So I have literally tried everything to find my loss of vacuum. The only other questionable hose is the vacuum line from the fpr to where ever it goes. I have replaced the section that goes from the regulator to the hardline, but can't trace the hardline much past that or find it's other end. Anyone happen to know where this hardline routes to and if there are any rubber sections with it?

I have physically inspected every hose, visually, and with the motor running and have not been able to find the source. I have also used propane in the case of a leaking gasket or injector seal to no luck. Leakdown test was excellent.

How do you have your evap system setup?

Green line is the FPR routing.

http://home.comcast.net/~r.files/WRX/fpr_line.jpg

Thanks for that picture, the line is ok.

Evap is now the last place to look. I have the original v2 charcoal canister mounted with proper valves up next to the radiator. I also am using the factory RS canister in the back as I have never removed it. Being a 1995 motor into a newer car I lost control of some of the fuel tank/evap stuff in the back. I left the extra wires that this ecu does not control unhooked. The first 5 months of driving the car I experienced no problems and had very good vacuum. Could something have changed back there?

I did disconnect the lowest line (under the top two fuel lines) and blocked it off and experienced no change in vacuum if that matters.

I'll have to go back and look it over, but I am pretty sure that isn't going to work properly. I need topost the details of my solution. I spent a lot of time evaluating both systems. Basically I removed the old WRX canister and use the RS one, but had to removed other parts of the RS system.

But if you haven't changed it, then it's probably not your current problem. Can you repost exactly what your current issue is?

-Rob

Current issue, and the original issue that ultimately caused my short block swap, is low vacuum (14" of Hg tonight) and the need to be in boost or close to it to keep the car moving, especially on the highway.

how about the gasget around the IAC .. just throwing ideas out


how about disconeecting/plugging the charcoal system ..

I used a propane torch and couldn't locate any leaks within the engine bay and checked intake gaskets, iacv gasket, tb gasket, injector seals, etc etc. I also tried plugging the charcoal system with no luck. I have unhooked, checked, and double checked literally every vacuum line in the engine bay, none of which made any difference.

One thing to note is that even with various vacuum lines unhooked it still pulls the same vacuum and runs the same. With such a line unhooked, plugging it makes no difference, and I can even feel the vacuum being pulled through it when I rev the throttle.

DUDE!!! make a leak tester that hooks into your Intake. It will be a cylicone peace that you can tighten onto/after your maf. So you can pressurize your entire engine and heads. Set it to 20PSI and start listening for air escaping. You will have some that goes into the cyl, but other then that it should all be reletively quiet. Then get a bottle of soapy water and spray it around questionable areas, and look for bubbles.


Kirill

silicone, not cylicone. ;)

Tried that too. Only found a leak where my 90 degree intake elbow is cracked on the pre-turbo side so that wouldn't affect vacuum.

I was looking through some Mercruiser service manuals at work and they have an entire section on vacuum readings. The other possiblity with my reading could be an ignition or a cam timing issue. I know the belt is spot on. Could a timing sensor be bad causing erratic timing?

actually it will if air can travel through it ...it will certanly affect the maf reading ... i think i have an elbow if you need one

I've got one as well if you wanna come down this weekend...

Any chance you guys know if there are samco or other inlet hoses for the 20g?? Mine still feels subtle but I have the exact symptoms as kbahus - time to look for leak this weekend when I am installing my headlamp washers.

If anyone has one of these (the 90 that attaches to the turbo inlet) I need one. Jaxx nor Matt have one and mine is cracked bad enough that I can't fix it.

I did some searching on the uk forums and Samco does not make a replacement piece sadly.

I sealed my crack this morning and clamped the pvc lines in the intake elbow better, gained about .5" of vacuum which is good, but it still is not perfect.

Here is another thought, what would happen if the iac valve was not closing fully when the engine was warm? Would this cause a vacuum leak, or since it is routed back into the intake it wouldn't affect vacuum? I noticed this morning as soon as I started my car, the rev's dropped to about 830 as normal and stayed constant while my vacuum gauge fluctuated between 14 and 12 and I could hear the engine fluctuate but couldn't see it fluctuating in the tach.