I bought this 2001 VW Eurovan about 3 weeks ago. Road like a dream for a few days – just over the moon.
Van has 170k miles on it.
Read through huge stack of service receipts from the years. Engine was rebuilt 40k miles ago! Transmission was “re-serviced” as well. About $8k total invested at that time. What a deal I got!
Then I filled the tank with some mid-grade fuel.
[Queue suspenseful music]
1 Day after filling with mid-grade, check engine light comes on.
***? Did I get duped on the vehicle sale – maybe dude cleared fault code before I came and test drove. But the transmission felt fine! Confused.
Clear fault code and pray it’s a fluke (knowing it isn’t)
2 Days after filling with mid-grade, check engine light comes on again.
I clear codes again. I start paying a LOT more attention.
3 Days after filling with mid-grade, check engine light comes on again.
So to recap, I was getting the following errors:
By this time I had also read that low octane fuel can cause misfires (or pre-ignites) in older engines that call for high octane – high compression engines, like the 2001 VW Eurovan V6.
Theory -- It’s pretty hilly where we live now, and this scenario would cause what felt like excessive tranny slippage:
Testing the Theory –
I had about half a tank of mid-grade fuel left, topped it off with Mobil premium (high octane)
1 Day after topping with high octane:
2 Days after topping with high octane, one day after adding octane booster
I never got error codes again. I checked for codes even though check engine light has not come back on. Nothing.
Furthermore, the freaking transmission is shifting like butter! And going up low grade hills after an upshift with zero problems – no more sporadic downshifts.
I’ve driven a lot more over the past couple days, going up low grade hills at low acceleration trying to trigger downshifts… it’s doesn’t downshift because it doesn’t have to!
The fan does not stay on after short or long road trips now.
I think it’s safe to say the mid-grade fuel did not sit well with this particular engine.
I'm keeping my appointment with mechanic today, but the agenda is very different: check spark plugs, take a gander at tranny fluid, change oil... and don't touch anything else!
Van has 170k miles on it.
Read through huge stack of service receipts from the years. Engine was rebuilt 40k miles ago! Transmission was “re-serviced” as well. About $8k total invested at that time. What a deal I got!
Then I filled the tank with some mid-grade fuel.
[Queue suspenseful music]
1 Day after filling with mid-grade, check engine light comes on.
- Error code: 01192 – Torque converter lock up clutch (clutch circuit open)
***? Did I get duped on the vehicle sale – maybe dude cleared fault code before I came and test drove. But the transmission felt fine! Confused.
Clear fault code and pray it’s a fluke (knowing it isn’t)
2 Days after filling with mid-grade, check engine light comes on again.
- Error code: 16684 – Random/Multiple Cylinder Misfire Detected
- Error code: 01192 – Torque converter lock up clutch (clutch circuit open)
- Fan stays on after turning vehicle off for a couple minutes
I clear codes again. I start paying a LOT more attention.
3 Days after filling with mid-grade, check engine light comes on again.
- Error code: 16684 – Random/Multiple Cylinder Misfire Detected
- Error code: 01192 – Torque converter lock up clutch (clutch circuit open)
- Error code: #### (not sure which code) – Transmission Fluid Temperature Overheat
- Fan stays on after turning vehicle off for a couple minutes
So to recap, I was getting the following errors:
- Random cylinder misfire error
- Transmission fluid overheat error
- Torque-converter lock open error
By this time I had also read that low octane fuel can cause misfires (or pre-ignites) in older engines that call for high octane – high compression engines, like the 2001 VW Eurovan V6.
Theory -- It’s pretty hilly where we live now, and this scenario would cause what felt like excessive tranny slippage:
- Going up low grade hill in 1st or 2nd gear at slow speed and nominal acceleration
- As speed increases, tranny upshifts
- Random Misfire(s) from low octane fuel (theory at this time), decreasing motor power
- Torque-converter senses low power, down shifts
- High RPMs, vehicle gains speed as I give more gas, cylinders catch back up, engine has more power so again upshift
Testing the Theory –
I had about half a tank of mid-grade fuel left, topped it off with Mobil premium (high octane)
1 Day after topping with high octane:
- Check engine light came on only once
- Transmission shifted notably better
2 Days after topping with high octane, one day after adding octane booster
- ZERO ISSUES!
I never got error codes again. I checked for codes even though check engine light has not come back on. Nothing.
Furthermore, the freaking transmission is shifting like butter! And going up low grade hills after an upshift with zero problems – no more sporadic downshifts.
I’ve driven a lot more over the past couple days, going up low grade hills at low acceleration trying to trigger downshifts… it’s doesn’t downshift because it doesn’t have to!
The fan does not stay on after short or long road trips now.
I think it’s safe to say the mid-grade fuel did not sit well with this particular engine.
I'm keeping my appointment with mechanic today, but the agenda is very different: check spark plugs, take a gander at tranny fluid, change oil... and don't touch anything else!