Tps sensor low voltage... Brand new, any advice?

[GTR203]

Hello fellow gurus, I'm getting pretty stumped and frustrated on this one. I have been chasing an issue that once the car warms up it runs like crap like it's pulling timing and any power it has hits a brick wall. Turbos start fighting each other and it just does not run right. To give you am idea on where I'm at at this point this is what's been recently replaced. Cas, BRAND NEW nissan z32 mafs, new yellow jacket coils, coil harness, igniter, ecu 2 different ones now on a pfc and I'm using the handset for readings) good tested low mile alternator, and finally a brand new nissan tps. Granted I have not had it tuned yet but I am not driving the car and p/o had a similar setup plus it runs the same on the ecu that came in the car. Problem I am have is at WOT (car off) I'm only getting 3.6v out of the brand new tps ( old one only getting 2.5) could I have gotten a dud ? I can't return it as I bought it overseas 9 months ago then my car went to the bodyshop and I just got it back. Is there anything else that can cause the tps to have low voltage? I'd like to have everything set right before I send it off to the tuner. Thanks on a lighter note here's a few pics after the bodyshop, new quarters rockers and full respray in Integra type R championship white.









Next to my single turbo g35 that's been giving me fits lately as well

[GTR203]

My poor gtr needs help! Anyone else ever see this issue?

[caliber676]

Have you check power to the sensor? As well as ground and voltage drop? You might not be receiving full 5v signal voltage, or your wiring has a resistance causing a voltage drop across it. I would be more suspecting of the parts you haven't replaced as opposed to the new tps you just got. Let me know if your unsure how to do these tests and I'll try to guide you through it.

[GTR203]

Getting 5v power from the center pin in the connector, and I've replaced just about everything in the electrical system, I will check for voltage drop as well. What other parts are in line with the tps that can affect it?

[Dragon Humper]

What is the resistance range of the TPS? After all, it's just a glorified rheostat. There should be a range spec in the bible to tell you what it should be (don't have that handy right now). If it is off, I think there is a way to adjust it.



Jon.

[Skym]

TPS is a electronic version of an accelerator pump, if used to old school carb engines. TPS helps ECU to stop engine running lean (lean = engine hesitates before accelerating) when suddenly press throttle.

Just need power to ECU. Its the position on ignition barrel, just before starting engine.

Set TPS on idle contact first. With Nistune or Nissan's consult it's easy, as idle contact light's up in software when undo the 2x screws, rotate TPS. PowerFC should have something similar (idle contact check box in sensor menu), since it's based off stock ECU.

This is the TPS values from Nissan's Consult with my cars engine -

TPS failure voltages as below-

DEPRESSED : 3.60V
RELEASED : 0.42V
RANGE : 3.18V
SPEC : MORE3.0V

TPS correct voltages as below-

DEPRESSED : 4.02V
RELEASED : 0.44V
RANGE : 3.58V
SPEC : MORE3.0V

Released is no throttle (on idle contact), depressed is to the floor (WOT contact). The idle, WOT contact pins inside TPS on each end of track (0-5V) on circuit board tend to bend over time and voltage drops.

Also make sure throttle bodies, throttle body cable are adjusted correctly.

Edit: Also the 4.02V is 0.02V too high (that TPS failed later on), so should be 4.00V for depressed.

[GTR203]

Will play with it some more after work today. The pfc does have an idle light as well I've set it multiple times between 0.43-0.45 and still only get 3.5-3.6v at wot. I really hope this isn't a bad tps right out of the box.

[Bruizer]

If you had a modern standalone it could tell you fault codes and even the throttle percentage. I had this problem on my car and it was the tps needing more adjustment THEN calibrate the zero throttle point.
Your problem sounds like it never gets into the idle loop but is fine on warmup enrichment.
Also, my other problem was my timing was set in the wrong direction (had installed an ati damper but the markings were wrong so my timing was -14 not +14 so it was always mega rich and never idling.

For me, The vipec didn't like the stock position on the tps and was causing a ETS fault for me. Took a long time to figure out

Oh and the bible will not help you at all since this is a secular problem with a metal idol. Maybe check the FSM manual.

[Skym]

Will play with it some more after work today. The pfc does have an idle light as well I've set it multiple times between 0.43-0.45 and still only get 3.5-3.6v at wot. I really hope this isn't a bad tps right out of the box.

Sometimes you can get 3.6 volts if not pressing accelerator pedal hard enough to the floor. From memory, was reaching 3.6-3.8 volts until pressed accelerator pedal hard enough on my car. The plastic stopper for accelerator pedal might be loose, thus stopping accelerator pedal travelling fully.

[GTR203]

Will try to check everything tonight one thing to note I also tryed with my buddy using the throttle by hand as I thought it could be getting stuck as well, same result as pedal.

[GTR203]

Well when installing my recaros I pulled my carpet to steam clean and decided to check my harness out, the harness has major melts and in about 7-8 spots all burnt to crisp. This is the dash harness setup found the short replaced broken wire and bought a new Interiour harness. Anyone think this can cause low sensor voltages?

[Alak]

It could cause a number of problems, including that.

However, if you are getting 5v into your tps, it should output the correct range provided the tps is working properly. I would check to see if your throttle linkage is actually opening up all the way or if it is misadjusted as previously stated.

Also does the tps not show a percentage on the pfc? (It does on my rx7)

[GTR203]

Throttle is opening up all the way triple checked it. I am new to the pfc so have only been using the sensor check function on the unit but a multimeter confirms its accurate. I'll have the harness in a week or 2 then I'll be chasing the tps issue down again, I tore all the wiring out of the bay ( aftermarket add ons and sub standard installs factory harness is not touched and good shape) so once all these issues are sorted I will start fresh will all new electrical. This may have been biggest headache gtr is North America. After the wiring is done every possible wear item on the car has been replaced. Every cable down to the gas door has gone every hinge has been replaced, every bushing in the car has been replaced every sensor on the engine is new. Not a single bolt has gone unturned in the car. Hopefully I'll get another 25 years out of it before she'll need a complete overhaul again!

[caliber676]

If your receiving 5v at the sensor and have a good ground then it stands to reason that your sensor is the culprit. What you've done is rule out the circuitry to and from the sensor, what's left is the sensor itself. Your only possible problems could be incorrect adjustment or a faulty sensor

[Skym]

Sometimes the wiring into TPS plug is the culprit (due to someone accidentally knocking TPS plug). It happens to MAF plug, TPS plug, engine ECU plug, etc. With one faulty TPS, could wiggle the TPS plug and engine nearly stalled while idling.