Golf MK4 Dipetane

GerTim

HI, I'm New to boards - first thread
I have a VW GOlf Mk4 1999 1.4 16V Petrol with 180K Miles on the clock
Failed NCT Emissions with Dipetane in the petrol
Lambda 1.06 CO 0.56 cvol%
Put 1 Lt in 3/4 of a tank for 300 miles before test and
put 1/2 lt into 1/4 of a tank 60 miles immediately before test - Failed
Did not drive car in 5th gear for lest 400 miles
Going putting new catalytic converter in before re-test
and unsure whether or not to replace the lambda sensor
Whats your opinion on the above and
What is your recommended ratio for Ditethane before NCT
Thanks in advance

Toyotafanboi

Your lambda value is out and no amount of dipetane is going to fix that, it's also unlikely that the sensor is faulty.

You need to fix the lambda problem to pass.

GerTim

Thanks toyotafanboi for reply
How do i fix the Lanbda problem?
will a new catalytic converter solve the lambda problem?

Tuco88

Not sure about diptane and other additives, I wounder is it the hard drive people do putting in the diptane do that does the trick.

I remember seeing a diesel fitter putting a drop of petrol into a big CAT dozer once talk about a spring clean.

greasepalm

I think car needs to be hooked up for diagnostics for any fault codes and read lambda on oscilloscope for proper up and down readings and how good it is.

GerTim

Hell All, My Golf passed the NCT Emissions Re-Test
CO 0.01 cvol% and Lambda 1.03 - Lucky just on the limit.
Here is what we did
Pluged in car to Delphi diagnostics tester for any fault codes and found none.
Got catalytic converter from motor factors - 100 euro - and fitted that
Got second hand Lambda sensor from 03 mk4 golf from car dismantler - origional bosch and fitted that
Put Dipetane in petrol at correct ratio of 1:200 - I emailed Dipetane and they said no point in over dosing just use correct ratio and get car good and hot before retest.
Thanks to all who posted replys

greasepalm

I always found dipetane brought up emissions if in tank while testing.

Leonard Hofstadter

greasepalm wrote: »

I always found dipetane brought up emissions if in tank while testing.

I've never understood this fascination with this product either, seems to be something unique to boards. It seems to me to be a sticking plaster at best not a solution for an underlying problem.

A well maintained car with a healthy engine doesn't need dipetane or anything else either, just a good blast on the way to the NCT centre (and maybe some decent fuel if it hasn't had a decent drive in a while).

Even cars that burn oil should be fine once it's not using say a litre every 100 miles or something ridiculous.

greasepalm

The issue is the owner has not got a clue about how diesels work as just used for short journeys so crap builds up.
Next quality of oil in use and regular oils and filters changing.
Cars need driving to keep them clear.