2 Questions about TPS sensor on 95 Z
how did you reset the TPS? And that IAC idle thing, since your's is a OBD1 and mines the same, but with OBD2 port, do you think that might work? Or should I just leave it alone for a while and see how it levels out?
April 2011 ROTM
Joined: Mar 2009
Posts: 22,007
From: Tokeland, Washington
ROTM Winner's Club
they sell a plug that goes between the connectors at the tps and you connect the ohm meter to the gray and blue wire. i got this set, http://www.rickscamaros.com/camaro-t...1993-1997.html at least i think its the gray one. blue is the sending wire. do you have the aldl setup for datamaster? that would be another way.
Well with my auto xray scanner I can see the TPS voltage, that's what I used this morning to set it. I could also see the IAC normal and learned steps. It also said that the normal/regular/something idle was 800 RPM's. That's the first thing it shows when I go into data monitoring on it, then it shows the actual RPM's the next screen. I do have the aldl cables for my PC, but I haven't messed around with any programs except for the one to load the PCM4less program. Do you know of a good program that you can adjust and monitor with? I'm sorry, I haven't looked at any of the programs but been thinking about it for a while now.
April 2011 ROTM
Joined: Mar 2009
Posts: 22,007
From: Tokeland, Washington
ROTM Winner's Club
your set then. only thing it may need is the minimum idle set, or not. it may adjust itself after a few starts. to set minimum idle you need to get the system into diagnostic mode with the motor not running. i do the paper clip thing and if i hear the fan come on i know its in diagnostic mode, (being the paperclip trick wont work on yours i believe a scanner will) i then unplug the iac motor/valve before turning the key off, once turned off i unplugg the paperclip/scanner and start the motor and set the idle using the set screw on the tb. plug the iac back in and your done. (once you do that and if the idle setting on the tb is moved then the tps needs reset). i used datamaster to get info so far, its free. im still learning, someday i may try burning a chip and see how it comes out. you have a different ecu that doesnt use a chip, i think you reflash it, not sure how, i havent looked into them. i want to watch mine get dyno tuned and see if it sinks into this thick skull.
Last edited by craby; Jun 23, 2010 at 09:06 AM.
I thought I had it figured out, but today, the idle is around 1500 so some reason. I'm going to do some searching and see what I can find. I think maybe the IAC needs reset somehow. I'm going to unplug the IAC and see if it'll start and what it does.
April 2011 ROTM
Joined: Mar 2009
Posts: 22,007
From: Tokeland, Washington
ROTM Winner's Club
thats what mine did when i had the set screw to low or butterfly closed to far. it would not idle down so i set it down and it would get higher so i would set it down, did that till it would go no farther. once i got everything where its supposed to be it still took a few starts for it to settle. if you radomly unplug the iac then it will stay open to were it is. thats why you need to get it into diognostic mode, the iac is closed then.
Ok, I found all this stuff online.
Reset the IAC Position
• Depress accelerator slightly
• Start engine, then release accelerator pedal, run engine for 5 seconds
• Turn ignition "OFF" for ten seconds
• Restart engine and check for proper idle operation
It is NOT recommended to to push or pull on the pintle of an IAC that has been in service. The force required can damage the threads on the worm drive. Also, do not soak the IAC in any liquid cleaner or solvent, as damage may result. When installing a new IAC, you may move the pintle to match the measurement of the old one. The force required to move a NEW valve will not cause damage to it. Use engine oil to lubricate the o-ring. Tighten attaching screws to 27 lb. in.
Note that the 1993 IAC has a square electrical connector and the valve screws into the throttle body, instead of being held on by screws like those of later years.
Adjusting the GM TPS (Throttle Positioning Sensor)
by Chad Golen
In this article we will discuss how to properly adjust the GM TPS (Throttle Positioning Sensor).
If you are installing one of our 383 cubic inch engines it will require more air to start and idle properly therefore you will need to move the throttle blades to allow more airflow but once you do this the TPS voltage reading will be off. The computer needs to see the proper voltage reading in order to know where the throttle blades are at any given time to keep the engine running properly. Follow the steps below to properly adjust your TPS and keep your engine starting and idling perfectly.
In order to make the adjustment you will need the following tools:
A voltmeter, small file and a torx screwdriver will help make short work of this task.
Step #1 It will be easiest to take the throttle body off the intake so you can make the blade adjustment via a small set screw in the side of the throttle body. (see picture A)
Picture A
Start by turning the set screw until you see the throttle blades open slightly, (see picture B).
