Miss @ High boost w/ a 93 street?

[ATEUUP]

My TTA is missing when I turn the boost up over 18 psi. I swaped the usual stuff (module/coil pack, wires, plugs gaped to .032, etc.) Nothing seemed to have an effect.

My combo is below

stroked stock block 252 ci,Champion heads / intake,212 206 roller, TA-49, A/C 3000 stall, 40 lb red stripes, JC 93 street and the usual bolt ons.

I was maxing the maf at 255 w/ only 12-14 psi.

Could the fueling of the street chip be causing the miss even though the 02s look good at high 700s w/ 0kr.

I want to go fast and this is holding me up. Need to figure it out before it's time to take the car out in the spring.

Thanks for any ideas,
Greg

 

[ijames]

One problem with O2 volts is that you can't trust them once the motor starts to miss . If you turn the boost back down a couple of psi do the O2's rise into the mid-800's? Otherwise you may be going lean and not realizing it. A couple of times over the years I've been bit by a miss at full boost with good-looking O2's and it was the fuel filter plugged up so the motor leaned out enough to miss. After the first time I'm embarrassed to admit how long it took me to diagnose things the second time. Now I change the fuel filter every other oil change (GM said 7500 miles stock and we all have much higher volume fuel pumps that stock).

 

[ATEUUP]

Thanks for the reply.

The fuel filter is new. But, that doesn't mean it's not the problem. I'll change it out. It would be great if it was that simple!

Forgot to mention I have a Walboro w/ hotwire

 

[Sleeper]

FWIW
You may be getting the dreaded MAF drop out, where the MAF maxes out and resets. If you are running DirectScan you will see the drop outs. One solution is... Translator+ setup so you can go over the 255 limit.

Paul

 

[JayC]

If the chip is fairly recent, he isnt suffering from MAF dropout

 

[ATEUUP]

Jay,

The chip is from Cottons and it was from the begining of last summer.

If it's not that do you think it could be the 93 street?

I'm running out of things to check here!

Give me some ideas....

Thanks,
Greg

 

[Sleeper]

What scan tool are you running? Are there any recorded runs we can look at?

Does this miss happen at a specific RPM?
Does it occur in all gears or just top end?

Just throwing some stuff at you that you probably already checked but...
Checked all your grounds?
How old is your 02 sensor?
Are you positive it is a miss and not wastegate flutter?

lastly, with your combo... you may be running out of injector.

Paul

 

[JayC]

If I had to make a guess, I would say that you are just out of injector. For your combination, I would step up to some 50s or 52s or something along those lines.

 

[Intercooler]

As you can see at the bottom of the sig I had the same problem the entire length of the track with a RA-93 chip. It doesn't have enough duty cycle! I plopped in the Max-Effort and it was gone with no other changes. O2's came up and it would run crisp until the moon! Unfortunately I was still 100% DC with the 55's so that is the reason you see the 75's in there now! Don't try to go for kill on a street chip, get a good race chip with some DC and if that doesn't do the trick maybe it is time for injectors.