Cold Start Idle Speed - Page 2 - Audi Forum - Audi Forums for the A4, S4, TT, A3, A6 and more!

12-06-2003, 06:37 AM

#11

Bill Graham

Guest

Posts: n/a

Re: Cold Start Idle Speed

Great. I already have both both of those cleaners, for other applications.

Thanks,

Bill

> Yes, checking all the connections is a good idea. I use DeOxit from Caig
> Labe to clean them. Radio Shack CRC tuner cleaner works fine too. A
> dielectric protective grease is a good idea but if it is too conductive
> it could cause a problem if bridged between adjoining conductors.
>
> I had a problem on a previous '87q that turned out to be the connections
> on the knock sensor having become bad. cleaned and re-connected.
> Problem gone.
>
> Tony
> '91 100q 5spd
>
> Bill Graham wrote:
>> Thanks for all the effort on this post Tony.
>>
>> I know what you're talking about. I was planning on replacing the throttle
>> control switch anyway. They're on $41.00 and was informed this is a must-fix
>> before making any boost/ECU/wastegate upgrades.
>>
>> I believe that the threaded screw and locking nut on the linkage is at the
>> back of the linkage on the right side of the throttle body (facing the car).
>> It's pretty corroded looking back there. I'll clean it all off and the
>> proceed with that.
>>
>> On another brief note: when it gets a little warmer here (I have to work on
>> the car out in the driveway) I was planning on going through the whole
>> engine compartment and cleaning all electrical connections. Then applying
>> some dialectic grease to the points to keep them somewhat insulated. This
>> procedure was an advised one here:
>>
>> http://www.humanspeakers.com/audi/tuning-cise.htm#y
>>
>> Do you support this process?
>>
>> Thanks again. I've got plenty of things to try now. I really appreciate it.
>>
>> Bill
>> ---------------
>> '89 200TQ
>>
>>
>>
>>> b4 you worry about the O2 sensor you should check whether the idle
>>> switch on the throttle body is working and telling the ECU to operate
>>> the ISV.
>>>
>>> The idle switch and the WOT (wide open throttle) switch are both in the
>>> throttle body between the rubber intake boot and the intake manifold. It
>>> is the place that the throttle linkage goes to and moves the throttle
>>> plate when you push on the gas peddle. You are probably completely aware
>>> of this but just in case...
>>>
>>> On the back of the Throttle body there is an electrical plug easily
>>> accessible that contains three wires. This plug takes signals from the
>>> switches to the ECU. Use an Ohm meter to test between these contacts
>>> (going back to the throttle body) to confirm that when the linkage is
>>> closed (idle) that one of the pairs of contacts changes from open to a
>>> closed circuit. This will change just a VERY small distance b4 the
>>> linkage closes. If this change occurs then the switch is operating,
>>> telling the ECU to ISV and the problem is elsewhere.
>>>
>>> OTOH, if the switch does not go to a closed circuit when the linkage is
>>> closed then the ECU has no information to operate the ISV.
>>>
>>> Possible correction:
>>>
>>> - There is a threaded screw and locking nut that operate as a stop on
>>> the linkage. Try to back this off a bit (very little at a time) to see
>>> if closing the linkage will now close the circuit. Sometimes the linkage
>>> gets dirty and corroded by the return coil spring. You can try WD40 to
>>> loosen this up and then carb cleaner to remove the WD40. Lubricant on
>>> this can gather dirt and make the problem worse. Also try to close the
>>> linkage with your hand with a little force to see if the contact on the
>>> idle switch can be made. This worked for me on my current type 44 but
>>> that was to correct a low idle problem.
>>>
>>> If this doesn't help : (
>>>
>>> - The idle switches on pre '91 years have a tendency to crack their
>>> contacts even though they are soldered. I think that you need to open
>>> the throttle body to get at the switch. try to re solder the joints.
>>> Works for some people. Others replace the switch from a 'donor car' with
>>> a known good switch.
>>>
>>> Wheew.
>>>
>>> Good luck,
>>>
>>> Tony
>>> '91 100q 5spd
>>>
>>> Bill Graham wrote:
>>>
>>>> Got it. Thanks.
>>>>
>>>> Somewhere I heard or read that one way to test your ISV was to disconnect
>>>> the power to it when the car was running. I think the point was, if there's
>>>> no change then you have a bad one. It might have been this newsgroup even
>>>> where I read this test. I did that test today and it made no difference. I
>>>> have cleaned the unit before as well.
>>>>
>>>> I'm going to have the voltage on the O2 sensor next week from a cold start,
>>>> and I ask them to check the MFTS too.
>>>>
>>>> Thanks,
>>>>
>>>> Bill Graham
>>>>
>>>>
>>>>
>>>>> Multi Function Temperture Sensor.
>>>>>
>>>>> Bill Graham wrote:
>>>>>
>>>>>
>>>>>> Sorry, MFTS is?
>>>>>>
>>>>>> Bill
>>>>>>
>>>>>> '89 200TQ
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>> Check your MFTS to see if it is telling the ECU the correct engine temp.
>>>>>>>
>>>>>>> Tony
>>>>>>> '19 100q 5spd
>>>>>>>
>>>>>>> Bill Graham wrote:
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>> That's what I thought, so obviously I've got something wrong. Wonder
>>>>>>>> what
>>>>>>>> it
>>>>>>>> is. I've heard the cold start valve rarely go bad, but related items do
>>>>>>>> i.e.
>>>>>>>> ISV.
>>>>>>>>
>>>>>>>> Bill
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>> "Bill Graham" <whgraham@nc.rr.com> wrote in message
>>>>>>>>> news:f248043b.0312041309.43d839cc@posting.google.c om...
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>> "IF" the cold start valve is working right, or warm up components
>>>>>>>>>> (yep, I'm ignorant), should the idle be faster or slower than when
>>>>>>>>>> warm. 1989 200TQ is the car.
>>>>>>>>>>
>>>>>>>>>> Thanks,
>>>>>>>>>>
>>>>>>>>>> Bill Graham
>>>>>>>>>
>>>>>>>>> Idle when cold is always higher. Remember the old choke?
>>>>>>>>>
>>>>>>>>> Ronald
>>>>>>>>>
>>>>>>>>>
>>>>>>>>
>>>>>>>>
>>
>

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