Alright here is the deal I did the vacuum hose job about three weeks ago. I get everything done and get the car running. vacuum was around -14/-15 just like before the job when I had no boost issues, then I go for a drive and the car is only boosting to 4lbs max and then not transisting to the secondary like before. Things I replaced during the job were the turbo/wastegate control solenoid the top solenoid first on the rack (if your looking from the front back) and the second solenoid on the bottom of the rack due to broke nipples (i.e.-solenoids I replaced are used). I also replaced every hose including coolant hoses. I am very confident I don't have a boost leak, cause no leak sound anywhere, also vacuum seems normal. I suspect a kinked hose or bad solenoid that I replaced. I am wondering if anyone recognizes this problem or have had the same problem? Does anybody think this could have to do with the wastegate line restrictor pills being positioned wrong? anybody with 4 lbs boost problems?

 

Sounds to me like a huge boost leak (I know you said you didn't think it was), because you should get 7 psi (basic WG spring) even if things were screwed up if you didn't have a leak.

Also, good vacuum does not preclude a boost leak before the throttle body (where boost leaks occur).

There are many other things that could cause boost problems, but I would look for a boost leak first.

 

Tighten all couplers. Building 4lbs and then not transitioning sounds like a coupler is loose or you have a hole in one of the pipes. This is the easiest way to start pinpointing the problem.

David Jerome

 

After you have checked for a leak, then make sure the two solenoids on top of the rack are plugged in to the correct plug. If you have switched them, you will not be able to boost properly.

 

why am I not hearing any unusual sounds or any hissing? by the way I did this vacuum hose job with a friend that successfully has completed 2 hose jobs prior and we checked every hose and went over the hose diagram to ensure it was right, for anyone that understands the sequential system well, what kind of leak could cause this kind of problem. could it be the control solenoids or what? I figured I should be at least getting 7lbs even if there was a problem. What about a kink in one of the hoses? what result would that bear?

 

I have a small tear in the bottom intercooler hose right at the end that goes to the crossover pipe. Could that be the culprit? I also put a custom intake on and have the air pump and blow off vented individually? just some more info.

 

Perhaps you have a check valve backwards. But really I think a coupler leak makes more sense. They don't always make noise.

The checkvalve arrows are shown more clearly on this one:
http://www.davidgeesaman.com/rx7/93v...lor.edited.jpg

Oh, and I found that putting the UIM in place kinked a couple of hoses. You may want to double-check that.

Edit: hell yeah a tear on either coupler at the intercooler will be a boost leak.

Dave

 

YUP!!!!!!!

 

Did you read my above post? That is the culprit. THe stock intercooler hoses are known to tear and cause this problem. WHen the car only builds 3-4lbs and wont transition it is usually because of what I described above. The more pressure builds up the air takes the path of least resistance and finds the easiest way out which is usually a loose coupler or busted stock intercooler pipe. Change it out and you should boost just fine. Good luck

 

I just found out that the lower intercooler hose (the "s" shaped one goes to the y-pipe) is $183.00, by itself from Ray at Malloy. Great!! I guess I am looking at the greddy elbow and intercooler pipe kit from the 7 store. anybody not recommend this?? I am pretty sure that the tear at the end of my stock hose is the boost issue culprit. What is the cheapest way to get some hard pipes on there?

 

Go to the 3rd gen parts section, and put in a WTB ad. Someone will have that part.

 

Im sure you can find a stock intercooler with piping for about 60-70 shipped in the classified section.

David Jerome

 

what about intake couplers? if they are not on right would it cause boost issues?

 

i have the same damn problem........ i'll be back gonna check my piping and couplers.

 

there i a taer on the coupler going to the elbowcould that be it.

 

Anything leading from the y-pipe to the intake must be air tight. Please note that cranking the snot out of the coupler clamps is a bad idea (you'll pinch into the rubber and have a leak soon enough) - things must be well aligned and in good condition.

Dave

 

1LUCKYGUY sounds like we have the same issue. I only get 4lbs max and no transition. I definitely have a tear on my intercooler hose right where it connects to the crossover pipe. Otherwise I replaced every other hose there is. I am ordering the hard pipes and greddy elbow and we will see. Otherwise I have a turbo control problem, maybe the turbo precontrol solenoid I got is bad? I don't know. damn holla back when you figure out your prob.

 

Yeah I have some pretty low quality couplers on the intake hoses, I always had a problem with them from the getty up. Guess I will get those out of there too.

 

alright I replaced the intercooler pipes and couplers and still only 4lbs of boost I am wondering if it has to do with the turbo precontrol/wastegate solenoid or the charge relief or double throttle control solenoids, those were the only ones I replaced or maybe a kinked hose. does naybody have any idea why I would get only 4lbs and no transition, I need causes for this problem so I can diagnose what is going on.

 

***Update***
I found the problem to be a failed Charge Control Actuator and four failed solenoids, including double throttle control solenoid. I also found a ripped y-pipe coupler. I replaced all mentioned above and I also replaced all the check valves with Dales Viton check valves. After that I have a normal boost pattern of 11-8-11. Pulls hard, runs nice. Wanted to follow up on this thread just in case any of you have similar problems.

 

Congrats! Thanks for the followup