I got a Holley 52mm. It has ran perfect since I got it but lately when the car is in drive and I come to a stop the idle fluctuates. Idles around 900 and drop quickly to 700 and bouces back. When in park or neutral its fine. I wanna test the tps but dont know how to do it.

 

in this thread there is a TPS test how-to by INJUNEER

http://web.camaross.com/forums/showt...&highlight=tps


jesse

 

says the link is inactive....

 

SJS
sorry, i edited and fixed that link it should work now.
jesse

 

your voltage is off you have to drill the holes in the tps bigger and adjust it... call me if you need help 972-824-0793

 

exactly how do you test it though....???

 

Um...did you read the link?

 

"check for the 5V reference signal between the gray wire and the black ground wire. Readings between 4-6V are OK.

Then put the connector back on, and check the signal voltage. Read from the dark blue signal wire to the black wire. That's the number that needs to be between 0.20-0.90V."


yeah I did....I mean as far as using a multimeter and such.

 

Yea i guess thats it i set mine to 0.65 it was in the 0.35 before yours is probably in the 0.30 to 40,s...... get itt as close to 0.90 and dont forget to drill the tps hole bigger...

 

No.... any value between 0.20-0.90V will satisfy the PCM, and allow it to baseline the closed throttle position as 0%. But.... some people feel they get the best results in the range of 0.50-0.67V. Most of the stock setups I have personally checked have been in the 0.65-0.67V range. My 58mm Holley is adjusted to 0.65V. I have never seen anyone recommend a 0.90V setting. You are getting too close to the upper threshhold.

 

Hey guys...thanks....love ya all But no one has explained to me how to do it yet. I know to get it in the range of .20 and .90v, drillin the holes to make adjustments. But HOW DO YOU TEST IT???

thanks my friends....

 

I'm not sure what part of this you are having a problem with. There are three wires that go to the TPS sensor. A black wire, which is a "ground". A gray wire that supplies +5V from the PCM. A blue wire that is attached to a contact that slides along a resistor in side the sensor. The voltage reading on the blue wire, referenced to ground is the signal the PCM receives to identify where the throttle blades are positioned.

First, make sure you are getting +5V on the gray wire. Unplug the connector from the TPS. Set your digital volt meter (DVM) to "DC Volts". Stick the red wire probe of a DVM into the hole for the gray wire. Stick the black wire probe from the DVM into the hole for the black wire. With the key turned on (do not try to start the engine) the DVM should read +5V. If that is what you get, the PCM is supplying the correct voltage to the TPS, and the wires are good.

Now reconnect the connector to the TPS. Using something like a pin in each DVM lead, pierce the blue wire with the pin on the red lead (or run the pin down into the connector so it contacts metal against the blue wire.). Do the same with the black DVM lead, piercing the black wire. With the throttle blades closed, read the voltage. It should be in the range of 0.20-0.90 Volts. If it is, good. Then with everything still in place manually open the throttle fully. The voltage indicated on the DVM should increase smoothly as the blades rotate, and should reach approximately 4.0 Volts above the closed throttle voltage.

Release the blades, and make sure the TPS voltage has returned to the original closed throttle value. If everything measures as indicated above, you TPS sensor is fine. If you would like to adjust the closed throttle voltage, "slot" the bolt holes in the sensor. With the DVM attached as above, and the throttle blades closed, rotate the TPS sensor slightly and watch the voltage change. When you get it to about 0.65V, tighten the screws down.

Now.... if you have a scanner or scan software, you do not need to use the DVM. Just set your scanner to "TPS" and watch the readings as you move the throttle blades.

 

Holy crap Fred..... I remember I put up a post about what Shoeboxes story was and I think it was you who suggested he put up a donation box on Paypal or something. I think you need to do that yourself. That was the most detailed explaination I have ever got. Counldn't have gotten a better one standing in front of a mechanic. I built this motor but have no idea how to test electical stuff with meters and all that. Sorry for being an ID.

Thank you very much. I appreciate the effort.

 

Also, I heard that if its not adjusted properly you could really screw your motor up. Is that true?