Primary boost troubleshooting, whats next?
10-09-10, 09:53 PM
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Primary boost troubleshooting, whats next?
Im having the same problem as riprx7: https://www.rx7club.com/3rd-generation-specific-1993-2002-16/bnr-primary-boost-problems-915311/
I did all the tests that dgeesaman posted up: https://www.rx7club.com/3rd-generation-specific-1993-2002-16/how-test-your-solenoids-actuators-other-turbo-stuff-802060/
This is a JDM engine that I just put in a couple months ago so I thought maybe it was the turbos so I installed my other set of turbos from my first engine and im still having no primary boost. Also, I checked if all the plugs were connected to the right solenoid and they are unless the JDM engine has a different order then the US one because I swapped out the JDM wire harness with my US wire harness . All I hear when im driving under 4000rpm is a loud ssshhh sound, then it goes away at 4000rpm and the secondary turbo gets full boost.
So what’s next?
I did all the tests that dgeesaman posted up: https://www.rx7club.com/3rd-generation-specific-1993-2002-16/how-test-your-solenoids-actuators-other-turbo-stuff-802060/
This is a JDM engine that I just put in a couple months ago so I thought maybe it was the turbos so I installed my other set of turbos from my first engine and im still having no primary boost. Also, I checked if all the plugs were connected to the right solenoid and they are unless the JDM engine has a different order then the US one because I swapped out the JDM wire harness with my US wire harness . All I hear when im driving under 4000rpm is a loud ssshhh sound, then it goes away at 4000rpm and the secondary turbo gets full boost.
So what’s next?
10-09-10, 10:00 PM
#2
Have you checked your Charge Control operation?
http://www.autosportracetech.com/RX-...leshooting.htm
The Charge Control Valve controls the transition from Primary to combined Primary and Secondary Turbocharger operation. When ever the pressure applied to both Chambers of the Charge Control Actuator are equal, the spring force of the Charge Control Actuator will open the Charge Control Valve.
Below 4500 RPM this actuator is ON, (actuator rod pulled in), this closes the valve between the Primary and Secondary Turbochargers. This valve seals the air passage the same way as a throttle butterfly valve.
A simple test for the Charge Control Actuator is to start the engine and let it idle, the actuator rod will be pulled in. Stop the engine and remove the hose from Chamber A and the actuator rod will be out.
Chamber B is always connected to the Primary Turbo Compressor and normally will have 0 to 12 psi of boost pressure applied. Chamber A is connected to the Charge Control Solenoid, from 0 to 4,500 RPM a vacuum, from the Vacuum Chamber is applied, above 4.500 RPM the Secondary Turbo Compressor is applied to chamber A.
From 0 to 4,500 RPM with a vacuum applied to Chamber A, the Charge Control Valve stays closed, as Primary boost is always greater than a vacuum. Note, that the vacuum supply is from the Vacuum Chamber, thus leakage of the one-way check valve for the Vacuum Chamber will result in Primary boost applied on both sides of the actuator resulting in this valve opening when it should not, dumping Primary boost through the Charge Relief , Secondary Turbo and out the Charge Relief Valve. Another symptom of a leaky Vacuum Chamber one-way check valve is a loss of boost that is restored if the throttle is let off, (re-charging the Vacuum Chamber from engine vacuum) then quickly re-applying throttle results in boost.
Below 4500 RPM this actuator is ON, (actuator rod pulled in), this closes the valve between the Primary and Secondary Turbochargers. This valve seals the air passage the same way as a throttle butterfly valve.
A simple test for the Charge Control Actuator is to start the engine and let it idle, the actuator rod will be pulled in. Stop the engine and remove the hose from Chamber A and the actuator rod will be out.
Chamber B is always connected to the Primary Turbo Compressor and normally will have 0 to 12 psi of boost pressure applied. Chamber A is connected to the Charge Control Solenoid, from 0 to 4,500 RPM a vacuum, from the Vacuum Chamber is applied, above 4.500 RPM the Secondary Turbo Compressor is applied to chamber A.
From 0 to 4,500 RPM with a vacuum applied to Chamber A, the Charge Control Valve stays closed, as Primary boost is always greater than a vacuum. Note, that the vacuum supply is from the Vacuum Chamber, thus leakage of the one-way check valve for the Vacuum Chamber will result in Primary boost applied on both sides of the actuator resulting in this valve opening when it should not, dumping Primary boost through the Charge Relief , Secondary Turbo and out the Charge Relief Valve. Another symptom of a leaky Vacuum Chamber one-way check valve is a loss of boost that is restored if the throttle is let off, (re-charging the Vacuum Chamber from engine vacuum) then quickly re-applying throttle results in boost.
