Ok. I have searched "2nd turbo doesn't kick in","second turbo doesn't kick in","Turbo problems" and a couple of others but I can't find anything specifc related to my problem

I have a 2000 Series VIII Mazda RX-7 with the stock sequential setup. I have many mods including: (sorry about the quick cut/paste)

* C-WEST Style Bodykit (Front Bar / Rear Bar / Side Skirts)
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* Mazdaspeed Style Bonnet
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* Full Respray in Black with a Blue Pearl through it done in November 2006
*
* Rear wing removed. Holes welded and resprayed. (OEM rear wing supplied)
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* Brand New 18" Advan AVS Model 5 Style rims in gold with Nexen 235/40 Fronts and 265/35 Rears Installed December 2006 (Fitted, Balanced & Aligned) - 99% Tread
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* EBC Slotted & Dimpled Brake Rotors in Anodized gold (Centre Hubs will not rust) - Installed December 2006
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* Bendix Advance Brake Pads on all 4 wheels - Installed July 2006
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* Greddy M-Spec Front Mount Intercooler sprayed perfectly in a subtle gold to match rims - Installed December 2006
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* Power Enterprise Impulse II Intake system with custom piping - Installed December 2006
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* HKS Twin Power Ignition System - Installed December 2006
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* Innovate LC-1 Digital Wideband O2 Sensor - Installed December 2006
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* Apexi Power FC with commander - Installed December 2006
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* Datalogit with software for tuning - Installed December 2006
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* Custom 3" Downpipe - Installed December 2006
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* Hypersports front parklights surround

* 3" SMB Metallic Substrate High Flow Catalytic converter - Installed December 2006
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* 3" - 4" Apexi Catback exhaust - Installed July 2006
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* Bosch 044 High Flow Fuel Pump - Installed December 2006
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* Extreme Super Heavy Duty Clutch - Installed December 2006
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* Tein Superstreet Coilover Suspension - Installed December 2006
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* Short Shifter - Intalled July 2006
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* HKS EVC Boost Controller - To be installed
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* Catz Zeta HID Lighting Kit - Installed July 2006
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* Pioneer CD player with built in Bluetooth - Installed July 2006
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* Polk Audio speakers 6.5" Fronts and 5"x7" Rears
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* Razo Brushed Aluminium Gear Shifter ****
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* Tinted Windows 30% Black on the sides (with a small rotor symbol embedded in gold) and 20% Black on the rear hatch


I'm picking it up from the workshop in an hour but they have informed me that the problem is when i take off from the line at low rpm the 2nd turbo won't kick in in 1st or 2nd gear. But if i coast at around 3k or 4k rpm and then punch it, it always kicks in. He has spent 30 hours trying to identify the problem but to no avail.

I'm pretty depressed that I have spent all this money to drive a car that was (honestly) quicker when it was rock stock.

I appreciate ANY advice, thanks in advance.

Ryan

 

Mine had a defective check valve in the "Rat's Nest" boost control circuit that wouldn't allow the 2nd turbo to come in.

 

Unfortunately his car would have the 'black box' of solenoids and check valves. It's plumbed differently from the rats nest the earlier FDs have.

I would have to say the problem is somewhere in these solenoid or check valves. Would you be able to get a whole new black box from a low mileage car? That would change a whole bunch of them.

Dave

 

Thanks for your inputs. Something maybe to note... I bought a 3" downpipe from rx7store.net not even thinking about LHD or RHD. So I accidentally bought a DP designed for LHD. My mechanic had to modify it to fit around the steering column though I'm worried that the welding may be poor and causing unsuitable back pressure

Or is this completely unrelated?

 

IMO, that would be completely unrelated as you stated 'sometimes' you have secondary boost. Since your downpipe isn't changing each time you hit the gas, you would see the problem all the time if it was related.

As far as I know, the mechanics of the sequential turbo system didn't change in the later models, just how its setup (i.e. the black box instead of all the solenoids out in the open but it still functions the same).

In that case, the first thing to look at would be your turbo control and its actuator.

 

It could be a vacuum leak (or a check valve):
Case 1, the manifold is in boost.
Case 2, the manifold is in vacuum.
A leak could empty (or is it fill???) your vacuum chamber by the time it tries to operate the solenoid.

 

+1 i would check the turbo control actuator... i had to change mine because it was stuck open and would only get the 2nd turbo to kick in once in awhile... The actuator has problems usually on high mileage cars, mine being 179k on the chasis, it was bound to happen sooner or later...

