[ds968]

Question for Tip owners out there :


How much does your RPM drop from idle to when it's in a gear ?


Mine drops a little more than 200 rpm -


This 200 + rpm drop when it it's in gear happens consistently and regardless of the RPM idle setting ( for testing purposes only, I adjusted the throttle screw so it idles at various levels from the usual near "900" , to as high as 1200 . )


If I turn in the AC it drops by a negligible incremental amount - maybe 50 rpm, but the 200 + drop is always there. Seems a bit much - or is that normal ?

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[unknown4u]

Normal. Mine raises in rpm by around 100 rpm when switched the ac on. Without it revs around 850 rpm. When you put it in gear it is around 750 rpm. But read on the revcounter. The revcounter is not as accurate so I can control it with an external if nescessary.
Normal. Mine raises in rpm by around 100 rpm when switched the ac on. Without it revs around 850 rpm. When you put it in gear it is around 750 rpm. But read on the revcounter. The revcounter is not as accurate so I can control it with an external if nescessary.

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[ds968]

So that's 100 rpm drop on your car . Mine is between double and triple that .

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[968Syncro]

Checked yesterday (estimates from the dash tach), it idles at about 1,000 RPM, then down to about 900 when in "drive", for about 100 RPM drop.

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[ds968]

Thanks . So that's consistent with Ritchie 's / unknown4u car, and might be the norm. At more re than double and pushing triple that, either there's something wrong with my car, or , the extra load from the

SC drags the rpm that much more down .

Flash , does that make sense ?

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[flash]

how is the vacuum reading?

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[ds968]

I'll check, but I remember you checked the vacuum reading when I was there and said everything looks as it should . So unless something happened in the last 1k miles it should be fine. But this level of rpm drop has always been the case since I bought the car ..remember I raised the idle to about 1200 for that reason ..and to mitigate the vibration also .. Now when it's fully warmed up the idle is right at the 1k line . When I put it in R or D it drops to 800. - that's without the A/C on , with the AC on ( which is 99% of the time ,lol ) it drops to about 700..ish. Way too low; if I bring it to a fast stop the car almost stalls .

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[flash]

that's why i asked about vacuum.  if you altered the throttle plate position, it could change the vacuum balance, and mess with the idle.

 

i'm leaning toward a bad ICV though.

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[ds968]

vacuum gauge reads  14  on cold starts when the idle is just around the 900 rpm level.    when it's fully warm and the idle is a hair over 1K  the needle is about one bar over (a little less than a bar, maybe half way..)            

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[unknown4u]

I agree with Bob.

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[flash]

vacuum should be NO LESS than 17 when warm at idle

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[ds968]

i'll check the warm idle when i get home this afternoon .


Ok, did that ; When fully warm it reads 18 at idle . When I put it in gear it goes to 14 .

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[ds968]

So we have :

1) very rough cold starts / hesitating / stumbling until it warms up for a couple of minutes ,

2) vacuum drop ( when fully warm ) form 18 at idle to 14 when in gear

3) weak to almost no throttle response until the gas pedal travels about a third or half of the way down, unless I'm at mid-high rpms when it responds well . ( the throttle cable is tight, so it's not the problem ) .


Reasonable to conclude with a high degree of confidence that 1+ 2+ 3 = sticky ICV valve ?

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[ds968]

Update to the last post :


1) that symptom simply went away all of a sudden and for the last couple of weeks the car runs perfectly fine right away after the cold start . WTF ! Not complaining , just a curious wtf

2) still the case, but not affecting anything

3) that only happens when the car is in " D " , whereas in tiptronic mode the throttle response is normal , so must be the automatic transmission's programming ( maybe designed to prevent the two gears downshift from happening too quickly.. ? )

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[unknown4u]

Item 3.


The tiptronic is a selflearning module.

Our cars are very common with resistance in the connector due of age. Perhaps you have an extra resistant in the connectors between the motronic and the tiptronic module in the trunk of the car.


In the early days of its life it should have got a new harness I read in the manual. Is that harnass installed? I do not know how you can recognise it. But perhaps it solve this problem as well. I think Bob can make a search in the old database if there is a post with more details.

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[flash]

while the tiptronic is "self-learning" its memory is short.  it forgets after a few minutes of not driving beyond program 1, and reverts back to it.  it also reverts back when you turn off the ignition.

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[Kim]

very much like my memory of things on the "honey-do" list.

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[az968]

Kim, thanks for giving us a new excuse!

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[unknown4u]

Bob I did not know that memory was so short on duration that even an alzheimer patient remembers more.

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[Bulti]

What was this topic about?

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