Cleaning/Testing the TPS and ICV M40 318I
Moderator: martauto
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Shiz
- E30 Zone Newbie
- Posts: 178
- Joined: Sun Dec 30, 2012 11:00 pm
Hi, as the other threads suggest I have had very random idle, I have changed the rubber hose, afm and still things are bad.. I understand previous owner had a field day with the afm screw and probably tried compensating by screwing the black screw tighter on the throttle cable. Now to test and clean my tps is it difficult to do ? the ICV looks handy enough to pull out and clean out. Any help would be appreciated.
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Billwill
- E30 Zone Regular
- Posts: 363
- Joined: Sun Jun 26, 2011 11:00 pm
- Location: South Africa
You should hear a "click" as you move the butterfly slightly off of its stop screw....this is the screw, with locking nut, that is factory set and locked with paint. However lots of people try to adjust the idle by turning this screw in to open up the butterfly a bit.
Slacken off the cable adjuster and turn the stop screw in until you hear a distinctive "click" coming from the TPS....which sits under the throttle body...as you slightly open the throttle and let it relax.
If you cannot get this "click" you may have to remove the throttle body and adjust the TPS switch....loosen its mounting screws and rotate the switch slightly.
You can test the switch with an OHmeter to see if it is working...the centre pin is common and makes contact to the one other pin when the throttle is relaxed....this tells the ECU that you are at idle. The centre pin makes contact to the other outer pin when the throttle is fully depressed...this tells the ECU that you need maximum power! Ideally you need to check the TPS switch functionality right at the ECU connector in case of broken wires!
It is always worth pulling out the ICV and cleaning it...I have to do mine every few months as it gets blocked up.
Remove the ICV....note that the arrow should be pointing towards the intake manifold and clean it with some carburetor cleaner or petrol and give it a spray with some WD-40 or similar.
If you briefly apply +12 volts to the ICV it should snap open and close again with voltage removed...do not leave +12 volts connected for long or you will burn it out.
You can leave the ICV out but still electrically plugged in and watch its action as you rev the engine....engine will splutter but you should see the ICV valve moving around.
Also check the Blue Sensor under the intake manifold id working properly if you are having idle problems in cold weather.
Slacken off the cable adjuster and turn the stop screw in until you hear a distinctive "click" coming from the TPS....which sits under the throttle body...as you slightly open the throttle and let it relax.
If you cannot get this "click" you may have to remove the throttle body and adjust the TPS switch....loosen its mounting screws and rotate the switch slightly.
You can test the switch with an OHmeter to see if it is working...the centre pin is common and makes contact to the one other pin when the throttle is relaxed....this tells the ECU that you are at idle. The centre pin makes contact to the other outer pin when the throttle is fully depressed...this tells the ECU that you need maximum power! Ideally you need to check the TPS switch functionality right at the ECU connector in case of broken wires!
It is always worth pulling out the ICV and cleaning it...I have to do mine every few months as it gets blocked up.
Remove the ICV....note that the arrow should be pointing towards the intake manifold and clean it with some carburetor cleaner or petrol and give it a spray with some WD-40 or similar.
If you briefly apply +12 volts to the ICV it should snap open and close again with voltage removed...do not leave +12 volts connected for long or you will burn it out.
You can leave the ICV out but still electrically plugged in and watch its action as you rev the engine....engine will splutter but you should see the ICV valve moving around.
Also check the Blue Sensor under the intake manifold id working properly if you are having idle problems in cold weather.