economiser fault
Moderator: martauto
Hi everyone, have not been here for a while, E30 now only summer car and for few years had no issues just minor. It was stationary for the last few months and now took it out and noticed that economiser does not work, it was in the left position all the time until the revs go to around 3000 and then it jumps to the right side, so basically only stays in those 2 positions - on the left before 3000 rpm and on the right after 3000 rpm. Just to mention that I had fuel leak and one of the fuel pipes was replaced by local garage but I did not notice this issue then so not sure if garage reconnected something wrongly. Any advice on this? Consumption wise nothing unusual and everything else seem to be working as it should. It's E30 1989 320 convertable. Thank you in advance!
Someone correct me, but as i understand that eco gauge takes data/signal from the CPS (Crankshaft Position Sensor)?
I would like someone to correct me first, before we start mentioning what to check, in order not to waste time.
I would like someone to correct me first, before we start mentioning what to check, in order not to waste time.
Thank you HJ1981, hope to get more feedback on this
- Brianmoooore
- E30 Zone Team Member

- Posts: 49358
- Joined: Mon Jan 10, 2005 11:00 pm
Well, since you asked, I will!
Eco gauge uses signals from the speedometer (road speed) and a signal from the engine ECU (fuel rate). CPS signal isn't relevant.
OP. - Check that the throttle position switch is working correctly.
I stand corrected ^^Brianmoooore wrote: ↑Fri Nov 13, 2020 7:03 pmWell, since you asked, I will!
Eco gauge uses signals from the speedometer (road speed) and a signal from the engine ECU (fuel rate). CPS signal isn't relevant.
OP. - Check that the throttle position switch is working correctly.
On m20 throttle position switch is on the bottom of throttle body is that correct? I checked connector that goes into it and noticed that there was a lot of oil, I guess I will have to remove it and check.Brianmoooore wrote: ↑Fri Nov 13, 2020 7:03 pmWell, since you asked, I will!
Eco gauge uses signals from the speedometer (road speed) and a signal from the engine ECU (fuel rate). CPS signal isn't relevant.
OP. - Check that the throttle position switch is working correctly.
- Brianmoooore
- E30 Zone Team Member

- Posts: 49358
- Joined: Mon Jan 10, 2005 11:00 pm
That's the TPS. Because it's mounted under the TB, oil in the inlet tract finds its way down the shaft and into the switch. Solution is to drill a very small hole (1mm) right in the middle of the housing at the bottom, and flush it with switch cleaner after it stops dripping. Leave the hole open afterwards.
The idle switch is a miniature enclosed standard microswitch, so it might take a while and more than one flush to get the oil out of it.
The idle switch is a miniature enclosed standard microswitch, so it might take a while and more than one flush to get the oil out of it.
Check this video out:Brianmoooore wrote: ↑Mon Nov 16, 2020 7:01 pmThat's the TPS. Because it's mounted under the TB, oil in the inlet tract finds its way down the shaft and into the switch. Solution is to drill a very small hole (1mm) right in the middle of the housing at the bottom, and flush it with switch cleaner after it stops dripping. Leave the hole open afterwards.
The idle switch is a miniature enclosed standard microswitch, so it might take a while and more than one flush to get the oil out of it.
I did this last summer, got an expensive internal 5-9mm expander pulley but came out without breaking, it has been dry ever since.
Thanks for video, will see if I can get those bearings here. Also it's wise to use a proper tool to remove old ones out

