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Rough idle and injector cleaner

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Gaffa22
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Rough idle and injector cleaner

Post by Gaffa22 » Sun Jan 13, 2019 5:19 pm

Thought some of you may find this interesting

Last winter if the car had stood for more than 2 weeks on start up it would idle really rough. Fault code reader showed misfire on 2 cylinders. I stood the car again for 2 weeks then removed the spark plugs. Two were really wet.
I was going to replace all the injectors, but as the car had only done 29500 miles I replaced the spark plugs and decided to try injector cleaner.
Now I normally consider injector cleaners as snake oil but thought what can I lose.
So used two full tanks of fuel treated with Techron then changed the oil.
Since then each tank of fuel has been treated with Lucas Upper cylinder lubricant / injector cleaner. Fuel used for each fill up was Shell V Power.

I started to notice an improvement after the first two tank fulls with the Techron, the car would start instantly with no misfire. Even after being stood for 3 weeks.
The car was last used end of October so had not been started for over 2 and a half months, this morning it stated instantly and idled as smooth as a sowing machine.

It is is possible the improvement was just down to the Shell V Power, but I will continue with the Lucas treatment as I bought a litre bottle.

So am really pleased with the results and the difference it has made. The Idling is now perfectly smooth a considerable difference to how it was before, The fuel consumption has also improved
I can only assume the rough idle and misfire was caused by dirty injectors, and the V Power and treatments have cleaned them out.
2010 E89 35i DCT
2017 Honda CBR1000RR fireblade
2016 Honda VFR1200F
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Doddsy
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Rough idle and injector cleaner

Post by Doddsy » Sun Jan 13, 2019 6:26 pm

Great Success! :thumbsup:
Now: Z4MC Titan Silver
Gone: E86 3.0Si Sport Titan Silver - M exhaust + bumper - Battery Relocated - Aero Front
E86 3.0Si Sport Silver Grey - Carbon Diffuser - Aero Kit - B/Box Mod - Storm MW V2
E85 2.5 Si Sport Titan Silver

flybobbie
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Rough idle and injector cleaner

Post by flybobbie » Sun Jan 13, 2019 8:14 pm

Surely wet plugs means faulty ignition coils. Ambient temperature would make a difference.

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ronk
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Rough idle and injector cleaner

Post by ronk » Sun Jan 13, 2019 8:35 pm

You replaced the plugs, used the snake oil, posh petrol and UCL ? - You won't ever know for certain what fixed it :D
You don't stop playing when you get old - You get old when you stop playing!
So I bought a 35is with all the toys to play with. :thumbsup:

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Gaffa22
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Rough idle and injector cleaner

Post by Gaffa22 » Sun Jan 13, 2019 9:05 pm

It stilll misfired after I fitted the new plugs until I'd run the two ranks of Techron through it.
2010 E89 35i DCT
2017 Honda CBR1000RR fireblade
2016 Honda VFR1200F
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Gaffa22
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Rough idle and injector cleaner

Post by Gaffa22 » Sun Jan 13, 2019 9:08 pm

flybobbie wrote: Sun Jan 13, 2019 8:14 pm Surely wet plugs means faulty ignition coils. Ambient temperature would make a difference.
Yes I thought that which is why I wasn't sure it was improved until the colder weather, and I tried swapping the coils which made no difference still got misfire on same cylinders so pretty certain it was injectors
2010 E89 35i DCT
2017 Honda CBR1000RR fireblade
2016 Honda VFR1200F
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Rough idle and injector cleaner

Post by eff1guy » Sun Jan 13, 2019 9:39 pm

Well done Gaffa, I've always wondered about the so called benefits of using aftermarket additives. No problems with mine as of yet but think I'll give this a whirl to keep the E89 dreaded injector problems at bay :thumbsup:
Next Z landed ..... Z3 3.0i Sport Roadster

Z4 35iS ..... Gone to a new home

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ronk
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Rough idle and injector cleaner

