UKC

Recently, when sort of half warm, and when only very lightly on the accelerator, my car (mark IV Golf 1.9 TDI) has started occasionally doing a sort of misfire/judder. To this point, it's not been a problem when it's warm and I suspect, given the age and mileage on the car, that it's the injectors slowly coming of age...

Until now, I've done a lot of driving, but from the end of April, that's going to change, and we'll only need the car very much on a second car kind of basis, if at all. I'm looking to get the car through the next two months or so, and then I'll be a lot more relaxed about what happens to it.

I was wondering if it would be worth trying some diesel additive, to try to maybe clear the injectors. What is the general opinion on additives for diesel? I'm generally very wary of putting anything extra in fuel or oil, and am always careful to use oil with the right code on it when doing an oil change. I just thought it might be a possibility of solving the problem for the next 3000 miles or so for not very much money, but obviously if there's a chance I'm going to ruin the engine, then I'll steer clear!

Cheers.

In reply to Green Porridge:

I doubt there's much to lose in trying. It's only a few £ a bottle and what harm is it likely to do.

In reply to Green Porridge:

I've been using this.
http://www.halfords.com/motoring/engine-oils-fluids/fuel-oil-additives/mill...

My check injection warning kept coming on, someone suggested this and it comes on far less often now.

In reply to gethin_allen:

Well, indeed. I'm not concerned about spending a tenner or so and it not doing anything, for me it's worth a shot. I'm more concerned about spending a tenner or so and wrecking the engine! At least looking at reviews on amazon, it seems that there are a small amount of reviews where people say "pointless, doesn't work" but noone who says "tried it and the engine fell out"

In reply to Green Porridge:

I've found the Forte diesel cleaner to be the only one worth using. It used to be something only dealers could get, but ebay has loads of people selling it now.

It seems to be one of the few additives that is just a cleaner, rather than a cetane booster and I think cetane boosters are considered a bit of a snake oil. Forte was the cleaner of choice for the local MOT place if a diesel car had failed it's MOT on emissions. They'd drop a bottle of it in the tank, give it a quick Italian tuneup and sure enough, no more heavy smoking.

Also what fuel do you use? BP & Shell etc have a better mix of cleaners in their fuel compared to supermarket fuel. My car seems to get about 6 or 7% better mileage using shell or BP over supermarket fuel. Same with my motorbike, but I always assumed that was due to supermarket petrol having a higher ethanol content.

In reply to Green Porridge:

I went on a few petrolhead forums when my warning kept coming on, my conclusion from what I read was the very cheap ones were pointless, the one I linked to works, and that its also worth changing my route home when I can to give it a bit of a blast because all the traffic I spend my time in doesn't do it any good. Didn't see any warnings about engine damage.

Mine has gone from doing what you describe and a warning every single time I accelerated over 50mph, to doing it once in a while.

In reply to Green Porridge:

After reading a load of conflicting information i decided to stick 20 pounds of super diesel in my Octavia and give it about an Italian tune up of about 2 minutes of 50mph in third gear. Sorted all my smoking problems out.

In reply to Green Porridge:

When my old Clio TDI was trundling along on part throttle it would sometimes do a juddery "bog down" and even flooring the throttle would produce no more acceleration but huuuuuge clouds of smoke.

Are you getting any smoke when you're juddering?

In reply to Green Porridge:

It is highly unlikely to do any damage to your engine.

I occasionally put Redex diesel treatment in my old car - Focus TDDI. I also found that the fuel used made a huge difference - I use Shell wherever possible, then BP. I won't touch supermarket fuel again, after I filled up at Sainsbury's once and it took 2 tanks of Shell and a bottle of injector cleaner to get the performance back to what it should be.

Not yet put any treatments in the Audi.

Ideally put the additives in the fuel just before a long journey, so the engine is properly warm and they have time to work.

In reply to Green Porridge:

Thanks all for the replies. I have decided it probably won't do any harm, so got some stuff from liqui moly, filled up with finest grade extra virgin premium diesel, and shall run it through on a 200km autobahn run this evening. Hopefully that'll put the problem off to a time when the car will be nice to have rather than necessary.

Cheers!