Funny throttle positions

[brookes 0]

This is going to sound like a funny problem but l'm just wondering if anyone has experienced the same thing. The accelerator on my 'rado seems to work fine (bit stiff) but on some occasions, especially when there is only a small amount of pressure on the accelerator, the car judders and lurches forward - a bit like when you release the clutch too quickly at low speed and it kangaroos forward.

 

It has done this on the motorway about 70 mph but also pottering around town at 30mph. It only seems to occur at low revs but when you stick your foot down it flies and there is no prob. Spoke to a mechanic mate and he suggested the throttle sensor position but when we had a look he didn't have a clue - l'm not very mechanical either.

 

If anyone has any suggestions would be greatly appreciated. Gonna change the accelerator cable soon to see if this improves things but will keep you informed.

[G60Jet 1]

Change the Cable first, only about €22 here in spain, order a new gromet to go into the bulk head too and one that goes in the pedal (if the pedal has been stiff the grommit in the pedal will be out of shape and the cable may pop out, Happened to me). grommits cost peanuts after all.

 

You will need your chassie number to order the cable as there are several for all ages of C

[Kevin Bacon 5]

VR6?

 

Could be the TPS but more likely the MAF sensor or Blue temp sensor.

 

Kev

[brookes 0]

Cheers Kev,

 

Could you give me some moree info about the MAF sensor and the Blue temp sensor. Not sure what these are or where they would be located?

[Kevin Bacon 5]

Could also be the O2 sensor thinking about it :?

 

The MAF sensor is on your airbox with a silver bit and a plug attached. It measures air volume and determines the fuelling amount. These are renowned for malfunctioning! They're hard to diagnose so the usual solution is to replace it, having checked it's associated wiring first, for breaks etc.

 

The blue temp sensor again tells the ECU how much fuel to squirt in the engine, depending on temperature (of the coolant). It's the middle one of a row of three on the thermostat housing, which is on the front of the engine in front of the radiator fan.

 

The O2 sensor (also known as Lambda probe) is yet again related to fuelling and these can cause the symptoms you describe too.

 

MAF sensor is £150 - £300, depending on where you buy it.

Temp sensor is around £15 I think.

O2 sensor is around £90 from VW but you can buy 'universal' ones at a cheaper price.

 

First thing to do is hook the ECU up to a diagnostic machine and see what error codes it reports. The MAF won't report an error unless it's totally dead and the O2 sensor is best tested with a Multimeter, any good mechanic will know how to do that.

 

Getting a VR to run smoothly is quite a task, even with engine monitoring tools!

 

Good luck!

 

Kev