Is it worth trying a petrol additive?

[Deleted member 65149]

Not really. The de-NOx storage catalysts are temporary 'buffers' that hold enough NOx during lean-burn operation that can then be processed at times in the journey when the engine is under enough load to warrant a move back towards Lambda <=1, in other words when there's less oxygen in the feed gas. This will happen pulling away from the lights or going up hills in the normal way. Lean-burn operation will most likely be limited to steady light-load conditions.

The main problem for the NOx sensors in your case is I think that the majority of your journeys are short urban trips.

I don't know whether the additives you've listed above perform as per the claims made by the manufacturers, I've not used acetone before as a fuel additive. The dose rates they mention are quite high (500ml/15 litres) and it's worth considering that some of whatever goes in the fuel also ends up in the engine oil/sump. So if you do end up trying it out, it might be prudent to change the engine oil afterwards too.

Excellent advice. Annoyingly the engine oil was changed just a couple of weeks ago.

 

[Smiley]

You echo my thoughts on what the root cause is. I’m not so convinced about your solution. 100 miles a month would cost over £200 a year in petrol alone, as well as the cost of wear and tear on tyres, brakes, suspension. I’m only thinking of a £10 dose of additive once, then perhaps once a year to keep carbon build up at bay if it works.

Given the overall costs associated with running a 9 yr old 3.5 litre petrol car I would have thought that less than £20 a month to solve the problems that you are having would be cheap. You are trying to find a work around for the first symptom (Nox sensors) associated with the poor use that the car is being treated to - there will be other problems down the line such as corroded discs and possibly auto transmission problems caused by it never getting up to temperature. Up to you as it is your car but you could at least give it a go for a couple of months and see what happens.

 

[DITTRICH]

My old s124 E300D managed to clean its own exhaust when I had to join the swedish motorway in a hurry. I floored the pedal, initiating kickdown, and the trusty diesel obliged. I could have hidden a destroyer in the cloud I created. Re-engaging cruise control from a standing start at the traffic lights was reasonably spectacular as well. Short small city journeys favour petrol rather than diesel cars. A long 100 mile drive once a month might help including a bit of kickdown and redlining once the engine is hot should enable the pdf regeneration to help get rid of the carbon build up.

 

[Deleted member 65149]

Sorry for the delayed response to this, I’ve been serving a ban!

Well I tried with Wynn’s Catalytic Converter & Lambda Cleaner and it hasn’t worked . On the plus side, fuel consumption has improved, although that may be because it’s only been my wife driving for the last three weeks since I managed to break my ribs. She did an 80 mile journey the other day on A and B roads and got 42mpg - pretty dam good for a 3.5 litre petrol engined car.

 

[AMGeed]

^ Welcome back

 

[Deleted member 113659]

Sorry for the delayed response to this, I’ve been serving a ban!

Well I tried with Wynn’s Catalytic Converter & Lambda Cleaner and it hasn’t worked . On the plus side, fuel consumption has improved, although that may be because it’s only been my wife driving for the last three weeks since I managed to break my ribs. She did an 80 mile journey the other day on A and B roads and got 42mpg - pretty dam good for a 3.5 litre petrol engined car.

WB Tim.

 

[markjay]

Welcome back, from your avatar buddy.

 

[Deleted member 65149]

Thanks guys, it’s good to be back.

I need to be more careful when tilting at windmills because I fell off my horse and broke some ribs three weeks ago. OK, I really tripped over when not looking where I was walking. Not being able to come here added to my frustration at not being able to do anything physical. But progress is being made, I no longer feel like a lance is being thrust through my heart when I sneeze!

 

[davymead]

Sorry for the delayed response to this, I’ve been serving a ban!

I wondered where you’d gone ?
Glad you’re back.

 

[zipdip]

Welcome back,do you have saving grace that maybe you were pi--ed when you fell over,I am afraid as we get older falling over happens,I fell of the stepladder cutting a hedge last week,landed on top of the ladder and got away with just one badly bruised arm,and needing to buy a new stepladder

 

[E55BOF]

I need to be more careful when tilting at windmills because I fell off my horse and broke some ribs three weeks ago. OK, I really tripped over when not looking where I was walking. Not being able to come here added to my frustration at not being able to do anything physical. But progress is being made, I no longer feel like a lance is being thrust through my heart when I sneeze!

I broke eight ribs when I was knocked off my bike by a lorry in 2012. Untl they healed, I only sneezed the once. If necessary, I'd have hit my nose with a sledgehammer to prevent it happening again...

 

[Deleted member 65149]

Welcome back,do you have saving grace that maybe you were pi--ed when you fell over,I am afraid as we get older falling over happens,I fell of the stepladder cutting a hedge last week,landed on top of the ladder and got away with just one badly bruised arm,and needing to buy a new stepladder

Thanks. Unfortunately I was completely sober when I did my version of a swallow dive, but into the ground instead of a swimming pool. I was out for a walk with my wife and daughter and we were heading back home. We’d already done 14km and I wanted to check we were heading in the right direction so I checked the map on my wife’s iPhone. We’ve all seen and criticised those people walking along with their faces planted into their phones - I only managed a few seconds before tripping on the uneven ground. My first thought was to protect the £1200 map in my hand, so I held it aloft as the ground rapidly approached. This meant that my chest hit first, closely followed by my face, then finally my arms! The phone survived but I didn’t.

