Adjust throttle plate - what am I doing wrong?

Need technical Q/A then you're in the right place

Moderator: martauto

Post Reply
User avatar
jimrat
E30 Zone Newbie
E30 Zone Newbie
Posts: 12
Joined: Tue Jun 28, 2011 11:00 pm

Fri Feb 17, 2012 9:04 am

Hi

I've adjusted my throttle plate as described in the Bentley manual: 0.4mm clearance between plate and wall at idle position.

However, to get the TPS adjusted correctly, I had elongate the holes in the sensor mount so that I could rotate the TPS enough for it to see the idle position. ???

Once adjusted, I checked it with a multimeter, and the TPS adjustment was fine. But now I've fitted it, the car idles way too high, like 1500rpm.

What have I done wrong? I used a 0.4mm feeler gauge (15 thou). Is this too much?

The reason I was messing with it is my car won't idle. I've spent hours checking EVERYTHING, and the throttle was the only thing that wasn’t as per the Bentley manual

Cheers
Jim
User avatar
redcar
E30 Zone Squatter
E30 Zone Squatter
Posts: 1610
Joined: Wed Jul 20, 2011 11:00 pm
Location: Hertfordshire

Fri Feb 17, 2012 10:02 am

8O
User avatar
Billwill
E30 Zone Regular
E30 Zone Regular
Posts: 363
Joined: Sun Jun 26, 2011 11:00 pm
Location: South Africa

Sat Feb 18, 2012 10:28 am

What E30 do you have?

I am not a great fan of Bentley to be honest. :(

There is a Wiki here that describes replacing a E320 Throttle Body with one from a E325.....final step states that there must be no gap at all of the butterfly when closed but it must not stick! :?
e301988325i
E30 Zone Addict
E30 Zone Addict
Posts: 3701
Joined: Fri Feb 01, 2008 11:00 pm
Location: Taunton, Somerset

Sat Feb 18, 2012 1:45 pm

jimrat wrote:What have I done wrong? I used a 0.4mm feeler gauge (15 thou). Is this too much?Cheers
Jim
Way too much, try using the corner of a bit of normal white A4 paper which should achieve a gap of 0.1mm.

Then adjust the TPS to suit.

The fact you had to modify the TPS should have been a give away that something was clearly not correct.
I said:

Can anyone suggest how to test if the boot lights are staying on with the boot shut?

e30topless said:

lock the wife in there
User avatar
Brianmoooore
E30 Zone Team Member
E30 Zone Team Member
Posts: 49358
Joined: Mon Jan 10, 2005 11:00 pm

Sat Feb 18, 2012 1:50 pm

Adjusting the throttle stop requires the use of a BMW special tool - basically a dummy idle control valve with a fixed opening - NOT a feeler gauge.
In the absence of the tool, I blank off both ICV connections (or fit a blocked up ICV) and adjust the stop to give a very low and rough idle that threatens to tear the engine off of its mounts.
Once this is set, the throttle position switch will need adjusting, or checking at least.
Best advice is not to touch the setting in the first place. It does not need adjusting.
User avatar
fixedwheelnut
E30 Zone Regular
E30 Zone Regular
Posts: 909
Joined: Sun Nov 20, 2005 11:00 pm
Location: South East London

Sat Feb 18, 2012 10:02 pm

For throttle stops I have always used a piece of paper between the stop screw and housing gently pull the paper as you screw in the stop screw until it grabs the paper.
Then screw it in 1/2 a turn and lock it up.

Thats always worked well for me :)
Post Reply