10-09-10, 11:53 PM
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Have you checked your Charge Control operation?
http://www.autosportracetech.com/RX-...leshooting.htm
http://www.autosportracetech.com/RX-...leshooting.htm
But how do you test all these chambers "by hand"?
10-10-10, 02:08 AM
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So I got the primary boost to work by zip tying the Charge Control Actuator in the closed position but of cores the secondary turbo wont come on because the actuator is forced closed from the zip tie... so now I know both turbos work and Im guessing the Charge Control Actuator is not wanting to stay closed under 4000rpm however when I start the car and its at idle the actuator is closed. So I still really don’t know what’s the problem here.
10-10-10, 09:02 AM
#6
So I got the primary boost to work by zip tying the Charge Control Actuator in the closed position but of cores the secondary turbo wont come on because the actuator is forced closed from the zip tie... so now I know both turbos work and Im guessing the Charge Control Actuator is not wanting to stay closed under 4000rpm however when I start the car and its at idle the actuator is closed. So I still really don’t know what’s the problem here.
Charge Control valve itself
Charge Control actuator
Charge Control solenoid
Vacuum lines
Check valve to the UIM
Vacuum chamber
I'm assuming with your previous checks, you are sure your vacuum lines are routed properly and you've tested the solenoid. So, that leaves the other items that you need to check/test.
10-10-10, 04:33 PM
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yep, well the hoses that are conected to the CCA and the CCS...
ok thank! ill go through that list and see what I find. Which vacuum chamber do I check and what would be the best way to test them? And when you say charge control valve itself are you talking about the Charge Relief Valve?
So, you have a few components in the mix here:
Charge Control valve itself
Charge Control actuator
Charge Control solenoid
Vacuum lines
Check valve to the UIM
Vacuum chamber
I'm assuming with your previous checks, you are sure your vacuum lines are routed properly and you've tested the solenoid. So, that leaves the other items that you need to check/test.
Charge Control valve itself
Charge Control actuator
Charge Control solenoid
Vacuum lines
Check valve to the UIM
Vacuum chamber
I'm assuming with your previous checks, you are sure your vacuum lines are routed properly and you've tested the solenoid. So, that leaves the other items that you need to check/test.
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10-11-10, 02:28 PM
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ok, so I checked the valves to the UIM and they were all good. I checked the pressure chamber and the vacuum chamber by adding between 5 to 10psi to them and they were both good. so then I decided to swap out the whole back manifold with Charge Control Actuator/valve out with a spare one I had from my old engine that I tested before I put in and it passed. So now I go to test drive it and I finally hear the beautiful primary turbo spool up and hit .7 bar in all gears, never going higher then 3500rpm because i just wanted to see if the primary turbo was working. And just because, I then turn off the car, waited a few min and turned it back on and test drove it again to see if it still worked and it did. Now I wanted to see if the secondary turbo would work so I was driving and everything seem fine, the primary turbo hit .7bar then I come around 4000rpm and it feels like the secondary gains boost and then SSSHHH!! I drop down to no boost at all. i slow down to see if I even have boost in my primary turbo and I have nothing. I drive back home look to see if any vacuum hoses popped off even though I zip tied them all and they all were still in place.
What do I do now?
Also, I took off the hose connected to the pressure chamber between the alternator and the UIM and I heard air either being released or sucked in I dont know, is that normal?
What do I do now?
Also, I took off the hose connected to the pressure chamber between the alternator and the UIM and I heard air either being released or sucked in I dont know, is that normal?
10-11-10, 05:28 PM
#12
I did all the tests that dgeesaman posted up: https://www.rx7club.com/showthread.php?t=802060
It's not too bad to swap that one for another solenoid for testing.
10-11-10, 08:06 PM
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HA!! you know what, there was one step I remember not doing because I didnt have a 9V battery and that was one of the tests for the solenoid (Third, the energized leak test). Oh man if this is the problem then im going to kick myself because I did every test but the ones that involved the 9V battery.
If it is a bad solenoid can i swap it out with any other solenoid or does it have to have the same number on the side of it?
If it is a bad solenoid can i swap it out with any other solenoid or does it have to have the same number on the side of it?
10-11-10, 08:32 PM
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Props for staying with it. Another good way to test the solenoids is to use an old PC power supply, since you'll get the full 12v.
I unclip mine one at a time for testing and pull it out to make sure they work. Little bit of a pain in the rear if you have the acv still in there tho, that thing really gets in the damn way.
One funny thing about them is they can also work ok cold, but not when heated up.
