LS3 Throttle Position issues

[GarethGTR]

Hi

Completed a lot of my wiring today and fired up the ecu. All good except that the throttle position is showing a minimum of 21% and a maximum of 83% ... ?

I have an LS7 throttle/pedal assy, I thought they were compatible ?

I have made sure that the lever on the throttle/pedal assy moves its full travel.

Any ideas?

Gareth

[anonymous-user]

Generally, potentiometers used for automotive systems do not "go to the end stops" so that the control ecu can detect a failed (disconnected or shorted high) input. Hence, the output reads 15-20% at the lower mech "stop" and ~85% at the upper mech stop. Any output of voltage exceeding or not meeting those values can be determinded as a fault very easily. You ecu should have a method to "adapt" or be told what voltage is considered the min /max mech stops for your pedal sensor etc?

[738 driver]

When you do get it somewhere nearer Gareth... they dont actually fully open if operating corrctly... I cant recall the figure but its 87-97% ish butterfly open to 100% pedal deflection....Richard (efi live guru/PH'er) will likley confirm.

[Steve_D]

GarethGTR said:

Hi

Completed a lot of my wiring today and fired up the ecu. All good except that the throttle position is showing a minimum of 21% and a maximum of 83% ... ?

I have an LS7 throttle/pedal assy, I thought they were compatible ?

I have made sure that the lever on the throttle/pedal assy moves its full travel.

Any ideas?

Gareth

Sounds to me like you have the exact opposite to our problem.
The early TB has a different motor gear ration to the later ones. In our case the pedal was trying to open the TB further than it would go so we had to buy an earlier TB.

I have a nice later TB for sale!!!!!!!!

Steve

ETA You are welcome to borrow the TB and see if it fixes your problem.

[GarethGTR]

Hi

PM Sent :-)

Gareth

[GarethGTR]

Hi

Ii had a closer look today....

despite the fact that all of the throttle positions reported by the ecu are 20%/80% ish, the actual throttle butterfly opens and closes fully when the pedal is pressed. Now I am really confused ???

Anyone?

Gareth

[anonymous-user]

What is reporting the throttle percentage, and is it TPS (throttle plate sensor) or PPS (pedal position sensor)?? Is there an Offset and scalling that you need to apply to the values??

[spatz]

I think you are ok, there was an earlier explanation that supports this behaviour. Others hat problems with the throttle blade not opening full or being fully opened at half travel.

[Steve_D]

Evident senior moment.
The TB is still fitted to the car. The replacement TB (silver butterfly) is still sitting on Paul's desk. It could be a week or two before we can swap them and ours becomes available.

Does anyone else have one they could lend Gareth?

Steve

[GarethGTR]

Hi

FIRED HER UP for the first time yesterday - Oooooh! nice :-) just got to fix the alternator alignment issue and then good to go.

The TPS thing has got me. ALL parameters show 20% ish min ans 80% ish max, although the butterfly does open and close all the way.

I noticed that after I blipped the engine the revs dropped too far and then jumped back up past idle before settling down to idle. I suspect this is normal until the ecu learns ... ???

Oh, and SMOKE! lots and lots of smoke, but again, I guess this is just all of the new components getting shot of coatings etc...

WhoooHoooo BIG moment for me.

Gareth

[UltimaCH]

Great to hear and I hope everything works out well and you will soon be enjoying the car on the road.

[spatz]

btw gareth have you completed this project with the electronic fuses ?

[Graham-P]

GarethGTR said:

Hi
I noticed that after I blipped the engine the revs dropped too far and then jumped back up past idle before settling down to idle. I suspect this is normal until the ecu learns ... ???

Mine does that aswell....sometimes it would cut out if the revs dropped too far, but of late it hasn't cut out, so I guess as you say it's learning (still bounces a bit though). When you blip the throttle is yours a clean response, mine isn't, when I blip it hesitates a bit and all you can hear is great sucking of air...need to get it sorted just finding the time to go to the EFI Live guy to do it.

[GarethGTR]

Graham-P said:

Mine does that aswell....sometimes it would cut out if the revs dropped too far, but of late it hasn't cut out, so I guess as you say it's learning (still bounces a bit though). When you blip the throttle is yours a clean response, mine isn't, when I blip it hesitates a bit and all you can hear is great sucking of air...need to get it sorted just finding the time to go to the EFI Live guy to do it.

Hi

Yes, it seems to rev up smoothly. Hard to tell because my belt has destroyed itself as I have the alternator aligned incorrectly.
Tomorrow I will get a new belt and take it form there....

Gareth