Post by ronk » Sun Jan 13, 2019 9:46 pm

Gaffa22 wrote: Sun Jan 13, 2019 9:05 pm It stilll misfired after I fitted the new plugs until I'd run the two ranks of Techron through it.
:thumbsup:
You don't stop playing when you get old - You get old when you stop playing!
So I bought a 35is with all the toys to play with. :thumbsup:

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JimsZ
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Rough idle and injector cleaner

Post by JimsZ » Sun Jan 13, 2019 9:56 pm

I use redex every few tanks. Fuel consumption goes up around 2mpg on my commute.
E89/28i Msport gone :( .. Zx10r track bike gone… time for a KTM 350 exc-f and some green laning and dirt bike excursions…. Let’s see how this goes… : :evil:

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ronk
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Rough idle and injector cleaner

Post by ronk » Sun Jan 13, 2019 10:32 pm

Is Redex ok? With all the sensors on the exhaust side and the cats, I‘m a bit concerned about potential contamination?
You don't stop playing when you get old - You get old when you stop playing!
So I bought a 35is with all the toys to play with. :thumbsup:

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Rough idle and injector cleaner

Post by JimsZ » Sun Jan 13, 2019 10:35 pm

Pretty much used it for years on all my cars including the Z, no complaints from me.
E89/28i Msport gone :( .. Zx10r track bike gone… time for a KTM 350 exc-f and some green laning and dirt bike excursions…. Let’s see how this goes… : :evil:

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R.E92
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Rough idle and injector cleaner

Post by R.E92 » Mon Jan 14, 2019 11:45 am

I've been chasing an annoying issue down on my old E46 320d for the last year. The car would occasionally stutter during light acceleration and it was gradually getting more frequent. I'd replaced the usual suspects like MAF and MAP sensors (they were long overdue anyway), fixed several boost leaks and replaced the fuel filter but still no improvement. It was looking like it was either a failing injector or bad electronic wastegate on the turbo which are both fairly expensive things to resolve.

I was always of the opinion that injector cleaner was snake oil too but by chance I stumbled across a YouTube video where they took a couple of really old high mileage cars, ran them on a dyno then carried out several service items like changing spark plugs, oil, filters and finally fan a tank of fuel system cleaner though. Each step was followed by another run on the dyno and each step resulted in single figure horsepower gain including the fuel system cleaner which I think revived around 5hp from the engine. I found plenty of other videos with some fairly convincing tests and all appeared to show some improvement and none looked obviously sponsored by Techron.

So I bought a pack of Techron diesel cleaner from Costco for £10. Treats 16 tanks of fuel in total, I'm only 2 tanks through it and already the issue is completely resolved. Really didn't expect it, but I'm happy with the results.

My Z4 has new injectors courtesy of the warranty so no need to use any in that car just yet.

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Rough idle and injector cleaner

Post by Smartbear » Mon Jan 14, 2019 12:26 pm

I wonder if those with injector issues are using super-unleaded or normal fuel?
In theory the detergents in super should prevent this sort of thing :?
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R.E92
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Rough idle and injector cleaner

Post by R.E92 » Mon Jan 14, 2019 12:34 pm

Smartbear wrote: Mon Jan 14, 2019 12:26 pm I wonder if those with injector issues are using super-unleaded or normal fuel?
In theory the detergents in super should prevent this sort of thing :?
Rob
I've always used premium fuel in the Z4, purely because the tune requires it.

Injector issues in the 35i are common regardless of fuel, age and mileage of the cars. BMW now have a new revised injector design that is less prone to failure.

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Gaffa22
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Rough idle and injector cleaner

Post by Gaffa22 » Mon Jan 14, 2019 12:53 pm

Well it does make you wonder how many injectors have been replaced that just needed a clean

I am absolutely certain my injectors were leaking which is what can cause the rough idle, as the spark plugs get wet because of the excess fuel in the cylinder.
Admittedly mine were not leaking too bad, as it only ran rough if stood for more than two weeks.
But I am also convinced that either the premium fuel or the additives, or a combination of the two, cleaned what ever deposits were causing the leaks

In which case I believe its definitely beneficial to run our cars on premium fuels
2010 E89 35i DCT
2017 Honda CBR1000RR fireblade
2016 Honda VFR1200F
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