Strange 7 psi boost on stock turbo control. 10 psi only on second turbo w/ profec
07-21-07, 11:10 AM
#1
Strange 7 psi boost on stock turbo control. 10 psi only on second turbo w/ profec
Ok so I've searched but this is kind of a weird problem, but I'm assuming a very simple vacuum leak. I would like to ask and see what might be leaking to cause such a strange problem. Maybe the turbo solenoid?
My car has a 3" down pipe, a after market hi-flow cat, a Flowmaster 40 series muffler, an Apex'i intake, a after market SMIC (Mazdaspeed I was told.), a Profec B-spec II boost controller (to lower boost spikes), the fan mod, and probably a few other things done to the engine but a 35k mile rebuild currently. Automatic
The car will not boost higher than 7 psi (6.8 according to Greddy boost controller) on the stock turbo control. I have checked all of the vacuum lines I can get to without pulling the intake manifold off. I noticed the problem after the boost controller was going crazy not being able to control boost at all. That was a busted vacuum cap on the waste gate. I then hooked up the boost controller again and the car will not boost higher than 7 psi under 4500 rpm. However at 4500 the monster comes out and the car launches at a full 10psi without a problem. Any suggestions? A vacuum leak? I have tried resetting the ECU but it did nothing. Thanks for your help!
My car has a 3" down pipe, a after market hi-flow cat, a Flowmaster 40 series muffler, an Apex'i intake, a after market SMIC (Mazdaspeed I was told.), a Profec B-spec II boost controller (to lower boost spikes), the fan mod, and probably a few other things done to the engine but a 35k mile rebuild currently. Automatic
The car will not boost higher than 7 psi (6.8 according to Greddy boost controller) on the stock turbo control. I have checked all of the vacuum lines I can get to without pulling the intake manifold off. I noticed the problem after the boost controller was going crazy not being able to control boost at all. That was a busted vacuum cap on the waste gate. I then hooked up the boost controller again and the car will not boost higher than 7 psi under 4500 rpm. However at 4500 the monster comes out and the car launches at a full 10psi without a problem. Any suggestions? A vacuum leak? I have tried resetting the ECU but it did nothing. Thanks for your help!
07-23-07, 03:36 PM
#4
The stock turbo control is set for 7psi. The reason the car boosts 10 stock is a kind of manual boost controller(pills in the lines) installed by the factory. Its possible that you have a vaccuum leak in your rats nest(the lines and solenoids under the UIM).
When you crank the boost controller does the boost respond accordingly?
Is the boost controller hooked up to both precontrol and wastegates actuators?
Id venture to guess that youve got a loose electrical connection to throw code, maybe the TPS.
It also sounds like youve got stock, non pilled lines for the precontrol and the boost control is only hooked up to your wastegate actuator.
When you crank the boost controller does the boost respond accordingly?
Is the boost controller hooked up to both precontrol and wastegates actuators?
Id venture to guess that youve got a loose electrical connection to throw code, maybe the TPS.
It also sounds like youve got stock, non pilled lines for the precontrol and the boost control is only hooked up to your wastegate actuator.
07-24-07, 01:34 PM
#5
I thank you for your suggestions.
The boost controller does change the boost accordingly but only on the second turbo. The primary turbo does not change.
I took the UIM off yesterday and all the lines are good and in working shape. I didnt check all the electrical connections but I did find one blue connector on top by the ypipe disconnected not sure what it does.
I do only have the boost controller hooked up to the wastegate and the precontrol is still hooked into the rats nest.
Should I try doing the boost controller hooked up to the wastegate and precontrol?
The boost controller does change the boost accordingly but only on the second turbo. The primary turbo does not change.
I took the UIM off yesterday and all the lines are good and in working shape. I didnt check all the electrical connections but I did find one blue connector on top by the ypipe disconnected not sure what it does.
I do only have the boost controller hooked up to the wastegate and the precontrol is still hooked into the rats nest.
Should I try doing the boost controller hooked up to the wastegate and precontrol?
07-24-07, 02:22 PM
#6
You should check your pre-control and wastegate control pills. The wastegate spring is a 7 pound spring so you are getting what the spring is allowing. Even if your pills are there I would try getting a new hose with them. Mine was having the problem and I had the pills but my hoses where old and had stretched around the pills allowing extra air to bypass the pills.
07-24-07, 03:43 PM
#7
What's your point ?
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Guessing since you have an after market hi-flow cat you don't have an air pump ? That would be the blue connector IIRC. May be your EGR plug if it's a 94....pretty sure it's your air pump.
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07-26-07, 02:04 PM
#8
The air pump is on but I don't think it's hooked up to anything. I will probably remove it soon. I tried hooking the boost controller up to the precontrol along with the wastegate and I get 10 pounds so it must be the lines. Can you get these anywhere other than the stealership? Maybe Autozone? (Wishful) Thanks
07-27-07, 12:42 PM
#11
No they are rubber and go between the pre control and wastegat actuators.
http://www.autosportracetech.com/RX-...BigPicture.htm on the right side of the pic are the actuators and the lines coming from them.
http://www.autosportracetech.com/RX-...BigPicture.htm on the right side of the pic are the actuators and the lines coming from them.
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