Just pulled my IAC out to clean it, and hope to fix my stumble at idle. I figured i would check the TPS voltage as well...So i removed the harness, started the car, and put my ground on the black pin, and my red on the dark blue pin, and i got a reading of .03v I cant understand why, it should be .54 at idle right? Well, the white wire pin has 5v, so know that is right, and after testing the harness, i plugged it back into the sensor, and like i thought, the idle bumped back up. Why would i have so low of a reading? Also, what might cause the engine to surge by about 300 rpm at idle, then return to normal. Thanks A lot, Alex

 

What year and type of car?

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1989 IROC-Z 5.7L
NOS 5151 150HP kit
ProBuilt 700R4, PI Vigilante 2800 stall lockup
Baer Brakes 12" Sport System

 

sorry 1992 B4C Camaro 5.7 TPI

 

I got funny readings like that as well...but I just figured I was doing something wrong and haven't got around to trying it again.



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1987 Camaro IROC-Z
350 TPI (L98), HyperTech Airfoil, K&N Filters and modified airboxes, AC Delco RapidFires, Taylor SpiroPro 8mm wires, Energy Suspension polyurethane bushings for front and rear LCAs and sway bars, KYB struts and shocks, BFG g-Force Z-rated tires, MAC STB, MAC SFCs, JET low temp stat, CarSound Hi-flow Cat, DynoMax 3" Mandrel-bent pipes, Flowmaster muffler, 3" chrome tailpipes, Corvette Servo, TransGo Shift Kit, Corvette 2000 Stall, TruCool LPD tranny cooler, T-tops, and White exterior with red leather interior.

2001 Sunfire GT
Bone stock 2.4L, 5-speed, K&N cone filter, interior detailing, 200W Monsoon Sound System (8 speakers), Silver Metallic exterior with grey interior.
3rd Place Stock Class at annual 2001 JCO Bash

Web: http://www.angelfire.com/on3/whitelightening

 

Wait a second, you 'removed' the connector and tested the voltage? That is not the right way to do it first of all, you either jumper into the connector with it plugged in, or you simply pierce the leads w/ your tester ends.

However, with it unplugged the TPS signal wire should pull up to ~5V, however, i think you are mistaking what each wire is and got it backwards, cuz it makes perfect sense that you would see a small potential difference if you were measuring the potential across the 5V reference and signal wire, as they are the same node in the ECM, seperated by a pull up resistor which defaults it to 5V with the sensor end floating.

But for now, just check the TPS voltage the corrcet way and get back to us.
...ed

 

Dohhhh!!! *bangs hand on forehead*
Yeah, i was doing it wrong. I went back, hooked up the jumpers and got a good reading. .53v at idle, and 4.22v at WOT. Now i still have a bad idle, doesnt really surge, but it will idle at about 600, then jump up to 1100 after a few seconds, and stay there. I think it is the IAC, as it doesnt move at all. It is supposed to move right? Well, i set the IAC and TPS according to the tech article, and everything was good, except when i plug the IAC back up. Then like above, the idle will jump up and remain at 1100rpm. So, i suppose the IAC has gone bad correct?

 

Double Post

[This message has been edited by makinemtap (edited August 24, 2001).]

 

Ok, while I'm stupid too then! I'll try it again the proper way this time. Me bad...




------------------
1987 Camaro IROC-Z
350 TPI (L98), HyperTech Airfoil, K&N Filters and modified airboxes, AC Delco RapidFires, Taylor SpiroPro 8mm wires, Energy Suspension polyurethane bushings for front and rear LCAs and sway bars, KYB struts and shocks, BFG g-Force Z-rated tires, MAC STB, MAC SFCs, JET low temp stat, CarSound Hi-flow Cat, DynoMax 3" Mandrel-bent pipes, Flowmaster muffler, 3" chrome tailpipes, Corvette Servo, TransGo Shift Kit, Corvette 2000 Stall, TruCool LPD tranny cooler, T-tops, and White exterior with red leather interior.

2001 Sunfire GT
Bone stock 2.4L, 5-speed, K&N cone filter, interior detailing, 200W Monsoon Sound System (8 speakers), Silver Metallic exterior with grey interior.
3rd Place Stock Class at annual 2001 JCO Bash

Web: http://www.angelfire.com/on3/whitelightening

 

Ed...Need your help here then. I was going by the instructions found on thirdgen.org (https://www.thirdgen.org/newdesign/tech/tpimod2.shtml) and it says to disconnect the TPS connector. Can you please give me proper step by step instructions, because now I'm a little confused. Thanks in advance for your help.



------------------
1987 Camaro IROC-Z
350 TPI (L98), HyperTech Airfoil, K&N Filters and modified airboxes, AC Delco RapidFires, Taylor SpiroPro 8mm wires, Energy Suspension polyurethane bushings for front and rear LCAs and sway bars, KYB struts and shocks, BFG g-Force Z-rated tires, MAC STB, MAC SFCs, JET low temp stat, CarSound Hi-flow Cat, DynoMax 3" Mandrel-bent pipes, Flowmaster muffler, 3" chrome tailpipes, Corvette Servo, TransGo Shift Kit, Corvette 2000 Stall, TruCool LPD tranny cooler, T-tops, and White exterior with red leather interior.

2001 Sunfire GT
Bone stock 2.4L, 5-speed, K&N cone filter, interior detailing, 200W Monsoon Sound System (8 speakers), Silver Metallic exterior with grey interior.
3rd Place Stock Class at annual 2001 JCO Bash

Web: http://www.angelfire.com/on3/whitelightening

 

Just looked at that and i reckon it could be confusing for a newbie. It says to remove the TPS connector to jumper into it. It assumes that you know to then plug it back in, lol.

Anyhow, all you do is put small wires in the connector such that you can measure the voltage w/ the TPS pluggged in. Just strip some small guage qire back alittle bit, wrap the stripped end around the post in the connecotr, and plug it back in.

 

hey, IROCKER, quit hijacking my thread....lol

Yeah, when i went back and read it again, it made perfect sense...I guess i wasnt paying attention, being as pay car idles like s**t, and i need to get it fixed before i work this weekend...

Well, any info on whether or not the pluger on the IAC is supposed to move or not would help out a lot, before i got and spend 75.00 on a new one