Throttle potentiometer 3b/rr vs aby/aan/aah/adu/abc/ahk

[domas]

Hi guys.

sorry for posting this as it was discussed before, but really, nobody has answered it for sure.
So my 3b pot is taking a crap on me. But details in the end of the post.

So once and for all, are those two compatible or not? I guess nobody will use 3b pot for newer application as 3b is quite rare, but will 3b be 100% happy with with aan pot?

Info and keywords for search:

vag 034133154f / 034 133 154 F bosch 0280120410 / 0 280 120 410 for engines 3b and RR.

VAG 078133154 / 078 133 154 bosch 0280120431 / 0 280 120 431 bosch new replacement F026T03075 / F 026 T03 075 for following 2,2 20vT's: aby, aan, adu, 2,6 12v: ABC, ACZ 2.8 12v: AAH, 2.4 12v: afm, v8: abz, abm, agh, ahc, akg, aew, akj ahk, akh
Can i use it in 3b application? It was discussed so often before, and most of the post say that it should work. Any hands on experience? Stock motronic.

Here are details of mine, resistances do not matter really, as it is a simple voltage divider here. Voltages in mine are as follows:
At idle, engine off, the pot only gets 4.7V, with engine running it gets all 5.00V
So measurements are taken of ign on, no engine running:
idle: 0.217V pedal to the metal: 4.67V
Another test when gnd is taken of exhaust pipe instead of GND pin on pot:
0.265v - 4.71V

yes i know i may have grounding issue but that will be sorted later.

The reason i am changing my pot is that i get a misfire at low loads, exactly at 5-10% of throttle. Never at moderate/full loads. This is where you keep the car running at constant speed, which is logical that the car has spent most of throttle position there.
It is a harsh bang every 10 minutes on average when it is hot outside (30+C)

When it is less than 10C, i hardly have this happen at all. I do not get pot code though. Problem is quite random ant can not be replicated on purpose, but it definitely happens at the same throttle position.

[UrS4boy]

G69 / F60 Throttle valve position potentiometer /idle switch info

It would seem that your G69 / F60 Throttle valve position potentiometer /idle switch has a worn or dirty spot where it normally sits, causing a period issue (maybe a broken wire in the potentiometer that is held together - most of the time but breaks loose once and a while.)

I agree that the 034133154F is for the 3B and RR engine

I also agree that the 078133154 is for the AAN, ABY and ADU and a bunch of other stuff, e.g. V6s.

However, I disagree about your test method, measuring voltage, not resistance (yes, I know that they are related)

According to factory information, based on the schematic below, the testing is as follows:


Testing the F60 Closed Throttle (Idle) Switch:

Across Pins 4 and 6 on the switch:
Closed = 0 ohms (continuity)
Open throttle (slightly) = infinite ohms (open)
If either fails, adjust switch as per procedure above.

Testing the G69 Throttle Position Potentiometer:

Across Pins 1 and 2 on the switch:
Must be 1500 to 2600 ohms

Across Pins 2 and 3 on the switch:
Throttle closed = 750 to 1300 ohms
As throttle is opened from closed to WOT = increase to 3600 ohms
If NO, replace sensor.

AAN wire colours (ignore for 3B etc) - diagram is just to make the above make sense.


REFERENCE: http://forums.quattroworld.com/s4s6/msgs/20405.phtml

[domas]

urs4boy

thanks for the input, but reference link was read many times before as well as other related pdfs.
I measured both, resistance and voltage. When ignition is on, current is flowing through the pot and might easier reveal the problem/voltage cutout at specified position, while the resistance testing is using very weak current flow from the tester. In some cases, load is needed. When you measure voltage, there is 5v across the resistor, which is a small load, but still a load. The proper test would be to use loadpro cables that i have, but I was afraid of overloading 5v ref in ecu, as I have no idea how much that ir rated for.

My resistance tests were as following
Idle sw: passed test (never had problem before), even though it is little more than ideal 0ohms, but still okay, and open at wot, instantly after movement, so does not seem to need adjustment.
So the trimpot:
My 1-2 pin was 1.91kOhm
2-3 at idle 924Ohm; 2.67kOhm at full throttle

So does not follow into the limits, but I don't think it is a problem as it is now. There is only one problem, at high temps under the hood, and it is very intermittent and very specific throttle angle.

And the diagram you have handdrawn or sourced it somewhere else is a bit wrong, I have to go now and I will let you know later, what is wrong with it.

[UrS4boy]

My G69 Testing results

Testing the G69 Throttle Position Potentiometer:

Across Pins 1 and 2 on the switch:
Must be 1500 to 2600 ohms I got 1975 ohms, so okay

Across Pins 2 and 3 on the switch:
Throttle closed = 750 to 1300 ohms I got 1019 ohms
As throttle is opened from closed to WOT = increase to 3600 ohms
If NO, replace sensor. I got 2670 ohms at WOT. Exactly the same as you got. This is very common. I am starting to think that the 3600 ohms is a typo.

