Throttle Sensor
Track Day
Joined: Aug 2004
Posts: 24
Likes: 0
From: Orange County, California
You have two Throttle position sensors on the throttle body. What you got rid of by going to Drive by Wire was the IAC (idle air control valve). The TPS is a three wire potentiometer with a power, ground and signal wire. Back probe both signal wires with a Scope , key on engine off , as you press down on the accel pedal from idle to full throttle you will see one sensor go .5v to 4.5 the other go the opposite 4.5v to .5v . The slope should be smooth with no drop offs. TPS sensors are damaged usually thru Throttle body cleaning when the butterfly valve is moved and the sensor was not disconnected.
Three Wheelin'
Joined: Nov 2007
Posts: 1,402
Likes: 10
From: Maryland
FWIW, my car kept going into limp mode a couple years ago and the fault code (cant remember the exact #) ref'd throttle potentiometer. however, the code doesnt say if it's the one in the TB or the accel pedal and i didnt have the right tools to check. anyhoo, story of my life, i made an exec decision to change the TB first - thinking it's in the engine, gets more wear, etc right?? - but of course, that didnt solve the problem. it was only after i replaced the accel pedal that the problem disappeared.
Thread Starter
Instructor
Joined: Dec 2013
Posts: 246
Likes: 3
From: Florida
The problem I am having is when I take off in first gear, it acts like it stalled, but engine does not shut off. As soon as it happens, I take my foot off the pedal and put it back on immediately and car takes off like it supposed to. It also does it in second gear as well. It is occasional. When I drive the car and put the pedal to the floor, more than the casual easy drive, it does not happen. I think it has to so with the drive by wire system and thought it to be a sensor at the pedal.
No codes, and have no way to find the fault.
No codes, and have no way to find the fault.
Rennlist Member
Joined: Aug 2008
Posts: 684
Likes: 47
From: Moorestown NJ
Another consideration is a bad tire sensor monitor. My previous 2005 997 had a bad wheel sensor which fooled the car into thinking it was in a spin and shut off the throttle. No faults either. Took running while being monitored with piwis to detect the bad sensor.
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Three Wheelin'
Joined: Nov 2007
Posts: 1,402
Likes: 10
From: Maryland
no codes? you mean showing on the dash? you prob have some in the ECU. take it to a pep boys or similar - a few places will read them for free. or just buy a cheap one from an auto parts store and report back here - plenty of us can tell you what they mean.
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Rennlist Member
Joined: Aug 2008
Posts: 684
Likes: 47
From: Moorestown NJ
Your problem is sounding more and more like the headache I had. I threw good money after bad chasing down this problem. New pedal potentiometer, new throttle body. Again no faults for me on Durametric either.
Thread Starter
Instructor
Joined: Dec 2013
Posts: 246
Likes: 3
From: Florida
Rennlist Member
Joined: Aug 2008
Posts: 684
Likes: 47
From: Moorestown NJ
Nope. I had the dealer replace the offending wheel sensor which only triggered a small fault on the piwis otherwise I would have had to replace all 4 and hope for the best. For me, the problem would produce a dead pedal lasting a few seconds while driving. Very scary
Here's my original thread
https://rennlist.com/forums/997-foru...continues.html
Here's my original thread
https://rennlist.com/forums/997-foru...continues.html
Three Wheelin'
Joined: Nov 2007
Posts: 1,402
Likes: 10
From: Maryland
Hmm maybe a fuel pump issue? Or (doubtful but) clutch, even?
Well when u rule out the possible, only the improbable is left, yeah? So have you tried the "stupid stuff" like checking gas cap is tight, checking visible hoses and wires in the engine bay to make sure nothing obvious is disconnected etc?
Good luck.
Thread Starter
Instructor
Joined: Dec 2013
Posts: 246
Likes: 3
From: Florida
Nope. I had the dealer replace the offending wheel sensor which only triggered a small fault on the piwis otherwise I would have had to replace all 4 and hope for the best. For me, the problem would produce a dead pedal lasting a few seconds while driving. Very scary Here's my original thread https://rennlist.com/forums/997-foru...continues.html
It also did it as I was in a turn doing about 20 mph, in second gear. One thing you have to do is give yourself plenty of time before you pull out in traffic.