Throttle Adjustment

[TurboB5]

hey guys, i just got my logger and noticed today doing my first few baselne pulls that i was only getting 75-80ish % throttle. i tried adjusting the throttle cable. im not sure what its called but its on the cable, a rail with 2 bolts holding the cable, but thats what i tried adjusting. you can see it a little to the left of this red arrow. to no avail ll it did is make my idle go up and down.

i am not sure how to adjust the throttle to make sure its 100%. i went to this site http://members.shaw.ca/dsm.1000q/Engineprimer/1G/throttlecables.htm and they said i have to adjust some screw that i must have not seen on the back of the motor by the red arrow.even if i take off the ic hose and tb elbow how should i go about adjusting it?

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TIA

 

[steve]

First you don't get to adjust the throttle to make it 100%.

You get to adjust the throttle for the correct reading at idle with the throttle closed and the cable loose. Then you get to adjust the throttle cable for the right slack on the cable. Once you've don't that whatever the TPS reads at WOT is what you get and like it. The ECU doesn't really care that much what the value is at that point.

Don't forget that there are adjustments in the cruise control cable/pully assembly for slack too.

Steve

 

[steve]

I was under the assumption that I wasn't gettign 100% throttle because the butterfly valve wasnt opening up all the way in the TB. You said I'll have to adjust for the correct reading at idle. How should i go about doing this, and where should I adjust. I tightened up the slack on the throttle so that the idle was still reasonable at ~800.

My logger read 80% WOT, so do I just turn that idle screw little by little until i start to see 100% WOT?

Im sorry for all the questions im just trying to start with fixing things before I do anything.
Thank you for your time.

Joe

The TPS may not read 100% when the throttle butterfly is fully open. That's not a big deal.

The butterfly may not open 100% because of slack in the cables or stuff under the pedal. This would need to be corrected.

You don't turn any screws to adjust the TPS reading except for the two lock bolts holding the TPS in place. The BISS is for setting the idle speed. The idle speed must be 750 RPM for the ECU and ISC to be working corectly. If you raise the idle by pulling the cable too tight the throttle will never close. If you raise the idle by turning the BISS you will drive the ISC out of range and cause other problems.

Those two screws in on the manifold are for the cable adjustment. After everything else is adjusted you slide the cable bracket back and forth to get the right amount of slack.

I've posted the correct procedure for adjusting the TPS before and you can find them in the archives. The VFAQ procedure is wrong.

Like I said before, your TPS should read 10% with the throttle closed at idle. What it reads at WOT doesn't matter very much as long as the throttle butterfly opens 100%.

Steve

 

[Sivad87]

The TPS may not read 100% when the throttle butterfly is fully open. That's not a big deal.

The butterfly may not open 100% because of slack in the cables or stuff under the pedal. This would need to be corrected.

You don't turn any screws to adjust the TPS reading except for the two lock bolts holding the TPS in place. The BISS is for setting the idle speed. The idle speed must be 750 RPM for the ECU and ISC to be working corectly. If you raise the idle by pulling the cable too tight the throttle will never close. If you raise the idle by turning the BISS you will drive the ISC out of range and cause other problems.

Those two screws in on the manifold are for the cable adjustment. After everything else is adjusted you slide the cable bracket back and forth to get the right amount of slack.

I've posted the correct procedure for adjusting the TPS before and you can find them in the archives. The VFAQ procedure is wrong.

Like I said before, your TPS should read 10% with the throttle closed at idle. What it reads at WOT doesn't matter very much as long as the throttle butterfly opens 100%.

Steve

Good advise, i only think you missed one of the obvious things that should be checked. Make sure there isnt a floor mat or something else in the way of the pedal causing it to not fully go to 100%

 

[steve]

Good advise, i only think you missed one of the obvious things that should be checked. Make sure there isnt a floor mat or something else in the way of the pedal causing it to not fully go to 100%

The butterfly may not open 100% because of slack in the cables or stuff under the pedal.

Steve

 

[Sivad87]

Steve

oh snap, somehow i didnt notice that. anyways good man!

 

[dspecv]

I have a question on this. My car only surges until it's warmed up. When I adjust my biss, I should have it so that it is idling at 750 when warm correct? Then once I have the correct biss setting, then try to adjust the TPS? I've done so many searches on the TPS, ISC, and other problems for idle surge and there is so much conflicting info that I'm lost.

Steps that I have taken are to replace the ISC, which did not fix the problem, as well as adjusting the biss, which obiously does not work. I think I'm going to try to clean the throttle body, and adjust the TPS next to see if that fixes it. Then I may try to replace the 02 sensor as well. I'll be running a data logger on it this weekend also to see where I need adjustments since I'm finally getting ahold of the cable to do so with. Is there anything else that I should be looking for?

 

[steve]

I was under the assumption that I wasn't getting 100% throttle because the butterfly valve wasnt opening up all the way in the TB.

That may or may not be the case. you have to open the hood and check while someone pushes the pedal.

You said I'll have to adjust for the correct reading at idle. How should i go about doing this, and where should I adjust.
I tightened up the slack on the throttle so that the idle was still reasonable at ~800.

My logger read 80% WOT, so do I just turn that idle screw little by little until i start to see 100% WOT?

You adjust the TPS by rotating it on the throttle body until it reads 10% on your data logger.

You'll have to loosen the throttle cable first. That's not how you adjust the idle speed, the BISS is there for that. Remember that the factory setting is 750 and to run something different you need to change the software in the ECU or the ISC won't work correctly.

Steve