car not driving right....powerlight ect

[SoCal LS-L]

Originally Posted by 1986nate

Ok, no worries

Chris, do you still have that EGR code and issues with that? Perhaps that is coming back to cause some issues as well? It may be a long shot, but good info to put out for anyone else who may be looking to add input Maybe run the engine codes again to see if there are any in addition to that after these problems.

Edit: I believe you can get a new TPS from Advance Auto Parts (at least around here) you could buy one and if it solves all the issues, you know its the culprit. If it does not fix the problems, then you could always return the part. (you may have to do some convinceing for them to refund you but I know good lines to give to the employees when returning stuff)

Oh yes, the EGR code remains!

Ill order one thru the shop, im starting to lean right to it with your guys' responses. It made it 18 1/2 years, cant complain.

[Trevor]

Kia ora Chris,

Earlier on, you showed that the price of a new TPS did not thrill you. You can check it, and treat it, with very little effort.

After removal the unit it is easily checked with a meter for smooth operation or otherwise. Evan without dismantling the unit a spray with CRC or similar cleaner and a work out will do wonders.

The resistance end to end (black to red) should measure very close to 5000 ohms. Measuring resistance between white and red or black should show a smooooooth change in resistance when moving the control shaft over full distance.

With the unit in place, a voltage check on the output, as the mechanism it is operated while connected and energised, will also give an indication of possible intermittent contact. Here you are looking for a smooth change in voltage

Stick a pin or needle right through the white insulated wire, so that you can clip your meter lead onto it to make measurements. A fine pin will not damage the conductors as they will spread and there will be no significant damage to the insulation. Measure between the wiper, i.e. white wire and ground by connecting to the engine, or battery negative.

A meter with a bar graph will show up short duration faults much better than a normal instrument, digital or analogue, as both have an inherent time delay before indication is registered. This factor should be taken into account but should not deter you. I can advise on simple alternative tests which do not involve sophisticated gear.

[SoCal LS-L]

Cool, thanks Trevor.

I did at one time check the TPS resistance and voltage values, but it was nearly 8 months ago.

I guess ill call around and see if my shop discount beats the online route. My engine has felt a bit subdued lately so im wondering just how much influence the TPS has on fuel pulse or timing advance.

[Trevor]

Originally Posted by SoCal LS-L

Cool, thanks Trevor.

I did at one time check the TPS resistance and voltage values, but it was nearly 8 months ago.

I guess ill call around and see if my shop discount beats the online route. My engine has felt a bit subdued lately so im wondering just how much influence the TPS has on fuel pulse or timing advance.

The TPS tells the ECU what your right foot is doing. No more and no less, and in particular it does not provide a signal directly accessed by the TCU.

Sorry to down your hopes, but you never know, your butt dyno might get excited.

[SoCal LS-L]

I always thought the TPS provides the ECU with the cue to advance the throttle initially, so theres not a delay in throttle response. Maybe im wrong or thinking of a different system. Gonna call tomorrow and see what the dealer wants at shop rate.

[b3lha]

Originally Posted by Trevor

in particular it does not provide a signal directly accessed by the TCU.

Are you absolutely sure about that Trevor? In the interests of accuracy, I think you should check your wiring diagram again.

[Trevor]

Originally Posted by SoCal LS-L

I always thought the TPS provides the ECU with the cue to advance the throttle initially, so theres not a delay in throttle response. Maybe im wrong or thinking of a different system. Gonna call tomorrow and see what the dealer wants at shop rate.

The TPS is mechanically linked to the throttle so that both move in unison. However other adjustments will probably be signalled in advance/anticipation as the throttle is opened, so as to improve engine response, and is probably what you have in mind. Phil will be clued up on this one and may chime in.

[Trevor]

Originally Posted by b3lha

Are you absolutely sure about that Trevor? In the interests of accuracy, I think you should check your wiring diagram again.

Thank you Phil,

As is usual you are correct. Even though operating voltage is sourced only from the ECU, the output voltage is delivered to both the ECU and TCU.

Sincere apologies, Trevor.

[b3lha]

Originally Posted by SoCal LS-L

I always thought the TPS provides the ECU with the cue to advance the throttle initially, so theres not a delay in throttle response. Maybe im wrong or thinking of a different system. Gonna call tomorrow and see what the dealer wants at shop rate.

Somebody on Nasioc explained it very well:

Originally Posted by ride5000

when you open the throttle plate the almost instantaneous reduction in manifold vacuum causes a big rush of charge air to enter the chamber. this occurs even before the maf sensor detects a change in airflow. as a result you'll get a lean stumble before the fuel metering/delivery system "catches up" to the actual airflow.

the tip in enrichment performs the exact same function as a throttle pump in an old carb setup, and for the same reason.

there may very well be a throttle off enleanment for the same reason... snapping shut the plate will cause the reverse to happen.

That's one reason why the ECU needs to monitor the throttle position.

For the TCU it's even more important. The shift maps are indexed by "vehicle speed" and "throttle position". The power mode selection is based on "throttle position" and "rate of change of throttle position".

[SoCal LS-L]

Originally Posted by SoCal LS-L

I always thought the TPS provides the ECU with the cue to advance the throttle initially, so theres not a delay in throttle response. Maybe im wrong or thinking of a different system. Gonna call tomorrow and see what the dealer wants at shop rate.

Stupid me not proofreading, I meant advance timing and not throttle.

So it looks anyways like its time for a new one, ill post any noticeable changes in engine behavior when the dirty deed is done.