Picture B
Step #2 You will need to remove the TPS and carefully file the holes so you can make an adjustment (see picture C) pay close attention to where you will need to file in relation to where the screws go into the throttle body, it is a rotation adjustment. You can also use a drill bit or any other tool that works to make the mounting holes bigger.
Picture C
Step #3 Bolt the TPS back onto the throttle body and tighten the screws slightly so you can make easy adjustments, then take the lead on the voltmeter and pierce the center wire it should be blue in color, (see picture D) until you get a voltage reading.
Picture D
You will need to have the ignition key in the on position but the engine not running. The voltage reading you are looking for is .67 volts if you have a LT1 from 94-97 MAF (Mass Air Flow) (see picture E) and .50 volts if you have a TPI from 85-92 or a LT1 1993 speed density.
Picture E
Once you find the perfect adjustment tighten the TPS screws and recheck the voltage reading to make sure that it hasn't moved. At this point reinstall the throttle body, you will in most cases need to go back and forth with the throttle blade position and chase it with the proper TPS voltage adjustment until you find the spot where the engine starts and idles perfectly.
(consult Golen Tech Support for the proper idle RPM for your engine).
If you have any problems with making this adjustment please contact
Golen Engine Tech Support to avoid damage to your new engine.
The facts:
The factory TPS is not adjustable (you must slot the mounting holes to do so).
The computer does not control the IAC. The IAC is a sensor that sends throttle position values to the computer.
When installing an aftermarket TB, you often have to adjust the TPS to keep it in the allowable closed throttle range (.3v-.9v).
Altering the throttle stop will change the TPS value.
With an aftermarket TB, it is a good idea to monitor the IAC counts when adjusting the throttle stop. Stock values are normally in the 20-30 range at hot idle. Cammed cars normally higher. If IAC values are way high, the IAC is trying to let in more air to allow it to idle. Opening the blades a little more should bring the counts down (remember to check your TPS setting again).
Why do you care about the IAC counts? If the idle counts are way out of range, it will be very hard or impossible for the IAC to properly control the idle in all situations.
TPS and IAC readings are very easily read with a scanner.
So with my auto xray scanner I did some test. Before it was idling at about 1500 all day.
1st: With IAC unpluged.
idle @ 1050-1100 RPM
Coolant temp @ 186.8 *F
TPS Voltage @ .50
IAC POS @ 0 steps
Learned IAC POS @ 36 steps
2nd: Couldn't move TPS enough to get to .67 Volts as mentioned in the Golen article so I moved the idle screw on the TB to get it to where it was back and forth from .66 to .68 Volts. And plugged IAC back in.
idle @ 1125-1175 RPM
Coolant temp @ 194.9 *F
TPS Voltage @ .66
IAC POS @ 0 steps
Learned IAC POS @ 36 steps
3rd: Left TB set screw so TPS voltage was at .66 and tried to reset IAC with above method.
idle @ 1150-1200 RPM
Coolant temp @ 198.9 *F
TPS Voltage @ .66
IAC POS @ 0 steps
Learned IAC POS @ 36 steps
4th: Everything the same as 3rd test, but unbolted battery for about 5 mins in order to attemp to reset IAC.
idle @ 1175-1225 RPM
Coolant temp @ 198.9 *F
TPS Voltage @ .66
IAC POS @ 0 steps
Learned IAC POS @ 36 steps
From this I'm pretty sure I need to have my IAC reset. If my thinking is correct, the IAC has learned with my stock TB that 36 is the starting point. And I need it to relearn with the new TB. Is this correct?
Now how do I do this?
Reset the IAC Position
• Depress accelerator slightly
• Start engine, then release accelerator pedal, run engine for 5 seconds
• Turn ignition "OFF" for ten seconds
• Restart engine and check for proper idle operation
It is NOT recommended to to push or pull on the pintle of an IAC that has been in service. The force required can damage the threads on the worm drive. Also, do not soak the IAC in any liquid cleaner or solvent, as damage may result. When installing a new IAC, you may move the pintle to match the measurement of the old one. The force required to move a NEW valve will not cause damage to it. Use engine oil to lubricate the o-ring. Tighten attaching screws to 27 lb. in.
Note that the 1993 IAC has a square electrical connector and the valve screws into the throttle body, instead of being held on by screws like those of later years.
Adjusting the GM TPS (Throttle Positioning Sensor)
by Chad Golen
In this article we will discuss how to properly adjust the GM TPS (Throttle Positioning Sensor).
