TURBO PROBLEM!! first and second gear only tho
08-05-07, 10:44 PM
#1
TURBO PROBLEM!! first and second gear only tho
OK well iv had this problem for about a month now and I'm sick of it.. didn't think much of it till now i wanna fix it (because of new job i haven't had time to drive it)
OK problem.. I get full boost in first till 4500 then the boost starts fluctuating between 5-8 psi and u hear the air pushing out from the engine bay (bov or the crv )going with the bouncing turbo gauge (and the turbos seem a bit louder now at this point)all the way till up till i shift to second which it sometimes does it here too, but in third and up i get full boost all through the rpms.... so it only happens in first and second.. any reason?...
info on the car.. stock port.. intake, DP,straight exhaust, air pump removed, PFC Steve Kan tuned.
OK problem.. I get full boost in first till 4500 then the boost starts fluctuating between 5-8 psi and u hear the air pushing out from the engine bay (bov or the crv )going with the bouncing turbo gauge (and the turbos seem a bit louder now at this point)all the way till up till i shift to second which it sometimes does it here too, but in third and up i get full boost all through the rpms.... so it only happens in first and second.. any reason?...
info on the car.. stock port.. intake, DP,straight exhaust, air pump removed, PFC Steve Kan tuned.
08-06-07, 04:08 AM
#4
it could be your actuator arms are a little loose. check to make sure there is no rattle or play in them. this will tighten up the response of the actuators. it is common to not quite hit 10psi in first... sometimes second? but since you spend more time in 3rd and up, your engine creates enough load to overcome a minor amount of play in the actuator. makes up for a weakness with a chance to create more volume... in a sense.
08-06-07, 02:40 PM
#7
From the site:
The Turbo Control Solenoid / Actuator is one of the more complicated actuators as it requires both vacuum and pressure to operate properly. This actuator is controlled by two solenoids, (both are wired together to the one ECU output) one solenoid applies pressure to one side of the actuator and the other applies vacuum to the other side of the actuator. With pressure on one side and a vacuum on the other side of the actuator, the speed of the actuator is improved. A typical problem is loss of Secondary boost in 1st or 2nd gear at 4,500 RPM, but reliable operation in other gears. This points to one side of the Turbo Control Actuator not getting it's pressure/vacuum, so it will still operate but not quickly enough.
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08-06-07, 09:07 PM
#10
Dave
08-07-07, 08:46 AM
#13
The first thing you need to do is to test the two Turbo Control solenoids. The FSM has procedures as to how to test them. As a test, you can swap the Turbo Control solenoids which is on the rack (not the ACV) with one from one of the emissions control as a test. Typically, that's the one that fails.
08-07-07, 08:38 PM
#16
Those tests are pretty basic. To get more in depth, try the KOKO test (see http://www.fd3s.net/boost_test.html). You will want a helper to watch the actuators as you key on/off.
Dave
Dave
08-07-07, 09:12 PM
#17
Those tests are pretty basic. To get more in depth, try the KOKO test (see http://www.fd3s.net/boost_test.html). You will want a helper to watch the actuators as you key on/off.
Dave
Dave
08-08-07, 03:28 AM
#18
The FSM tests are too simple to ensure that the solenoids are working properly - one reason why Dave Disney worked out his more intensive bench test. So jumping right to the FSM tests could easily lead you to believe the turbo control solenoids are working properly when in reality they are not.
I think it's quite sensible to use the KOKO, and if the TCA isn't moving correctly, to simply replace both TC solenoids and move on. I've seen both TC solenoids misbehave enough that this approach is not wasteful.
Dave
08-08-07, 08:54 AM
#21
Solenoids are known to also fail under heat which means the KOKO test can give the same false/positives as the FSM tests (if the car is cold). I do believe the KOKO test is a good test to do "without getting dirty", but in the end the components should be tested individually or else you are following the Mazda way of testing:
Engine won't run, replace everything.
08-08-07, 11:33 AM
#22
I disagree. The KOKO test does the same function as the FSM test (i.e. sending voltage to the solenoids). But, the FSM test actually break the test down into testing the individual components, not as a unit as well as making sure the solenoids themselves are flowing air in the right direction.
Solenoids are known to also fail under heat which means the KOKO test can give the same false/positives as the FSM tests (if the car is cold). I do believe the KOKO test is a good test to do "without getting dirty", but in the end the components should be tested individually or else you are following the Mazda way of testing:
Engine won't run, replace everything.
Solenoids are known to also fail under heat which means the KOKO test can give the same false/positives as the FSM tests (if the car is cold). I do believe the KOKO test is a good test to do "without getting dirty", but in the end the components should be tested individually or else you are following the Mazda way of testing:
Engine won't run, replace everything.
If you do the KOKO procedure on a hot car after a test drive you'll get real-world results. To get the same response on the bench you need to bake them in an oven and use a Mityvac. It's not so much about avoiding work as taking the shortest path. Once the KOKO has verified the operation or failure of some key items you can divide further with component tests.
Neither approach is incorrect. But it must make it clear that the procedure in the FSM is not sufficient to find all problematic solenoids. The better tests (Disney's method and baking them) are really important if you have the means to do so.
Dave
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