It clears out at about 2100 rpm and then pulls strong to redline. But at idle it smells rich, and back fires and stumbles like it's vacuuum, also with the front mounted intercooler I still have to find a place for BAC hook up currently I have it pulling from right behind the airflow meter and I wonder if that maked a difference. im going to have a bung welded on the charge pipe from the turbo like it was on the original top mount.. I've checked TPS, Timing, and spark, as well as air flow meter and idle mixture solenoid.

 

By having it there you won't be affecting your idle. The reason the BAC is plumbed to the charge pipe is that under boost if for any reason the BAC is open (either from pressure, sticks, whatever), that the pressure is equalized on both sides and you're not dumping boost back to the TID. The absolute easiest way I've found to identify a vacuum leak is to push the AFM door open with your hand at idle and see if you can get it to smooth out. It doesn't take a whole lot of movement, but just play around with it and see if it smooths out. If it smooths out and runs like it should, it pretty much tells you to start hunting for the leak. Basically you're just making up for the air that's bypassing the AFM by doing this. If you can't really find a spot that helps, you may have an issue elsewhere.

 

I'm afraid of running the motor too much , especialy driving it if it's lean (AKA vacuum leaks) could it just be that it hasnt seated yet? cause when I pull the plug wire for the rear lead plug it acts like it isnt contributing much to the over all running of the motor. But I will try your air flow meter trick to see if it smooths out . This thing has got me, and not too many thing can get me as i have quite extensive experience in this field. But your little trick will help me . But I will say this the more I run it the better it seems to idle so maybe it just need to seat or maybe i'm just crazy

 

search pressure testing, it will allow you to find leaks with the engine off.

 

Pressure checking? is there a thread on this subject on here that will point me in a direction?

 

Tid ? I will do the Air Flow meter check . and looks like I have some replumbing to do so all will work the way it is supposed to .

 

If it is rich at idle, it is likely not a vacuum leak, they add unmetered air and make the mixture too lean.

Is there spark present on both leading plugs? Fouling? Timing?

 

yeah I've checked spark on both, and power balanced both so so who's contributing the most. lead and trailing on #2 arent contributing that much. acting like low compression.

 

im thinking that low compression in the rear rotor could be causing my condition , and the possibility that the rear seal hasnt fully seated yet is causing the low compression . so should I put more miles on the thing to seat things in more to see if this condition improves.