Checked TPS voltage.

[Vettefan87]

So all I need to do is adjust the TPS and I am all set to go except maybe backing out the idle screw correct? How do you reset the TPS, reset the battery?

 

[wishuwerehere82]

So all I need to do is adjust the TPS and I am all set to go except maybe backing out the idle screw correct? How do you reset the TPS, reset the battery?

Sorry, I meant recalibrate the TPS by rotating it back to book value.
First get it to idle speed, then set TPS voltage.
If idle is too high, back off the idle screw to get back to idle. When you do that the TPS voltage will go down. So you will have to adjust the TPS back up again.
It's a process where you will have to do a few times to get idle right and TPS voltage right at the same time.

 

[vetteboy86]

Well I am not sure who is right or wrong in this matter, perhaps nobody. However the TPS is basically a variable resistor, or a potentiometer. Over time moving the wiper, age, and other things will change the resistance of this resistor. So it would make sense that GM would use a window, or somekind of limits for wot, and the idle. I am not sure if they did, but to have it set once at the factory, would warrant us all to check ours yearly to make sure it is still in spec.

 

[Vettefan87]

Sorry, I meant recalibrate the TPS by rotating it back to book value.

Ah, that makes a little more sense. Something in my mind tells me the last time I adjusted it to where it is now, I had to back the idle screw out all the way to get it to idle down. I hope that is not the case, and I wont have to many problems. What kind of room do I have with the low side being .58 volts, can I not go over that amount?

 

[wishuwerehere82]

You should try to get it as close to 0.580 V as possible. if it's too high, the mixture will be too rich, and your ECM will throw out some error codes.

 

[Vettefan87]

I am pretty sure it is at .54 volts now. I thought I read somewhere here it was best to be at .58 volts?

 

[wishuwerehere82]

Well I am not sure who is right or wrong in this matter, perhaps nobody. However the TPS is basically a variable resistor, or a potentiometer. Over time moving the wiper, age, and other things will change the resistance of this resistor. So it would make sense that GM would use a window, or somekind of limits for wot, and the idle. I am not sure if they did, but to have it set once at the factory, would warrant us all to check ours yearly to make sure it is still in spec.

The typical failure is a dead spot forms on the potentiometer, and that causes a "jump" on the throttle. The dead spot usually forms at (you guessed it)the idle position because that's where it always returns to most often.

 

[wishuwerehere82]

I am pretty sure it is at .54 volts now. I thought I read somewhere here it was best to be at .58 volts?

OOPS, that is what yours is set to now. Set it to what the book value indicates. If that is 0.580V so be it.

 

[Vettefan87]

Well the book is vague. It says around .5 volts at idle, and around 5 volts at WOT, but I dont know if I consider over a half a volt off to be close...?

 

[wishuwerehere82]

Set it to .5 V. A range of 0.5V-0.52V should get you in the ballpark. The ECM will monitor the position and adust your mixture with the IAC motor.

 

[Moonunit 451]

Sorry, I had to leave, and I meant to respond to you, Justin as well as bradfordsvettes. I think wishuwerehere82 has done a pretty good job in explaining what I responded to before as well as trying to explain the .5 or 5 volts or what ever it is. I can't remember the exactly what it is.

My recollection is that the idle should be .54 as you said you are set now. My problem was that I couldn't achieve the 5 + V that is specified by the General and maintain the .54 V as 82 described. when I was able to achieve the .54 and get close on the WOT side, my idle was too high and I threw a code. I had no further adjustment available on the idle screw, it was all the way out.

So I think I comprimised both sides a little until I got the right idle, and sufficient 5 V WOT for the car to run well, and believe me smoking the 315 D3's is not a problem without the brake

Now, I am not a guy who is in the trade, and I mean no disrespect to Bradford, but my best friend is.

My best Vette buddy, who know a heck of a lot more than me, insisted on setting it by the book, idled too high, hated it, and it threw the code.

My best friend, the tech, who basically won't touch my car, cause he repairs stock vehicles cause that is where he can get the answers from the maufactures to repair them, insists that WOT is not obtained until you hit the 5 V, and that he only ever worries about the WOT when tuning without complaint.

My experience wouold support this advice. You got nothing to lose but some more time by trying what I have done. I considered asking you about the TPS in some of your recent posts, but thought it was someting that you surely had dealt with. That 44 does not look good to me
BTW a new TPS is not a lot of bank.

 

[Vettefan87]

Thanks again Moon, and everyone else. I might have to buy a new TPS, if it comes to it that is fine by me. I might later today set it at 5 volts WOT, even though it is somewhat hard to do with one person. With looking at the meter, tightening the screws, then to find out it moved again. I am getting a little excited, I hope I don't get dissapointed again.

 

[bradfordsvettes]

there is a procedure in the manuel for setting min air rate if it is not set correctly all sorts of drivability problems can crop up if any one wants the proce dure i will be more than glad to post it .in my opinion slight voltage variations one way or another is not counter productive in my book Steve

 

[Vettefan87]

there is a procedure in the manuel for setting min air rate if it is not set correctly all sorts of drivability problems can crop up if any one wants the proce dure i will be more than glad to post it .in my opinion slight voltage variations one way or another is not counter productive in my book Steve

Yes please do post it. My neighbor just got this C5, and is ranting and raving about how fast it is blah blah blah... Hopefully I can get it running right and show him how "slow" C4's are .

 

[vetteboy86]

I am very curious where this thread is going. I am not a pro, but do have some electrical background. My TPS is set at .508 V at idle, and 4.38 V at WOT. This puts mine lower then my brothers (vettefan). So is it possible, I am not experiencing full throttle as well? WHo knows, I just hate messing with my car when it is running good, but I just have to know.

 

[Vettefan87]

Nah leave it. Let me adjust mine tomorrow and we will see how mine runs.

 

[rrubel]

You need to find someone with one of those plug-ins that fools the computer into thinking you're at WOT even when you're not. it just increases the voltage. Get one of those and a GTech, and run both cars with and without that mod. That'll give you a degree of confidence... but I'll admit it kills the bench racing...
[RICHR]

 

[vetteboy86]

Yeah I have seen those that use an amplifier circuit or something to achieve WOT voltage at say around 3/4 of the throttle.

 

[Vettefan87]

Okay I went out and started playing with it and at .81 volts with the key on, it is only reading close to 4.7 volts at WOT. Do you guys think my TPS could be going bad? I have not started to car to see how it runs, I am sure it will idle high. We will see though.

 

[Vettefan87]

Warm idle in park is around 750-800, and in gear it is around 5-600. I don't think the car runs better at the levels I set it at. Should I just buy a new TPS or could it be something else giving it these wacked up readings? I looked at the butterflies and they are fully opening.