I unclip mine one at a time for testing and pull it out to make sure they work. Little bit of a pain in the rear if you have the acv still in there tho, that thing really gets in the damn way.
One funny thing about them is they can also work ok cold, but not when heated up.
10-11-10, 08:34 PM
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Props for staying with it. Another good way to test the solenoids is to use an old PC power supply, since you'll get the full 12v.
I unclip mine one at a time for testing and pull it out to make sure they work. Little bit of a pain in the rear if you have the acv still in there tho, that thing really gets in the damn way.
One funny thing about them is they can also work ok cold, but not when heated up.
I unclip mine one at a time for testing and pull it out to make sure they work. Little bit of a pain in the rear if you have the acv still in there tho, that thing really gets in the damn way.
One funny thing about them is they can also work ok cold, but not when heated up.
man i feel like im getting so close!!
10-13-10, 12:33 PM
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I tested all the solenoids by applying pressure to port A first and then putting power to them. Before I apply the power to the solenoids it holds the full 12psi and once I apply power to the solenoid it release the air out from port B. Same goes for the vacuum test. Does that mean they pass? The reason why I ask is because not only did it do that to all of them but on here: https://www.rx7club.com/showthread.php?t=802060 it says “Connect the power source to the solenoid. It should click open immediately, and release immediately when the power is removed.” and “Repeat the energized test again, using pressure. I start with 12psi. Pay close attention this time to whether it releases immediately after disconnecting the power.”... my solenoids release the pressure once I connect it not disconnect or remove the power from it.
10-13-10, 04:12 PM
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well
good news: all the solenoids passed.
bad news: I still have not found the problem
does anyone in this forum live near Fresno Cali so they can take a look at my car and see whats up?... i cant seem to find the problem at all!!
good news: all the solenoids passed.
bad news: I still have not found the problem
does anyone in this forum live near Fresno Cali so they can take a look at my car and see whats up?... i cant seem to find the problem at all!!
10-18-10, 08:16 PM
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I know its kinda rediculous that im still having boost problems and that this thread keeps on coming up but I have ran into a new problem.
I got the primary boost to work, hitting .74bar(10.73psi) according to the PFC.
However, the secondary turbo wasnt getting any boost.
So today I tested again the wastegate control actuator, the turbo precontrol actuator and the turbo control actuator and they all passed. But because I thought that it would have to be the wastegate thats causing the problem I also replaced the wastegate control solenoid and the turbo precontrol solenoid that are connected together in front of the UIM.
The results;
I test drove the car today and got a little over .74bar for the primary turbo but once I hit around 4000RPM to 4500RPM the car does a big jerk and pulls hard and because I didnt know what was with the big jerk I let off the gas and looked at the PFC and it said I hit 1.02bar(14.50psi)!!
I dont know if that was a boost spike or what but now I need major help because I dont want to blow my turbos!
It should of not gone that high because I believe the PFC is set to .80 for primary and .7 for secondary boost.
please help.
I got the primary boost to work, hitting .74bar(10.73psi) according to the PFC.
However, the secondary turbo wasnt getting any boost.
So today I tested again the wastegate control actuator, the turbo precontrol actuator and the turbo control actuator and they all passed. But because I thought that it would have to be the wastegate thats causing the problem I also replaced the wastegate control solenoid and the turbo precontrol solenoid that are connected together in front of the UIM.
The results;
I test drove the car today and got a little over .74bar for the primary turbo but once I hit around 4000RPM to 4500RPM the car does a big jerk and pulls hard and because I didnt know what was with the big jerk I let off the gas and looked at the PFC and it said I hit 1.02bar(14.50psi)!!
I dont know if that was a boost spike or what but now I need major help because I dont want to blow my turbos!
It should of not gone that high because I believe the PFC is set to .80 for primary and .7 for secondary boost.
please help.
10-18-10, 10:12 PM
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Do you have exhaust mods? It's recommended to post a full list of all mods before people can help. I'm no expert on this car but I'll try to help as much as I can.
What is your boost pattern now?
regarding the secondary turbo :One other thing to check is the o ring in the rear half of your y-pipe (where the 2 sections join together) I suppose it would be possible with the CCA closed to get full boost to the primary, then have a boost leak when it opens to the secondary if that o ring were damaged somehow. Just guessing here since you've checked all the check valves, chambers and solenoids.
FWIW the sequential system can be a bitch and it causes a lot of people to throw a non-sequential conversion at it in frustration. If you stay with it though you'll fix it, its just a matter of having the time and patience to figure it out.