Had I been in my preferred inebriated state I wouldn’t have been able to compute that I needed to check on the best route home, I wouldn’t have been walking so fast, and I’d probably have collapsed in an ungainly heap with no more than a grazed knee. From now on I’ll ensure that I don’t repeat my mistake; I’ll only walk when pi55ed.

 

[Deleted member 65149]

I broke eight ribs when I was knocked off my bike by a lorry in 2012. Untl they healed, I only sneezed the once. If necessary, I'd have hit my nose with a sledgehammer to prevent it happening again...

Exactly. I wouldn’t have been able to pick up the sledgehammer though, not least because with a sneeze approaching I grabbed the left side of my chest with both hands to try to offer some support to my ribs during the upcoming explosion. My facial contortions as I tried to suppress the sneeze had my daughter split between laughing and concern.

 

[Nicebutdim]

Welcome back. I wondered where you were. Get well soon.

 

[Deleted member 159894]

I was wondering where the old duffer had been.

 

[Fastcar155]

Hi , I have a 1996 2.8diesel Pajero.When I purchased the car the engine had a slight roughness on tick over.I tried everything to sort out the problem , premium fuel , injection cleaners , regular engine oil changes and the list goes on.

My daughter borrowed my car to go on holiday and I forgot to tell her to engage the overdrive system when crusing on the motorway.The 300 miles driven was the Italian tune up and now the engine tick over is perfect.

This car has a basic diesel engine with no emission controls and has never been failed on exhaust gases.

I have a 2015 C207/E400 and the only product that goes into the fuel tank is Shell V Power.

 

[Deleted member 65149]

I was wondering where the old duffer had been.

In the cooler for heinous crimes!

 

[markjay]

In the cooler for heinous crimes!

Good to have you back. All is forgotten. Your conviction is now spent.

 

[PunkyB]

https://seafoamworks.com/uploads/2021/05/1420-SF-4001CA-SFMT-SDS-CA-ENG-v20210526-sfi.pdf
PETROLEUM DISTILLATES/SOLVENT -----POSSIBLY OXYGENATED AROMATICS e.g. TOLUENE ---AND 20-30% ISOPROPYL ALCOHOL
the name sea foam will give a clue to its carburettor based marine engine origins with its ingredients designed to sequester/ mop up water in fuel/oil systems----since its likely to contain oxygenated species to do this-- and its the oxygen in water that damages the NOx SENSORS I WOULD NOT RECOMMEND YOU USE THIS PRODUCT!!!!!!


UNLESS THE AFTERMARKET PRODUCT DESCRIPTION STATES SPECIFICALLY ITS DESIGNED FOR USE IN VEHICLES WITH NOx REDUCING EXHAUST SYSTEMS ---DO NOT USE ANY AFTERMARKET FUEL TREATMENT

Also no point using fuel additives such as Redex etc in direct injection engines as the fuel and additive won't be going through the valve. So not only ineffective but also as you pointed out potentially damaging.

Personally I've always used Shell 99 V Power despite having a W169 A Class with the M266 which has no valve timing etc. I doubt the fuel map will advance ignition beyond what it would for 95 octane which is the recommend. I use it for the detergent though. I had some crappy injectors on mine I tried Redex, Redex Advanced and STP. Liqui Moly Jectron got my problems sorted and I regularly use their regular injector cleaner now. I also sometimes use their Speed-TEC gasoline additive. It's not an octane booster but increases the ability of your fuel to atomise by increasing its surface area. Definitely not snake oil or placebo, gives great extra mid range shove especially where the VLIM changes over the air intake path.

I think everyone should use a little Redex now and again, it's so cheap that even if it were to be snake oil it's not like it's going to ruin you. And everyone should be using premium fuels if they care about their car even if they don't say they need it, everyone with a direct injection engine should certainly be using high octane only!

 

[markjay]

Also no point using fuel additives such as Redex etc in direct injection engines as the fuel and additive won't be going through the valve. So not only ineffective but also as you pointed out potentially damaging...

That's not quite accurate. In Direct Injection engines the fuel (and additives) doesn't flow through the intake valves, true, but it does flow through the piston crowns and combustion chambers, and crucially also through the exhaust valves - the latter being far more prone to carbon deposits (leading to leaks and burnt exahust valves) than the intake valves.

So while the detergent in fuel additives isn't as useful in Direct Injection engines as it is in the Port Injection engines of old, it is still highly recommended.

(And, some Direct Injection engines have an additional fuel injector in the intake manifold, precisely for this purpose i.e. allowing the intake valves to be washed by fuel)

As for potential damage... you seem to be confusing products like sea foam with conventional detergents. The latter are in common use anyway - to some extent in all fuels, and to a higher degree in premium fuels - and are perfectly safe to use.