Tipper Truck and Limp mode - Two Surprises OUCH!

Honest John Back Room » Motoring discussion
View Threaded
Wed 24 Sep 2014 18:50
Tipper Truck and Limp mode - Two Surprises OUCH! - oldroverboy.

Driving on the A41 Hendon way, saw the lights change and decided not to chance it, so braked and stopped for the lights, Tipper truck behind emergency braked and whatever he had in the back (big and heavy) broke loose and hit the front of his load compartment with an almighty bang, although he stopped a good 3 feet from the back of my car.

Oooof!

Driving up an A road couple of days later, car shoots across from the right (VW passat) and suddenly loses power and then proceeded to drive very slowly up the road, obviously unable to accelerate. I managed to brake sufficiently to stop, and when we pulled into a petrol staion the driver said sorry, I saw you etc and said he would call the breakdown services.

young rovergirl said both times, don't they watch the road and what else is on it.

One guess for my reply..

Reply | Report as offensive | Link
Wed 24 Sep 2014 19:17
Tipper Truck and Limp mode - Two Surprises OUCH! - brum

As I described on another thread the passat probably had transient throttle pedal sensor fault (the twin track potentiometer disagrees, usually some fluff on one track). The dangerous default chosen by the firmware programmer is to latch a fault, and fix revs and power at low power, typically around 1400 revs. This is a ridiculous strategy as moving the throttle a bit clears the disagreement, but because the fault is latched, the engine needs to be switched off to reset the fault, and also it is not recorded in the history.

I came close to a fatal head on in exactly the same situation, I reckon many accidents have happened due to this incompetent software, some fatal, and no evidence leads to "driver error" conclusion by investigators.

Reply | Report as offensive | Link
Wed 24 Sep 2014 22:27
Tipper Truck and Limp mode - Two Surprises OUCH! - Avant

For heaven's sake, why does a throttle pedal need a potentiometer (whatever that may be)?

It was only about 20 years ago that the throttle pedal cable on my Espace (normally very reliable, but it had done 90,000+ miles) broke. I'm no mechanic but my swimming costume was in the car and I managed to tie one piece to the other and not even have to limp home. It survived for over 100 miles I seem to remember, and I drove to the Renault garage with no problem.

Such is progress.....

Reply | Report as offensive | Link
Wed 24 Sep 2014 23:12
Tipper Truck and Limp mode - Two Surprises OUCH! - brum

For heaven's sake, why does a throttle pedal need a potentiometer (whatever that may be)?

Its a (cheap) way to measure throttle pedal position/demand electronically that is needed by the ecu.

Cable operated butterfly valves are not compatible with modern fuelling systems and are unable to meet euro legislation and emission requirements. They are also not that reliable.

Reply | Report as offensive | Link
Wed 24 Sep 2014 23:50
Tipper Truck and Limp mode - Two Surprises OUCH! - gordonbennet
Such is progress.....

Or not, you probably get recovered on a flatbed now if you manage to survive a VW throttle potentiometer failure by the sound of it.

Music to your ears Avant, original throttle cable on the old Merc is still going strong, the autobox downshift cable snapped at one of the nipples about 5 years ago, i used one of those chocolate block connectors to piece the two parts together, worked as good as new, finally got a new downshift cable on about 2 months ago.

Daughter's right ORB, they drive about 10 feet from the front of the bonnet, anything else doesn't seem to compute.

Edited by gordonbennet on 24/09/2014 at 23:52

Reply | Report as offensive | Link

If you cover no more than 100 miles per day and have easy access to a charging point at home or work, then an EV is ideal for you.

Is an electric car right for me?