Interesting Rev issue

[Justin]

I have a Q45 on a RonR short runner FFIM. When I hold the accelerator at about 1k the engine will pulsate from 1k to ~2.5K without even slightly moving my foot.

With the key in the Ign position the maft pro reads my TPS as from .35 to 4.~8.

Any suggestions?

 

[Justin]

I'll add, to bump the thread, that I have no codes. The car also runs and drives pretty darn well. It sounds like a subby though; my comparison, and another supra owners.

 

[jetjock]

Stock TPS? If not what did you do about the idle contact? Does it do it with the pedal held to the floor?

Sounds like fuel cut caused by IDL remaining closed. Check to see if it's going to 5 volts when the throttle is cracked. A stuck IDL contact won't set a code and iirc is not monitored by the maftpro.

 

[Justin]

Stock TPS? If not what did you do about the idle contact? Does it do it with the pedal held to the floor?

Sounds like fuel cut caused by IDL remaining closed. Check to see if it's going to 5 volts when the throttle is cracked. A stuck IDL contact won't set a code and iirc is not monitored by the maftpro.

Q45 TPS.

I'll go pull up the diagram I have of what I did, without it I will not have a clue how to answer your questions

What does it do with the pedal to the floor with the engine running? Begins to bring the revs up pretty damn fast :-D While the engine is running, and I'm just driving everything appears to operate correctly.

 

[jetjock]

I'm not fam with that TPS but it must either have an idle contact or you rigged something else up. Anyway, it doesn't appear to be a case of grounded IDL because it'd do it anywhere off idle...even with the pedal floored.

 

[Justin]

This is the diagram I used

http://www.supramania.com/forums/attachment.php?attachmentid=7784&d=1151272333

This is the thread I followed

http://www.supramania.com/forums/showthread.php?t=21379&highlight=nissan+throttle

And here are two pictures of the wiring I did


http://www.supramania.com/forums/attachment.php?attachmentid=16612&d=1184794825

http://www.supramania.com/forums/attachment.php?attachmentid=16611&d=1184794821

 

[Justin]

Anyone have any ideas?

 

[adampecush]

did you calibrate the TPS when the engine was warm, or cold? Do you have the coolant lines hooked up to the TB? The reason I ask is that, when the throttle body is sitting at ambient conditions, a thermostat-like actuator keeps the throttle plate open a tad. When the engine warms up, the throttle plate closes. If you calibrated the TPS when the TB was cold, your IDL will remain closed when the throttle is opened slightly at operating temperature. Slightly opening the throttle plate at operating temperature (when the actuator allows for complete closing of the throttle plate) will essentially mimic full closure of the TB at ambient temperature. Hopefully that made sense.

 

[jetjock]

The reason I ask is that, when the throttle body is sitting at ambient conditions, a thermostat-like actuator keeps the throttle plate open a tad

I have no idea where you got that information but there there is no such thing.

 

[Justin]

My method of calibration was to adjust to a set voltage that has been used by many other Q45 users. I adjusted the TPS in the ''ign'' position, wth the engine off. I do not have any coolant lines running through the TB.

I wonder what the issue is :\

 

[adampecush]

I have no idea where you got that information but there there is no such thing.

that was an oversimplification. The thermostat/actuator (circled in the picture) pushes the throttle plate closed when operating temperature is reached (I assume...as it is connected to the coolant lines). If you have a q45 tb at hand, it is pretty obvious how it works.

 

[p5150]

that was an oversimplification. The thermostat/actuator (circled in the picture) pushes the throttle plate closed when operating temperature is reached (I assume...as it is connected to the coolant lines). If you have a q45 tb at hand, it is pretty obvious how it works.

I second that. The Q45 TB has such a thing. Of course, that is assuming that you havent disabled it by pulling the arm that it actuates off of the TB.

I removed mine because I didnt plan on running the coolant through the throttle body, and I didnt want ambient temperatures and heat soak to change my idle characteristics.

 

[adampecush]

That is the other way to go about things - I was contemplating doing this to avoid any potential interactions between the ISC circuit and the idle speed control on the throttle body.

 

[jetjock]

Do'h. Sorry guy...I stand corrected. I had stock TB on the brain. I'm clueless about the Q45. Need to pay more attention...

 

[p5150]

justin - how does the output of the q45 TPS compare with the stock specifications at different throttle inputs?

 

[gofastgeorge]

Best thing to do would be to mount the Supra TPS on the Q45 throttle....

 

[Orion ZyGarian]

Best thing to do would be to mount the Supra TPS on the Q45 throttle....

I was considering this route if for nothing else than the fact that the TPS on our cars is adjustable unlike dumbass Nissan, who similarly, doesnt like to slot hoods to allow for adjustment either. Not to mention that you can keep the stock connector for the TPS. I'm going to have to look that up to see what people have done in that regard.

Well shit, since you can only search for terms that are 4 characters or more, "tps, q45," and "tb" wont show.