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Ok, made it back. I think the coolant sensor was loose so the engine was racing up to almost 3k and then wouldn’t start, my mistake.
I tried Vee’s Hail Mary disconnecting TPS test, it made no difference. I think all that’s left is a manual adjustment of the TPS or a trip to a garage. As I live in the middle of nowhere, it’s manual adjustment time!
So, I remove throttle body, loosen TPS screws, give it a wiggle, reinstall throttle body, get under the car as it’s running, wiggle the TPS until the idle drops, then shut off the car, remove oil filter, tighten screws, check idle.
You can manually do it from the top without removing TB after a couple of beers , I think it was a # 5 torque bit and some Red Stripe with it's unique roasted red barley
If you can't get enough of an adjustment , remove the sensor and drill up a size the plastic mount holes on the sensor
If you can't get enough adjustment of the brain , grab another Red Stripe
Best to know where you started from so record your Green / Yellow return wire voltage , ever have a problem of the throttle naturally return to idle stop or have to manually twist the butterfly ?
The most frustrating point is the final tightening of the mount bolts which shifts the sensor slightly
So, I remove throttle body, you don't have to, but it does make it easier loosen TPS screws if the TB is off the car, it will allow you to enlargen the TPS holes which will give you more bandwidth to work with, give it a wiggle not sure this is necessary, you just want it loose enough that it takes some effort to reposition/rotate the TPS, so tight, but not too tight, reinstall throttle body, get under the car as it’s running no need to get under the car, you should be able to reach around and make the adjustment from above, but just be careful as engine should be warmed up and you don't want skin on engine metal, wiggle the TPS until the idle drops you're not wiggling, you are rotating the TPS, then shut off the car I would tighten the screws with the engine still running so that you know it's locked in without any additional rotation caused by tightening the screws, remove oil filter huh? When did we do this?, tighten screws, check idle.
Remove oil filter to get at it below and tighten all up, but other than that seems straightforward enough. Didn’t record voltage before starting, oops.
I managed to get the TPS loose, and I’m in the process of adjusting it with the engine running. I suspect someone has done this before, it’s moving a lot side to side. I managed to get it down to 800rpm, so I stopped. Turned car off and on again, and it’s back up to 1400. Rotating the TPS with the engine running seems to be making no difference to the RPM now.
Is it possible the TPS slid back into it's original spot?
I wonder if you slid the TPS lower than 9% keeping the TPS outside the range the ECU can read it at? What happens when you rotate it the other way? I know the RPMs should go up, but then what happens when you restart the engine?
By cycling the engine start it seems to be resetting something
You may have hit a TPS target value that triggers the IAC to the correct position and then you restart / cycle away from it
To add to the TPS knowledge base if there is a bad spot on it's TPS rotation the ECU will revert to a less then optimal engine regulation and when the ECU receive a signal in expected range it will use the signal going back to optimum regulation ( time delay between both mode switching )
Is it possible the TPS slid back into it's original spot?
I wonder if you slid the TPS lower than 9% keeping the TPS outside the range the ECU can read it at? What happens when you rotate it the other way? I know the RPMs should go up, but then what happens when you restart the engine?
I’ve moved it pretty far in both directions, not making any difference to revs. If I make a few sudden movements side to side the revs will dip, but then come back up a moment later. How much movement is required usually, a couple of mm or an entire inch, because an inch is what I’m working with.
It suddenly dropped to 670, so I shut the engine down. I’m gonna tighten the bolts up without moving anything, hopefully, then restart and see what happens. What’s the best method to tighten this up without moving anything?
You may have to do a full very slow TPS sweep meter test , you can do this from the ECU connector or same Green / Yellow ECU return wire on top of the engine as a single person operation
What you don't want to see is a sudden bip or change on the meter
You can have a bad spot in the sweep at or very near to the idle stop
Everything’s put back together now, all connectors connected. Adjusted TPS tightened up. Now the car won’t start! Just cranking. Tach is moving, smells like fuel, almost as if spark is missing.
Can adjusting the TPS cause a non start if you get it wrong?
Even a bad TPS should still allow the car to start? Maybe flooded again?
Can you pull a voltage reading? I'm curious where the TPS has been adjusted to. You don't need to start the car, just turn the key enough that the car is on, but engine is still off.
If it's cranking but no light off you may have put the cylinders in a bore wash condition , common , same as earlier experience of no start
bore wash is raw fuel washing the oil film off the cylinder walls to have adequate seal for compression
To overcome this is the same hold the gas pedal to the floor ( no fueling in this state ) while cranking and the oil film will reestablish from the underside of the pistion
Can you use a multimeter to see what the voltage is when you tap into the Green/Yellow and Black/Yellow wires at the TPS? (Wires have to be connected to the TPS)
For the TPS to fail would be an open on the sweep ( connector on and locked ? )
It is feed 5.0 volts and the return is a lower resisted value , at the idle stop it should read closest but defiantly a amount from 5.0
Wide open throttle ( higher resistance ) will be furthest amount from 5.0
Reference page 56 ECU return wire pin PI 105 - 12 ( 4.9 volts WOT ) so something backwards
If no voltage return bad TPS sensor
The TPS is a finger ( that can lift off from ) that contact a wound resistor loop so it a variable rotary resistor like an old school light dimmer knob
Can you use a multimeter to see what the voltage is when you tap into the Green/Yellow and Black/Yellow wires at the TPS? (Wires have to be connected to the TPS)
OBD voltage is irrelevant for this.
Green/middle: 4.25v
Black/left: 0.144v
Is that any clue? The car wouldn’t start with the TPS plugged in again, I had to unplug it to start it up briefly.
For the TPS to fail would be an open on the sweep ( connector on and locked ? )
It is feed 5.0 volts and the return is a lower resisted value , at the idle stop it should read closest but defiantly a amount from 5.0
Wide open throttle ( higher resistance ) will be furthest amount from 5.0
If no voltage return bad TPS sensor
The TPS is a finger ( that can lift off from ) that contact a wound resistor loop so it a variable rotary resistor like an old school light dimmer knob
Yeah, I'm more curious to see if the TPS has been rotated further away from the expected 12.9% or 0.60v or closer. If he was already at 9% (Let's assume that coordinates to a 0.40v) and he rotated down to 6% to get the RPMs down, that might have set the TPS way out of bounds for the ECU to believe, and it could be ignoring it.
I'd like to see tobywood13 try to get closer to 12.9% (or 0.60v) before I can call this manual adjustment a failure.
The ECU may be reading this value as you want to overcome bore wash by not adding fuel since you have very low RPM against the WOT TPS value / gas pedal
06-05-2024, 01:22 PM
