I can't boost lower than 14-15 PSI and I think my O2 sensor is out
 

Ok, well i was driving my car today and i just noticed that my O2 readings are not accurate anymore. When I am at idle, my O2 is at 5.00 Volts. When I am driving it around it jumps from 1 volt to 2 volt. I'm pretty sure my O2 sensor went out. Will this affect my car in any way?

My other question-
I cannot get my boost any lower than 14-15 psi. I dont know why. I made a custom boost controller. I am 100% sure that everything is hooked up right. Also, my Injector d/c is maxed out to 105%. I need to lower my boost! I have a 3/S fuel pump in my car, I was wondering if this was causing me to not boost any lower than 14-15 psi.

Well the mod list is on my signature. Can you guys tell me whats wrong? I've ran out of ideas.

Re: I can't boost lower than 14-15 PSI and I think my O2 sensor is out
 

I think its your manual boost controller. Is that when you noticed the difference in psi, is when you installed the boost controller? You could change our you o2 sensor, but the readings is not affecting performance, just gas mileage, and CEL on a 2g.

If you cant change you boost right away, turn your base timing down, that should help out with any knock, and maybe lower injector duties.

Re: I can't boost lower than 14-15 PSI and I think my O2 sensor is out
 

Remove your boost controller and plug the vacuum line directly into your wastegate and see what you get for boost. That will help rule out if your boost controller is bad or if it's your wastegate.

Re: I can't boost lower than 14-15 PSI and I think my O2 sensor is out
 

Fix and replace.

Re: I can't boost lower than 14-15 PSI and I think my O2 sensor is out
 

You answered your own question.

Re: I can't boost lower than 14-15 PSI and I think my O2 sensor is out
 

How are you reading the O2 volts? That is a 0-1 volt sensor. You shouldn't be getting much over 1 volt ever. If it is sending 5 volts to the ECU, that could be a problem, I don't know if that input is designed to handle that much voltage.

Re: I can't boost lower than 14-15 PSI and I think my O2 sensor is out
 

Turbo boost pressure & mass air flow are independent of fuel pump output & fuel pressure.

Re: I can't boost lower than 14-15 PSI and I think my O2 sensor is out
 

replace the o2 sensor, if you ever get more then 1volt then the 12volt heater wire is shorting out somehow inside the sensor and some of the voltage is bleeding off into the data wire going to your ecu.......so imagine if all of a sudden 12 volts jumped down a line into your ecu where the ecu is only equipped to handle 1volt.

get a joeP MBC, they are pretty good.

Re: I can't boost lower than 14-15 PSI and I think my O2 sensor is out
 

Ok, but will the 02 sensor affect my car in any way? I want to know so i can store it or drive it.

Re: I can't boost lower than 14-15 PSI and I think my O2 sensor is out
 

The O2 sensor is extremely important, a properly running car needs one, I wont say that simply replacing your broken O2 sensor will fix all your DSM's problems, but when it comes down to fixing a dsm, you really cant be half-assed about it, fix what you know is wrong, and then go from there

Personally i would never trust my engine's life to a boost controller that I concocted, this is another example of why half-assing your dsm just wont work.

So please, take it from someone who has been where you are now, its not worth your time to try to duct-tape fix it, just cough up the money and move on, hell, a used o2 sensor should be really cheap, its no big deal, just buy a new one

Re: I can't boost lower than 14-15 PSI and I think my O2 sensor is out
 

Sell your DSM and get a Civic with altezzas, it would be a perfect fit for you.

Re: I can't boost lower than 14-15 PSI and I think my O2 sensor is out
 

Reread the god damn post. It says "I think my o2 sensor is out." All i wanted to know if it was my o2 sensor or something else. I dont have much free time to repair the damn car. That was why I wanted to know if it was still ok to drive it or not so i can store it or not. This car is my daily driver. I am just trying to save the hassle of doing replacing every part to figure out that none of it was what i needed to replace. Im just trying to cut to the chase and get others opinion on it. So dont post if you have nothing good to say.

Re: I can't boost lower than 14-15 PSI and I think my O2 sensor is out
 

Oh yea, and my cars not half assed just to let you know. And I trust my boost controller that I made. Who here doesnt make thier own custom shit for a dsm.

Re: I can't boost lower than 14-15 PSI and I think my O2 sensor is out
 

Your o2 voltage is off, sensor is probably dead. In the manual, which you should own if you work on your vehicle yourself, there is a procedure to test for restistance values. It will affect your car, as the majority of your car's operation is based off it.
The fuel pump size should not MAKE YOU run a amount of boost. If its way oversized, it could mess up your tune and the ability to tune, but running xxx fuel pump doesn't automatically make the car run xxx amount of boost. They are not directly connected to each other in that way. They are components of seperate systems, that are interconnected in your vehicle, which eventually connecting to your motor. I had a 3kgt pump in my auto, running 11psi of boost off the factory bcs...everything was gravy. Your boost controller is sticking and failing. Too stiff of a spring? Sticky ball? Kinked line? Something is out of whack. Maybe your wastegate actuator is bad?
Yes. See above. Also, running open downpipe isn't the most effective way of making power on a street car.
With the stated 1/4 time, either your car has severe tune issues, or you need to drive the car in a different manner.
Good luck.

Re: I can't boost lower than 14-15 PSI and I think my O2 sensor is out
 

Ok, i found out the issue on the boost. I hooked up the lines straight to the wastegate actuator. It isnt the boost controller. My wastegate actuator spring is bad.

Well, when i ran the car at the track at 14.6 @ 83 MPh, It was all stock. The mod list i have right now was after i ran the 1/4 mile. Also, my timing was off a teeth when I ran the 1/4. It is all fixed now.

Re: I can't boost lower than 14-15 PSI and I think my O2 sensor is out
 

Why would you want to run less than 15psi anyways? When you make the intake and exhaust paths less restrictive, you often can't run very low boost on an internally gated turbo, even the stock ones.