I Still Have My Boost Problem!
 

ok i am running out of ideas here. so here is the bacground info, i posted a thread a few months back, i had instaled a boost guage and it was reading 11-5-6 so i was kinda disapointed, so i posted the thread asking what was going on. i got some help and one of the guys told me to swich the elctrical plugs on the wastegate and prespool solenoids, so i did, and the guage read 12-10-15 so i got really scared and stoped. so they figured it was those 2 solenoids and they needed to be repalced. so i finaly got around and bought a low mileage set from a guy of the fourm. i received them today and installed them. i warmed up the car and took it for a drive, SAME READINGS! 11-5-6 so i swiched them and got
12-10-15 again. i dont know what to do now. please give me some suggestions. any help is greatly apprechiated!

thanx

preston

p.s. im not gonna go non-seq...lol

12-10-15 sounds about right for the hosing/electrical side of things.
check around the solenoids and system for leaks... your high boost is likely due to either (too) much improved airflow or a leak in the turbo control system vacuum hosing.

my money is you are looking for a leak in those hoses.

try larger waste gate and prespool pills.

Unplug both connectors and do a 3rd gear test....what boost do you get?

"Apxi Intake w/ Polished Piping, '99 Twins, Enfi Y Pipe RE DP, HKS High Power CB"

I would expect to see more than 10psi with these mods. The 12-10-15 is what you're getting when the solenoids are connected correctly. You need to improve your boost control. A PFC might cut it, but a manual or electronic boost controller will help more.

Rynberg's suggestion of running with both unplugged is a worthwhile experiment.

Dave

ok ill go and try that out. i would think tho that 15 psi on the secondary is alittle high i could see 12-10-12 but 12-10-15 seems alittle abnormal.

ok the results are in 8-7-9 with conectors unpluged. what does this mean? no bad news please ;)

It means that thing appear to be working but running too high. This is common when running multiple flow mods with stock ecu and stock boost control. Since you have no ecu listed, you've GOT to get those numbers down under 12psi, preferably right at 10. 15 is downright scary.

Before we jump into panic though, I suggest you find a way to ensure your boost gauge is reading exactly. Either a second boost gauge, mityvac, or something similar to get a 'second opinion'.

Install a boost controller on the wastegate and you should be able to tweak those levels down to steady levels.

Dave

ok well as long as everything is working properly. when i bought those items i thought that there was that "3 mod limit" i never really counted the turbos and y pipe into the mix. isnt there a way to put two MBC on to control both turbos? i will try to fing another boost guage to use but i dont wanna buy a new one. also when the seconday hit 15 psi, it felt like 15 psi ya no?... that shit was fast as hell! lol but i think for now if i leave the reversed so that my readings are 11-5-6 that will be safe for now right? until i get a MBC.

Anything over 10 psi on the stock ECU is playing with death of your motor. The three mod rule was a rule of thumb as it generally didn't give you boost over 10psi, with the exception of the CAI, DP, and mid pipe. Seems that either the mid pipe and stock cat back, or stock main cat and after market cat back would not yeild boost over 10 psi. Since you have moded to the point that is putting you over the 10 psi rule it is a mater of time before you toast your engine.

well i defenetly dont wanna toast my engine, ill gust have to keep my ffot out of it until i get a mbc.

Keep in mind two things
1.) in 3rd, 4th, and 5th gear as it does not require full throttle to reach or go over 10 psi.
2.)and in second you can go over 10 psi but you will have to put your foot in to it pretty well to do this.

i know i know, i was just sayin... but im sure 11 psi cant hurt it that much.

11psi, no problem. 12-15psi, big problem.

RX007 - If your 15 psi that you are getting is creeping up from 10, then read this thread.

Meaning you get 12 - 10 - [11, 12, 13, 14, 15 and it tops out at 15]. If the boost slowly rises with the rpm, that's creep. Of course you probably know this.

The link above is a cheap and easy way around the creep. Then you'd have 12 - 10 - 10. And may be able to tune the last 10 to 11 or 12 if you wanted to.

- JyRO

ya it does creep... and that is a really great thread. ill have to look into that! thanx

What do you have where the main cat goes?

Dave

... the main cat, my flow mods are intake, dp,cb, i guess u could say the '99 spec turbos, ant the efini y pipe but im not sure if that actualy flows more than the stock plastic one.

I wouldn't expect you to have boost creep with a stock cat in there. Is there any chance it's been gutted?

Dave

not to my knolege, i actualy highly doubt it because when i bought the car it was completely stock, i mean not one thing on the car was from the aftermarket. and the car doesnt sound very loud like a gutted cat. maybe i was mistaken in stead of it creeping it could have just been a slow spool because i might have been a low rpms i cant really remember.

ok so now no matter which conector is where i still hit 15psi on both turbos now...

ya i really have know idea what the problem is now all the hose look fine they are in theyre original posittion and i just repaced them today(the ones on the turbo control solenoids) now i dont know what is wrong like i said i keep hitting 15psi on both turbos plz help. and i cant find my stock intake either :(

I think you should leave those connectors unplugged for now. If what you said about the plugs means that unplugging them now still results in the same high boost, then your problem is simple: a leak in the lines between the wastegate/precontrol solenoids and the tree on the primary compressor housing.

