ImranRX-7

Please take a look at the following thread:
https://www.rx7club.com/3rd-generation-specific-1993-2002-16/weird-problem-boosting-480079/

I'm having the same issue.I just had major work done to my motor and baught 99spec turbos (still in standard configuration). Rotary Power in Gardena, CA did all the work. When I get the rpm +4500 (second turbo comes online) and let the rev's come down to first turbo range (3000 ~ 4000), the exhaust note gets deep and loud, but it keeps the gate open instead of closing to primary turbo only. It does this for a few seconds, the harder I push it before the revs drop, the longer it takes for the gate to close. Jeff replaced my primary turbo control soleniod thinking that it might be faulty (they tested it and sometimes it would stick sometimes not) but even with the new one I still have that issue. They can't seem to solve it. When I dynoed the car, the boost graph showed no boost before until ~4000 and then it progressed up sharply to 14.8psi. Any help is much appreciated. Mods in sig. Thanks.

ImranRX-7

93 FD3S - Race Ported 13B; 3mm Apex Seals; 99-Spec Turbos; 1300cc Secondary Injectors, Nippon Denso Supra Fuel Pump; APEX'i Power FC; APEX'i GT-Spec FMIC; APEX'i Intercooler Kit; Fluidyne Radiator; HKS Downpipe; Bonez High-Flow Cat; Racing Beat Dual-Tip; Exedy Stage 1 Organic Clutch; Exedy Lightweight Flywheel

Mahjik

iTrader: (1)

There are two solenoids that control the Turbo Control actuator. Both of them need to be working properly for the actuator to work properly. Where both of them tested and/or replaced?

tiger18

iTrader: (1)

Mahjik is right theres a pressure side and a vacume side solenoid for the charge control actuator,,, i have exactly same problem as you have mate,,,,,and im gonna replace both them solenoids because i swear one of them is sticking and not letting the control actuator close after letting off the gas

ImranRX-7

Thanks Mahjik and tiger18...

Here's a picture (of old solenoid) which was replaced. Not sure if it's the vacuum side or pressure side. Where is the other one?



tiger, when you do replace both, please let me know if that solved your problem. It used to work fine before my build and the new 99-spec turbos. Also, previously I did my own hose job (orange hoses in my avatar), and Jeff and Alan at Rotary Power said they supposidly weren't the corect thickness (which I don't believe), and they re-did my hose job with new hoses (now red). Everything worked fine the way I had it, now I got all sorts of bullcrap after the build (idle issues, was really lean with Rotary Power Tune, boost issues). Tell me what you guys think.

Mahjik

iTrader: (1)

The second one is on the solenoid rack:

http://www.fd3s.net/vacuum_hose_diagram2.jpg

ImranRX-7

Thanks Mahjik...
Mahjik, is it the "turbo control" solenoid or "turbo precontrol" solenoid on the rack that may be faulty?

Mahjik

iTrader: (1)

It's "Turbo Control" for the one pair with the Turbo Control solenoid (on the ACV) from your original picture.

DVSseven

I am having the same problem as of now as well, this has all occured since my rebuild as well. I dont think that its human error I believe once the solenoids are out of commission for a prolonged amount of time they lose the ability to function for some apparent reason. My problem is when I do hard pulls to transition as well. When im making a hard pull all the way to transition upon transition I can hear the excess boost being diverted elsewhere rather than to the secondary turbo and the transition will not occur. But, if I "blip" the throttle upon transiton the secondary comes online and the car pulls like gangbusters. I need some help here as well.

Thanks, Jamie

DVSseven

any progress on this thread?

ImranRX-7

Hey Jamie, I'll try to get to it soon. Really busy with work and stuff. Anyone know what steps to take to test the solenoid? Don't want to go place an order at Mazda, wait for parts to arrive, pickup, remove UIM, install, and it not even be the Turbo Control Solenoid.

Also, not to sway far from the issue at hand, I'm a Web Developer/Engineer, and own rotaryproject.com. Trying to make a site for only FD and FE mechanically inclined owners which will help solve issues like this without the long threads which dont have solutions. I've got a fairly complex database modeled to make this all happen. Anyone have any input on what they would really want out of it, from a technical point of view. I know theres a wide variety of information here on rx7club and even great other how-to sites, but a lot of them focus on major issues vs smaller ones like this, or the infamous idle issue (which I've been searching this forum for with no luck for weeks!). Also, most sites dont provide a search functionality (unless forum based).

Thanks everyone for your advice!

dgeesaman

iTrader: (7)

You might want to look at www.fd3s.net. It's another site loaded with good information. Also, this site has lots of good stuff if you dig thru the search, but you're right, many people don't follow up with their results, or they quit pursuing the problem.

