View Full Version : I can't boost lower than 14-15 PSI and I think my O2 sensor is out
94talonawd
10-25-2005, 08:49 PM
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.
turbo2086
10-26-2005, 12:28 AM
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.
Matt D.
10-26-2005, 08:18 AM
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.
Shotgun!
10-26-2005, 09:14 AM
Fix and replace.
Kracka
10-26-2005, 09:46 AM
My other question-
I cannot get my boost any lower than 14-15 psi. I dont know why. I made a custom boost controller..
You answered your own question.
Shane@DBPerformance
10-26-2005, 10:57 AM
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.
Jakey
10-26-2005, 12:43 PM
Turbo boost pressure & mass air flow are independent of fuel pump output & fuel pressure.
iceminion
10-26-2005, 03:52 PM
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.
94talonawd
10-26-2005, 10:02 PM
Ok, but will the 02 sensor affect my car in any way? I want to know so i can store it or drive it.
iceminion
10-26-2005, 10:24 PM
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
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