matwey

OK, did a search on boost and had over 500 hits! Primary turbo produces no boost. Have had vacuum lines redone and did a visual, none seem to be popped off. MAP sensor good ( checked voltage for middle wire and wire closest to firewall), check valves seem good. Secondary Turbo comes on at 4.5k as it should.
NOT running pmc right now.

2-Rotor

10psi on the secondary? Highly unlikely you need at least 8psi on the primary turbo to prespool the secondary turbo. Check your vacuum hoses and intercooler piping for loose fittings.

ttpowerd

check again or take it somewhere to be checked, something is not right

matwey

I know the secondary has to have 8 lbs. of boost before it will come online, but it must be getting it somehow. My guage reads 0 lbs. then at 4.5k it jumps to 10 lbs. I also don't hear the BOV venting until after 4.5k. I also don't feel the power until after 4.5k. All piping seems ok. No air leaks that I know of.

johnchabin

iTrader: (2)

OK, I may have to think about this a bit, but the first thing that comes to mind is your Charge Control Valve is not closing and you are losing all the boost from the primary out the Charge Relief Valve.

Above 4500 rpm, the CRV closes, and the primary + secondary turbos add up to your 10 lbs of boost.

cash money

maybe its non seq.

az_lynx

Alright bro... you have the same problem that I have right now...

Before you start your car push the hoses above your y-pipe away until you can see your y-pipe.

There is a peice on the back half of the y-pipe (thats actually connected to the y-pipe itself) it looks like a diapharm and has a short rod comming out of the back of it. It also has 2 hoses going into it... one really short one thats right there on the y-pipe and one that goes somwhere else (I think the lowerintake (can't remember)) This is called the Charge Control Accuator it connects to a flap in the y-pipe that cuts off your secondary turbo.

Keep an eye on that rod and have someone start your car. The rod should pull in.... if it does not than this is your problem. It could be.... the CCA, one of those hoses right there maybe has a leak? or some other things like the senolid on the rack that controls it or a leak in your pressure tank.

If it doesn't pull in I would first check those 2 hoses and then if you have a vacuume pump handy check the CCA itself. Mine does not go in and those hoses are fine so I have a feeling when I did my hose job I either swaped a hose or somthing else. I have not had a chance to take the UIM back off and find out exactly what the problem is yet but my next step is to check the pressure chamber and make sure the car is holding pressure then I'm taking off the UIM and rechecking all the hoses and senolids.

Good luck... let me know if you find anything out.

Chris....

matwey

not non-seq.
Just bought a vacuum pump, but it's pouring rain. I'll give it a shot tomorrow. Thanks for the advice.

Wade

iTrader: (1)

matwey,

This is exactly what the problem is... can be caused by the CCV hose being pinched closed so the CCV stays open. Below 4500 RPM the CRV is open and primary boost gets vented through it accidentally, but at 4500 RPM the CRV closes and you then have full boost.

Wade

matwey

OK, guess I lost a few posts. Checked the charge releif valves (primary and secondary) w/ a vacuum pupm; both OK. Checked the Actuator (charge control) [CCV] and replaced both hoses coming from it. Also did a vacuum test on it and checked to see if the rod moved, all OK. I then ran out of Vacuum lines. I will replace the one behind the CCV tomorrow. Any other ideas? It does seem to built 1-2 lbs. of boost, but can't hear the BOV until over 4.5k rpms.

matwey

Ok, replaced all remaining vacuum lines. STILL no primary boost. It reads: -20 to -15 at 1/8-1/4 throttle. As throttle increases, it will rise until it hits 0, then will not move until after 4.5k when it jumps to 9-10 psi. Had vacuum lines replaced 2.5 years ago, mabey one under expansion chamber broke off, but if so I couldn't see it by peeking at every angle. PLEASE HELP!!!!

P'cola FD

Have you tried the boost leak test in this thread https://www.rx7club.com/forum/showth...threadid=98645
It may help. I bet if you "T" into the line coming off of the y-pipe you'll see plenty of pressure. You're just losing it somewhere.

johnchabin

iTrader: (2)

I agree a boost leak could be part of the problem, but I would expect like a 5-3-10 or something similar. It's bizarre that he gets NO primary and 10 on the secondary.

I'm still thinking a problem with the CCA/CCV. Maybe misrouted hoses. Are the 2 hoses on the CCA swapped?

Does the vacuum system hold vacuum when t-ed into? Tee in at the vacuum chamber and WOT from 2500 rpm in 3rd gear. Do you see vacuum the whole time or do you see pressure?

Really bad check valve from the vacuum chamber to the Extension Manifold?

matwey

OK, first thanks to everyone for their advice. The problem was the Actuator (Turbo control). It was stuck in, thus I guess venting all boost until after 4.5k. I thought I had checked it, but obvoiusly I did not. It is now unstuck, but I guess I have to order a new one. Any ideas on the cost? Thanks again for all the help.

johnchabin

iTrader: (2)

Buy a used one from a non-seq or single turbo guy.

spooledUP7

I have one, $20 bucks plus shipping, but did you fix it? are you now getting boost?

johnchabin

iTrader: (2)

That's a deal. I'm sure Mazda wants a LOT more than $20.

PsToNs SuK

I am sort of new at this whole rotary thing, not to mention turbo thing....what does 0-0-10 mean. I know it has something to do with boost by how is it determined and what numbers are what?