2G Throttle body problem

[ITSME4G63]

WHenever I push the gas pedal down to the floor, my logger indicates that the thorttle is 85% at wot. So after tinkering and adjusting the throttle cable, with no slack at all , it still is 85% at wot. I turned the car off and left the ignition on and took my logger in the engine bay and tried to pull on the throttle by hand at the throttle body and voila, it went to 100%. Im thinking the tb spring lost tension or what else could it be? THanks.

 

[GVR4592]

How is your throttle cable adjusted? Is it loose at all?

 

[ITSME4G63]

How is your throttle cable adjusted? Is it loose at all?

no slack at all! eaither way with slack or not, the throttle wotn go past that percentage.

 

[Eastwood95]

Do you have cruise control?

 

[ITSME4G63]

Do you have cruise control?

yesssirreeebob

 

[TimG]

yesssirreeebob

Then take the black box off (2 x 10mm bolts) and adjust the cables in there. Just don't forget to tighten her back up.

 

[arash15]

i'd adjust the throttle position sensor on the throttle body

 

[TimG]

i'd adjust the throttle position sensor on the throttle body

I hate to say it but that is dumb. Think about it before you say something.

 

[arash15]

I hate to say it but that is dumb. Think about it before you say something.

it isnt dumb to recalibrate the sensor so it could be exactly on point.

 

[GVR4592]

it isnt dumb to recalibrate the sensor so it could be exactly on point.

He can't get 100% throttle by pushing on the pedal, but he gets 100% throttle if he manually rotates the throttle plate. That means the sensor is fine and the cable isn't adjusted correctly or one of the mechanical pieces in the system isn't working properly.

 

[arash15]

He can't get 100% throttle by pushing on the pedal, but he gets 100% throttle if he manually rotates the throttle plate. That means the sensor is fine and the cable isn't adjusted correctly or one of the mechanical pieces in the system isn't working properly.

i was talking about the adjustment on the tps after the throttle cable is adjusted. thanks.

 

[Kevin Jewer]

It's not uncommon to lose full travel with the cruise control box hooked up. There is an adjustment on the pedal cable side to get a little more, but adjusting that can be tricky. Before getting into that, make sure you are adjusting the throttle cable properly. I will provide what I have found through years of assing around with warm idle problems and lack of travel to be the best procedure to set the cable.

Loosen the bolts holding the cable bracket. Have a friend (or a brick if you have no friends) floor the throttle pedal. Pull the cable back opening the throttle all the way to the stop, and tighten the bolts here.

This gives you 100% opening, with the maximum amount of slack your hardware will allow (to prevent high idle when warm, cable expands with heat, etc). If this still does not provide 100% throttle (mecahnically, not on the sensor) at WOT and 0% at throttle closed, there is a hardware problem.

Only after the cable has been set properly can you then adjust the TPS. Anything over about 90% will be considered WOT by the ECU, but the higher you can get it the better. Very few cars can run the whole span from 0-100% in my experience. It's usually better to have it set to 0-1% at throttle closed. This is especially important on 2Gs, since the throttle closed switch is incorporated into the TPS (the 4th wire, compared to a 3 wire 1g unit), and the switchover happens around 1% throttle position. If the 2g ECU does not see the closed throttle switch activate when the throttle is closed, it will not go into closed loop control of idle speed. For a 1g, there is a seperate one wire sensor that provides this function, the procedure for setting is similar (switch closes at 1-3% TPS).

Moral of the story, shitcan the cruise control if at all possible (non-cruise cables are very cheap, 20-30 bucks), set the cable properly, and then set TPS properly and throttle closed switch properly. For people diagnosing idle problems (suspecting ISC or FIAV for example), it is pointless to do anything until all of these steps have been followed first.

 

[ITSME4G63]

Then take the black box off (2 x 10mm bolts) and adjust the cables in there. Just don't forget to tighten her back up.

Just did it, tps was 33% with no throttle at all and the maximum I could get it to with that is 97.2%, when I truned teh car on its started idling at 5k rpms. So I set it back to where it was before, the tps is at 15% now and everything is how it was before, not hitting past 85% at wot that is. I am using a 2g tps senor because I thought mine went out in the first palce and the only 1 I could get ahold of was a 2g one. I believe though the tps should be at 10% with the 1g one though.

95GSXracer:

So what you are saying is loosen the two bolts which hold the cable on the intake manifold and then get the tb to swing all the way till it hits the stop and then what?

The spring on the tb seems really slacky, I do not know how much tensioned they come but this one I can just move around up and down when its not at 100% swung up. I was wondering if anybody else could check how their tb spring looks to compare, is it on tight or just so and so?

 

[TimG]

Just did it, tps was 33% with no throttle at all and the maximum I could get it to with that is 97.2%, when I truned teh car on its started idling at 5k rpms. So I set it back to where it was before, the tps is at 15% now and everything is how it was before, not hitting past 85% at wot that is. I am using a 2g tps senor because I thought mine went out in the first palce and the only 1 I could get ahold of was a 2g one. I believe though the tps should be at 10% with the 1g one though.

Do this THEN adjust the regular cable. See if it helps at all.

 

[ITSME4G63]

Do this THEN adjust the regular cable. See if it helps at all.

you mean, the bracket at the intake manifold with the 2 screws? Yeah, its adjusted, no slack at all.

 

[GVR4592]

It should have a small amount of slack, it shouldn't be tight.

 

[steve]

I was wondering if anybody else could check how their tb spring looks to compare, is it on tight or just so and so?

Tight.

Your correct that it doesn't matter if you are using a 2G TPS you have to adjust it using the 1G setting since the 1G ECU isn't looking at the IPS inside it.

Like the guys have been saying the throttle cables from the pedal to the cruise pulley and from it to the throttle boby need to be adjusted to remove any non-standard slack before you adjust the TPS position. Then once the TPS is set to spec whatever the WOT reading is is what you get as long as the mechanicals are working and opening the butterfly so that it's parallel to the throttle bore.

Steve

 

[Kevin Jewer]

95GSXracer:

So what you are saying is loosen the two bolts which hold the cable on the intake manifold and then get the tb to swing all the way till it hits the stop and then what?

The next step was to tighten the bolts that hold the bracket to the manifold to hold this setting.

Loosen the bolts holding the cable bracket. Have a friend (or a brick if you have no friends) floor the throttle pedal. Pull the cable back opening the throttle all the way to the stop, and tighten the bolts here.