Installed my Apexi EL EGT P/W/H & Apexi EL Mechanical Boost Gauge today, everything went smooth except when i go wide open it only shows 12.5psi on the gauge. I know the gauge works cause it worked when it came off my Eclipse GST. I tried 2 differant Sources to tap into and i checked all the connections really good. The Vacuum on the gauge works great seems to be normal. The Gauge is real responsive but it stops a1 12-13 everytime. Im at a loss as to where to start trying to figure out this problem.


Also this is still on the Stock Boost Controller. No Reflash that im aware of, although the car was bought used and had mild mods already done to it. All my Mods are listed in my Sig. Thanks for any help guys!!!


Sean

 

No one has any ideas?

 

are you running factory boost? because if you are then that is correct, the boost tapers to about 13 psi

 

This weekend I helped a friend troubleshoot the same problem. Usually a 12-14 psi spike then it would fall to about 11-12 psi. Basically what had happened is that there are two pills in the factory lines. One pill goes after the compressor before the plastic T and one pill goes before the sylinoid inlet which is on the closes inlet of the sylinoid. If you can you should remove the lines and try to squeeze them to see if you can feel any hard spot in them. Be very carefull but the restrictor is very small in the line so check them good.

If you are missing one what I would suggest to rule it out. Just simply go down to Mitsu and order a new set of vacume hoses that run for the turbo&Wastegate Actuator to the boost control sylinoid. I am pretty sure it would fix your issue, it sounds like you are missing a pill or you have the line turned around backwards. If the line isn't exactly right it won't pull the boost it needs too.


I hope it helps.

 

Does it feel like it's running low boost? If not, it might be a instrumentation issue like GTVEVO said, or it might be a faulty gauge.

 

I would guess you are missing the restrictor pills in your vaccuum lines. You can order a set of lines from the dealer, or if you are planning to put in a boost controller you won't need the lines. Without those restrictor pills the car will only run about 12-13 psi.

-Paul

 

Guess i will have to take a look at that then. You guys are refering to the lines that run into the factory Boost Control Solenoid?? Or the lines at the Wastegate outlet and Compressor housing?? It feels like it pulls pretty hard, but it feels the same as the day i got it, but if it was wrong to start with i could be comparing the feel to something that is wrong, cause i know the Vacuum lines in there were replaced by Mitsu before i bought it used. Like i said im 99% sure the gauge is working right cause it worked perfect when it was in my Eclipse, Unless sitting un-used for 2 months or so ruined the gauge, but i cant imagine that it did.

I know it tapers off, but wouldnt it still hit the peak then taper back to 12.5 / 13psi, not just stop dead at 12.5psi??

Couple of things running through my mind.

1) if the BOV was leaking after 12.5psi would it just stop dead at 12.5psi or would it spike and then tapper down the the 12.5psi

2) How much of a differance would the ID of the vacuum hose make a differance? a Noticable differance?? I used the same size vacuum hose as where i tapped in at the FPR.

3) Anyone got a better spot to get a positive boost level other then the Fuel Pressure Regulator Line??

Sean

 

um guys the factory doesnt use special vaccuum lines, we buy the same crap as what they have at any parts house.

 

If you are refering to the vacume lines used from the turbo hot pipe outlet and the wastegate actuator they must be the factory size to retain the restrictor otherwise they won't work. As for were you tapped it is fine for a boost reading, not the best place that I prefer but it is fine. I prefer the same place the bov, right after the throttle body.

 

wow now im really confused!!!! =) I called Mitsu and talked to the service Tech and he said that they have seen a issue with a leaky boost solenoid ? Can anyone else confirm problems with this?

the vacuum hoses are all the normal size as far as i know, ive never changed them. I was refering to the vacuum hose connecting my Boost gauge to the "t" spot at the FPR. i used the same size hose that the FPR uses. Should it be smaller???

 

As long as there aren't any leaks in the line, the size of it shouldn't really matter. Also, as far as where to tap in for the boost gauge, I tapped mine in the line to the BOV. Seems to be pretty accurate.

-Paul

 

That is partially true. The lines aren't special, but the small, brass restrictor pills inside the lines aren't available at any parts house. That is why it is often necessary for people to purchase the lines direct from Mitsu.

-Paul

 

well we at mitsu purchase these lines directly from a parts house. and i havent ever seen or run across this pills inside the vacuum lines, but only in the clutch line. and i have never heard of a leak problem with the boost solenoid. i have only heard of one solenoid to be bad and it was and electrical problem not a leak.

 

No it sounds fine. The only lines you have to be very carefull with are the ones comming from the turbo and wastegate/act to the sylinoid. If they aren't perfect with the brass pills in the correct place you will not make the correct amount of boost.

 

And you work at Mitsubishi? It is a well known fact that there are 2 restrictor pills in the lines. It scares the hell out of me that you are replacing the lines with lines from a parts store and causing problems on a customer car.

For the original poster, GTEVO has you in the right direction. One pill is at the boost solenoid, if I remember correctly it is the top hose and it is located about 3/4 of an inch down from the solenoid. Just squeeze the hose with your fingers and you will feel it in there, or not.
The other is in the small hose off the tee that goes to the lower IC pipe fitting.
This is more difficult to get to and unfortunately is the one that will cause low boost. The top one missing will cause high boost and high spikes. If they are both missing, I believe it will once again be a low boot problem.