flyboy1717

Hello, and Happy Winter,

My '92 (217k miles) tip has developed a new problem, or should I say a problem seems more apparent now that temperatures have started to dip. When shifting from Reverse to Drive, the RPM's dip low and the car often stalls. This is much more prominent when the engine is cold. Also while in drive or neutral, if I blip the throttle the RPM's come up as they should, but then dip well below normal idle. The engine will hunt for a little, and this can also cause stalling. This weekend I pulled out the Idle Stabilization Valve (ISV) and sprayed some cleaner in it. It actually wasn't all that dirty. The valve appeared to be free, although I did not apply 12V to the pins to see if it rotated. Aside from the ISV, is there anything else I should be looking at. Is this something that can be fixed with a chip? I know that alot of the 5sp guys with LWF's fix what seems to be a similar problem with chip. Any other ideas would be welcomed.

Thanks,
Roger

jimq

my TIP has done it a coupletimes lately with this cold weather we are having down here. I was wondering if there is some type of choke or something that isnt working.

RichieRoo

I think your problem is that the tiptronic's automatic transmission fluid (ATF)
is too low. In colder weather this becomes more apparent.

Have a look at my thread here.

I couldn't understand why my car would stall when selecting reverse or at one
particular junction every day when it was cold. It appears the torque converter is
reluctant to release if the ATF is low.

To add ATF check out my post in the DIY submissions section here.

If you read the sympoms at the end you'll see they are very similar to yours.

Hope this helps.

Let us know how you get on.

flyboy1717

Rich,

Thanks for the tip (no pun intended). This could definitely be, as I did change the ATF fluid 3000 miles ago, and filled it without the hammer to measure the ATF temperature. I followed Adrian's book, but will take another look. That would be great if that were the problem. I don't get the same pulling feeling like you described in your thread, but it is normal for my car to idle at 500rpm when in gear and my foot applied to the brake. This in turn creates a low oil pressure situation where the low oil pressure light comes on. I wonder if simply adding more ATF could kill two birds with one stone. I'll try to take a look at it this weekend, and let you know what I come up with.

Not related to the ATF solution, but what is the general consensus of using the Steve Wong Chip with the tiptronic. Could this help solve the rough idle, stalling. Part of me is just looking for an excuse to pick one up other than just being horsepower hungry.

Thanks,
Roger

RichieRoo

Hi Roger

The continuous slow idle speed and oil light is odd. Mine would dip revs
intermittently. Have you checked all the vacuum pipes are secure? Any sign
of a vacuum leak on the inlet side?

I wouldn't swap the chip until this problem is resolved, it will just add another
variable to the situation. The car has an issue that needs to be resolved before
altering other parameters.

Chips have been hotly debated on this forum. There are plenty of long threads
discussing the pros and cons of the various chips available, including Steve
Wong's. Have a quick search around.

I have run my Tip car with an after-market chip and with the original -
I couldn't discern any difference any respect.

Good luck

Rich

flyboy1717

Hello Rich,

Thanks for the follow up. I did add a little bit of ATF using your DIY. It wasn't grossly under filled, but it could stand a little bit more. After I filled it to what I felt was a good level, I took it off the lift and went for a quick 5 minute drive, everything appeared fine. I brought it back into the shop, back up on the lift to install the plastic cover, and as I was backing out of the garage, it stalled again. It since has stalled a couple more times, so unfortunately I don't think adding more ATF helped, but it was certainly worth a try, and I'm glad that I've added some as I think I did have it mildly under filled, so thanks.

You raise good points about not adding the chip until I have some of the other problems figured out. I have not thoroughly checked the vacuum system, and that is something I will check next time I'm down the shop. The 500 RPM idle while in gear is nothing new for me. If I am in Neutral or Park the engine quickly settles on 840 RPM's, so I had always just assumed this was normal. As for the low oil pressure light coming on at low RPM's, I also assumed this was somewhat normal as it is stated in the owners manual that this may happen when in traffic or stopped. I'd be interested to hear what other Tip owners typically idle at when the vehicle is in gear, but stopped.

Thanks again for your feedback, and continued follow up.

Roger

sml

I dont think your problem is specific to your tiptronic trans.
I think it is the same problem experienced by numerous manual owners also (myself included).

Potential reasons:
- ISV
- Bosch Hammer adaptation
- leaking vacuum lines on intake system
- faulty oxygen sensor
- misadjusted idle switch
- cylinder head temperature sensor
- distributor belt
- airflow meter MAF
- spark plug leads

My idle subdipping (the term used by steve wong) is still yet to be resolved. a new oxygen sensor is on the way for my next attempt.

flyboy1717

Looks like I have some work to do checking some various systems.

As for the oxygen sensor...can the hammer diagnose a faulty sensor? I'm not getting a Check Engine Light (CEL), and assumed that if I did have a faulty sensor I would.

Is a cheap way of doing the throttle adaptation just to unplug the battery for 30 minutes to reset the DME?

I've also noticed a dip in my mileage lately, averaging 21mpg's on the highway, where I was getting 25-26 early this year. My exhaust also smells a bit rich. I did recently install a 100 cell sport cat so I assumed the rich smell of exhaust was attributed to that, although the cat that I replaced was very old and some of the baffling inside had worked itself loose. I was hoping the poor fuel mileage was due to winter fuel, but perhaps this is indicative of some other problem, such as a faulty sensor, or some other fuel injection issue.

Does anyone on Cape Cod or south eastern Massachusetts have a hammer they'd let me use to do some diagnostics.

Thanks again for all of the help. This forum just adds to the pleasure of ownership.

Roger

sml

Some say yes. Others say the hammer adaptation is critical.

My opinon .... I think I had better success with the hammer adaptation although more testing would be required to confirm (which is hard when I only have access to a hammer at the mechanic which = $).