E30 Zone

The main symptom of a dying TPS is a high idle combined with the econometer not going all the way over to the left when you lift off the throttle like it used to, so i thought i would have a crack at a guide while i pulled mine off and gave it a clean out....


The first thing out is the air box and to disconnect the throttle cable


Plenty of clips and pipes to disconnect in here, make sure you remember where they all go, theyre pretty self explanitary though, i needed a couple of new jubalee clips to replace the single use clips on the 2 pipes on the right.


Its a good oppertunity to check the bellows, mine are ok for now but have jumped a few places up the TO-DO list


Bit mucky in there but nothing out of the ordianry, i found an old toothbrush and some brake cleaner did the trick once the 4 10mm nuts were off, the bottom pair can be tricky so i used a 1/4'' drive socket with a 4" wobble ended extension.


Use a proper phillips screwdriver for the tps screws, they will be a bit tight and you don't want to chew the heads out



Mine looks like it has been glued together, after 15 mins with a stanley knife and small screwdrivers it wasn't having any of it sooo...


It got a small hole drilled in it, which will also allow any future oil to drain out


Plenty of this was sprayed in, shook about then flushed out with more untill it was coming out clean.


The TB after a spruce up.


The tps was screwed back into position and tested, it clicks very nearly as soon as the butterfly starts to move and has continuity between the middle and left pin when closed, towards full throttle it gets continuity between the middle and right pins, all working properly


As they say, fitting is the reverse of removal, if the TB gasket is intact then there is no need to replace it, just make sure its clean with no splits or rips. And dont loose the rubber O ring between the TB and TPS

Excellent write up! Should STICKY this i think is the correct term?

Where did you "drill the hole for the oil to escape from" in the actual TPS, or in the TB somewhere?

The hole is in the TPS, the 18v drill was a bit of overkill for a 1mm hole but it just about managed it

I took a 2nd pic which shows it better

ah ok! Excellent will do that tooo!

Swapped mine out after it completely died only a week ago, does make a big difference cleaning it all up

Yes it does dosen't it , just been for a run and its got its 4K surge back and it idled properly...... untill 2 streets away from home

Off to B&Q tomorrow for some superglue De-bonder so i can have another go at splitting it apart to clean it properly, if not then Zimmerbimmer will be getting a call on payday.

hi, this is very hepful i;m just about to do mine, on the shot of the second engine bay i see that where the fuel relays go, one is missing, this is what i found on my m20, but some m20's have the white DME relay and two orange fuel relays, what does this mean? great photos too very helpful thanks

the missing relay is sometimes for the O2 sensor inside CAT equipped cars. However if your car doesnt have a catyltic converter this relay is not required!

Good write up

Well i finally got it apart with the glue remover, gave it a good clean out and its been faultless for a couple of days now

Will try this later. Mine is the 1985 model. What's the significant differences between a good and a screwed up tps?

pictures wont show for me..... is it my computer? this is one of my next jobs

Strange thay all show for me, try right clicking and pasting the links? If that won't work i can Email them


stormhunt3r:-
For me the symptoms were that the car felt 'flat' i know its a 320 and will never set the world on fire but i had a 320 2 door before which felt much more livley at higher revs, also the idle would normally be fine but somtimes the econometer wouldn't go above 50 on over-run and the idle would be at about 1K.

Since cleaning it out the car has its 4K surge back and on the motorway it has a deffinate kick when you put your foot down which wasn't there before, also the idle and econogauge are both doing what they should

Whats a tps

Throttle Position Switch/Sensor

On an E30 it tells the engines computer when you are it idle or full throttle, or somwhere inbetween where it looks to the air flow meter (AFM) to decide how much petrol to put in

great advice I will do this while the 320's in the garage

Excellent write-up. When car is at idle what should the MPG meter be doing?

It should be sat on 0 mpg if the car is not moveing.