Previous Post with full results:

http://forums.quattroworld.com/s4s6/msgs/240061.phtml

[macspring]

Domas,

Not a great help, but maybe consider, and while it may not be possible, another option may be to borrow or buy a known good throttle body and try that just to see.

I presume you already know if any members live near you.

Post what was the problem when you find it to complete the thread.

Best of luck with it.

Regards.

[domas]

Domas,

Not a great help, but maybe consider, and while it may not be possible, another option may be to borrow or buy a known good throttle body and try that just to see.

I presume you already know if any members live near you.

Post what was the problem when you find it to complete the thread.

Best of luck with it.

Regards.

I am traveling with my car right now and i do not really know any members where I am (Hungary, Budapest). Will definitely do it in July. I will most likely just drop in a used one to start with. I will probably go with a8 4.2, or something newer. If it works, I may be getting a brand new Bosch unit, maybe sticking to used until it fails.

But really guys, potentiometers failure is very obvious here. And resistance and voltage testing is pointless here, as the car is driving perfectly 99.9% of the time. It only misfires once in 10 minutes at worst - and it only happens when cruising at +30c temps.. And after it happens there will go some time after it will happen again. probably copper expands and crack in resistor opens or something like that. Misfire results in a huge bang (a lot of play in the drivetrain) and everything is normal again.

Another weird thing is that when it is happening, i.e. under same conditions, may be together with this misfire, maybe not - very difficult to notice (as misfire can happen when I am starting to go downhill/and or releasing the pedal - and it hits the dead spot - you can barely notice it sometimes)
that my tacho needle jumps by ~1 section ~200rpm for a split of a second. Could it be anyhow related? Seems to happen under similar circumstances, or even at the same time. At first i thought i was hallucinating regarding tacho/rpm needle, but my dear passenger confirmed this yesterday
I know this is very weird.

[macspring]

Hi Domas,

Note your reply. Sorry I can't offer more help. Hopefully someone might have some good advice.

[hunker7]

TPS on my V6 was dead, nothing happened. It just goes in limp mode and that's it. I did 5000km with it like that (UK-LV).

[domas]

Tried driving it with tps disconnected. Even though rpms goes up with the car stationary with no problems, driving expierience is very very bad. Car does not want to move with less than 3-4t rpms, and rpms are very unstable between 1-2t rpms.

[mike74]

Have you checked out the inlet air temperature sensor (IAT) at all? If it was knackered, it might not be telling the ECU when to back off boost etc when the engine gets hot. Just a thought anyway

[domas]

Have you checked out the inlet air temperature sensor (IAT) at all? If it was knackered, it might not be telling the ECU when to back off boost etc when the engine gets hot. Just a thought anyway

Hi. No. Not sure how I can do that if engine misbehaves in very rare occasions. Never on idle with hood open so..
And gain this is not boost related. It happens when driving at cruising speeds (thus an assumption of faulty pot due to the same angle of throttle) without any boost, normally at -0,3bar boost or 0,7bar absolute. Car accelerates perfectly.

I think i am getting a replacement pot (aan/aby etc code) for 10euros, used one, to see if behavior changes or not. Cant really go wrong with this price.

[domas]

it works

Can confirm that car works with updated pot as supposed. As I live in the city center now I did not have a chance to test it properly. It requires a long trip 1h+ and hot ambient best is +30C to make it misfire while cruising. But normal engine operation is not disturbed because of different p/n. So it remains a mystery of why p/n is different. Probably Audi forgot (or did not give a ****, typical) about dropping old p/n and making a new replacement.

I have got a used pot.

And here comes a psychological effect, that idle is much more stable, especially on cold start. Probably has noting to do with TPS and i am f***king with my own head ;-]

[domas]

after few months I can confirm that new pot has solved the mysterious misfire issue.

[predding]

G69 / F60 Throttle valve position potentiometer /idle switch info

It would seem that your G69 / F60 Throttle valve position potentiometer /idle switch has a worn or dirty spot where it normally sits, causing a period issue (maybe a broken wire in the potentiometer that is held together - most of the time but breaks loose once and a while.)

REFERENCE: http://forums.quattroworld.com/s4s6/msgs/20405.phtml

Hello URS4Boy - Is it possible to open the potentiometer assembly to clean out the interior as I am having gulping of air effect on throttle pressure and slight misfires on loading it up. About 8 years ago I had a throttle cable break (UR 20VRR) and had to jam the throttle actuator open at about 30% to drive 5kms home and I ofetn wonder if this caused subsequent damage. I will do all the volt/ohm tests tomorrow but would be nice to get inside and clean it

Also mixture at exhaust is very rich

Sorry for resurrecting the post
Paul

[johne]

Just to note, URS4Boy who used to be very active on the forum hasn't visited in over 6 years.