Boost issue thread #1001
06-12-12 | 10:44 PM
#1
Boost issue thread #1001
Hey guys I have been reading through the forums for what feels like an eternity trying to solve my issue and haven't quite gotten an answer for my specific question. So here it goes:
It is basically the usual. Boost is fine ~10psi all the way up to the 4500rpm transition. No hesitations, no drop, no spikes. If I let off or shift before 4500rpm boost picks right up in the next gear, no issue. If I take it past that magical 4.5 line on the tach, though, boost instantly drops and exhaust note changes drastically. It sounds to me like the wastegate has opened. If I drop back under 4500 and let it get situated, boost is back to normal. That's it, no chatter sounds, no spitting or sputtering, or anything else that others have reported. The turbos are not leaking oil, there is no residue in the IC piping.
All that being said, I have '99 twins, 3" dp, bonez midpipe with 3" cat welded in, apexi n1 catback, and a blitz bov. Otherwise the car is stock. The engine has about 1.5k miles on a fresh rebuild from Speed1 (formerly KDR) They freshened up all the vacuum lines while the motor was out and said they checked all the solenoids, which were good.
I have checked the charge control actuator, CRV, and check valve for the pressure chamber and vacuum chamber. I didn't have time to remove the UIM tonight so everything in the rats nest was more of a visual check.
I have tried to cover everything I found in previous threads short of systematically testing every solenoid (which I may end up doing) to speed up the process.
SOOOOOOOO.....I have developed a theory. Because it seems that the wastegate is open and stays open at the 4500 transition and beyond would the wastegate control solenoid be my culprit? I found that mazdatrix sells it and the turbo precontrol solenoid for about $150.
Any ideas? I figure someone who has dealt with this before can give some insight before I needlessly spend a few hundred bucks.
Thanks,
Really Appreciating the Turbo System on My S4 Right Now
It is basically the usual. Boost is fine ~10psi all the way up to the 4500rpm transition. No hesitations, no drop, no spikes. If I let off or shift before 4500rpm boost picks right up in the next gear, no issue. If I take it past that magical 4.5 line on the tach, though, boost instantly drops and exhaust note changes drastically. It sounds to me like the wastegate has opened. If I drop back under 4500 and let it get situated, boost is back to normal. That's it, no chatter sounds, no spitting or sputtering, or anything else that others have reported. The turbos are not leaking oil, there is no residue in the IC piping.
All that being said, I have '99 twins, 3" dp, bonez midpipe with 3" cat welded in, apexi n1 catback, and a blitz bov. Otherwise the car is stock. The engine has about 1.5k miles on a fresh rebuild from Speed1 (formerly KDR) They freshened up all the vacuum lines while the motor was out and said they checked all the solenoids, which were good.
I have checked the charge control actuator, CRV, and check valve for the pressure chamber and vacuum chamber. I didn't have time to remove the UIM tonight so everything in the rats nest was more of a visual check.
I have tried to cover everything I found in previous threads short of systematically testing every solenoid (which I may end up doing) to speed up the process.
SOOOOOOOO.....I have developed a theory. Because it seems that the wastegate is open and stays open at the 4500 transition and beyond would the wastegate control solenoid be my culprit? I found that mazdatrix sells it and the turbo precontrol solenoid for about $150.
Any ideas? I figure someone who has dealt with this before can give some insight before I needlessly spend a few hundred bucks.
Thanks,
Really Appreciating the Turbo System on My S4 Right Now
06-12-12 | 10:59 PM
#2
If you really think that the wastegate and precontrol solenoid are your problem then you can buy 2 MAC solenoid to replace it but i'm not sure if it work on oem ecu. +-30$ each
https://www.rx7club.com/3rd-generation-specific-1993-2002-16/testing-mac-vs-oe-solenoid-valves-other-boost-control-strategies-874031/
https://www.rx7club.com/3rd-generation-specific-1993-2002-16/testing-mac-vs-oe-solenoid-valves-other-boost-control-strategies-874031/
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