Adjustable TPS

[El Corvino]

I do not have a scan tool.... but I do have a digital voltmeter. Are there any negatives to doing this myself the first time? I am very good with electronics, but seems like with the proper scan tool, an auto shop wouldn't charge much to put in a new one and setting it up to 0.40 with the key on and then 4.55 to 4.85 at WOT is realistically a 5 minute job for a place experienced with GN's.

 

[El Corvino]

Also, I do not have a scanmaster. I planned on getting one after the winter resto... so I'm assuming that would be my only way to verify the IAC counts are between 10-40, with a target number of around 20-25 counts.

ok, i found the manual way to reset the IAC... but I'm reading to set the throttle stop screw to set the idle to 500 RPM +/- 50 at idle... that seems a bit low.

This shouldn't take someone with the scan tools to do it, more than 30 minutes at most... I think I should play it safe at just let them do it until I have all of my own scan tools come fall.

 

[rodruckus]

Your TPS numbers are not ideal. You'd want them set somewhere in the .42-.44 and 4.75-4.9 at WOT range.

 

[El Corvino]

thanks!

 

[John Larkin]

Backprobe the blue wire on the TPS with a small paperclip, clip your positive lead on the DVM to it, ground the negative lead to a good ground. Set it to DC and then you can set your TPS.

Ideal idle speed should be around 900.

 

[El Corvino]

^^^ Thanks. The gnttype site write up said to shoot for 500 RPM +/- 50... I was looking at it oddly thinking that sounded a bit low.

 

[mikestertwo]

^^^ Thanks. The gnttype site write up said to shoot for 500 RPM +/- 50... I was looking at it oddly thinking that sounded a bit low.

The gnttype site is correct on the idle rpm. That rpm is set with the IAC set in diagnostic mode and then disconnected. This is to set the throttle stop. Once that is set, the TPS is set correctly, and the IAC is reconnected the engine will idle at whatever rpm your chip is programmed for. This should give you the proper IAC count when the engine is at idle.

 

[El Corvino]

why are you in Oregon and not on the east coast. Back in South Florida there are quite a few quick grand nationals on the streets and reputable shops to take care of them. I'm up in the NE for 2 years and don't know anyone and all this is new to me, so I am trying to read as much as possible and do it myself before some hot shot mechanic thinks he knows what he is doing and just wants to take my car for a joy ride.

 

[fastblackracing]

Some helpful tips on setting your tps/IAC Regardless of of what Base rpm you set your idle screw for the chip will make the engine idle at what ever rpm the chip programmer has set in the chip. IE: you set the base at 500 the chip will raise it to 800 or so with the IAC........ The reason it is important to understand this is The IAC plunger is shaped like a wedge, and if the IAC is running at a low count number such as less than 40, an correction of 10 counts can have a big effect on the idle speed control because it is so close to the seat...... and exactly the opposite is true if it is idleing with a high count number the same 10 count correction wont have much effect......so what does this matter?..... There is no absolutely right number to go by, each combo will idle different and if you understand the function of the system you can manipulate it a bit to get YOUR car to idle and behave better for you........ You can play with the idle counts in gear and various tps settings, to help YOUR car once you understand it.........Now for setting the TPS if you loosen the 2 screws that hold the sensor to the throttle body and put a phillips screwdriver in the screw to the left of the sensor you can use the screwdriver as a small prybar to force the sensor to the front of the car.....This gets it out further on the lever arm for a bigger sweep and wider voltage swing..........There is really no need to go over 4.7---4.8 volts at WOT, and can throw the check engine light if it is too high at WOT it will think the sensor failed. ....lightly snug the 2 screws release the throttle and use the butt end of the screwdriver to tap the sensor down to set your idle voltage....... .40 to .46 idle and anything over 4.6 WOT usually works fine.. HTH ........ And for what its worth I used a fluke dvm as my first tuning tool to read o2 volts and knock sensor activity, managed to run bottom 12's using this.

 

[El Corvino]

Why are none of you remotely close to Delaware? haha

 

[bison]

why are you in Oregon and not on the east coast. Back in South Florida there are quite a few quick grand nationals on the streets and reputable shops to take care of them. I'm up in the NE for 2 years and don't know anyone and all this is new to me, so I am trying to read as much as possible and do it myself before some hot shot mechanic thinks he knows what he is doing and just wants to take my car for a joy ride.

I'll be at the event at Cecil county and can set your tps and minimum air in about 5 minutes if you are going


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[achalmersman]

If your not going, where are you located in DE?

 

[El Corvino]

I'll be at the event at Cecil county and can set your tps and minimum air in about 5 minutes if you are going


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when is it?

 

[El Corvino]

Also, I followed the instructions given and used my volt meter. I was determined to figure it out. The old one was reading 0.61 at closed throttle. The new one is a crispy 0.41 and running much better.

 

[Drewster]

Make sure the foot pedal full throttle voltage is over 4.55 so you get to power enrich mode.


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[El Corvino]

I actually could only get it to 4.3X volts at WOT. I'm not really sure what adjustment I could do to fix that issue? Closed throttle is right where I want to be, but WOT is a little low?

 

[El Corvino]

I'm wondering if that is because it has a chip set up for the LS1 MAF and translator and when I bought it it, they had removed and sold that and put the stock MAF back on?

 

[Drewster]

There are adjustments for the TPS. ( search on this site or in GNTtype.org).
The Idle air is also effected when the TPS is adjusted so you have to find where both are happy. Might go easier if just playing with upper setting.
If you can't pull the TPS sensor forward to get the upper adjustment, make sure transmission cable is not restricting the throttle plate, and use a rat tail file to elongate the slot.
Just make sure you get the desired settings through the pedal because that's what happens when you're driving. The rugs and transmission cable have an effect on the setting.


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[mikestertwo]

I actually could only get it to 4.3X volts at WOT. I'm not really sure what adjustment I could do to fix that issue? Closed throttle is right where I want to be, but WOT is a little low?

4.3 volts is plenty high. You don't need >4.5 volts. Power Enrichment (PE) is based on load (160) not TPS voltage alone.

 

[El Corvino]

I'm an idiot... I was trying to hurry when I originally set it before the rain came and was thinking of the unit in terms of only forwards and backwards.... not that it was moon shaped and could also be tilted. I changed the nasty old fuel filter and as I was adjusting my "moon" up and down, I got it to 0.41 volts closed and 4.91 at WOT. Sure enough it started to drizzle a little so I closed the hood. Now that I realize what I did, I think a slight adjustment to bring the WOT voltage down a bit and keep my closed volts right where they are and everything should be happy.