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-   -   Where did all my boost go? - sequential troubleshooting (https://www.rx7club.com/3rd-generation-specific-1993-2002-16/where-did-all-my-boost-go-sequential-troubleshooting-1151927/)

championadrien 08-28-21 12:45 PM


Originally Posted by SwappedNA (Post 12483140)
So by both, you mean the lines at the wastegate and turbo precontrol?

No just the Wastegate. Leave the pre-control alone. I'm suggesting to remove both lines from the wastegate to have 0 chance supplying boost to the actuator.

SwappedNA 08-28-21 04:41 PM


Originally Posted by championadrien (Post 12483184)
No just the Wastegate. Leave the pre-control alone. I'm suggesting to remove both lines from the wastegate to have 0 chance supplying boost to the actuator.

Okay, I see what you are saying now. I wasn't sure if you wanted me to disconnect the hose from the precontrol or not, the numbering looked like it might have pertained to it, but I wasn't sure.

I'll have to get on that, I'm assuming the best way is to just cruise under light throttle to 4500, increase throttle until I see 10psi, then let off?

championadrien 08-29-21 11:07 AM


Originally Posted by SwappedNA (Post 12483218)
Okay, I see what you are saying now. I wasn't sure if you wanted me to disconnect the hose from the precontrol or not, the numbering looked like it might have pertained to it, but I wasn't sure.

I'll have to get on that, I'm assuming the best way is to just cruise under light throttle to 4500, increase throttle until I see 10psi, then let off?

That's how I would do it. Try it in different gears too.

rx7girlTK 09-05-21 10:17 AM

I’m having a similar problem except my primary boost only goes to .40-.48 then drops off at secondary to like .20. I changed the hosed on my CRV and I looked at the vacuum hoses and one from the wastegate solenoid was off. I put it back on went for a test drive and it seems to almost be worse. Neither of my connectors have a white dot on it. The flap in the ypipe moves fine by hand. I have yet to take a look at the actuators. When I came back I pulled a hose off of the pressure tank by the UIM and hair came out so that is holding pressure

SwappedNA 09-05-21 02:49 PM


Originally Posted by championadrien (Post 12483295)
That's how I would do it. Try it in different gears too.

So it turns out, talking to the tech that did the job, he's tested the wastegate already. I've also checked the PowerFC on the off chance that the sequential turbo control was set to off, but it is confirmed to be on.

Here are the techs notes about testing the wastegate:

"After installation of parts, found secondary turbo still only making around 50 kpa per gauge on dash. Found workshop test procedures for testing wastegate actuator. Test one is to apply 14-15 Psi to actuator, and test two is to apply 7 psi. Test procedures align with indicated boost pressures on test drive. Car is exhibiting normal operation"

So my question is, if he tested the wastegate actuator and it's performing like it's intended, what else could be causing my issue? I really don't think its a clogged cat, but I'm not about to rule that out. Once I hit 4500 and the issue begins, if I let the RPMs drop below that and try giving it more throttle, it still won't build back up to 10 PSI. Any thoughts?

championadrien 09-13-21 11:17 PM


Originally Posted by SwappedNA (Post 12484200)
So it turns out, talking to the tech that did the job, he's tested the wastegate already. I've also checked the PowerFC on the off chance that the sequential turbo control was set to off, but it is confirmed to be on.

Here are the techs notes about testing the wastegate:

"After installation of parts, found secondary turbo still only making around 50 kpa per gauge on dash. Found workshop test procedures for testing wastegate actuator. Test one is to apply 14-15 Psi to actuator, and test two is to apply 7 psi. Test procedures align with indicated boost pressures on test drive. Car is exhibiting normal operation"

So my question is, if he tested the wastegate actuator and it's performing like it's intended, what else could be causing my issue? I really don't think its a clogged cat, but I'm not about to rule that out. Once I hit 4500 and the issue begins, if I let the RPMs drop below that and try giving it more throttle, it still won't build back up to 10 PSI. Any thoughts?

It is good that it was tested, but that doesn't necessarily test all the same metrics as the test I described. Artificially applying 14-15 psi to the 6mm ports on the actuator would ensure it moves eventually. Applying 7 psi to those same ports ensures it moves at its rated spring pressure. What it doesn't test is if the spring pressure is enough to hold the wastegate door closed against the buildup of boost. There is no artificial way to supply pressure to the wastegate door -- you must have the turbos build that boost. In short, he's not tested the wastegate, he's tested the wastegate actuator.

In addition, this doesn't eliminate the possibility that something in the sequential control system is or is not directing 7 psi or more, post-transition, into the wastegate actuator. Remember that once the wastegate actuator sees 7 psi, it begins to open. This could be caused by incorrect vacuum hose routing and/or bad wastegate actuator solenoid(s).

I still recommend going through with the test we discussed above. There really is no other replacement for this test.


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