Sleepy accelleration?

[getty150]

I have to rev high and hold with the gas pedal for a minute or two.
And still while driving the pedal doesn't keep up with engine speed.
Problem somewheres between
Throttle, gas pedal chip, disa valve or fuel filter heck could it be the fuel pump? Cleaned the MAF sensor.
Used foxwell scanner...dtc 2786 throttle-valve potentiometer 1
Miles on the car 221k
Every summer there is a issue that discontinues my driving pleasure, but I learn.
Help needed here please.

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[andrewwynn]

Sounds like you have a defect the scanner is telling you.

You can confirm with the foxwell.

It's telling you one of the throttle potentiometer is defective.

The foxwell will show real-time value of the two throttle potentiometers. Find them and display both at once as a graph.

They oppose each other one ramp up from low to high the other starts high and goes low.

When one breaks the car can operate but only in "limp home mode". Without the redundancy it can't be assured of not requesting full throttle and put you through the nearest wall so it greatly mutes the throttle input request.

Most likey this means a new throttle pedal in your future. You can disconnect and clean the contacts or trace the wire loom for a damaged wire. (contact can be dirty at the DME in the ebox also).

Once you get the graph set up you can watch the two values they should basically add to an almost constant.

Eg 1v +4v = 5v and at 1/3 throttle, say 2v + 3v = 5v. And at full throttle 4v + 1v = 5v.

( I seem to recall them not getting to either end of the normal control line voltages of 0-5 but I could be recalling a different similar value of the throttle position sensor). TPS is under the hood at the literal throttle not the "gas pedal" which we call the throttle but is really just the human suggested throttle input request knob.

If the readings are normal reset the code and the throttle retainer m response should return to "normal" until the error comes back if it is an intermittent problem.

[getty150]

Yeah, it is an intermittent problem with the TB.
thanks you've confirmed it and all my research.
I order a TB but in my haste turns out to be for the 2.5 m54...Damn it!
They are not interchangeable are they?
Your a big help...

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[andrewwynn]

You shouldn't have to replace the whole TB. Most often just the TPS.

I actually misread the initial post thought the error was with the pedal not the throttle position.

You can use realoem.com to confirm part number compatibility.

You didn't mention which motor you have in the post.

Looking at the parts list I don't see a separate part for the TPS which sadly didn't surprise me but if you search it might be available you'd have to swap or over to the TB.

[getty150]

Ok isn't the TPS in the throttle body...?
And I was not clear (frustrated)...Im dealing with the m54 3.0 BMW engine.


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[getty150]

Heres a link from the e46 fanatics
Seems to speak to my situation...

https://www.e46fanatics.com/threads/...ensor.1028022/

Two sensors? See response #4
What's your thoughts?

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[andrewwynn]

Yup but I thought you were talking about error in the pedal. It's nearly identical sensors.

Re reading I saw the error is TB not pedal so you are going the right direction.

Before replacing parts, check and clean the connectors.

[andrewwynn]

There are actually four sensors. Two measure the pedal position two measure the throttle position. Redundant design but if any of the four fail you'll get a limp home mode where the engine will run but with very very limited power output.

I'm both cases the two sensors are built into one unit. You can't replace TPS sensor a or b.

[BimmerBreaker]

Replace the throttle body, it is M54 3.0 specific.

Keep in mind if that doesn't fix it it could also be the wiring harness but the TB fails more often than the harness on M54's and TB's are not that expensive.

[getty150]

Great advice fellas...
I was uncomfortable installing the 2.5 TB on the 3.0 m54 engine. I'll also visit the wrecker see if I can find a pedal as well...that should do it I think...keep ya posted.

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