I'm talking about the pink and green hoses in this diagram:
http://www.davidgeesaman.com/rx7/93v...lor.edited.jpg

Dave

ok so what ur sying is that if i go and unplug them now that i sould be seeing the same boost pattern? which is 15psi on both turbos. and sorry for my newbyness but what do u mean by tree on the primary compressor? is it that blue line? also i dont know it this has any thing to do with it but my ecu threw me a code for the pressure sensor... thanx for all ur help

u know what? when i had replaced the solinoid hoses i put them in the wrond spot... i feel pretty dumb any ways that vacum chart u gave me helped out alot! so now im back to square one... 12-10-15 or if i swich the conectors its 11-6-7 with a apike at 13 on the primary. i looked all over my garage and couldnt find my stock intake. do u think if i fab up that piece that that guy posted earlier about the 2 in flange thing the u put in the exaust to restrict the air flow will that lower my boost or will it just reduce boost creep?

It should reduce both.

ok so then ill probably start fabing up a couple of pieces one 2.5 in and another 2 in... thax for all ur help dave, uve allways been there for me!

also on another note i tried to put a home depo BC were it says incert boost controler here on the diagram. and it says to take out the restricter pills.
are the restricter pills in the actual hose or are they some where else? and
if they are in the hose then i might have a problem, because when i pulled my hose out it waqs empty.

https://www.rx7club.com/attachment.p...d=174768&stc=1

that's not entirely true, with just intake and a DP i saw 12 psi on a cold night and now i've got GT spec exhaust. But haven't seen over 12 so apparently the stock cat is the thing to have. Too bad mine's shot.

12 is where fuel cut comes in, and where fuel supply with an all-stock system gets scary. But the point is that if you set your boost above 10 (say 11 or 12) you have no margin for error.

If you don't have pills, look in the nipples attached to the compressor. In some turbo assemblies, they reduced the inner diameter at that spot instead.

Dave

that could be it, they are '99 spec not sure if they did that for those turbos ill go and measure the diameter. still havent had a chance to make those exaust restricters because of mothersday but ill get on it asap and tell u the results.

ok so i mad one of those pices and it didnt seem to hel really. my patern was 15-10- spike at 13 then down to 10 and a 4k rpms it studered. the hole i made was just a litele smaller than 2 in. i think im gonna try and put my stock exaust on and see what that does. any other sugestions?

ok so i got around to puting my stock exaust back on and no real promising results... patern was 15-7-12 and just like my last post it studered at 4k rpm... this crap is gettin really old. some one please help me.

Are your wastegate and precontrol actuator rods still attached properly? Make sure the e-clips didn't pop off.

15psi indicates something is very wrong.

Dave

ill check them but i think that they are on. i have the solenoids swiched right now so the pattern is what i origanaly posted which is 11-5-6 so its some what safe. ill go and check them imediatly!

ya the rods are still on there and so are the clips. man i do not get this... would it be possible to get a MBC and reduce the boost? any other ideas? thanx

bump

hey preston i think you should just sent it back to Rotary extreme and see what they can do...u have been at this for awhile now...but yeah Goodluck! i would help you but i dont knwo what to do haha

Now... I haven't been a 3rd gen owner for very long but what about the MAP sensor coming off the back of the Throttle body?
I was thinking maybe that could be having an issue. Without having proper readings of manifold pressure/boost the ecu wouldn't see the proper pressures to open/close the solenoids in time. Thus giving you a boost creep/spike. Or a leak in the line maybe... Or maybe those solenoids have another sensor they get their info from....
Maybe you want to check the line running to the MAP sensor... or the checkvalve which runs to it... I could be way off but it looks like you have tried all the more obvous things. ;) It couldn't hurt.

hmm, maybe i have no idea where the MAP sensor is but now that u say that... you know the studs that goe thru the intake elbow? well one of them on the bottom broke in half along time ago, i was able to screw the nut back in but maybe it didnt make a proper seal. what dou you think?

Nope, a leak at the intake elbow will lose boost if anything.

A manual boost controller will probably help or solve the problem.

Dave

MAP/Pressure sensor location is in the picture below:
http://www.davidgeesaman.com/rx7/93v...lor.edited.jpg

Look at the top right of the picture. You can't miss it...

OH that thing? actualy it threw me a code a few weeks ago, but it went away, do u think i would need to replace it?

You could at least swap it with another. On a weekend we could swap it with mine and test to see if your boost is fixed.. or even one of these evenings as I could drive my Jeep around for a couple days. So long as its warm and sunny outside. ;)

Otherwise maybe someone else around you has one laying around also check the vac lines and that little filter attached to the vac line. Make sure everything looks decent.

Definately if it threw a code you should check it out.

alright, sounds good i really apreciate it, im free any time since i just quit my job so when ever ur free we could do this.