[Danderson]

As some of you know i am/was having problems with my tuner and getting car tuned right. so here is what is happening... we did some live viewing of the computer via diablosport of my cars fuel. car is running at 13.1 ish a/f at idle and is running boosting fine. i wanted that idle a/f up to 14.6 like it should so with is computer he did the following.
with the car showing its pulling 25% fuel on both banks he removed 25% fuel.
the result is...

a gain in a/f to 11.0 running richer as we watch what the computer is doing it goes from -25% to +25 fuel on one side while the other is still at -25%, so 1 side is at 25 and other is -25 wtf.

next he tries to remove even more fuel from the car and the result is 9.9 a/f and the car wont even run at this point on his own.

i want input on what could be causing the problem.
i have removed all the spark plugs and they are black from running rich i have removed the o2 sensors and they seem undamaged. the only other thing i can think of is the boost a pump is reading boost and dumping fuel in.

tuner suggested replacing the o2 sensors could this be the problem?

[Danderson]

oh yeah and he put the original tune back on the car and it wont run.

[stal94gt]

i would re-run your bap so it is pre fpdm. this will get rid of the hob's switch which is not a good thing to run on a returness fuel system. after that your tuner will probably have a much easier time mantaining 40 psi in the rails. since your running pig rich you may have a boost leak after the maf. are you still draw threw? if so and your still running the stock vortech intake check the slinky hose for tears. what maf are you running? your short term fuel trims should sit anywhere from .95-.98 at idle.

[stal94gt]

if you could please post pics of your set up, trust me it helps cause there is alot of little things that people run wrong.

[stal94gt]

btw a common thing that sets one side diff from the other is the egr or an exhaust leak at the header, if it leaks it will lean out the driver side, that is if he is trying to tune your car off the short term/long term fuel trims

[Danderson]

i think he was trying to tune it on short term fuel trims im not 100%. i think the idle 1k was just over 1.0 on the fuel table. the car is a blow thru set up with front mount and a vortech mondo bypass 42 lb injectors. i have the iac after the mafs. the mafs has a diabo mafia on it. i will try and get a picture up.

[stal94gt]

since it is real hard to determin what the problem is with out seeing how all your lines are hooked up i would eliminate the possible things that could be wrong. check for leaks after the maf for one. that includes makeing sure your intake manifold has not cracks. i would check your egr and make sure its not leaking. make sure your maf is in a real strait section atleast 8 inches long. if its not the counts could be getting turbulated causing fuel trims to flutter. check for exhaust leaks at the header. double check all everything, you never know what you missed. fuel trims are mainly controled by the maf and o2 sensors. your computer will bump the fuel mixture from the o2's to the tps sensor, and maf. how is your tuner ajusting things, is he using the tuner only or does he have the correct software to make the ajustments, for sct it is required to have pro racers package

[stal94gt]

btw i would pm tricktuners for help on this, the guy knows his shit

[Danderson]

*UPDATE I FOUND THE PROBLEM* It was the diablo puck that plugs to the mafs. It was messing up the computer. THE car is running on a 42# injector tune only so no boost for me (will peg out). So now that i know what the problem is i need to find a mafs that will work with my blow thru set up and a NEW TUNER! May be look for a power pipe also.

AS a side note y do cars with front mounts switch to a blow thru set up when u could do a draw thru just as easy. 90% on factory superchargers are all draw thru with intercoolers?

[stal94gt]

holly crap you were running a lightning maf in blow threw setup. bad setup your maf counts would be threw the roof. the reason people go blow threw is drivability improves if a proper maf it used. also people like bov's and you cant vent atmosphere with out blow threw

[Danderson]

was a stock mafs not a lightning 90mm.

[Shaun03GT]

Stock MAF with a MAFia setup as a drawthrough? Damn lol. Atleast you figured it out.

I have the PMAS blow through MAF and have 0 problems with it, I like it. Another good option is the SCT BA2600. Or a slot style MAF, but thatll be alittle more expensive rather then a PMAS or BA2600

Reps for stal for the help

[tbirdscwd]

A draw through setup will become more difficult to tune as you increase the boost pressure. "Most setups," as in non-intercooled entry level kits, run draw through because of space constraints as well as pd blowers cannot really run them any other way.

[stal94gt]

i really dont care for draw threw in a ic setup cause your metering air 9 feet away from the tb. that is a lot of pipe for something to go wrong.

[Eagle2000GT]

I've never had a draw through set up. ProCharger's come from the factory with a blow through configuration. I have seen posts where people have had countless tuning problems with their draw through setups after installing an intercooler that went away when they changed over to a blow through by moving the BOV. Blow through setups appear to be easier to tune.

I understand why non-intercooled setups are draw through but I don't know why you would want to run that way with an intercooler. Why recycle hot air and why would you want to heat up the intercooler with air you don't use?

[blownstang]

Who was tuning it? Go to Tim Barth at Mr. Norms Garage. Get an hpx slot style maf. You can run blow thru or draw thru. Most of the chicagoland guys run draw thru with Sct BA 2400/2600 mafs. I will be converting to blow thru when I add my intercooler and will be back by Tim for a retune.