3rd Generation Specific Talk about 3rd gen RX-7's here.

secondary boost problems

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Old 07-23-2006 | 09:20 PM
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New Mazda reman engine with vacum simplification & Hallman valves. The entire charge system worked fine before the old motor popped. Once I got past the injector problems and got the new engine running I have been having boost problems. Initially it was a 7-10-5 pattern. I installed hallman pro valves in place of the w/g and prespool actuators. Now I have a 10-5-5, or 10-8-5 pattern and I cant feel any kind of transition, just slowly falles on its face, then breaks up at about 7000-7500 rpm (almost like a fuel cut). Here are the results of my testing so far:

-KOKO- CCA: good / TCA: bounces about 1/4 inch but doesnt stay open

-Vac chamber holds vacum

-Press chamber holds pressure

-TCS(vac one) 18" vac at 5k rpm

-TCS(press one) 10psi at 5k rpm

-Tee'd into the nipple between the TCA and secondary compressor and saw 0psi until the TCA opened...so the secondary turbo is not making ANY boost.



I checkd the operation of the prespool and w/g actuators and both operate @ 10-14psi



I could really use some help with this..
Old 07-23-2006 | 09:35 PM
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I also pulled the TCA and it operates just fine with either vacum or pressure, which is just confusing me even more since both solenoids passed the road test...
Old 07-23-2006 | 10:33 PM
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Ive been through this a couple different times first time it was a cloged dp cat the other time was my plugs the electrode was halfway gone and the plugs had tons of carbon build up. u should always start with the easy stuff no need in jumping into more complicated issues
Old 07-23-2006 | 11:19 PM
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Originally Posted by JBs93FD' post='829801' date='Jul 23 2006, 06:33 PM

Ive been through this a couple different times first time it was a cloged dp cat the other time was my plugs the electrode was halfway gone and the plugs had tons of carbon build up. u should always start with the easy stuff no need in jumping into more complicated issues


It has a full exhaust with a high-flow cat, and the plugs are clean.
Old 07-24-2006 | 09:34 AM
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So basically everything you've checked works fine correct?? All the solenoids/check valves/vac. hoses?? Just keep checking the vac. hoses and solenoids, one of those if probably your problem.



Also if you have a PFC check to make sure the seq. turbo option is turned on in the ETC. menu, sounds like the secondary is just not coming on at all, causing the primary to run out of juice in the higher rpms.
Old 07-24-2006 | 11:22 AM
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Originally Posted by SPICcnmGT' post='829840' date='Jul 24 2006, 05:34 AM

So basically everything you've checked works fine correct?? All the solenoids/check valves/vac. hoses?? Just keep checking the vac. hoses and solenoids, one of those if probably your problem.



Also if you have a PFC check to make sure the seq. turbo option is turned on in the ETC. menu, sounds like the secondary is just not coming on at all, causing the primary to run out of juice in the higher rpms.


Stock ECU, and all the hoses are new silicone. I have had the uim off a few times checking for popped off hoses and re-checking that everything is hooked up properly. I pulled off the secondary intake pipe to check the turbo and I spins freely, no excessive shaft play. I'm just going to do the non-seq mod quick to make sure there is nothing else wrong.
Old 07-24-2006 | 05:25 PM
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I'm curoious how you did your simplification. Usually when people say simplified twins means no emission. Since you are running stock ECU, its seems like you'll have some issues doing this "simplified system".



And this also goes with doing non-seq. You might need to get PFC or maybe I'm missing something... I am getting old and not as Hardcore anymore
Old 07-25-2006 | 02:50 PM
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I installed resistors in place of the solenoids that have been removed. Not sure if or why the stock ecu would have any issues if it still thinks everything is hooked up.



I did a couple boost runs with the "poor-mans nonseq" and it boosted just fine(10psi), but there is something else wrong. At 7k in second it hits what feels like a really bad fuel cut, and the same in third @ 6200. I'm wondering if the secondary injectors are bad, or mabey there is a fuel pressure problem.
Old 07-25-2006 | 03:20 PM
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I'm assuming boost is staying at 10psi?? It almost has to be a fuel cut, probably in the ecu. I would almost bet the boost is creeping causing it since it is at a lower rpm in a higher gear. Did you try 4th??



As far as simplified twins basically all it does is remove all the emission stuff, it should probably be called "no emissions vac. diagram". Maybe one of the lines hooked to the vac. chamber or something got put on the wrong way. It really just takes some time and you need to check and recheck everything Even after messing with them for the past year, I still second guess myself, which is really annoying sometimes.
Old 07-25-2006 | 04:23 PM
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Boost stays at 10psi, and I didnt check 4th, or first for that matter. I already tried switching the ecu. I ported the w/g and have never had a problem with boost-creep, and the boost gauge stayed at 10psi, didnt creep or spike at all. I did have an issue with leaking secondary injectors (thanks RC) when the reman was installed, so I switched the complete secondary rail with ont that had been sitting around for abut 3 years... mabey there is something wrong there?



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