nxto

So my car stutters and hesitates a lot at low rpm, so i adjusted the tps with the ohm meter. It didn't help one bit...so I'm thinking the tps needs to be replaced. But before that, is it okay for me to disconnect the tps and drive around? Because the tps plug is together with another sensor(not sure what, it looks identical to tps), would it be alright?

satch

iTrader: (1)

With the car fully warmed up set the TPS to 1 volt w/key to on by measuring the Green/Red wire.

nxto

Ya I did that, and it didn't solve the issue.

satch

iTrader: (1)

You might want to make sure the leading coil is firing properly and the fuel pressure is within spec. Perhaps disconnect both electrical plugs (not spark plug wires) at the trailing coil and see if it runs the same or not at all.

Turbonut

iTrader: (1)

It's an S5 so use the light method in the connector. Over the 22 years of ownership, neither the ohms nor volt method has ever proved to be perfect, but the light method has always worked, unless the TPS is kaput.

Aaron Cake

iTrader: (1)

If you disconnect the TPS, the car will go into limp mode.

If you have an analog meter or scope, observe that the TPS reading is smooth throughout its entire range.

Also, make sure the car is fully warmed up before you try and set the TPS.

LunchboxCritter

iTrader: (9)

+1 on the test light method. I had no luck with mine by setting it to 1.0V, but the test light fixed me right up.

HAILERS2

Test light will only light up when the ECU sees approx one volt dc.

See post #6 as to why you should not disconnect the TPS on a series five.

Turbonut

iTrader: (1)

The key word is approximate and this small difference is what I've found to be critical and is corrected when using the light method.

HAILERS2

Using the LED light method is also APPROX.

Fully HOT engine key ON engine OFF.

Turn the TPS screw counterclockwise til no LED is on.

Turn the TPS screw clockwise til ONE LED light comes on.

A digital meter backprobing the TPS harness connectors pigtail.......green/red wire, will show 1.10vdc

Now turn the TPS screw clockwise til both LED lights come on. Then turn counterclocwise til only one LED light stays on. Digital meter backprobing the TPS harness connectors green/red wire will show 1.01vdc.

So approx using the LED two light method has a range of 1.10vdc down to 1.01 vdc using that method of rigging the TPS.

Now start the fully HOT engine and read the green/red wire at the TPS pigtail (green/red wire) by backprobing the green/red. Reads 0.97vdc on my 86 non turbo.

I can set the TPS output down to 0.9vdc or up to 1.10vdc and drive it all day and notice nothing peculiar at all.

TPS does not directly control the amount of fuel. TPS rigging decides when the Relief and Switching solenoids are triggered for control of the ACV. TPS decides when you get either on or both fuel injectors to shutoff when you let off the gas pedal.

TPS decides when the fuel injectors come backonline after the ECU cuts the injectors off when decelerating.

The RX has *zones* of operation and the TPS setting decides when your in one of those *zones* of operation.

Narrow range output is at full value at ??? approx 18* throttle angle or put another way it's at full value at the point where the secondary plates just start opening and stays at the value all the way to full pedal stomping has been reached.

Just arguing for arguings sake and nothing more or less.

TPS setting is overrated imho.

EDIT: Forgot to mention if you walk away from what was a HOT engine and come back and look at the previous output of the engine OFF key ON.......the previous figure you saw on the digital meter will have changed especially on a cold windy day 'cause the thermowax is now starting to retract and move the throttle linkage which in turn moves the TPS plunger which in turn causes the meters value to go up.

This is what I do while my West System epoxy is setting up on my boat building project. Gotta go sand on the boat now.

Turbonut

iTrader: (1)

I actually always adjust the TPS on a cold engine holding the fast idle cam up with a screwdriver as it's easier on the Turbo. In past experience I'd get a hiccup or hesitation on light acceleration when adjusting with either of the two alternative methods, but with the light method it would correct the issue, so stayed with the lights. Sorry, but certainly can't argue the particulars as I've never checked the volts/ohms after the light adjustment corrected any problem. Maybe next time I will.

Hailers, you never cease to amaze me!