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 Possibly an o2 sensor issue?

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LLcoolJames
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PostSubject: Re: Possibly an o2 sensor issue?   Wed Jul 14, 2010 11:07 pm

makes sense now, just was a little confused lol
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PostSubject: Re: Possibly an o2 sensor issue?   Wed Jul 14, 2010 11:15 pm

Blackout wrote:
Well, the fuel is boost dependant until you reach Full boost. So say Im running 30 PSI of fuel pressure base, and I boost it 15 PSI. My reading at 15PSI should be 45 PSI on the gauge. The computer should adjust the pulsewidth wider as the rpms go up, but it should lean out a bit considering there is only much that the ecu can increase the duty cycle.


As the injector duty cycle increases, its my understanding that it can only go so much..... causing it to lean out twards the upper limits. After all, its still at the same 45PSI fuel pressure.

that would only be the case if you were running out of injector. pulse width at low rpm might only be sav 5% at idle and only 70% at WOT and peak rpm you can tune it up or down. if your injectors are maxed out then you will hit a point where it gets to 100% and can't go any higher that is where added fuel pressure helps out. it also helps in doing kind of an auto tune as boost comes up so does fuel pressure so that the injectors don't have to adjust pulse width so much from idle with lots of vac to wot with boost. most try to stay at or below 80-85% duty cycle to help injector life.
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PostSubject: Re: Possibly an o2 sensor issue?   Wed Jul 14, 2010 11:18 pm

I think that I'm going to get the O2 sensor on the car and see where it goes from there. At the very least, its a questionable part and should be changed out, so its not exactly throwing parts at it. Honestly, the "parts i havn't changed" list is getting VERY short. I really am not expecting this to change much, since Ive had other bright ideas in the past and its all ended in dissapointment. If it fixes the problem, or improves it...... bonus. At least it subtracts another variable from the problem.

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PostSubject: Re: Possibly an o2 sensor issue?   Wed Jul 14, 2010 11:19 pm

Once Nate gets his Dyno back up and running, i'll take it out there and see what the sheet says. Power is gonna be WAY low, but at least I can get a good indication of what A/f is at what RPM.

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PostSubject: Re: Possibly an o2 sensor issue?   Thu Jul 15, 2010 1:50 am

Sounds like its time for a good tuning software where you have control as to what happens and not throw shit at it and hope the ecu corrects for it.
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PostSubject: Re: Possibly an o2 sensor issue?   Mon Jul 19, 2010 7:04 pm

Put the new O2 sensor in today, and tried to set the fucking cam timing again. Car still runs like shit. I'm apparently having some issues setting the cam timing, so i think thats a lot of the issues that im seeing. No matter what I fucking do, it always seems to be off in some way shape or form. Anybody have any ideas?

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PostSubject: Re: Possibly an o2 sensor issue?   Mon Jul 19, 2010 7:45 pm

Did you mention before you had worries about the valve springs?

I know you had talked 02 at the shop last week (by the way, did the camber change?) and mentioned getting one. Your FP was spot on....

I wonder if the factory mappings just can't handle what is going on? The boost is up from stock isn't it?

I know the way with Fords....tighten and check all grounds, Coolant temp check, Baro, 02, then check all the grounds again....then start worrying about other stuff.
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PostSubject: Re: Possibly an o2 sensor issue?   Mon Jul 19, 2010 10:40 pm

The stock tune should be able to handle what is done to the car so far. I checked literally everything you have just listed. Everthing is at factory spec. BTW, the camber didnt move a centemeter.... all is good. O2 sensor didnt do a damn thing lol. The valve springs were replaced, and that fixed the car dieing at high rpms thing it was doing.

Its pretty much GOT to be cam timing.... something is defcinitely off in that department.

No matter what i do, its always off somehow...

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PostSubject: Re: Possibly an o2 sensor issue?   Mon Jul 19, 2010 10:48 pm

MAF/flapper door
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PostSubject: Re: Possibly an o2 sensor issue?   Mon Jul 19, 2010 11:20 pm

brngrhd wrote:
MAF/flapper door



Flapper door..... replaced as well. The voltages seem to be correct vs RPM. The door does flap if held in one position too long, like at 55 MPH in 5th gear....Ive attributed that to a bit too high of spring tension on the door. (I can lower the spring tension and it stops flapping... but then it runs REAL rich) But the meter doesnt have any flat spots in its travel, and reads correct voltages throughout the range of door motion. It WILL be eliminated next year, by Megasquirt. Speed Density FTW.



Honestly, the Cam timing HAS to be the problem, or at least the major portion of it at this point. Before the cam swap while running the crappy worn to hell stock slider with the SAME MODS i got 28.8 MPG. After the cam swap, I get 15-16PMG.....The cam grinder has put this very cam in lots of cars, and nobody has ever had MPG issues with it at all. Most people are running this cam with more mods than I am and getting well over 25MPG..... so SOMETHING is fucked up in the cam department. I just need to get the crank pulley off somehow and go over everything lining it up again. As soon as the crank pulley is off, I can line up the crank mark, and then the cam correctly. OR, i need to find true TDC (the plastic cover might not be accurate) and go from there. Its just frustrating that summer is over half done, and Ive had the car out ONCE.

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