 

intermittent secondary boost can come from the turbo control solenoid that controls the actuation of the turbo control actuator. if the solenoid sticks sometimes it can be a problem. sometime it can open the actuator and allow exhaust to fully spool turbo 2 and sometimes it might not open. unfortunately i know nothing of how the"blackbox" system is setup. in earlier model FD's u just take off the uim and hunt for the solenoid that eventually is plumbed to the vacuum chamber.

 

hey guys, i got a question thats semi-related. when you reached 45oo and the second turbo is supposed to kick in, can you feel it, and if so to what extent? i ask this because i test drove an fd that seems pretty good and the first turbo went on for sure but as i kept revving past 4500 the boost seemed the same, there was no extra kick, so to speak. my apologise if this is a dumb question.

 

if the fd was stock then you'd probably notice a subtle change since the boost only dips to 8 psi for a few hundred rpm before going back up to 10. if it was modded like downpipe or something you'll feel it because the 2ndary turbo will spike when it comes online up to maybe 12 psi and you can definately feel that. either that or the fd you drove was made non-sequential

 

yea it was stock, thx for the help. i was jus asking cause i heard some people talking about how it felt with the second turbo.

 

If you were standing outside the car...it would sound like....VRRRRRRRRRRRRRMMMMMM...WOOOSHHHHAAAAAAAAAA (transition)..RRRRRRRRMMMMMMMMMMMMMM! When it didn't sound like that when my car was getting dyno-tuned (and seeing a sub-200hp dyno pull), Steve said the second turbo didn't kick in. I have a solenoid issue somewhere. When you're sitting inside the car, it sounds a bit more muffled.

Anyways, that's just a random, alternative method of "listening" for the second turbo.

Troubleshooting goes here:

http://rx7.voodoobox.net/howto/solen...oid_check.html

 

So an easy way i found out to check if your car is keeping vacuum presure and there isnt a leak. Have someone look in the engine bay where the actuator is for the secondary turbo its right on top only small actuator around should have two vacuum lines going to it( I think ) turn the car on and off the actuator should move in and out. If it doesnt then there is a leak. If it does then make sure all the check valves are working correctly I put one backwards once and no boost on secondary. Also if you have an aftermarket Blow of Valve(BOV) you have to make sure the ( I beleive ) third vacuum comeing off the Upper intake manifold(UIM) is blocked off its whatever line feeds from the UIM to the BOV on the secondary turbo stock. After you do that get a vacuum tester and take off the line going to the first BOV plug it in there and try to pull vacuum from the system if it holds vacuum your all good with leaks then you are going to have to make sure all the solenoids are working correctly and that will be a pain in the butt. Good luck

Chris

 

By the way these are the only mods you should list in reference to this. All the rest of the stuff is insignificant and just make for extra reading.


* Greddy M-Spec Front Mount Intercooler
* Power Enterprise Impulse II Intake system with custom piping - Installed December 2006
* Custom 3" Downpipe - Installed December 2006
* 3" - 4" Apexi Catback exhaust - Installed July 2006

 

the test works. the vac/pressure chambers should be holding their air. if not a bad vac line or check valve. just key on/key off test it. on the site mentioned above, it is the best explanation of how the system fully works. it's pretty complicated at first but once you understand t things will come together. just remember to check the obvious and easy things first. print out a vac diagram and atleast from what you can see without digging too deep make sure things look like they're were they should be. i messed around forever with mine, and it ended up being that the previous owner mixed up a few lines...
he connected the vacuum chamber directly to the little evap catch tank under the throttle body and connected the purge control solenoid to where the vacuum chamber SHOULD have gone. it wasnt until after countless hours testing solenoids and **** that i saw it, fixed it in 30 seconds, and it drove perfect.

 

I want to thank you all for your input. I am getting all of this looked at tomorrow and printing out these posts to show my tuner.

I will let you know the outcome

Thank you

 

I don't think anyone has mentioned this yet, but too much pressure in the pressure tank will cause the turbo control solenoid to stick. If you are getting more than 11psi in the pressure tank (12-16psi is not uncommon), install a pressure regulator to keep it at 8 or 10.

Many secondary turbo problems are caused by this.

Dave

 

yea i've read the thing on that..how some solenoids stick at the 12 psi point.. this can be tested be pressure testing it with a mityvac and pressurizing the solenoid up to 12-13 psi. although the mity vac i have atleast doesnt measure pressure, just take your boost gauge if you can and tee it off the line going from the mity vac to the solenoid. and then use a battery to make sure the solenoid is still working under that kind of pressure.