Car fuel additives - Do you use one?

[Paddy]

Lots of these type of questions in the car forum "I bought a car that's done 2,000 mile in 12 months, owned by Miss Daisy. What can I do". Usual answer is bottle of Redex/STP and an Italian Tuneup. Saab TTID especially don't like short journeys, just clogs up the DPF, then there's the EGR, plus the swirl bars. Don't get these problems with a petrol engine.

If everything is working fine on the engine and depollution side then a quick trip up and down the motorway will re-generate the DPF. If not you can force regeneration with the right diag.

I forgot to mention that the auto regeneration will only start with at least 1/4 tank of fuel in the tank. This is because extra fuel is used to burn the carbon in the DPF. The burn only lasts a few minutes there is no message from the car to say when and what is happening. Only the diags and scan tool can inform you.

[BigDataPro]

OBDII tool for a tenner is what I use.

The Ford Mondeos have an issue with EGR valves as they get older. Every year the emissions tests are squeaky bum time. Every MOT I was revving the bits off it for 20 minutes to pass the emissions tests. Now a couple of weeks before the MOT I pop a couple of bottles of redex through the petrol tank. Now it sails through without a care. EGR valve failures are rare.

£4 to pass an MOT seems cheap to me.

Amazing! There seems to be opinions For and Against the effectiveness of these additives, both from very well informed people. Some say it works very well and some think it's like Snake oil. Probably there isn't any standard pattern of outcome using it or not using it.

Ordered and received STP Ultra System Cleaner, 5 in 1 Concentrated Cleaning Formula for Diesel Engines

https://www.amazon.co.uk/STP-Cleaner.../dp/B00NC1ER3U

I'll update here with my experience here at some point, so that it may be useful to some one.

[Lance]

Amazing! There seems to be opinions For and Against the effectiveness of <INSERT CONTROVERSIAL CLAIM/PRODUCT>, both from very well informed people.

you're surprised?
Head on over to an audiophile forum where they argue about whether a £500 USB cable is better than a £50 USB cable.

[Paddy]

Amazing! There seems to be opinions For and Against the effectiveness of these additives, both from very well informed people. Some say it works very well and some think it's like Snake oil. Probably there isn't any standard pattern of outcome using it or not using it.

Ordered and received STP Ultra System Cleaner, 5 in 1 Concentrated Cleaning Formula for Diesel Engines

https://www.amazon.co.uk/STP-Cleaner.../dp/B00NC1ER3U

I'll update here with my experience here at some point, so that it may be useful to some one.

The additive is going in the fuel, and will be diluted to the nth degree. It may help clean injectors but it will be burnt along with the fuel and have zero affect on the DPF and EGR and other bits in the depollution system. The picture is of a blocked ERG valve, no amount of snake oil will clean it or resolve other issues in the engine.

[anonymouse]

If everything is working fine on the engine and depollution side then a quick trip up and down the motorway will re-generate the DPF. If not you can force regeneration with the right diag.

I forgot to mention that the auto regeneration will only start with at least 1/4 tank of fuel in the tank. This is because extra fuel is used to burn the carbon in the DPF. The burn only lasts a few minutes there is no message from the car to say when and what is happening. Only the diags and scan tool can inform you.

Then the usual next question on the forums is "my oil level has gone up and it stink of diesel & now have limited performance warning / CEL", why has it failed the regen. Yes, OBD does show the DPF % and is one of the first pieces advice. The next question is "how do I delete the DPF/EGR/Swirl flaps. Can I get them mapped out".

[DonaldJTrump]

Real motorists blank off EGR valves

HTH

[vetran]

The chap who does our annual MOT recommended the redex, he believes it works and he does 20+ MOTs a day (its a place that only does MOTs) . 3 years struggling to pass the emissions tests and afterwards 2 years passing first time.

Combine with good blast on the motorway.

worked for me.

[Paddy]

Then the usual next question on the forums is "my oil level has gone up and it stink of diesel & now have limited performance warning / CEL", why has it failed the regen. Yes, OBD does show the DPF % and is one of the first pieces advice. The next question is "how do I delete the DPF/EGR/Swirl flaps. Can I get them mapped out".

Good question!
(1) Putting aside the legal issues, I would love to remove the ERG and DPF etc. However, remapping can f**k up the ECU if it's not done correctly and that would end up costing £1000 + to put right. Anything can go wrong when remapping so the car electrics have to be in perfect condition with a power back-up while doing the re-mapping.

(2) The depollution system is partly designed to get rid of nitrous oxide but by doing so it lowers the combustion temperature by pumping exhaust into the inlet. The result is a small amount of black smoke of which is removed by the DPF. Do away with the EGR system and your engine will run better and use less fuel but it's illegal.

(3) By trying to fix a problem by doing a delete EGR is merely coving up the symptoms but the original problem will still exist and come back to haunt you in a different form. You need to find the underlying problem. You need a good garage to diagnose the issue but there are very few good garages. There are a few self-employed specialists who will come to you or a garage to diagnose the car.

(4) Back to basics. A Diesel engine needs air, fuel and most importantly high compression. The most common failure causing black smoke is the lack of compression. Solve the issue and the DPF will take care of itself. The DPF and EGR issues are symptoms not the causes.

[xoggoth]

Use Premium fuels like BP Ultimate - for diesel it improved range for me, making it actually cost efficient buy. Expect at least 3 full tanks before any difference is visible.

I could save money? Keep wondering whether to try it but then say nah! cos I'm a mean old bastard.

[Paralytic]

Driving is soooo 2019.