Running lean at stock boost....????

[yellerandahalf]

Hey dudes, I have noticed a new issue with my car. Since it warmed up to a nice 70 degrees down here in NC, I've been wanting to put my MBC back on. That is, until i noticed that massive hesitation my car seems to have found. Thing is, around 5k RPM or so, I'm watchin my A/F meter, and it goes back and forth, back and forth, LEAN, for like a SECOND, then BAM, it goes into rich crazy and starts pulling. Massive hesitation and power surge, and no discernable interruption in boost pressure. Any ideas? Didn't do that last summer...hmmm
I'm flashed BTW, and with I wasn't. but that's another issue
-yeller

 

[03MSP]

Well, the ECU switches to open loop at weird places. Where most of the cars I've worked with switch right at WOT, the MSP switches depending on a lot of different factors...shouldn't worry too much about it, just pay attention the the mixture when it finally pegs down.

 

[mspeed101]

Hey dudes, I have noticed a new issue with my car. Since it warmed up to a nice 70 degrees down here in NC, I've been wanting to put my MBC back on. That is, until i noticed that massive hesitation my car seems to have found. Thing is, around 5k RPM or so, I'm watchin my A/F meter, and it goes back and forth, back and forth, LEAN, for like a SECOND, then BAM, it goes into rich crazy and starts pulling. Massive hesitation and power surge, and no discernable interruption in boost pressure. Any ideas? Didn't do that last summer...hmmm
I'm flashed BTW, and with I wasn't. but that's another issue
-yeller

Ive noticed the same thing with my car! It will lean and go back to rich. I wonder if putting a boost controller will help?

 

[jflo]

most cars do that at idle, too

 

[ylmazdaspeed]

The air fuel gauges you're using aren't totally accurate. Most of the time the MSP does have a problem with too much fuel. Be concerned with leaning out at peak boost.

 

[mp5jeff]

get a wideband and sell your a/f gauge.

 

[Emode]

get a wideband and sell your a/f gauge.

that is correct!

 

[EvilMSP]

Whats a wideband?

 

[mp5jeff]

wideband o2 sensor...tells you the CORRECT a/f ratios.

 

[EvilMSP]

Interesting. Does it display the data in a gauge like the a/f micture ones? If it is better I assume it costs a lot more or else more ppl would have it (i always hear about a/f ration guages).

 

[Rich24km]

my car only does that in 4th at about 3000 rpms when you are 3/4 throttle.....and back off a little..

 

[JeRNuT]

wideband o2 sensor...tells you the CORRECT a/f ratios.

does it cost a lot more? Can i get a guage to go with the wideband? I wanted to get a A/F guage but i keep hearing they are worth s***

 

[t3ase]

does it cost a lot more? Can i get a guage to go with the wideband? I wanted to get a A/F guage but i keep hearing they are worth s***

The Greddy EGT gauge is pretty accurate or so it's supposed to be. A wideband normally has a LCD screen with it instead of a gauge.

 

[seatbackfurther]

You can get PLX wideband for 319 w/shipping. They also have a narrowband gauge to wideband gauge converter for 40 w/shipping.
http://www.plxdevices.com/onlinestore_domestic.htm

AEM also has a wideband with gauge which is about 450 w/shipping.

 

[BinaryRotary]

Hey dudes, I have noticed a new issue with my car. Since it warmed up to a nice 70 degrees down here in NC, I've been wanting to put my MBC back on. That is, until i noticed that massive hesitation my car seems to have found. Thing is, around 5k RPM or so, I'm watchin my A/F meter, and it goes back and forth, back and forth, LEAN, for like a SECOND, then BAM, it goes into rich crazy and starts pulling. Massive hesitation and power surge, and no discernable interruption in boost pressure. Any ideas? Didn't do that last summer...hmmm
I'm flashed BTW, and with I wasn't. but that's another issue
-yeller

Which O2 sensor do you have the gauge hooked to? The first O2 sensor is going to send the A/F meter into a frenzy. If you have it on the second O2 sensor it should be a LOT more accurate.