TPS re-install boo-boo (snappics); HELP???

[Schrade]

Alright; this one is solved - re-install adjustment.

But the original problem persists...
TPS response...

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I re-installed the TPS, pulled the trigger, and it held at 2,200 RPM's.

Didn't do it before; I missed the link-arm hookup here.

I DID dis-connect the battery BEFORE dis-connecting the TPS.

It can't be re-calibrating??? (made that mistake with an '87, and it took a couple of Closed Loop cycles to re-calibrate.

Anyone see my mistake here? Any chance someone could post a shot of their own - or link a closeup? Dynomite???

[Schrade]

Got it; thanks...

[Franke]

Hi Schrade. Saw your post. Did your TPS checkout ok then? Just wondering, were you having some kind of off idle stumble or hesitation etc? Was the TPS arm in the wrong position?

[Schrade]

No - no tune problem there Franke; I was just checking out why the 'off-idle sag' that you referred to in the other thread.

No one posted why the pot appears (in mine anyway) to be exponential vs. linear through the range of motion. That appears to account for why the slow response to the gas pedal.

Further reading shows that the TPS has to be adjusted by getting a volt reading with ignition on, and rotating the TPS, with upper and lower securing screws slightly loose, then 'rolling it', until spec 'idle' voltage shows on either the Tech 1 (no got), or on scan software (also no got (yet) ).

I can backprobe the TPS 5V reference feed and return sockets to get that done. I can do a vid, but I've never posted vids to Y/T.

Modding the TB butterfly shaft cam pulley, to fix the TPS, response will take some thought here, IF it can be done at all...

[Schrade]

So we got the TPS 'adjusted'.

Loosen the sensor mounting screws, get a spot of WD in the screws, so that the TPS can be rotated smoothly.

I removed the TPS, then stuck a paper clip into the backside of the signal RETURN feed line - middle socket, Dk Blue, circuit 417, and re-mounted the TPS. Mounting screws JUST loose enough to smoothly rotate the TPS.

(+) multimeter clamped onto the paper clip, (-) onto a good ground. Turn the ignition on, and get a reading. SHould be around .5V - .6V.

Tap lightly the TPS accordingly, to get the readout showing .54V. Tighten top screw, and bottom screw, just a little at a time (so to not throw off the position, until properly torqued.

You might get a fluctuation, as the secondary pump kicks on and off. Mine went from .540V to .539V each time.

Joy.



Now - how to modify the cam on the TB shaft...

[Schrade]

Further investigation, by rolling the butterfly shaft of the TB through the range of motion, with the backprobes still in place, shows a STEADY voltage increase, with a reading at about halfway, of 2.52V.

This seems to indicate that the computer is indeed accounting for the non-linear increase in resistance, of the TPS's potentiometer.

This still does not account for the 'off-idle sag'.

Anyone with thoughts here?

[Franke]

Looks like you've eliminated the TPS as a possible problem. I don't know if the MAP sensor could be an issue as it also provides a signal to the ECM as to what the throttle/vacuum is doing. Only other thing I can think of would be a fuel delivery issue of some sort or possibly a vacuum leak.

[FU]

Did you disconnect the ecm or + battery terminal. In order to give the ecm time to relearn ?
Did you do the IAC relearn procedure ? Try doing the re-learn's one at a time first.

[Schrade]

No - sure didn't there Frank; I was believing that if the battery was dis-connected BEFORE dis-connecting the TPS (or any other sensor), then no re-learn was necessary.

Incorrect?

Like I was saying, I made that mistake once with an '87 automatic. Pulled the TPS with the battery connected. It carried each gear to high rpm's for several Closed Loop cycles, re-learning TPS.

Just did a road test (didn't make Closed Loop I don't think), but no problems.

My handheld for the 4L60e DOES have a manual TPS re-calibrate function. No problem there either... (holding breath, crossed fingers, crossed toes, eyes, teeth, hair, etc., ...)

[FU]

Give it time = relearn.

Good Luck !