What to do next...?

Stacey_K · Post by **Stacey_K** » Sat Jul 15, 2006 11:05 am

Hello again everyone, having more problems with the car and would like some help in diagnosing the problem...cheers.

Symptons to date:

1) The idle'd baddly (low), difficult to start, needed costant revs at junctions, would judder now and then while driving at constant speed...

2) Called out an mobile diagnostic van who plugged up the car and found an error. Mechanic print-out stated: '(Description = Idle adjustment) (Status = STO)'. basically told the idle switch was reporting an error...

3) Posted on here. After much apprechiated advise from ppl we cleaned the throttle body with carb cleaner...unplugged the negative lead off battery and waited 60secs after turning ignition to let the throttle body set.

4) Sinse then the car has started fine, and idles at 1k without issues in neutral. The car would run fine untill after about 5 mins of running (warmed up), after being run for a while the car would judder alot while driving at constant speed (especially at low speed). When approaching junctions, rounabouts etc with clutch in the revs will jump erratically between 1-2k for about 4-5 secs, in neutral with clutch out the revs settle down...

5) ordered a new throttle body of ebay, brand new and has same part number as orginal... replaced the old throttle body with new one (easy job), car started fine and ran perfect untill it warmed up again....so now we got a new throttle body but are having identical problems stated in 4.

Where Now?) Could the clutch have something to do with this, as the idleing issue happens when left in gear at junctions but corrects it self when put in neutral...

Sorry for the long post, but as you can understand this problem is now dragging on a bit and we would like to identify and fix problem without spending to much.... Thanks for looking, Stacey & Owen

Stacey_K · Post by **Stacey_K** » Sat Jul 15, 2006 11:16 am

Here's pics of the old throttle body if anyones interested....very easy job to remove and clean, all pics taken from phone, so not great quality:

Dirty Throttle body:

Cleaned using carb cleaner:

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Note: This was put back on car before brand new TB arrived. The new TB runs the same as the old cleaned unit...

Owen (the OH)

Polo Paul · Post by **Polo Paul** » Sat Jul 15, 2006 12:04 pm

The only other thing that i can think might result in bad idling is a faulty thermostat

large · Post by **large** » Sat Jul 15, 2006 12:19 pm

please dont take this as gospel coz i am not a mechanic!!

it sound like your lambda sensor is faulty! this sensor messures your emmisions and tells the engine what to do if they are to rich or to lean etc..
e.g. on my old corsa i used to have a K&N filter, this obviously lets more air through to the engine to burn the fuel quicker. so when the lambda sensor found that the emmision were to lean it would try and compensate by throwing more fuel down it wich caused iy to over rev coz it needed more air so it opened the throtle to burn the fuel etc..........
the one for my corsa was about Â£40-Â£50 and seemed to sort the problem out even with the K&N.

i hope this helps in some way but im not a mechanic please remember

good luck

Stacey_K · Post by **Stacey_K** » Sat Jul 15, 2006 2:52 pm

The only other thing that i can think might result in bad idling is a faulty thermostat

Soz...but not really sure where to start looking for the thermostat.

The temp gauge has never worked since we bought the car...is this down to the thermostat??, if so, where is it under the bonnet and how much should a replacement cost...Thanks

warrmr · Post by **warrmr** » Sat Jul 15, 2006 3:12 pm

Stacey_K wrote:
The only other thing that i can think might result in bad idling is a faulty thermostat
Soz...but not really sure where to start looking for the thermostat.

The temp gauge has never worked since we bought the car...is this down to the thermostat??, if so, where is it under the bonnet and how much should a replacement cost...Thanks

i dont think thats to do with the thermostat but more the temp sender.

the thermostat should be around by the waterpump IIRC all it does is opend when the car reaches operating tempriture to let the water flow around the radiator to coll it down and keeps the water around 90degrees.

i doubt its that causing the problems.

i think theres a sensor in the throttle body that you need to replace as some times that gets damaged when you clean them. i may be talking crap but ill have a search around hte forum.

its the air tempriture sender in the throttle body that dies sometimes when you clean them there around Â£30 from VW. try that then try the lambda probe.

Stacey_K · Post by **Stacey_K** » Sat Jul 15, 2006 3:37 pm

its the air tempriture sender in the throttle body

Cheers for that, is the sensor actually IN the throttle body, as the throttle body has been replaced - but the exact same symptoms persist

warrmr · Post by **warrmr** » Sat Jul 15, 2006 7:42 pm

Stacey_K wrote:
its the air tempriture sender in the throttle body
Cheers for that, is the sensor actually IN the throttle body, as the throttle body has been replaced - but the exact same symptoms persist

yes it is if you look at the haynes book page 4A.6 at the diagram you will see the TB ( its for the single point injection engine i cant find the same diagram for the MPI) but part number 7 is the temp sender and you can damage it by spraying carb cleaner on it.

Stacey_K · Post by **Stacey_K** » Sat Jul 15, 2006 8:04 pm

but part number 7 is the temp sender and you can damage it by spraying carb cleaner on it.

Dont think thats the cause as ive invested in a new TB which hasnt had carb cleaner near it.

Having a look through 'search' for some ideas in diagnosing the problem i came agross this post: http://www.tigerstyle.co.uk/poloforum/v ... ostat+idle
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After cleaning the throttle body, the problem went from almost stalling when pulling up, to racing between 1200-1500 rpm. when taking your foot off the throttle....only stablizing at 700rpm when stationary for about 5 secs.Having disconnected the battery terminal, on refitting the throttle body, i drove the car expecting the idle to settle down after a few days......it didn,t!.
As this is my daughters first car, in this condition, there is no way i would let her drive the car.
I took the car to an independant who wanted Â£50 to reset the ecu...more later!.
Not one to throw ones money away, on looking on the internet, I saw that Ross-Tech mention that a TBA may be needed if...
A.The vehicles battery is disconnected and re-connected.
B. The ECU has been removed and reinstalled.
C.The throttle body has been cleaned or removed and reinstalled.
D.The accelerator pedal has been removed or reinstalled.

If this is the case, then a TBA might be needed every time the battery is disconnected.........at Â£50 a pop that could get expensive !.

I have now invested in the program and the lead needed to perform the procedure myself.Bearing in mind i hadn't done it before, the procedure took all of 10mins...........if i did it again...... 2min max ...not bad if you are charging Â£50 !.
The process worked, and the cars idle is correct and revs sweetly!.

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Could this be the cause of all my problems....(if so) more importantly how do i fix it??

warrmr · Post by **warrmr** » Sat Jul 15, 2006 11:18 pm

try leaving teh battery unplugged over night see what that does for ya if nto you may have to take it bac to the guy you got to do the diagnostic and get him to reset it for you telling him you replaced the throttle body.