about the premature throttle closing

plalm · 2008-09-10 18:11:51

It's been mentioned about a possible throttle body closing at a certain RPM which could be robbing us of power in the mid to top end range. I wanted to test out this theory today. a buddy of mine let me use his ScanGaugeII connected to the plug under the steering wheel area. I had my friend watch the TPS reading as i drove. Oddly enough, and I'm not really sure how it is SUPPOSED to work, but even if i had the pedal ALL the way down it would only register a raise inthe number as i went farther thru the power band. I always thought that it should show how hard your pressing the accelerator, but i accepted it and looked for how high a number it would get to. Well at 7K rpms in 2-4th gears the highest i got it to read was 84%. at complete neutral idle it was going between 2-4%. I don't really know what to take from this just thought i would relay it to you guys. have anymore questions as to what i may have missed or what to do next time just let me know.

plalm · 2008-09-10 18:19:30

oh and just to let you know my car was running at an average 204 degrees when at a light. wasn't checking it while highway driving

jim morris · 2008-09-10 20:37:09

let me put my video on youtube. hang on a minute.

plalm · 2008-09-10 20:48:27

"Hangin by a moment!!"
yeah waiting

jim morris · 2008-09-10 20:57:04

pink line is tps blue is rpm...nothing else is hooked up.

http://www.youtube.com/watch?v=Hd9fMUNmv54

plalm · 2008-09-10 21:15:32

ok so then it is actually at 100% throttle. I'm still wondering if it measures that 100% throttle is being applied, but the throttle body itself still closes? that's the question at hand.

jim morris · 2008-09-10 21:28:40

Well if it did close...the tps would register that i would imagine. since it's directly connected to the throttle plate. That would make sense if i tapped the accelerator pedal sensor because it could close it with my foot still to the floor, but thats not the case. I tapped the tps signal wire. It's just a mechanical resistor that varies a 5 volt reference based on throttle position.

Stitch · 2008-09-10 22:35:14

Wheres Big J He had his thoughts on it, several other Nissans are afflicted with this issue, I wouldn't doubt it if it happened in the specs too.

However I feel a distinct power after 5500 rpms so it closing doesn't make sense, but we'll see.

sw0ggd0gg · 2008-09-10 23:49:22

Every car i have had has only opened to 84% reason being they aquaite for the flapper taking up room.

plalm · 2008-09-10 23:56:20

ok that makes sense. somebody told me that CVTV works somewhat like MIVEC where it allows more airflow past a certain rpm. don't remember who or when i heard that or if i just misunderstood that. but i feel a difference past 5500 as well. do we have secondaries?

Stitch · 2008-09-11 07:50:27

Nope no secondaries.

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