unstable idlling-stalling im going nuts

[Ensoniq5]

My point is that, on the 3rd Gen TB, the TPS cannot be adjusted without moving the point at with the idle switch triggers, since they are integrated into a single unit. For this reason the TPS setting procedure concentrates on the point at which the idle switch triggers rather than min/max resistance across the TPS range, which is only tested to verify that the sensor is working properly. The older 1st/2nd Gen setup was different, the idle switch was on the end of the concertina-shaped idle speed controller and the throttle position sensor was a separate unit.

My concern is that someone reading this thread may assume that tweaking the position of the TPS is a valid way of correcting some gear change behaviour in 3rd Gens, this may well be valid in earlier Magnas or other vehicles where the TPS is separate from the idle switch but is likely to introduce idling problems with the 3rd Gen throttle body setup, as far as I understand it. In most cases the TPS will never need to be adjusted from factory settings, so you're spot on regarding the white paint dot which will be unbroken in most cases.

[GRH]

My point is that, on the 3rd Gen TB, the TPS cannot be adjusted without moving the point at with the idle switch triggers, since they are integrated into a single unit. For this reason the TPS setting procedure concentrates on the point at which the idle switch triggers rather than min/max resistance across the TPS range, which is only tested to verify that the sensor is working properly. The older 1st/2nd Gen setup was different, the idle switch was on the end of the concertina-shaped idle speed controller and the throttle position sensor was a separate unit.

My concern is that someone reading this thread may assume that tweaking the position of the TPS is a valid way of correcting some gear change behaviour in 3rd Gens, this may well be valid in earlier Magnas or other vehicles where the TPS is separate from the idle switch but is likely to introduce idling problems with the 3rd Gen throttle body setup, as far as I understand it. In most cases the TPS will never need to be adjusted from factory settings, so you're spot on regarding the white paint dot which will be unbroken in most cases.

i'm no where versed as you guys are about engine stuff.. but what i observed when i was testing the TPS using a multimeter at ohm setting.. is it's off, then it's on and then provides increasing resistance (maybe decreasing not sure if i recall correctly) but either way it would be something like
off-on-1 2 3 4 5 6 7 8 9 as the sensor gets twisted. so it's basically acting like a volume potentiometer. i tend to think, since off means no pressure on the throttle so it should be set as near as possible to that position. the instant you step on the accelerator, cable gets pulled and throttle is now on and increasingly open in relation to the tps reading.. so if you start at the right spot.. it should continue with the right spot ( wrong assumption?)
adjusting this location merely by the feel, might be misleading.. well maybe not so much for experienced people i dunno...
if the TPS had a design such as not just off- on.. but off - idle - on - 1 2 3 4 and had there been a sweet spot between the on and off that is immeasurable.. then i'd see it's complexity.. but from my experience multimeter served me just fine. (3rd gen TW)
after i replaced the sensor idling etc had been all fine since the MAF began acting up.. from what i see it had been acting up all along just gave a long break from being a pita for some reason.

[leadfoot6]

i'm no where versed as you guys are about engine stuff.. but what i observed when i was testing the TPS using a multimeter at ohm setting.. is it's off, then it's on and then provides increasing resistance (maybe decreasing not sure if i recall correctly) but either way it would be something like
off-on-1 2 3 4 5 6 7 8 9 as the sensor gets twisted. so it's basically acting like a volume potentiometer. i tend to think, since off means no pressure on the throttle so it should be set as near as possible to that position. the instant you step on the accelerator, cable gets pulled and throttle is now on and increasingly open in relation to the tps reading.. so if you start at the right spot.. it should continue with the right spot ( wrong assumption?)
adjusting this location merely by the feel, might be misleading.. well maybe not so much for experienced people i dunno...
if the TPS had a design such as not just off- on.. but off - idle - on - 1 2 3 4 and had there been a sweet spot between the on and off that is immeasurable.. then i'd see it's complexity.. but from my experience multimeter served me just fine. (3rd gen TW)
after i replaced the sensor idling etc had been all fine since the MAF began acting up.. from what i see it had been acting up all along just gave a long break from being a pita for some reason.

