Not getting boost from secondary turbo
03-24-13, 08:53 PM
#1
Not getting boost from secondary turbo
So I bought a FD last year that needed a rebuild. I just got it running again in the last few weeks after the rebuild, upgrades, and other changes. It currently pulls good until 4-5k, then the boost drops to 5 psi and slowly drops to 0 by redline.
I did the simplified sequential vacuum setup with silicone hoses. From reading the boost threads I found online it's one of several issues, but everything I'm checking seems to be fine.
The charge control actuator does go in when vacuum is applied, and it releases when vacuum is removed.
I T'd into the secondary turbo vacuum line and I don't think it got more than a few psi. I can confirm that if needed, I went through a lot of testing today and I may have that wrong.
Any ideas what else I can test? I have a tuning session scheduled with Steve Kan on 4/6 that I need to be ready for. Here's a list of my mods, let me know if you need any more info.
Mods:
Large street port
3mm apex seals
Custom intake with K&N filter
V-Mount intercooler
Greddy Elbow
Removed double-throttle
Wrapped 3” downpipe
Bonez high-flow cat
Apexi N1 catback exhaust
V-Mount Radiator
180° fan switch
180° thermostat
Dual oil coolers with -10AN lines
Additional ground wires
PC680 mini battery kit
Rewired Supra fuel pump
Unorthodox main pulley
Removed air pump and A/C
Apexi Power FC w/ Commander and dataloggit
Greddy Profec B boost controller
ACT clutch
Ported wastegate
I did the simplified sequential vacuum setup with silicone hoses. From reading the boost threads I found online it's one of several issues, but everything I'm checking seems to be fine.
The charge control actuator does go in when vacuum is applied, and it releases when vacuum is removed.
I T'd into the secondary turbo vacuum line and I don't think it got more than a few psi. I can confirm that if needed, I went through a lot of testing today and I may have that wrong.
Any ideas what else I can test? I have a tuning session scheduled with Steve Kan on 4/6 that I need to be ready for. Here's a list of my mods, let me know if you need any more info.
Mods:
Large street port
3mm apex seals
Custom intake with K&N filter
V-Mount intercooler
Greddy Elbow
Removed double-throttle
Wrapped 3” downpipe
Bonez high-flow cat
Apexi N1 catback exhaust
V-Mount Radiator
180° fan switch
180° thermostat
Dual oil coolers with -10AN lines
Additional ground wires
PC680 mini battery kit
Rewired Supra fuel pump
Unorthodox main pulley
Removed air pump and A/C
Apexi Power FC w/ Commander and dataloggit
Greddy Profec B boost controller
ACT clutch
Ported wastegate
03-24-13, 09:57 PM
#2
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You can try looking at the actuator arm underneath the car. I had this issue and found that the c clip that holds the actuator arm to the wastegate (it opens and shuts the wastegate) had come off. This means there was nothing controlling the secondary. I got so mad I just went single lol. Hope this helps
03-24-13, 11:24 PM
#9
Fortunately our cars are old enough now where nearly every problem has already been covered/solved. If you look at the FAQ at the top of this forum you'll find lots of helpful threads.
You also may want to consider reading and/or printing out the sequential twin turbo trouble shooting guide linked below.
Trouble shooting guide ------>HERE
-Dan
You also may want to consider reading and/or printing out the sequential twin turbo trouble shooting guide linked below.
Trouble shooting guide ------>HERE
-Dan
03-28-13, 08:50 PM
#10
I just figured the issue out tonight, it was just stressful after spending a year building the car and KNOWING you did everything right.
After testing with the boost gauge, I discovered the boost line to the turbo control actuator was on a port that wasn't seeing boost. I had used a mix of two simplified sequential diagrams during the simplification. I just compared the diagrams I used, and the two of them show that line pulling from different ports. Here is the one on rx7club that shows it coming from the Y pipe, and here's the one I used from turborx7.com.
The one from turborx7.com has it connected to a port that's capped on the other side. I moved the line to the port from the rx7club diagram and everything works great now!
Thanks for the suggestions guys, I can't wait to get her tuned next week.
After testing with the boost gauge, I discovered the boost line to the turbo control actuator was on a port that wasn't seeing boost. I had used a mix of two simplified sequential diagrams during the simplification. I just compared the diagrams I used, and the two of them show that line pulling from different ports. Here is the one on rx7club that shows it coming from the Y pipe, and here's the one I used from turborx7.com.
The one from turborx7.com has it connected to a port that's capped on the other side. I moved the line to the port from the rx7club diagram and everything works great now!
Thanks for the suggestions guys, I can't wait to get her tuned next week.
04-26-13, 01:26 PM
#11
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Sorry to bring this thread live again but I'm having the same problem that you had. Boost pattern is 10-8-7-6-5
I pretty much have the same mods as you but I did not do the simplified vacuum line mod. It's still the original vacuum line setup.
I did check out all of the vacuum lines, they are properly ran and they have all been replaced with silicon hoses. No leaks and I even tried changing the solenoids. I also check all the other reasons why I might be having this problem like you did but everything checked out.
What are the pros and cons in changing over to the simplified vacuum lines versus the original setup? I don't have the double throttles, egr, air control valve, etc., so I don't need all them solenoids anymore right? I'm thinking of changeing over to the simplified vacuum line diagram and seeing if that would fix the problem.
Thanks for your help.
Tony
I pretty much have the same mods as you but I did not do the simplified vacuum line mod. It's still the original vacuum line setup.
I did check out all of the vacuum lines, they are properly ran and they have all been replaced with silicon hoses. No leaks and I even tried changing the solenoids. I also check all the other reasons why I might be having this problem like you did but everything checked out.
What are the pros and cons in changing over to the simplified vacuum lines versus the original setup? I don't have the double throttles, egr, air control valve, etc., so I don't need all them solenoids anymore right? I'm thinking of changeing over to the simplified vacuum line diagram and seeing if that would fix the problem.
Thanks for your help.
Tony
I just figured the issue out tonight, it was just stressful after spending a year building the car and KNOWING you did everything right.
After testing with the boost gauge, I discovered the boost line to the turbo control actuator was on a port that wasn't seeing boost. I had used a mix of two simplified sequential diagrams during the simplification. I just compared the diagrams I used, and the two of them show that line pulling from different ports. Here is the one on rx7club that shows it coming from the Y pipe, and here's the one I used from turborx7.com.
The one from turborx7.com has it connected to a port that's capped on the other side. I moved the line to the port from the rx7club diagram and everything works great now!
Thanks for the suggestions guys, I can't wait to get her tuned next week.
After testing with the boost gauge, I discovered the boost line to the turbo control actuator was on a port that wasn't seeing boost. I had used a mix of two simplified sequential diagrams during the simplification. I just compared the diagrams I used, and the two of them show that line pulling from different ports. Here is the one on rx7club that shows it coming from the Y pipe, and here's the one I used from turborx7.com.
The one from turborx7.com has it connected to a port that's capped on the other side. I moved the line to the port from the rx7club diagram and everything works great now!
Thanks for the suggestions guys, I can't wait to get her tuned next week.
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