another bloody idle post (but with a new idea!)

[thanuttiscotsman]

hi there,
just a wee update on the progress, well i have re-tracked it properly today and she is running even smoother than the last improvement! cheers mike . she is still idling high though. now after hours and hours of medling and testing i have made very little progrees with the idle. now the only difference now is she very very rarely does drop down to a 900-1000 rpm idle but even then she only stays there for max 1 minute. now from what i have learned and can guess it tell me there is a sensor telling porkys to the ecu or there is one thats not always talking to the ecu. so my next question for the tech heads is which sensors are responsible for giving the ecu all the info it uses to control the idle. im thining water temp sensor as it seems as if its just on choke all the time and dont come off cos the sensor dont tell the ecu she is hot enough now. next tech head question is which of the water sensors job is this.???

cheers rossco

[MoRtYMer]

Isn't the idle controled by the "thing" on top of the inlet manifold, on the right of the oil filler?

[kriskarrera]

I hate these problems, right bloody minefield trying to work out what's causing what etc.
But what I do know is that a high idle can occur if the throttle plates are adjusted to be too open at idle. This is because the idle speed control valve is unable to close enough to compensate for a throttle body that is allowing too much air through. And therefore cannot maintain 850rpm. So that is why it’s critical to have both the throttle stop and TPS correctly positioned. The throttle plates need to be closed as much as possible without actually catching on the casing of the throttle body.

[thanuttiscotsman]

hi kriskarrera,
what you say sounds totally right. but as the throttle stop isnt easily adjusted
thats why i was going to grind it down 1ml by 1 ml. you see i have a replacement throttle body on as i thought it may solve the problem, it didnt. but the point is that i adjusted it to be as closed as possible before fitting it so im sure the tps is set correctly. now the other thing the icv sometimes i think its not working cos its real quite since i lubed it but when i switch off and re-start it i hear it working, that rapid air sucking followed by metallic click noises. well also yesterday i tried pulling the plugs off the water sensors when ticking over just after start-up and the car started going nuts so i know my sensors are good.

well down to it i spoke to my mechanic uncle who for long time used to own a garage in perth years ago and actually did work for colin mcrae's dad supposedly a loooong time ago. well he said that (in 15 or 16 years ross dont you think some dirt gets into the hinge bits of the throttle body flaps and stops them from operating to their full ability, especially cos they are oily and attract dirt. so yes you can drown it in petrol and or chemicals for a few days to clean it out or you can just grind the stop screw down a bit but not too far as that might upset the tb in another way, what usually causes this problem is boy racers running their cars with no air filters in to make cool noises and allowing all the sh*t to get sucked into their engines.) well thats what he said, so i have decided that there is no other explanation for the problem that makes enough sense or that has been proven yet so iam today going to grind down a bit and see if that solves it. if it does then i will let ya'll know and anyone else with this problem should be able to solve it on their car too, of course after doing a few quick tests to make sure it aint one of the other possibilitys.


cheers rossco

[kriskarrera]

The linkages wear - big time!
I found this tps adjustment guide on the net years ago:

Remove the throttle body from the car and loosen the TPS adjustment screws
Hold the throttle plate and keep it from moving. Rotate the TPS clockwise, and then counter clockwise until a click is heard. Continue rotating until it stops but do not cause the throttle plate to move. Secure the screws.
Proper adjustment is obtained when you open the throttle plate and insert a feeler gauge at the throttle stop screw:
When you close the throttle against a .45mm feeler gauge, no "click" is heard from the TPS
When you close the throttle against a .15mm feeler gauge, a "click" is heard.

Well I just did that test on mine - and a click is heard with the .45mm feeler gauge so the tps needs adjusting.
Also i can make my tps "click" just by pressing the left of the bit the cable attaches to so it looks like my throttlebody is pretty worn