car = 91 240sx
engine = rebuilt with 7k miles
mods - cold air intake/header/exhaust
replaced/switched out - o2 sensor, ecu, dist cap, dist rotor, ignition coil, Mass Air Sensor, spark plugs n wires, cleaned air filter, fuel filter, took out my audio system, battery, and ran new grounds.
After all that.. I started thinking about my TPS and just disconnected it and tried to run without the TPS harness plugged in. Car ran exactly the same.
Good at first, then slow after about 30-45 mins. I think it has to do with the heat, because my engine seems hot after long runs. If the engine is running slow and I get on the highway for a bit and get some air on her she starts running better. My temp is good, Always at the 3rd notch. Any ideas?
TPS - Causing my car to get slow?
Re: TPS - Causing my car to get slow? (dubbs693)
Doubtfull it's the TPS. Usually one or two things happen with them: they get mis-adjusted, which will affect your off-idle response(un-smooth starts in 1st). Or, they will simply just go bad: the ECU may or may not recognize this(especially if it is 'stuck' in one position). If the ECU picks up on it, you won't be able to climb past 3k rpm.
It's pretty easy to check: just use a volt meter and look at the voltage on the middle(white IIRC) wire. It should sweep from ~0.45Vdc to ~4.5Vdc. To be even more sure, measure the signal at the ECU connector.
It's pretty easy to check: just use a volt meter and look at the voltage on the middle(white IIRC) wire. It should sweep from ~0.45Vdc to ~4.5Vdc. To be even more sure, measure the signal at the ECU connector.
Re: TPS - Causing my car to get slow? (slipnfall)
PS - I presume you have a 5spd? Auto's have some other TPS considerations.
Yes i do have a 5spd
I tried to test it with a multimeter, but it broke.. It puts out some crazy readings.. such as 6.88 volts on the battery... even though it starts no problem..
The thing i did was take out the tps harness, so basically i think i proved the TPS isn't doing anything.. If its plugged in or not there is no change in drivability.
To check the voltage.. Are you talking about testing the male or female end? Do you have to take anything off to get to the wires?
I tried to test it with a multimeter, but it broke.. It puts out some crazy readings.. such as 6.88 volts on the battery... even though it starts no problem..
The thing i did was take out the tps harness, so basically i think i proved the TPS isn't doing anything.. If its plugged in or not there is no change in drivability.
To check the voltage.. Are you talking about testing the male or female end? Do you have to take anything off to get to the wires?
Re: (dubbs693)
The TPS puts out 6.8Volts? Not possible, unless you were referencing to the postive terminal of your battery by mistake. Using your ground terminal of the battery, you have to 'back' probe: meaning you need to measure the voltage with the connector plugged in. I have found that apolstery T-pins work great for this(basically a long needle with a 'T' on the end). One wire should be ground, one wire is +5Vdc, and the other is the signal.
Re: (slipnfall)
Thats why i said the multimeter is broken.. but do you get what I am saying by me taking off the connector and the drivability not changing? That must mean its not working, right?
Re: (dubbs693)
Does that not make any sense? If the TPS harness is plugged in or not it doesn't change how the car behaves, that would indicate a faulty tps correct?
I'll try to get another multimeter but i dont think i need to..
Would you go with OE Nissan TPS or aftermarket?
I'll try to get another multimeter but i dont think i need to..
Would you go with OE Nissan TPS or aftermarket?
