For some reason my TPS has gone a tad potty.

 

Basically when i went out for a drive, first time i stopped the idle went to 2.5k and wouldnt come down. So I went back and though I test the TPS and got a reading of 0.41. Moved it around and the reading didnt change, not did the idle. So i disconnected the yellow plug at the back of the engine, so I could set idle. When i disconnected it the idle dropped to about 950rpm and If i reconnect it goes back upto 2,500 rpm. So left it off.

 

What the bad point in leaving that yellow connector off?

 

What do I need to do to get my idle back normal wiht it plugged back on?

mines was doing that, though my tps was ok so now i am stripping down the IAA valve to give a good clean. I bin driving around without the yellow connector on for a while even went through M.O.T. with it off.

 

dan.:smash:

Only thing i noticed with it off, is that if you stop pretty quick the car stalls

only problem I had was bit lumpy at start but couple minutes she purred no probs, I connected up to conzult and set the idle between the green marks and worked fine.

 

dan.:smash:

I'll leve it then :)

What yellow thingy ?????

The one you disconnect to adjust the throttle. its basically just behind the throttle adjustment screw

hmm...

 

mine is a similar also.

 

cut out last nite dropt so low,

 

so we all agree unplugging the yellow thing is a fix?

 

any is harmless?

leaving the yellow plug off is not a fix. it's just a way to ignore the problem although i dn't know if it causes any damage. i had the same problem and after changing the Idle valve for a working 2nd hand one (£20 off here) the idle was normal. might be a good idea to take it off and give it a good clean with some brake fluid cleaner. i also changed to a series 2 ptu and it now runs sweetly.

 

hth

yellow one just sends a signal to the ecu to tell it where the idle valve is set at i think. Will cause engine stumble without it connected though.

 

Your prob could be a dirty idle valve screw bit of carbon in there or something or maybe a jammed air regulator??? or air leak?

The yellow connector is the ECU's connection to the Idle control valve. The ECU controls the idle valve in certain situations - (1) if the base idle is set incorrectly and (2) when coming off the accellerator. As you've noticed, the car has a tendency to stall when you slow down quickly. That is because the ECU can't influence the idle. You need to reconnect the yellow connector because without it the ECU can't control the idle valve and hence the idle. When you disconnected the yellow connector the ECU lost control over the idle and it returned to the base idle setting. You may find that if you reset the ECU it will no longer raise the idle when reconnecting the yellow connector.

 

There are quite a few reasons why your idle sits too high - one of them being a clogged up idle valve. This is basically a spring operated piston which frequently gets "coked" up. This is particularly the case if you've sprayed carb cleaner into your throttle bodies to clean them. All that crap is passed through the engine into the idle valve where it sits and accumilates. Over time this will cause the valve to coke up and not be able to return to the base idle setting. The best thing to do here is to strip the valve down and clean it. This can be done but you do need to be carefull with all the little bits inside the valve.

 

The above is just one of many reasons. I think that if you do a search for "high idle" you'll find about 20 more reasons to investigate ...

 

Good luck and if you need more assistance, you know where to find me ! :)

 

Regards,

 

Dan