Chip Help

[BlownZ]

I posted this in General Tech too but with little luck so please bear with me...I have searched the archives, I thought I cured this problem 12 times. I think I know the answer...I would like your expert opinions.

Te61 Turbo set on KILL Wastegate ROD all the way In
100 Octane Unleaded
MSD 50lb injectors
Jim Testa Street Chip for 50s 19 deg. Timing I think
Walbro 340 Hotwired
Ported Irons
Ported Manifold
Ruggles 210/205 cam
RJC Plate
Headers
Rebuilt Engine with cam and valvesprings...approx 20k miles.
Fuel Pressure set from 43-48 no change in problem
New Coil/Module
Checked Grounds and Positive and Neg cables...all good.
New R42 TS gapped at .035

Car runs like a raped ape....UNTIL you hit about 20-22 lbs of boost. Then it stutters, misfires, pops, farts etc.

O2s at this point from .780-.812
MAF seems to be locked at 254 as the scanmaster reads that reading from about 10lbs on up.
TPS .42 idle...4.2 WOT

If I turn the boost down to 18 then it runs great...no KR ...no misfire etc....pulls hard and life is good.

This is my theory...good or bad. Is 19* timing enough to light off a 20 plus psi load? I am wondering if I simply need more timing. When it misfires at 20 or so psi I am not getting knock of any significance...it just stutters and surges until I let out of it. Would lack of timing cause an issue like this? I have a race chip in the mail with 26* of timing and that may cure the issue but I wanted to hear from the experts.

Do I need a Max Effort or Extender/TPlus combo with my setup? Am I barking up the wrong tree....Should I get some gas and a match? I am new to Turbo Buicks so I will take all of the free education I can get.

 

[ijames]

No you don't need more timing as the boost goes up (you'll make more power but need even more octane). Two things. First, what happens to the O2's as you raise the boost 1 psi at a time from 18 to 22 or wherever the popping first happens? If you leave the fuel pressure up at say 45 psi they should be over 800 mV at 18 psi and should smoothly fall as the boost goes up (don't let them get below 770 or so, raise the fuel pressure if you need to as you work the boost up). Second, after you do that series of experiments, try closing down your plug gap to 0.033" or maybe even 0.032". Okay, third thing -)), you might be running into MAF overflow. I don't know if you can see this without directscan, but what do your maf and lv8 values do right when it pops or misses? If either drops any at all that's your problem. See if a friend with a translator and lt1/ls1 maf will let you borrow it for a test (with the limit switch turned on inside the translator).

 

[BlownZ]

O2s are low .800s and drop slightly as third gear winds out. I have not tried increasing the boost in one pound increments. My O2s generally will stay above .800 the entire run.

My MAF seems to be locked at 254 the entire time that I am WOT...it hits 254 at approximately 10-12 psi and stays there all the way up. I suspect the chip locks the MAF? It is a Jim Testa 93 Octane chip. Does he normally lock the MAF?

I need to close the gap...that is one thing I have not tried as of yet. I have seen several references to it but I have yet to do it. I am going to try that tomorrow night when I get home from work.

I'll update the post then to see if it cured the problem.

 

[TurboJim]

I dont fuel a street chip for 22psi unless its an alky chip. Add to that the ported heads etc and I bet you're leaning out. SM says its rich, or at least OK most likely due to misfire causing an artificial rich condition.

Unless I programmed that chip special for you...sorry, I dont recognize the email address, its only fueled for 19-20psi tops.

Thats one reason I dont care for ALDL based scan tools....what are you missing in the 1.5 secs it takes to refresh the data?