Also, there are no WOT or No Throttle switches, only the TPS signal. And yes there is a procedure to reset the throttle position in the manual, however, the computer will self adjust itself over time anyway.

 

So McDan, does this imply that 'over time' the actual throttle position we adjust itself to 100%? So it comes from the factory at 87% but opens up fully over time?

 

I doubt it. But only Nissan knows for sure. I'd bet that the scan tool is just reading a little bit off, but don't know enough about it. Even if the butterfly is only open 87% that does not necessarily mean that power is cut down 13%.

 

So if the throttle is only opening to 87% or whatever and the TS ECU supposedly fixes this then why doesn't it make more power?

I mean if this is so critical and not very well optmized by Nissan then big gains with a re-mapped ECU for throttle settings, fuel maps, and timing should have yielded big gains but TS got next to nothing.

Sounds to me like another "... the ECU learns and negates any mods on the car..." crap.

 

the TB is not opening as much as it should be on accelleration and regular driving... the TB started to close up at the higher RPMs, i dont know why nissan is doing this.. but if the butterfly isnt open all the way, you're not getting as much air into the engine as it could.. Automatics dont even open fully even at wot.... Technos tried the relearning of the TB via instructions from the FSM, but they've still noticed these strange occuances after driving, so they went into the code and manually forced the TB to open more.

 

Okay then I will take your word for it.

Question remains why isn't the engine making more power at higher RPM's with TS ECU ?

 

Chebosto, how's the turbo coming? I wouldn't be too suprised if changing the throttle postion, especially at high RPM's was very good for it.

 

no luck,

I tried both the accelerator release learning procedure
and the throttle closed learning procedure and I still only
get 82% on full throttle.

Note that I could not find an "accelerator fully depressed learning procedure" nor a "throttle fully open learning procedure".
I think those 2 procedures, if they exist, are what we need.

Note 2, the autotap reads through the obd2 connector and
so it see what the ecm says it sees. It does not measure
the line voltage like a multimeter.

Note 3, the manual states that the accelerator position 2
signal is converted by the ECM internally (I'm reading it to
mean that it inverts the first signal for some reason).

Anyways, it should be easy to create a simple module to splice
into the accelerator 1 signal that increases the voltage to 4.75v
once that voltage rises above 4.x volts.

any takers? I would normally but my newborn is putting a
cramp in my schedule...

thanks,
rob

 

it IS making quite a significant gain over stock levels after 4k rpm... i dont know which dyno charts you are referring your question from...

 

I guess I could go see what my car says with autotap!

 

Take the Autotap reading and then compare that to a visual inspection.

 

This thread is stressing me out. Was this engineered into our cars to specifically cut power as a parts safety issue (doubtful) or what? Is it ok to open that thing up to 100%? Will the car run correctly with 100% TB opening?

 

my guess is, if it was engineered not to open 100%, that it is for future model year hp upgrades.

 

The 2nd TPS voltage is generated at the throttle control valve motor, not in the ECU. I think you've made a mistake in your readings, but I could be wrong. I've personally measured both signals in the wiring coming off the Throttle control valve that run to the ECU. Another thing to think about is the butterfly might not be the most restrictive portion of the loop. So if the tubing or intake manifold is itselft more restrictive than the throttle valve, there is no reason to have to open it a full 100%.

Dan

 

Just thought I'd throw in that Nissan did the same thing on the 300ZX

Thread on 300zxclub.com about throttle position

Video on 300zxclub.com of how it was fixed on the 300ZX

 

Notice at the end of the video that every warning light on the dash popped on!!

 

Just four of em, no idea why though, tach died too. I'm gonna guess it's unrelated to opening the throttle because they would have mentioned that in the post.

 

From what I understand, the ecu learns your driving habits and adjusts accordingly. If this is true, I'm sure the reason behind the NOT-FULL full throttle lies in fuel effeciency. Perhaps after a period of time of mellow driving, the ecu sets "foot-to-the-floor" as 87% opening. This would have great effect on miles-per-gallon. Try runnin' your car hard for a period of time and re-measure, you may see more full-throttle opening.

BMW's and Porsche's are set-up to where 1/4 pedal = about 1/2 actual throttle opening. This is purely for asthetic reasons(makes you believe the car has more torque than it actually has). Nissan set up the throttle to mimic the linear feel of a cable pull for more controlability.

Basicly...the car needs to be stretched out before you get the best results. It has to know what is expected of it well in advance.

 

Can anyone with a FSM tell us how to calibrate the throttle?

 

It's already said earlier in the post they tried that, and the car drove really poorly, so they had to go through and fix it in the ECU.