Gas Guage/trip computer reading wrong and suspension...

[mmaturo]

Anyone have issues with the read-out of miles left not matching what the gas gauge says...its thinking i'm getting 10 miles per gallon so when i fill up its says mileage remaining of 220-225. Usually its 365 or more and at the low end it is way off.

The cluster has been replaced and the fuel sending units but it is still acting up. Once i'm down to about a quarter tank on the gauge the gas gauge seems off also as it says i have 50 miles left, i'll park the car then come back to it saying 15 miles left and the gauge is in the red, so it drops from just under a quarter to nearly empty in just a matter of miles. What else would be affecting this? Could my car really be eating 10 gallons per mile and something is wrong there (as its not being driven that hard).

Also i have a pop in the front suspension they cannot figure out at slow speeds over uneven surface like a turn in to a driveway or parking lot. Singular pop but they replaced stabilizer bar and links, both upper and lower control arms on the side it soulds like (drivers side) but didn't fix it. They then blamed it on a loose axle at the CV joint but i wouled think that would make a continuous clicking noise not individual pops.

Thoughts?

[Bigglezworth]

My fuel gauge does that when I've run it really low and only put in a 1/4 tank or so. If I fill it up I don't have the bad reading.

[mmaturo]

I'm slowly figuring it out for them...turns out it IS thinking its only getting 10mpg...I read my owners manual for clues on how the trip computer and the computations are made and the various read-outs under the trip computer tell the story... the 'instantaneous' readout based on your last 100 meters or something is the basis for the miles left computation...and the computation at every start-up. Well mine is stuck on a constant 10.4 mpg regardless of how or what speed i'm driving while a few clicks on the trip computer shows the average over time for mpg constantly changing just like it should be. That explains the readout thinking i can get 50 more miles on a low tank with a few gallons left when i parked only to start it to find 15 as it went from thinking i was getting good mileage as an average over time to the 'instantaneous' value stuck at 10.4mpg.

So for some reason the reading is always 10.4. Fix that and problem finally solved. Funny (sad) i had to read my owners manual to get further clues to how the computations are made and see if i could reset them, ummm that on two trips to the dealer the techs couldn't come near the issue.

[hahnmgh63]

mmaturo, that is very confusing. I know you can change the way it calculates mpg with vagcom under the "instruments" module, and you can change the what the car thinks is the reserve fuel and totalizer readings? I think the raw data comes from fuel flow rates as well as speedo inputs although where the fuel flow rates come from who knows? I think it would be difficult for someone with Vagcom do change those setting unintentionally as it is a multi step process.

[mmaturo]

Well turns out when i said i was close to fixing it myself...sure enough. You were correct to. Turns out when i did the reset i figured it would clear ALL values in the trip computer not just which ever one was showing...so on my long drive to the dealer today (over an hour in chicago morning traffic) i played with it more. Turns out you need to clear and reset each value individually for them to all clear out (the time duration, the average speed, the average and instantaneous mpg). So once i did a reset in each setting...guess what...it all started to work like normal. So when the tech replaced my cluster and then a trip later he replaced the sending unit the one thing he did not do was reset the values so they never moved from whatever they were frozen on. Glad it took two visits but actually me reading the owner's manual to figure it out.

The popping noise however we will see....same tech trying again and took him for another ride and clearly proved it was not the CV joint/axel causing it...duh) so for the now third time maybe he can figure it out. Already replaced stabilizer bar and links, and upper and lower control arms on the side that the noise seems to be coming from.

Car is in for DRC recall too. Hesitant as my last regular repair was holding well. I have a good seat of the pants feel for it so should be interesting getting it back. I also measured last night the distance from my wheel arch to the edge of my 19" rim (4" in front and 4 1/2" in the rear).

[V8weight]

Your "popping sound" sounds to me like worn out upper shock mounts.

[mmaturo]

Your "popping sound" sounds to me like worn out upper shock mounts.

Hmmmm... it did occur to me as the sound seems higher (upper control arm area) and i've had a loose shock in another car that created interesting noises. Considering how high up in the compartment it sounds and that it occurs on any sloped surface i think you may be right that as it gets twisted it is moving the mount...its the only thing left...I sorta was hoping that when they replaced the shocks they might find something going bad...email being sent to service rep.

[DHall1]

Steering rack.

or rack mounts.




Hmmmm... it did occur to me as the sound seems higher (upper control arm area) and i've had a loose shock in another car that created interesting noises. Considering how high up in the compartment it sounds and that it occurs on any sloped surface i think you may be right that as it gets twisted it is moving the mount...its the only thing left...I sorta was hoping that when they replaced the shocks they might find something going bad...email being sent to service rep.

[DuckWingDuck]

ya, the computer is VERY unreliable on probably its last quarter tank, it always happens to me, guess I'll mess with resetting the entire computer to see if that gets eliminated...

[mmaturo]

Steering rack.

or rack mounts.


Yep that was my suggestion on trip number two for the problem. He checked it. I think the shock mount may be it. I'll know more tomorrow as i did send that suggestion to my service adviser. They haven't looked at it yet.

[mmaturo]

ya, the computer is VERY unreliable on probably its last quarter tank, it always happens to me, guess I'll mess with resetting the entire computer to see if that gets eliminated...

That's exactly what i brought mine in for (along with the popping 3 visits ago) as it used to be very accurate until my last two in quick succession engine drops in April. I think it still is off though as this last week the gauge did still drop very fast from just under a quarter tank to red again. They replaced the cluster and the sending unit. I only had 30 minutes after the reset and still 3/4 tank so no idea if it will be better. My service adviser figures i will find it is still bad at the low end (the gauge, not the computer aspect, but at least i have it agreeing now) as she has seen nothing but failures from 2000 on in the A6s...she seems way to familiar with it...and appears the lack of a real fix as the parts are all the same.