If you are installing one of our 383 cubic inch engines it will require more air to start and idle properly therefore you will need to move the throttle blades to allow more airflow but once you do this the TPS voltage reading will be off. The computer needs to see the proper voltage reading in order to know where the throttle blades are at any given time to keep the engine running properly. Follow the steps below to properly adjust your TPS and keep your engine starting and idling perfectly.
In order to make the adjustment you will need the following tools:
A voltmeter, small file and a torx screwdriver will help make short work of this task.
Step #1 It will be easiest to take the throttle body off the intake so you can make the blade adjustment via a small set screw in the side of the throttle body. (see picture A)
Picture A
Start by turning the set screw until you see the throttle blades open slightly, (see picture B).
Picture B
Step #2 You will need to remove the TPS and carefully file the holes so you can make an adjustment (see picture C) pay close attention to where you will need to file in relation to where the screws go into the throttle body, it is a rotation adjustment. You can also use a drill bit or any other tool that works to make the mounting holes bigger.
Picture C
Step #3 Bolt the TPS back onto the throttle body and tighten the screws slightly so you can make easy adjustments, then take the lead on the voltmeter and pierce the center wire it should be blue in color, (see picture D) until you get a voltage reading.
Picture D
You will need to have the ignition key in the on position but the engine not running. The voltage reading you are looking for is .67 volts if you have a LT1 from 94-97 MAF (Mass Air Flow) (see picture E) and .50 volts if you have a TPI from 85-92 or a LT1 1993 speed density.
Picture E
Once you find the perfect adjustment tighten the TPS screws and recheck the voltage reading to make sure that it hasn't moved. At this point reinstall the throttle body, you will in most cases need to go back and forth with the throttle blade position and chase it with the proper TPS voltage adjustment until you find the spot where the engine starts and idles perfectly.
(consult Golen Tech Support for the proper idle RPM for your engine).
If you have any problems with making this adjustment please contact
Golen Engine Tech Support to avoid damage to your new engine.
The facts:
The factory TPS is not adjustable (you must slot the mounting holes to do so).
The computer does not control the IAC. The IAC is a sensor that sends throttle position values to the computer.
When installing an aftermarket TB, you often have to adjust the TPS to keep it in the allowable closed throttle range (.3v-.9v).
Altering the throttle stop will change the TPS value.
With an aftermarket TB, it is a good idea to monitor the IAC counts when adjusting the throttle stop. Stock values are normally in the 20-30 range at hot idle. Cammed cars normally higher. If IAC values are way high, the IAC is trying to let in more air to allow it to idle. Opening the blades a little more should bring the counts down (remember to check your TPS setting again).
Why do you care about the IAC counts? If the idle counts are way out of range, it will be very hard or impossible for the IAC to properly control the idle in all situations.
TPS and IAC readings are very easily read with a scanner.
So with my auto xray scanner I did some test. Before it was idling at about 1500 all day.
1st: With IAC unpluged.
idle @ 1050-1100 RPM
Coolant temp @ 186.8 *F
TPS Voltage @ .50
IAC POS @ 0 steps
Learned IAC POS @ 36 steps
2nd: Couldn't move TPS enough to get to .67 Volts as mentioned in the Golen article so I moved the idle screw on the TB to get it to where it was back and forth from .66 to .68 Volts. And plugged IAC back in.
idle @ 1125-1175 RPM
Coolant temp @ 194.9 *F
TPS Voltage @ .66
IAC POS @ 0 steps
Learned IAC POS @ 36 steps
3rd: Left TB set screw so TPS voltage was at .66 and tried to reset IAC with above method.
idle @ 1150-1200 RPM
Coolant temp @ 198.9 *F
TPS Voltage @ .66
IAC POS @ 0 steps
Learned IAC POS @ 36 steps
4th: Everything the same as 3rd test, but unbolted battery for about 5 mins in order to attemp to reset IAC.
idle @ 1175-1225 RPM
Coolant temp @ 198.9 *F
TPS Voltage @ .66
IAC POS @ 0 steps
Learned IAC POS @ 36 steps
From this I'm pretty sure I need to have my IAC reset. If my thinking is correct, the IAC has learned with my stock TB that 36 is the starting point. And I need it to relearn with the new TB. Is this correct?
Now how do I do this?
So...I just back from my buddies shop where I was hoping he would have the scanner that could reset the learned IAC. But he didn't, but he did look it up and found the same method listed above. Well we tried and tried and never got it to work. But then he wanted to take both battery cables off and touch them together, supposedly that will reset the whole ECM. So we did that and then stupidly did the above method right after without testing to see if the battery thing worked. Well one of them worked, it went from 36 to 32, but still idling high, about the same. I think it needs to go down to about 5, that might be the right idle.