What is your boost pattern now?
regarding the secondary turbo :One other thing to check is the o ring in the rear half of your y-pipe (where the 2 sections join together) I suppose it would be possible with the CCA closed to get full boost to the primary, then have a boost leak when it opens to the secondary if that o ring were damaged somehow. Just guessing here since you've checked all the check valves, chambers and solenoids.
FWIW the sequential system can be a bitch and it causes a lot of people to throw a non-sequential conversion at it in frustration. If you stay with it though you'll fix it, its just a matter of having the time and patience to figure it out.
Last edited by twinsinside; 10-18-10 at 10:17 PM.
10-18-10, 11:42 PM
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Do you have exhaust mods? It's recommended to post a full list of all mods before people can help. I'm no expert on this car but I'll try to help as much as I can.
What is your boost pattern now?
regarding the secondary turbo :One other thing to check is the o ring in the rear half of your y-pipe (where the 2 sections join together) I suppose it would be possible with the CCA closed to get full boost to the primary, then have a boost leak when it opens to the secondary if that o ring were damaged somehow. Just guessing here since you've checked all the check valves, chambers and solenoids.
FWIW the sequential system can be a bitch and it causes a lot of people to throw a non-sequential conversion at it in frustration. If you stay with it though you'll fix it, its just a matter of having the time and patience to figure it out.
What is your boost pattern now?
regarding the secondary turbo :One other thing to check is the o ring in the rear half of your y-pipe (where the 2 sections join together) I suppose it would be possible with the CCA closed to get full boost to the primary, then have a boost leak when it opens to the secondary if that o ring were damaged somehow. Just guessing here since you've checked all the check valves, chambers and solenoids.
FWIW the sequential system can be a bitch and it causes a lot of people to throw a non-sequential conversion at it in frustration. If you stay with it though you'll fix it, its just a matter of having the time and patience to figure it out.
Here is the mod list:
A'PEXi PowerFC
A'PEXi Power Intake
Bönez Downpipe & High Flow Cat Combo
Racing Beat Stainless Steel Dual Tips "Catback" exhaust
Pulley kit
Simplified Sequential vacuum set up: https://www.rx7club.com/3rd-generation-specific-1993-2002-16/vacuum-diagrams-stock-simplified-sequential-non-sequential-single-turbo-749702/
There was nothing wrong with the O-ring I remember checking it before installing it back in.
As for the boost pattern, I don’t know how I would check or find that out. I know I get 10 to 11psi in my primary turbo but once it gets over 4000rpm the car seems like it drops boost and then gains it back again but with too much boost, over 14psi to be exact. And once the car felt like it was boosting too high I let off the gas quickly because I didn’t want to damage anything. So I don’t know if the boost was going to stay over 14psi or if that was a boost spike that the PFC should of caught.
Should I continue to drive after 4500rpm even though it hits 14psi and see what happens to the boost??
Last edited by mainboyd; 10-18-10 at 11:47 PM.
10-19-10, 12:13 AM
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The turbos should exhibit a boost pattern of approx 10-8-10. 10 psi on front, transition kicks in and drops it to about 8, then when secondary kicks in should go back up to 10.
From your description are you hitting 10 max, dropping into transition, then spiking up to 14 psi only when the secondary kicks in?
overboosting can be dangerous to the engine if it causes you to go lean, also the stock twins can't support 14 psi it can damage the turbo(s).
Your exhaust setup is fine and shouldn't cause overboosting from lack of restriction.
Since you didn'td have this problem before it could be related to the changes you made with regards to wastegate and turbo precontrol. The wastegate is probably not opening enough to keep you at 10 psi, causing you to hit 14.
From the autosport race tech site:
4,500 to Redline
The Turbo Control is fully opened, and boost pressure is created by the Primary and Secondary Turbochargers. When both Turbochargers are actuated, boost prerssure regulation is preformed by the Wastegate Control.
From your description are you hitting 10 max, dropping into transition, then spiking up to 14 psi only when the secondary kicks in?
overboosting can be dangerous to the engine if it causes you to go lean, also the stock twins can't support 14 psi it can damage the turbo(s).
Your exhaust setup is fine and shouldn't cause overboosting from lack of restriction.
Since you didn'td have this problem before it could be related to the changes you made with regards to wastegate and turbo precontrol. The wastegate is probably not opening enough to keep you at 10 psi, causing you to hit 14.
From the autosport race tech site:
4,500 to Redline
The Turbo Control is fully opened, and boost pressure is created by the Primary and Secondary Turbochargers. When both Turbochargers are actuated, boost prerssure regulation is preformed by the Wastegate Control.