Adjustable fuel pressure regulator, quick question.

[Swiggart]

I have read that i can change the setting a small amount and get my car to run more lean/ more rich with it. But i have also read that i can't because the mixture is read by the o2 sensors. I think i could do some quick, small changes with it and get my car running more stoich. I know the car doesn't use the o2's at WOT so would this help me in any way? I bought it and just curious what i could use it for, i think it could work in theory.

[Injuneer]

The stock tuning is too rich at WOT (power enrichment mode). The correct way to lean it out and pick up 10-15HP is to adjust the PE tables, to reduce the typical 11.7:1 target A/F ratio to something closer to 12.8:1.

Using an AFPR, you would lower the fuel pressure to lean it out.... for a while. While you drive the car at moderate loads, the O2 sensors feedback would richen the mixture right back to stoichiometric by raising the LTFT's = no change in closed loop/part throttle. Then when you exceed the RPM and TPS% limits for power enrichment mode, it ignores the O2 sensors, but if the PCM was adding fuel in closed loop, it will generally use the LTFT's in Cell 15, which would be above 128 (due to the O2 sensor feedback in closed loop), meaning it would actually run richer in PE mode.

What makes you feel the engine is not running at stoichiometry in closed loop?

[Swiggart]

It fouls plugs and the smell of raw gas is unbelievable. I think I need new o2 sensors. Is there a cheap place to purchase those too?

[Blackbird96WS6]

American-Powerhouse has the best price on brand new O2s that I've seen.

[American-Powerhouse]

Thanks for that post, Peter.

If you would please tell me what they are going? Year, model, engine...

I'd be happy to get you a price.

[Injuneer]

What year is the PCM? If you can run a data log, we can take a look at it.

[Swiggart]

Its a 94 pcm, shoot me a price. Its a 94 z28 camaro engine. I've been having issues with getting my pcm to connect to my computer. I've had it connected before but it wont connect anymore.

[Injuneer]

What software are you using? Have you tried GaryDoug's 94/95 OBD-1 LT1 software? If you have problems connecting he will help you sort it out.

[Swiggart]

I dont think I've heard of it? Where do I download/buy it?

[Injuneer]

BobDec posted a thread in this site with a link to the download site. I'll see if I can find it. I know where the link is on CZ28.com but I doubt posting it here would be welcome. It is totally free, and easily as good as DataMaster.

[EDIT] Go to post #4 in this thread:

http://ltxtech.com/forums/showthread.php?24987-Scanning-software&p=363257&viewfull=1#post363257