160 misfire and rough idle

[moulin12]

As for the slightly lumpy idle, I guess that's just how this engine is, may have to just live with it.


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As above, following a new set of injectors the lumpy idle disappeared on mine.

[greg7728]

New injectors are quite expensive and labour intensive/pricey job that I can't afford unfortunately, what did it cost u I heard about £400-500 including labour ? Lot of money if it doesn't fix the issue [emoji24]


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[moulin12]

Greg, I wasn't necessarily suggesting that you have the injectors changed - just simply noting that the lumpy idle isn't necessarily a feature of a 160 in full health.

In the five weeks my car was at the garage, I spent a great deal of time researching the engine issues for this unit (across the VW range). Whilst there are some very respected posters (not least RW1, who used to be on this forum) who found that correctly set up sparks plugs solved a number of the issues, there is some suggestion out there that the injectors on these cars - even up to 2011 models - are/can be a fundamental cause of the symptoms and catastrophic failures experience with this engine.

This is not to say that I wouldn't go down the route of changing SPs and Coils first. But I am suggesting that lumpy idle may well be a sign that the injectors are on their way out, and which longer term can result in engine damage.

The injectors on mine were changed under warranty, so I've no idea of the cost.

[blower]

Switch to Sainsburys 97 super unleaded, or Texeco super - these engine do not like shell v-power, Tesco momentum or Esso super, idle is more lumpy and can be surgy when moving off.
I'm not alone on this, the late and great RW1 came to the same conclusion some years ago.

I've had every fuel going in mine and there is a noticeable difference in idle, with v-power being the worst and Tesco momentum not much better.

The problem with the lumpy idle I believe is poor fuel ignition under lean idle conditions. It's not a misfire as such, as the spark is firing - but the air fuel mixture is hard to ignite properly with the weak small gap sparks on these engines. That combined with some intake coking affecting the air turbulence and hence mix at low air/fuel loads, adds to poor ignition. Seems, sainsburys 97 just ignites better under these conditions.

I've had all brand new injectors fitted to mine - made no difference to the lumpy idle. What does is the fuel, and also the smaller the gap the poorer the idle will be (to a point, too large a gap brings its own problems as RW1 found). Optimum spark gap size on these engines are 0.7mm to 0.8mm. Any less and idle will be worse, any more and misfires under high boost will occur.

[greg7728]

I'll try switching up fuels in addition to the Sparks and coils and hopefully that fixes it. Just would have thought VW would have recalled engines with such prominent issues


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[Roy_01]

Maybe its time to clean your intake manifold. There can be a big Carbon build op on the intake ports.

[greg7728]

At 20k miles I can't believe that the intake could need cleaning already. What the hell r VW trying to do to people - just want a car that looks after me when I look after it. My 1989 mr2 didn't give me this much trouble. I'll see what happens with the coils and sparks as hopefully that's what is causing the mis Fire. Maybe try some injector cleaner. [emoji24][emoji24]


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[Roy_01]

Your right that would be very weird with this low milage.
Its a shame this engines are so unreliable and have all sort of problems.
They should sort out this problem under warranty.

[greg7728]

Well I'll take the coils and sparks on the chin if that fixes it, if it doesn't and I've got to get injectors done I'll be hitting up warranty company - even if they only contribute it'll take some of the sting out of the tail for me. And if injectors don't fix it I guess it's taking engine apart and looking for damaged Pistons, however wouldn't have thought a damaged piston would only cause a very intermittent mis Fire reading (engine light to flash) if have thought if it was a piston it'd be misfiring all the time and running poorly like it was running on 3, but she still pulls well in all gears, just a lumpy idle.


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[blower]

If compression was ok, then your pistons will be ok and as you say a cracked piston ring will be putting that eml light on permanently with constant misfires and poor running.

[greg7728]

Had coils and sparks changed today. Guess wait and see still seems lumpy on idle, all be it not as much but maybe that's my mind playing tricks on me. Guess wait for another error light and see what happens.


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[blower]

I've not found a 1.4 TSI 160 that isn't a bit lumpy on idle, especially in damp/wet weather and it will also be worse if you run it in v-power, Tesco momentum etc.
It has a less lumpy idle on sainsburys 97.

If you get an EML again, get the codes read to see if its the same cylinder 4 - if so then its starting to look like an injector.

[greg7728]

Cheers blower. Hoping this is end of it, replacing parts is getting old and expensive lol.


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[moulin12]

[quote="blower"]I've not found a 1.4 TSI 160 that isn't a bit lumpy on idle, especially in damp/wet weather and it will also be worse if you run it in v-power, Tesco momentum etc.

quote]

Possibly it was the recommended fuel additive that I used for several tank refills that did it, but my experience was that v-power much reduced the lumpy idle. Can't compare the S97, however, since I didn't try it with this.

