need help with a boost problem
 

Sorry for making another post but I've been reading an reading, an getting lost because of so many different problems so I'm going to add to the mix,
My car will boost 5 psi when driving, it wont go over 0psi wide open throttle in neutral, I haven been trouble shooting for a while now gone over the vacuum system multiple times with the diagram, and for all of it I just can't figure out why it would do this, also shortly before I started having boost problems my fc commander programmer (the little thing with a display an some buttons" turned off on me when driving, I had to stop shut off the car an turn the car back on to get the display to turn back on. I have no idea about tunning or if it kept the tune or went dumb, could that be causing the boost problem if it went dumb?

You don't say
 

Well I know how you feel buddy. My car has been experiencing some boost problems lately. Mine doesnt feel quite as quick & crisp as it did but that isnt the real problem (I DONT THINK?). My symptom is: seems ok during med/hard acceleration lets say in 1st gear then when shift to second and try to get on it I hear this UMMMMHHHH!!! noise like air trying to get out a small crack and the car
doesnt take of good. Then shift to 3rd and the car seems to pull like crazy? However, what caught my eye about your post was that you said your remote commander shut off. Interesting because Monday driving on the freeway I just happened to look at the remote commander and it was blank. Now the car did not seem to be effected by this that I could tell. It then just came back on. It did
the same thing a few days after that. When the screen comes back on it brings up the APEXi logo like when you first start up? I dont really see how this could be related but I think that I would like to look at the screen next time my car shows the boost problem.

I'll be online tonight watching the Nascar race so hit me back if you want.

http://www.autosportracetech.com/RX-7/rx7stuff.htm

check that, also try checking your one way check valves. I had a similar problem with mine. Do you hear any leak at all like when driving and try to boost then shift (does it make a leak sound)? Anyways after messing around with my vacuum lines, I had inadvertedly put one of the check valves on wrong and it caused that same problem. But yeah just one more thing you can try to narrow it down.

WOW that's the exact same problem I am having. When going about 1/4 throttle, the most I can/ever have boosted is 5psi. Any more then 1/2 - 3/4 throttle, the boost drops, and the car pretty much falls on its face. (0psi)

Do you have the factory restrictor pills in your wastegate lines? I don't have any, and I think that could be the problem. I will try to get or make some this week to see if this is the problem. I have all new viton check valves, and I'm pretty sure they are all facing the right directions. Perhaps it could also have something to do with the turbo pre-control and wastegate control solenoids being mixed up?

^^^THANK YOU SO MUCH! Very useful information. That link needs to be in the 3rd Gen. Sticky. Many people forget or don't know about the pills in the pre-control and wastegate control lines when they do a vacuum line job. And Mazda dealers don't sell these pills. At least none that I've ever come across.

Mine did that when I first bought it. Found out the pills in the hoses attached to the turbocharger were gone. The turbos had been rebuilt at some point & I guess they were never put back in the lines or someone before me had been using a boost controller maybe. Don`t know. Something you could look at.

I don't know if it has the pills or not I've read about them but never seen what there were so didn't really know what I was looking for, how ever the vacuum line on I think the prespool actuator had popped off so the pill could have fallen out and I wouldn't have noticed. Does anyone know a source for getting the pills?
also I don't know if it matters I read something sayin the pills were part of the newer turbo manifolds, I have spec 99 turbo's maybe a 2 years old. Does that make a differance?

as for as the screen comming back on it didn't come back on for me when I was driving and I was worried about damaging the motor running with a runaway programmer so I turned of the car, when I turned it back on it loaded up like a normal start.

Yes, that would be the problem. You have to have those pills in the lines. As far as I know you can't order them from anywhere, you might be able to pick them up off members of the forum. Otherwise there is a way around it if you have a boost controller. (see version 2 in picture)

https://www.rx7club.com/forum/attach...&postid=952472

I had the same problem with my FD when I accidentally threw away the vacuum hose with a pill in it and did version 2 and it has worked perfectly ever since.


And Devlian, yes the 99+ turbos and heard some of the 94s/95s have them inside the wastegate. So if you have 99 spec ones then yours are more than likely still attached.

So I made my own pills, same sizes at stock specs. The car will still boost only about 5psi, and hold it there, sometimes it will spike to 7psi but rarely. It does seem to have better response however.

So using a boost controller using "version 2" would mean you wouldn't need the pre-control, or wastegate control solenoids? :dunno:

From that link you posted, I came across that another problem could be the double throttle plates being stuck closed. Sometime this weekend, I will try to make the double throttle plates stay always open, and see if that's the case. Really the only point of the double throttle plates is so that you don't boost the car more then 5psi until the engine is fully warmed up.

how doo you make your own pills...

I've wondered about the secondary throttle plates too, my secondary throttle has been disabled how ever the plates are still there, in some freak way, could they manage to close them self an cause the 5 psi boost limit? to make them stay open all you have to do is take the vacuum line off them, an plug it. should work good enough for trouble shooting at lest thats what I've read.

From this website: http://www.autosportracetech.com/RX-7/faqs.htm#Pills

(Lots of great info here)

I used little jewelry sized drill bits, closest in size as the specs needed, and drilled through these little metal rods that fit snug into the vacuum lines. I'm not sure where they're from or what they are normally used for, but I can find out and post pics of what they look like tomorrow.

I'm going to try that this week and see if that works. I think the throttle plates are normally closed? I'm almost positive that mine have always been closed. :icon_no2:

In the past, I have used Weber carb jets for replacement restrictor pills. Not sure exactly which ones you need, but if you take the specs of the stock pills to a shop that deals with a lot of carbs, they could probably get you a carb jet that's the same size as the stock restrictor pills.

So today, I took off the actuator for the double throttle, and made it stay stuck open.
Went for a little test drive, no difference. At first It felt like the car was a little more responsive, but it boosted exactly the same. I have no idea what else I could do other then get a boost controller :(

The pills (or vacuum lines INCLUDING the pills) are readily available from Ray Crowe at Malloy Mazda.

I seem to be having the same issue... lol, if you figure it out, let me know

oh, with the pills...does it matter what color'd ones you use?

still haven't found my problem, but would a exhaust leak precat 'cause enough backpressure loss to affect psi build? Sorry if this is a dumb question I'm new too turbo's.

i have exactly the same problem and still haven't figure it out yet either.... so gay

::Update::
So I finally threw in the towel. And took my car to be seen by a Fully certified Mazda Rotary tech. He managed to find a crack on the charger relief inlet hose that I managed to miss the millions of times I looked at it. So *crosses fingers* I ordered the hose and hopefully once I get it in the problem will go away. I let you guys know the results.

well how has it been ?