need a little LT-4 / TPI help in here

[azkkn]

ok so project sick vette is finally 99% done. i am stuck on this TPS issue. can you buy an adjustable TPS for a TPI style throttlebody? i have a accel/lingenfelter 58mm Throttle body on the LT-4 in the vette, and it uses a TPI style tps. the tps that came with the throttle body is F'ed up and reads 90% open all the time. atleast according to the FAST ecu read out. so i went and bought an oe replacement TPS for it, and when its bolted up to the TB it reads 16% open, and will only give me 81% at wot. the throttle blades are closed as much as they can be and it still reads 16%. so i am wondering if the fried TPS from lingenfelter is some special one, or if it is just a typical aftermarket adjustable TPS. Calling there TECH line is a PITA lately and i want to kill whoever invented HOLD. i want this car done and on the street so bad, i just spent 4 grand on the computer and fuel system to support the rest of the mods, and am stuck on a $20 part. thanks in advance guys.

[Kevin - Blown 95 TA]

Usually in a situation like that, they slot the sensor with a dremel and rotate it a little until it reads 0%. Then if it is not giving 100% at WOT you need to see if it is actually opening the butterflies all the way and go from there. I don't know what compatability issues there are from LTX to TPI, though, if any.

[azkkn]

the one that came with the TB has huge elongated holes in it so its completely adjustable, and there is no way i can slot out hte replacement that much, there just isnt enough material.

[Injuneer]

One possibility.... do you have the wires hooked up correctly to the TPS sensor? I had a problem when I got my car back from the shop, and they had switched the gray (5V ref) and the blue (signal) wires, and the voltages were just about what you must be getting to produce the limited range of 16%-81%.

The FAST should be supplying a 5V reference signal, same as the stock PCM. Is that correct?

How does the FAST "baseline" the TPS voltage? Can you tell it the values for "closed" and 100% open? That's the way my MoTeC works.

[Kevin - Blown 95 TA]

One possibility.... do you have the wires hooked up correctly to the TPS sensor? I had a problem when I got my car back from the shop, and they had switched the gray (5V ref) and the blue (signal) wires, and the voltages were just about what you must be getting to produce the limited range of 16%-81%.

The FAST should be supplying a 5V reference signal, same as the stock PCM. Is that correct?

How does the FAST "baseline" the TPS voltage? Can you tell it the values for "closed" and 100% open? That's the way my MoTeC works.

This makes more sense.

[azkkn]

here is the link to my supermotors site, you can see some pics of the tps in this link. Here are the pics

[Injuneer]

The sensor does have three wires, correct?

Does the FAST supply a +5V reference voltage?

What does the voltage on the TPS signal wire read when the blades are closed? .....when the blades are 100% open?

Does the FAST require a signal of 0.50V to set the 0% throttle position, or does the FAST programming allow you to tell it what the 0% voltage should be?

[azkkn]

as far as i know the wires are correct, gray=5 volt input, black is ground, and blue is the signal wire. i have the ground on top (A), blue center (B) and gray on bottem (C).

i am going to look into the program tonight and see if i cant tell it to accept 0% as what ever the sensor is putting out, and the same for 100%.

As far as i know the fast is putting out the 5 volts. as i get it from the referance wire.

[azkkn]

ook so the OEM one i bought was for a 1991, and it turns out that the factory ones from 1985~1989 were adjustable, and the 1990~1992 ones were not. i orederd an older one and will let you guys know how it turns out.

Thanks for all the input though!!!
Jeff