Primary boost missing, have question on TCA
#1
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Primary boost missing, have question on TCA
I get no boost under 4500 then the typical full boost at chang over. Now Ive had this problem before and I replaced my rusted TCA for a newer one. Now the same problem is happening and I cant seem to find anything. Which particualr hoses control primary boost?
Ive checked the plastic boost chamber, and air pressure is being held in it. also the car when trying to boost under 4500 makes the duck noise when shifting. Any help, thanks.
Ive checked the plastic boost chamber, and air pressure is being held in it. also the car when trying to boost under 4500 makes the duck noise when shifting. Any help, thanks.
#2
MAGNUM SE7EN
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Well, if it turns out you need another tca I can sell you one for $10 plus shipping.
morganf1@aol.com
morganf1@aol.com
#3
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http://www.autosportracetech.com/RX-...erOverview.htm
It sounds like your wastegate is stuck open. Check the actuators (including the turbo pre-control).
It sounds like your wastegate is stuck open. Check the actuators (including the turbo pre-control).
#5
i would look into the ccv venting primary boost because the cca (the door in the y-pipe) is open and allowing boost out before the transition. after 4500 the crv closes and so it is not a problem.
#6
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First, visually inspect the wastegate. Make sure the e-clip is still holding it together, and try to move the door - it should be snugly pulled shut by the actuator spring.
The CCA is the little actuator on the y-pipe. Disconnect the vacuum hoses and move it with your fingers - it should snap quickly shut and have enough spring force to stay shut. If it moves slowly, but the spring is still good - take apart the valve and arm and clean it. Otherwise replace it with a good used part.
If you haven't found anything wrong, use a Mityvac to see that both actuators move per the FSM specifications. Let them hold for a few seconds to make sure there is no slow leaks.
After these visuals, I would tee into these lines with a pressure gauge and see if they are receiving correct pressure or vacuum during WOT runs. That should show if this is a solenoid or actuator problem.
Dave
The CCA is the little actuator on the y-pipe. Disconnect the vacuum hoses and move it with your fingers - it should snap quickly shut and have enough spring force to stay shut. If it moves slowly, but the spring is still good - take apart the valve and arm and clean it. Otherwise replace it with a good used part.
If you haven't found anything wrong, use a Mityvac to see that both actuators move per the FSM specifications. Let them hold for a few seconds to make sure there is no slow leaks.
After these visuals, I would tee into these lines with a pressure gauge and see if they are receiving correct pressure or vacuum during WOT runs. That should show if this is a solenoid or actuator problem.
Dave
Last edited by dgeesaman; 01-17-05 at 11:42 AM.
#7
Da RX7 iz my Mistress
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If it makes the duck noise it;s normally a check valve. that will limit your primary boost and allow you to have boost over the 4500. Check your check valves and inspect your wastegate that should definantly narrow down the problem or you might find the culprit.
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#8
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Thanks again, Ill try checking the check valves. Ive had this problem before but it turned out to be a rusty CCA that was stuck shut all through the RPMs. But everything visually looks fine. Thanks again.
#10
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glad im not the only guy with a primary boost issue like this one.
I found a leaking pressure chamber check valve.I need to order a replacement though.Let us know what you find.Given the fact that im also suffering from the same symptoms.
I take it turbo lag is also an issue as well now compared to before.
I found a leaking pressure chamber check valve.I need to order a replacement though.Let us know what you find.Given the fact that im also suffering from the same symptoms.
I take it turbo lag is also an issue as well now compared to before.
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yup those are the ones.The one thats leaking on mine is the pressure chamber one thats connected to the Y pipe.Hmmm.
That makes sense I suppose.If its leaking then boost is leaking out the vacuum line when its not supposed to into the pressure chamber.Which explains why my primary and secondary might be limited to 7 psi.
That makes sense I suppose.If its leaking then boost is leaking out the vacuum line when its not supposed to into the pressure chamber.Which explains why my primary and secondary might be limited to 7 psi.
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I dont believe it is the check valves and I still have pressure in the plastic tank. Pulled my hoses when the car was turned off to confirm. Still need more investigating.
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