Misfire no CEL no Codes

[mr gee]

I found my Beetle (CTHD) was affected by the latest VW campaign 35E5 thanks to your last post. Will give VW a call tmr and find out whats that about

[jrpug407]

Hi there Hawk and the rest,

Hope you guys are all ok it's quite unfortunate that we've been experiencing these crazy endtimes scenario, I believe this is the closest we who are currently alive have come to the end.

Never has anyone living experienced this sigh anyways just to update the grp I was scheduled to send my car in to investigate the misfires etc, when the pandemic went out of control.

The gov has enforced an MCO (movement control order) all businesses to close for 28days pending which if cases drop then they'll lift the ban praying and hoping it will.

I did more searching up found on a ford forum that cold or random misfies could be due to a failing valve spring. In another vw forum some say it could be due to a faulty PCV valve too. I'll try to paste those links here.

Till then guys stay safe take care of yourselves

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Ok here's some updates with regards to the misfires.

Throughout MCO/lockdown that's roughly abt 40days for us I couldn't use the car that much occasionally a grocery run. However I have warmed the car once every 2 days or so.

Noticed that the during cold starts the car vibrates then fizzles off to a smooth idling so this has been my issue throughout the lockdown.

After all this time my fuel finally ran out which means it's been in the tank for at least 20 ought days or so I finally refueled the car on Saturday and today when I started the car (cold start) to my surprised it didn't vibrate like it did it was smooth.

Could be the fuel then? I will update this page soonest when I'm able to do a OBD 2 and will share the results here.

Take care all keep safe

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[tigger73]

Certainly could be fuel related if you had some lower octane fuel can certainly cause misfires/pinging.


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[jrpug407]

Hi all

I finally got around to service my Jetta mk6 as for the misfires it could be down to the Chinese made obd 2 that I've been using as the garage still can't detect misfires.

That being said there a new problem that just popped up right after servicing the car, it idles high at P position abt 1000rpm like as though you're still stepping on the throttle I tried a light tap on the throttle and it went back to normal 745rpm.

Could it be a faulty throttle sensor? It feels like the throttle is stuck and upon tapping on kinda releases it.
Not sure what to make of the problem.

Manage to get a video of it will try to attach to this post.https://cloud.tapatalk.com/s/5ef0de00...622_230826.mp4

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[The_Hawk]

I believe it will run richer and noisier on startup until it warms up, although clearly not the case here as it's 28C and the engine appears warm.

Revs will also sit higher if the AC is on (does that change things?).

PS. Fix the bulb.

[jrpug407]

hahahahaha Hi Hawk yea the change blub indicator has flashed for some weeks now, would need to change that this time round.

You've describing the way my car starts up (first start or cold start) yes that's normal, but the problem I'm describing here is an unusual one happens after the running the car and once parked the rpm sorts of notch up a little and maintains at 1000 rpm doesn't go down to normal levels ie 730 ish unless I tap on the pedal a few times. It's due back to garage next week will update you as to the outcome.

Jumping to other topic here I found that the abs esc lights have come on too which the garage indicates the wheel sensors are faulty so gonna get that change too. Here I'm asking if the abs sensor lights up obd2 is supposed to pick up the fault right? ....Mine doesn't sigh

Anyways how have you been doing Hawk hope all is good




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[jrpug407]

My fuel consumption is all over the place because it doesn't get driven. When it's only back and forth to the shops it can be as high as 12L/100km, on a trip that is down into the 7's. If I drive a decent distance it's more like 8.x around town.

I wouldn't say I've had any uneven acceleration or lurching and nothing at high speeds, so something doesn't sound right there.

Ok it's be awhile since I posted an update on the misfires my car is plague with. The walnut blasting I had done twice at the previous garage didn't help much.

In short *carbon build up* on the intake manifolds especially on the valves and *vacuum leaks* vent hose leaking breather valve
vacuum Hose & air Hose cracked and leaking after 9yrs had to be replaced these were the main culprits.

I had taken the car to another garage and the mechanic took his time to work on the car abt 12days @1.5k bill

As it stands, cold starts spluttering and excessive vibrations are no longer obvious, the engine starts up like a charm runs really well too.

However, that being said I maybe in the same boat as Hawk those annoying misfires are still present on cyc 1 according to OBDll, but this time at very low counts unlike before also those intermittent vibration felt under the seat is still noticeable.

So it's a paradoxical situation the problem by large is solved but not entirely so.

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[The_Hawk]

It does seem that one or two misfires on a fairly consistent basis is just how it goes for this little engine. There are lots of different ideas on what could be the root cause and I've read about people trying all the fixes with no definitive results.

I'd like to replace the coils with R8 ones for a stronger spark (one of the causes apparently being that the fuel injector blows out the spark). You need an adaptor to get them in there and the wiring needs to be modified (switch around the pins on the ignition coil plugs) before they work, but they end up being about AU$500 including shipping and customs (€187.40 for the parts and €119.53 for shipping for a total of €306.93).

Set of R8 coils With Adapter 1.4 TSI - Ignition Adapters - Adapters - Products

... yet again I have them in my shopping cart... but with the state of the world currently, I might just wait and see how things pan out before ordering things from Greece


edit: although a little googling says they are available here from one of our ex-sponsors here in Australia:
Volkswagen Audi Skoda 1.4 TSi R8 Coils Adapter Black RTMG Performance - Euro Car Performance & Electronics Upgrades

It works out to be a little bit more expensive at $560, but it's local and supports Australia business.

Damn you tempting things!

[jrpug407]

It does seem that one or two misfires on a fairly consistent basis is just how it goes for this little engine. There are lots of different ideas on what could be the root cause and I've read about people trying all the fixes with no definitive results.

I'd like to replace the coils with R8 ones for a stronger spark (one of the causes apparently being that the fuel injector blows out the spark). You need an adaptor to get them in there and the wiring needs to be modified (switch around the pins on the ignition coil plugs) before they work, but they end up being about AU$500 including shipping and customs (€187.40 for the parts and €119.53 for shipping for a total of €306.93).

Set of R8 coils With Adapter 1.4 TSI - Ignition Adapters - Adapters - Products

... yet again I have them in my shopping cart... but with the state of the world currently, I might just wait and see how things pan out before ordering things from Greece


edit: although a little googling says they are available here from one of our ex-sponsors here in Australia:
Volkswagen Audi Skoda 1.4 TSi R8 Coils Adapter Black RTMG Performance - Euro Car Performance & Electronics Upgrades

It works out to be a little bit more expensive at $560, but it's local and supports Australia business.

Damn you tempting things!

I was recommended by the pervious garage to change coil packs as a solution to fix the misfies. They gave me 2 options for the R8 ones OEM or originals which were double the price, went ahead with the oem ones sadly that didn't resolve the misfires.



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[The_Hawk]

While new coils might give a better spark than old ones, as long as they are working I can't imagine there is any real improvement replacing them with new ones... the whole point was the R8's was because they (supposedly) provide a stronger spark. Same reason people upgrade them on the GTI's as they turn up the power.

I do recall reading about people who did the upgrade and still saw misfires anyway... so who knows! If I remember correctly, part of the CTHD update was to move the injector further away from the spark plug than in the CAVD engines to help with misfires.