TTA RUNNING like SHI*

S

screaminchicken

New Member
Joined
May 19, 2003
My TTA isn't running that great since i bought it, before it use to be tunable to 13.2, then iwhen i got it its an entire scond slower, the best i ran was 13.9 in tucson in 50 degrees. My TL says theres no knock, IAC 111/ 44% LV8 255#, TPS 4.70 v, integrator 128 02 volts 813mV, o2Xcnt 0#, Mass air flow 226 GPS, block lean 128, MAT 95.5 Deg, ECS counts 2, spark retard 0.0 deg. Battery volts 13.5V Mixture: Rich loop closed, and only 94MPH!!! Can anyone see something wrong, this was on a thrasher 92, 19psi boost with 100 unleaded fuel, and 48psi fuel. no Malfuntions ETC. all this was taken right before i got off the gas. Any help would be great, I changed Valve springs to 100psi's, got a new o2 sensor, still no help!
Eric
 
Mass airflow on a pass should max out a 250-255 GPS so that is a problem. The instructions for my 92 thrasher indicate that fuel pressure should be set a 45 psi and anything more will cause drivability problems. The 92 is not really set up as a race chip. You are also running "fat" I would shoot for about .780 O2 volts. This can be achieved by turning your fuel down.

The time in my sig was run on a 92 thrasher with 45psi and 108 octane.

HTH
 
O2 Volts

Where are you seeing the O2 volts cause I think I posted 128 O2 Volts, so how do i drop it to .78volts? Also what do you think is the deal with my MAF GPS? Thanks for the help
 
.....he's saying you posted:

02 volts 813mV

That's the number that's a little fat. You can bring that down, get a little leaner. First thing to try is dropping the fuel pressure back to 45 like the Thrasher wants and get some new readings.
 
The maf reads a maximum of 255 grams/sec. Dying maf's usually show lower values. I would look at the filter to see if it is dirty, that'll cutdown on airflow. If a filter change doesn't do it, you can try to pull the screens out of the maf and see if the value changes. If not the maf is dying, reading the incorrect amount of air, thus making inaccurate corrections to the fuel.

Turn your fp down to 45 static(line off). Try running without the race gas. Race gas burns slower than 92 unleaded which could mean the combustion cycle isn't completeing itself causing it to run fat. I'd shoot for 760's to be safe. Running that kinda octane you'll need more spark than the thrasher cn give you.
 
Agree with others, fat on the fuel. I run 97 octane (93 pump + zylene) at 20 PSI (less octane, more boost) with a Thrasher 92 and still end up a little rich. I do have Blue tops. Any way, take (line off) fp to 45 as others said and see what happens. I actually run like 43-44 myself to lean mine down a hair more. The thrasher does like 45 for the idle but mine does fine, for me, a little less.

Brent
 
Ya need to start to learn how to tune the car. The thrasher will be an easy chip to tune since its WOT is open loop..which means it doesnt care what the O2 reads.

Drop your fuel pressure to 45 and make a pass..see what the O2 numbers are and watch the knock retard. As long as there is "zero" knock, keep dropping FP until final 02's get in the mid-upper 700's...once here..up the boost a little at a time..and add fuel a little at a time..watching for retard..as long as there is no retard..keep playing with it. The car will run fastest the leaner(less O2) it sees..use your knock numbers..they will show the lite.

Your MAF should peg 255 as soon as you get into it..within a short distance. If it doesnt..find the restriction or replace the MAF.

Stock the car will run mid 13's at over 100 mph fwiw.

Tuneup, clogged cat, clogged muffler, bad coil pack, bad wires..too many variables.

Lastly, its not the chip..my sig below was on a thrasher92 chip. And fuel pressure is a personal thing..mine likes 42 lbs vac line off.
 
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