[janherko]

Switch to Sainsburys 97 super unleaded, or Texeco super - these engine do not like shell v-power, Tesco momentum or Esso super, idle is more lumpy and can be surgy when moving off.
I'm not alone on this, the late and great RW1 came to the same conclusion some years ago.

I've had every fuel going in mine and there is a noticeable difference in idle, with v-power being the worst and Tesco momentum not much better.

The problem with the lumpy idle I believe is poor fuel ignition under lean idle conditions. It's not a misfire as such, as the spark is firing - but the air fuel mixture is hard to ignite properly with the weak small gap sparks on these engines. That combined with some intake coking affecting the air turbulence and hence mix at low air/fuel loads, adds to poor ignition. Seems, sainsburys 97 just ignites better under these conditions.

I've had all brand new injectors fitted to mine - made no difference to the lumpy idle. What does is the fuel, and also the smaller the gap the poorer the idle will be (to a point, too large a gap brings its own problems as RW1 found). Optimum spark gap size on these engines are 0.7mm to 0.8mm. Any less and idle will be worse, any more and misfires under high boost will occur.

I was wondering what's the original gap setting on the 03C905601B...

the ones recommended by Revo:
http://www.revotechnik.com/product-deta ... 6/stage-1/" onclick="window.open(this.href);return false;
https://www.ngk.com/product.aspx?zpid=9352" onclick="window.open(this.href);return false;

have the gap set at 0.8mm.

Which are of better use, though?

[blower]

I've measured the original gap size on a new set between 0.7 and 0.75mm.

They are spec'ed at 0.8mm but sparks are rarely the size they say they are from new - they allow for a bit of gap increase over their life span, so the average gap size is what they are actually spec'ed at. A new set is usually a slightly smaller gap, and a set at the end of their life is slightly bigger than spec.

BKR7EIX do work on the 1.4 tsi twincharger, and some people suggest they are better for remapped cars.
I have found that the shorter length of these plugs do result in a more lumpy idle, due to a less efficient burn at low fuel loads.

If you are using the APR stage 1 map these plugs are essential - the shorter length of the plug helps keep the plug out of the flow of the injectors, APR maps run a lot richer than all other maps and under full load the fueling can be high enough to extinguish the spark of the stock spark plugs. Other maps such as REVO don't suffer from this problem.

[greg7728]

On this engine can someone tell me what their idle revs are please ? When I got the car it was lumpy, now had new engine and idle revs are about 800rpm slightly less, but doesn't vibrate through the seat anymore - is this normal idle rev range? I thought would idle at about 1000rpm ? Just looking for someone else with this engine to advise if mine is working how it should. Engine now feels fine, just looking to see what other people with this engine run at for comparison. Ta.


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[blower]

Correct Idle revs, as per VCDS are between 680 and 720...this will look around 700-800 on the tacho.

Your idle is in the correct range if its just below 800 on the tacho after it has settled down.....when you come to a red light it will hover around 1000 for a short while then drop to this lower level.

Gone are the days when engines idle'd at 1000rpm....emissions and all that.

[greg7728]

I see, this is my first modern car - always had classics, so emissions never really been a massive thing. lol. That's good it does look in that range, most importantly no lumpy idle, no vibration through the seat or steering wheel, sounds fine. Think I have a working car back! [emoji4]


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[janherko]

I've measured the original gap size on a new set between 0.7 and 0.75mm.

They are spec'ed at 0.8mm but sparks are rarely the size they say they are from new - they allow for a bit of gap increase over their life span, so the average gap size is what they are actually spec'ed at. A new set is usually a slightly smaller gap, and a set at the end of their life is slightly bigger than spec.

BKR7EIX do work on the 1.4 tsi twincharger, and some people suggest they are better for remapped cars.
I have found that the shorter length of these plugs do result in a more lumpy idle, due to a less efficient burn at low fuel loads.

If you are using the APR stage 1 map these plugs are essential - the shorter length of the plug helps keep the plug out of the flow of the injectors, APR maps run a lot richer than all other maps and under full load the fueling can be high enough to extinguish the spark of the stock spark plugs. Other maps such as REVO don't suffer from this problem.

Thanks man...
Nope, don't have any remap due to previous issues with my engine (rectified some 40.000km ago, fingers crossed) and the car is powerful enough with new pistons anyway.
Just about to have the service done in some 1000km so I ordered new plugs as well (got a pack for 50 euros delivered).