Tps

[oldtimer]

I am sure this subject has been address.  I apologize if I am reviving the topic.  My question is:  What sign does one experience when a Throttle Position sensor (TPS) had gone bad?  I was inquiring about getting one from a local parts store, the first thing the parts guys ask was:  Is it hard to start?  Can someone share their experience when TPS was going bad or is bad.

[M3ayhew]

Hard starting it one, when it does start you wont have any response from throttle input and nomally it will want to die it it goes below a certain rpm

[RED IS 91]

check out this webpage detailing how engine management systems basicly work.
Hope this helps .There is a test for the TPS in the bentley.
Good luck

http://www.motorsave.net/enginemanagementsystems.html#1

[vfstyles]

I am sure this subject has been address.  I apologize if I am reviving the topic.  My question is:  What sign does one experience when a Throttle Position sensor (TPS) had gone bad?  I was inquiring about getting one from a local parts store, the first thing the parts guys ask was:  Is it hard to start?  Can someone share their experience when TPS was going bad or is bad.

when my tps failed i was driving down the road and the car died when i tried pressing the gas.  It died in the middle of the road i was trying to cross, luckily  i had enough speed to coast down the hill.  If you are fairly certain that TPS is bad just replace it.  when it finally does fail completely you dont want to be driving, trust me.  started hard but would idle fine.  As soon as you push the throttle it would hesitate to rev or just not rev at all.

like previously mentioned, check the sensor using the process listed in the bentley.  Replacing the TPS kinda sucks because you have to remove the throttle body to get one of the screws out of the TPS because its mounted in between the intake runners of the manifold.  Replace both TB gaskets while you are in there.  Be careful when re-tightening the TB to the manifold.  There are three nuts and a bolt to fasten the TB to the manifold.  I broke the 1 bolt off in the manifold and had to pull everything back apart to extract the broken piece.

[oldtimer]

thank you for all the inputs.  I finally found the check in the manual.  since I am the second owner of the car and the previous pretty much didn't take care of it i decided to replace.  Oh yeah I was wondering how I was going to get to the second screw without taking the TB out.  I found  a new TPS for a good prize I have a week end work for me.  Additionally, a new topic here and I don't mean to piggy back on this one.  I am doing some testing on engine performance and mileage improvement.  I have not been successful in finding an article that gives me the PMG rating of this model.  Can some someone share what king of MPG this model was rated when new.

The theory I have been playing with is being tested on my 1984 318i thus far I have gain 3-5 miles per gallon both city and highway.  The gain is also on the performance and torque and throttle response.  I want to put the test on this car but don't have a manufacturer MPG baseline.

[xsjado]

if the TPS is unplugged and the car ran the same does that mean its broken/faulty?

[jazfe]

if the TPS is unplugged and the car ran the same does that mean its broken/faulty?

Probably....
Here's a link for the online manual.........

http://pdftown.com/Pdf-eBook/BMW.html

[roundel318]

I am not sure, also could be no connectivity from the AFM, I remember unhooking mine and pressing on the gas resulted in killing the engine, among it stumbling, idling fussy. :confused:
Are you diagnosing a 84 318 or a late model? If it's a 84, that came with a M10, not a M42 engine, I am not familiar enough to say if it uses the same sort of hardware, I presume it doesn't as Motronic wasn't around in the M10?
Just tossing that in......not sure if it helps
When it comes to mileage, my M42 see's 26-29 in town and 30-34 on the highway. At the time I think the factory MPG ratings were around 26-27 in town and 31-32 on the highway, not sure, just a guess.
Not sure how a M10 318 would fair MPG-wise.

[xsjado]

my e30 has an e36 m42 with ews.....when i disconnect the TPS nothing really happens....it has kinda erratic idle normally anyways.i dont know whether its faulty...nobody has another m42 in town for me to try with so im stuck.should i just repalce it and find out?anyone done that?

[roundel318]

XSJADO

Is idle erratic only during cold/warmup, hot, or both?
Have you inspected your rubber vac hoses (the medusa) for visual cracks, etc?
If those are good, disconnect the ICV (idle control valve, same looking 2 pin connector as on the TPS, just at the backside of the intake/throttle body, has a black hose running from the top of the engine into it, and out down to the medusa) and start it up and see how it idles then? The idle should dive a little when you present a electrical load (like turning the fan on high), is the idle less erratic?
Have you run a simple diagnostics using the gas petal / check engine flash procedure?

[EN318isPDX]

my e30 has an e36 m42 with ews.....when i disconnect the TPS nothing really happens....it has kinda erratic idle normally anyways.i dont know whether its faulty...nobody has another m42 in town for me to try with so im stuck.should i just repalce it and find out?anyone done that?

Put a volt meter to the pins and open and close the throttle. I knew mine was bad because around 75% to 100% throttle it went to 0.