Yes, you can test solenoids individually, but IMO you need a Mityvac (the 4050 kit is particularly versatile) and plenty of time. Basically, I removed all of them, bench tested them, then put them in the oven to hot-bench-test them, and ranked them by their proper function. If you are willing to do this, I can provide a few links to more info.

Dave

DVSseven

I suspect that my problem, which is similar to yours to lye within the Charge Relief Valve, or with the Turbo control solenoid. So, I think im going to replace them reguardless, hell they are 12 almost 13 years old now. So, how long before they take a **** anyway, and there's no reson to start getting cheap on the car now. These things are not hard to replace anyhow they take only a few minutes with a skilled hand. I tell you guys the best tool to have while working on an FD is a pair of "hemostats"! I have a pair of them, one set that is just straight and one with a 90 degree angle on the end. A friend of mine who has taught me eveything about these cars is a physician and got me into using these. If you do not have them go to the medical supply store and buy them they are the best tool in my box.

Dgeesman, yesterday I spent the day tracing every vacuum line and all is place. I also did the KOKO test for the actuator on the y-pipe and it reacted the way it is supposed to, in and out. I got under the car and checked the actuator rods off of the turbo's and the surclips are still in place and all is well there. I figured so, the turbo's are only a year old. Then I removed the Charge relief Valve and blew through like the diagram said to do and I could hear it click when I blew through it. Do you know if this means that it was opening when I blew through it, and is that supposed to be that way. I dont know what to do about my transition problem I have inspected everything and everything is in its correct place and seemingly in working order. All the check valves are in position and are brand new, they are the Viton's that Dale Clark put on for me.... Any help would be appreciated..

Thanks, Jamie

superfastrx7

You got to either love the twins or hate them. I am having the same problem too before and after a complete viton hose change out. I benched checked all the solenoids and found four of them sticking so I replaced them with a few extra used solenoids.... did the pressure test, ohm and voltage check. I should have stuck them in the oven but did not and now I am only getting about 7psi WOT on first gear, 11 psi on second down to about 6 to redline after 4500 rpm and pretty much same on third gear. My next step is to tee into the vaccum and pressure ports on the turbo control actuator and check for vaccum and pressure during the 4500 rpm transition. I think this is the best way to start testing my system before I start breaking everthing down one more time (I too think about replacing both of them solenoids regardless).

So I will try this in about a month or so.

How much are these damn solenoids anyways?

Anyone have any other suggestions? I will also check the connectors to the wastecontrol and the turbo precontrol. I have heard this too could create a big problem and it has been a common problem during vacuum replacements.

ImranRX-7

Hey Dave, thanks for the post. Yeah, I really want to create something that will benefit all fd owners. I'm working on a pure search, as well as a drill down troubleshooting solution. With work and all, this project is going to be in the works for a while, but I've already taken the hardest step (dreaded database modeling).

I'll go purchase the 4050 kit and start testing. Can you send me those links you referred to? I really hope this solves my issue. Thanks!

ImranRX-7

Hey Jamie, have you had any luck w/ this issue when replacing the trubo control solenoid in the solenoid rack?

ImranRX-7

Having issue with possibly the turbo-control valve sticking.
Please see the following thread
https://www.rx7club.com/showthread.p...9&page=1&pp=15

DaleClark

iTrader: (55)

One thing I noticed - the two vacuum lines going to your turbo control valve are relatively thin-wall. With the manifold on the car, they could be getting pinched, stopping or slowing flow of air. Worth looking at. Those two hoses can be tricky.

Dale

ImranRX-7

Thanks Dale, the UIM has been removed and placed back on after the issue started. I also have thicker vacuum hoses now. I'll double check though to make sure a vacuum line isn't pinched somewhere. In the mean time, any other suggestions? Thanks!

dgeesaman

iTrader: (7)

Please don't start a new thread to link to an old thread.

1) Look for pinches, especially as you put the UIM and pressure tank back in place.
2) Did you replace the other (pressure) turbo control solenoid yet?
3) Are you still getting any boost below 4000rpm? Is it consistent?

4) Run the KOKO test. You will need to get under the front of the car (or creatively use a mirror) to see the turbo control actuator, and maybe remove an intake pipe to see the charge control actuator. If things are working properly, each time you turn the key on or off, both actuators should switch from in to out or out to in. Since you said your boost takes a few seconds, I recommend finding a helper who can turn the key while you watch. They should snap pretty quickly - any hesitation indicates a problem.

Dave

ImranRX-7

Here the following thread contains the solution (well atleast for me and a few others).

Thread Link

All that was needed was a pressure regulator between the pressure tank and the turbo vacuum hose. I've posted many pictures there as well. Props to Walien for coming up with the solution!