I just recently installed a bbk cold air and bbk 75mm throtlle body on my 96 GT and now my check engine light is on and my tranny wont downshift when I floor it. Would a hand held tuner help this situation? or am i stuck going to a shop? I already have bbk underdrive pullys, trickflow upper plenum, and a shift kit installed. Which tuners are the best for a 96? thanks in advance for any info.

 

The only thing that would set off your Check engine light would be when you installed your plenum, maybe you didn't set the TPS sensor right or something! The CAI and TB would not warrant a CEL light! Go to your local autozone and have them check what is causing your CEL....its free!

Miguel

 

Your problem is the BBK intake. Take it off, its a waste of money anyways.

 

Yeah..but I still don't see how a CAI would set his CEL on..might be something else!

 

What size MAF? The car could be running lean, I also believe some brands of CAI's actually restrict airflow due to the 90* bend in the tubing.

 

yeah I've heard about that, he didn't mention anything about having replaced the stock maf, so I can only assume he has the stock one!

 

the problem is the TPS sensor, if its tossing a light and wont downshift the sensor is A- nopt hooked up, or B- not adjusted at idle it should read .99volts or as close as possible, but without going over .99 all you do is hook up a volt merter to each wire (one is positive one is negitive, and i dont remember which is which) then move the TPS sensor up or down to adjust the readings.

 

word......

 

thanks alot guys. the MAF is stock and just for clarification should the car be running when i attempt to fix the TPS to .99? and by adjusting the TPS you mean adjusting the idle screw to hold the tps to a certin spot or is there some other way to adjust the TPS i dont know about. some one also told me my down shifting problem was a kickdown cable needing to be adjusted. oh and for the final question if my engines getting to much air and running lean is there a simple way to add more fuel? without adding parts. mabye adjusting a regulator or something? :sign5:

 

Make sure you leave the screen on thats on the MAF.

 

Nothing you have done should put you in a situation to where "the engine is getting too much air" and leaning you out. I think you should try to TPS first.

1. Get a volt meter and a saftey pin.

2. Stick the safety pin into the power wire to the TPS. Don't push it all the way through - you don't want to break the strands.

3. Ground the negative lead to a good ground and put the positive lead through the "eye" on the safety pin. Make sure to make good contact with the eye "wall".

4. Volts should read (as stated above) .98 - .99.

5. If you do not get the above reading, loosen the brass screws that hold the TPS to the side of the TB. BE VERY CAREFUL BECAUSE THE SCREWS ARE REALLY IN THERE AND THEY WILL STRIP IN A HEARTBEAT. You don't have to loosen them very much - just enough to move the TPS up and down a little bit. Once you get it where you want it, you don't want to have to screw in very far anyway.

6. Move the TPS up and down. The screws will restrict it from moving hardly at all, but if you watch that meter you will see the volts going up or down quite a bit. When it boils down to it, the TPS is just a very sensitive potentiometer and it only takes slight movements to make the reading change. When you get to .99, hold it tight and screw it back in.

7. Take out the car and lay the hammer down.

 

that doesnt need ot be in there nor doe sit do much of anything.

our cars down have kick down cables the TPS does that so like i said adjust it. loosen the 2 screw that hold the sonsor on and then move the sensor up and down till you get as close as possible to .99volts. just dont go over.

 

i have a 96 mustang gt with a manual trans and i think im having the same problem when clutch in and shift the rpms wont come down they either stay the same or go higher is this the tps sensor?

 

Sounds like it

 

Nope, sounds like the idle air control valve, aka IAC its the big thing on the plenum. unbolt it and spray it with break cleaner etc.. and move the piston inside of it back and forth to free it up. they get stuck and or start not ot work once they get alot of carbon and oil built up in them. pretty common problem.

 

Look at MMFF back issue, they ran it on a dyno with it and without it. It did make a difference and they recommended against removing it. Unless you get a chip burned with the screen off leave it on as you will be creating a problem.

 

My and my freinds car run just as fast with or without it. dynos dont mean poop to me, its the timeslips that matter

 

Yep, I forgot about the IAC. I agree that this should be checked first for your problem.

 

Depending on your other mods, I have seen a 4.6 run so lean when intake and exhuast is drastically upgraded with stock fuel components, that it actually trips the CEL which is really bad because at that point you probebly already have detonation occuring. You can get an adjustable fuel pressure regulator to correct the problem. Did you have the Code read to find out what is tripping the light? That would point you in the general direction. Advanced auto and Auto Zone will usually read your codes for free.

 

i checked the iac and tps and they both are working fine the rpms still wont drop down this problem only started occuring after i put long tube headers on the car should i adjust the fuel pressure? or is it in the pcm computer?

 

SpikeAfrica,this forum is not to criticize on members suggestions unless there is inaccurate information. There is a reason members left other forums and we dont need any of that here.

 

The screen distributes the air evenly so the MAF sensor can get an accurate reading, so yes it is needed.

thank you :thumbsup:

 

oh give me a break, i was stating my experiences with it.

 

okay first i like to say thanks to everyone helping me out
im geting autozone to read my code tommorrow but it looks like the TPS went bad cuz when i checked it with the volt meter it comes up .10 thru .14 at idle and according to the hayes book it should be at least .5 volts or it is bad. when i tried to adjust it as layed out by STEEDA2000 earlier in this thread it didnt move the volts at all up or down. THANKS AGAIN :hello:
and ill let you guys know what the problem turned out to be.

 

I removed the maf screen, and never had any problems? Plus...I don't see how it serves to distribute air more evenly? Its just another filter if you ask me! 2 yrs without it and never had any problems!

 

hey it was the TPS! i replaced it thanks for everyones help!!

 

glad to hear it was just that.