Just in case, check that your throttle cable is adjusted correctly first i.e. no slack.

Not over stretched, not too loose, but just like Goldilocks.....JUST RIGHT.

It took me a quite a few months after I purchased my TL almost 5 years ago to realise that the throttle cable was loose.

And after I got it back from Mitsfix after the 380/6g75 swap it was loose again.....but even more so.

This is somewhat understandable, as the modified 380 upper manifold has the throttle cable bracket TIG welded on and is not a factory original fitting and the throttle cable adjustment may have been overlooked due to the time pressure that Brendan was working under.

It pays to check this very basic item.

[GRH]

Just in case, check that your throttle cable is adjusted correctly first i.e. no slack.

Not over stretched, not too loose, but just like Goldilocks.....JUST RIGHT.

It took me a quite a few months after I purchased my TL almost 5 years ago to realise that the throttle cable was loose.

And after I got it back from Mitsfix after the 380/6g75 swap it was loose again.....but even more so.

This is somewhat understandable, as the modified 380 upper manifold has the throttle cable bracket TIG welded on and is not a factory original fitting and the throttle cable adjustment may have been overlooked due to the time pressure that Brendan was working under.

It pays to check this very basic item.

no expert but i'm pretty sure it's just right.. the feeling is there, tightness and the response from the engine the instant i step on the pedal

[leadfoot6]

no expert but i'm pretty sure it's just right.. the feeling is there, tightness and the response from the engine the instant i step on the pedal

That sounds OK.

But just to be sure.....is there any slack in the cable when you raise it up by hand before the throttle pulley moves?

I did not seem to find anything amiss when operating the throttle from the cabin, but I only noticed the problem when I opened the bonnet and made a close inspection of the actual throttle body.....where I saw the slackness of the cable.

This youtube video:

https://www.youtube.com/watch?v=LAC_LX4ioOU

will give you a good understanding of what is involved.

Note at the start that the throttle cable is very loose.

[leadfoot6]

My point is that, on the 3rd Gen TB, the TPS cannot be adjusted without moving the point at with the idle switch triggers, since they are integrated into a single unit. For this reason the TPS setting procedure concentrates on the point at which the idle switch triggers rather than min/max resistance across the TPS range, which is only tested to verify that the sensor is working properly. The older 1st/2nd Gen setup was different, the idle switch was on the end of the concertina-shaped idle speed controller and the throttle position sensor was a separate unit.

My concern is that someone reading this thread may assume that tweaking the position of the TPS is a valid way of correcting some gear change behaviour in 3rd Gens, this may well be valid in earlier Magnas or other vehicles where the TPS is separate from the idle switch but is likely to introduce idling problems with the 3rd Gen throttle body setup, as far as I understand it. In most cases the TPS will never need to be adjusted from factory settings, so you're spot on regarding the white paint dot which will be unbroken in most cases.

In a brand new car, certainly, there would be no need to alter the factory TPS setting.

However, over time, all sorts of variables can be introduced that can alter the optimal settings.

Also, if there was only one correct setting the modern day TPS would be made with no adjustment.

Well, up to the TLTW, which is what I am familiar with anyway.

Bottom line: If the car with a factory original setting TPS is misbehaving, there is not much to lose by experimenting with the settings.

It doesn't cost anything, and it is relatively easy to return it to the original setting.

GRH has said that he has put on a new TPS, so the factory original setting is no longer there.

Tip: before "adjusting by feel" with the TPS take a voltage reading as per the workshop manual and write it down.

Use that as the starting point and make very small adjustments , road testing after each change and writing down the new voltage reading at each stage, and if it is ever perceived that no improvements are being made(or the behaviour is worsening), just return the TPS setting to the one written down at the start.

As I mentioned earlier, I have not had the need to adjust mine, but as I have seen first hand witnessing how a qualified transmission mechanic approached a transmission problem on a TR/TS Magna, I am confident that such a method as I witnessed may be transferred to other cars in a similar manner, even if they are not identical(e.g. my Nissan R31).