Cylinder misfire issue

[sled14]

Hello

I'm having an issue with my 2017 A3. I was previously gettin the code P2188 (System too rich at idle) along with P0900 (Random/multiple cylinder misfire detected), P0302 and P0303 (Cylinder 2 & 3 misfire). Looking at this issue online, it seemed the high pressure fuel pump could be the culprit so I replaced that today along with oil change and filter.

Started up, drove 10 minutes and parked, everything ran fine and no codes. Tried starting up 10 min later and it wouldn't, had to try again then it started. Drove for a minute, came to a stop and the car died. Took a couple starts then it idled fine. Drove for about 20 minutes and it wasn't doing it again.

Now every time I start, it takes 2 to 3 start attempts before it starts. The P2188 code went away but I'm now getting the codes P0300 (Random/multiple cylinder misfire detected) and P0303 & P0302 (Cylinder 3 & 2 misfire, respectively).

I'm thinking changing the ignition coils and plugs next but was hoping to hear you alls opinion on this issue. Thanks!

[EthanS]

Hello

I'm having an issue with my 2017 A3. I was previously gettin the code P2188 (System too rich at idle) along with P0900 (Random/multiple cylinder misfire detected), P0302 and P0303 (Cylinder 2 & 3 misfire). Looking at this issue online, it seemed the high pressure fuel pump could be the culprit so I replaced that today along with oil change and filter.

Started up, drove 10 minutes and parked, everything ran fine and no codes. Tried starting up 10 min later and it wouldn't, had to try again then it started. Drove for a minute, came to a stop and the car died. Took a couple starts then it idled fine. Drove for about 20 minutes and it wasn't doing it again.

Now every time I start, it takes 2 to 3 start attempts before it starts. The P2188 code went away but I'm now getting the codes P0300 (Random/multiple cylinder misfire detected) and P0303 & P0302 (Cylinder 3 & 2 misfire, respectively).

I'm thinking changing the ignition coils and plugs next but was hoping to hear you alls opinion on this issue. Thanks!

Yes I would recommended changing the plugs.

I've encountered cylinder misfires across multiple cars before just due to bad plugs...make sure they are gapped correctly too

[mroberte]

You need to address the car dying first. This is most likely the hpfp is installed incorrectly for it too be hard starting and dying at idle. Have you been checking your fuel pressure too/logging to confirm everything too?

I would check your sparkplugs too, however, address the first prob to isolate.

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[MikTip]

What are you using to see these codes? VCDS?

[sled14]

I used just a cheap OBD reader with the OBD Fusion app.

I replaced the spark plugs yesterday and with reinstalling the ignition coils I moved them all over 1. Now instead of cylinder 2 & 3 misfiring, I'm getting cylinders 1 & 4 misfiring.

The car drives fine under throttle, just starting occasionally it takes 2 tries. I should get the ignition coils tomorrow so will go from there.

Thanks for the input!

[MikTip]

https://www.audizine.com/forum/showt...ures-Attached)

[sled14]

I replaced the coils today. Driving it around it seems fine then the OBD reader starts showing pending codes P0300, P0301 and P0304 (Cylinder 1 & 4 misfires).

I pulled up to get gas and after shutting the car off and walking to the fuel door I notice there is fuel dumping out of the right side of the tank, running down the wheel well of the right-rear tire. It slowed then stopped after a couple minutes, then I removed the fuel cap and a noticeable suction/vacuum started for another minute or so.

Any ideas where to go from here? Thanks again for helping

[mroberte]

Your N80 EVAP actuator might need to be replaced.

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[sled14]

Could this be causing the misfire codes as well as causing the fuel tank to overflow?

[MikTip]

I replaced the coils today. Driving it around it seems fine then the OBD reader starts showing pending codes P0300, P0301 and P0304 (Cylinder 1 & 4 misfires).

I pulled up to get gas and after shutting the car off and walking to the fuel door I notice there is fuel dumping out of the right side of the tank, running down the wheel well of the right-rear tire. It slowed then stopped after a couple minutes, then I removed the fuel cap and a noticeable suction/vacuum started for another minute or so.

Any ideas where to go from here? Thanks again for helping

Yes

Do you have a yellow check engine light come on?

If not, your OBD reader is reading the DSG interrupting ignition to shift...

If you dont have a check engine light and specific code for miss-fire...theres nothing wrong. The ECU will alert you if there is an issue.

You need to stop filling the gas tank up all the way!

It has a initernal system of tubes that are now flooded.

The gas pouring out the back is the charcoal canister up behind the right rear fender
liner...its full of gas.

You need to allow the system time to dry out.

Stop filling the tank all the way up!

It should return to normal after a couple weeks if its allowed to dry out...

[PaperLion]

Curious if you are fueling beyond initial stop from the pump?

[sled14]

Yes the check engine light did come one. After I changed the above mentioned parts, I cleared the faults. I drive for about 10 minutes and the "cylinder misfire" messages show pending on the OBD. A little while later the check engine light comes on and those codes are showing under "permanent".

The issue started happening when the tank was less than half full. When I mentioned going to the gas station, I saw the fuel dumping out so waited for it to stop. The tank was at that point around a quarter or less full. Taking the gas cap off I heard the pressurization equalizing in the tank, waited a minute for it to slow then put the cap on, then more fuel started dumping out. Once that was finished I put just 2 gallons in to be able to get it home and that was it.

I won't be driving it for over a week now but am wondering why the charcoal canister would fill up to the point of overflowing? This is my wife's car and she says once the gas pump clicks off she stops filling the tank.

At home I let it run a bit but never saw more fuel coming out. I did notice if its running a while, taking the gas cap off I hear the pressurization equalizing more than I've ever heard before. Does it for a couple minutes or so.

Thanks again

[MikTip]

Yes the check engine light did come one. After I changed the above mentioned parts, I cleared the faults. I drive for about 10 minutes and the "cylinder misfire" messages show pending on the OBD. A little while later the check engine light comes on and those codes are showing under "permanent".

The issue started happening when the tank was less than half full. When I mentioned going to the gas station, I saw the fuel dumping out so waited for it to stop. The tank was at that point around a quarter or less full. Taking the gas cap off I heard the pressurization equalizing in the tank, waited a minute for it to slow then put the cap on, then more fuel started dumping out. Once that was finished I put just 2 gallons in to be able to get it home and that was it.

I won't be driving it for over a week now but am wondering why the charcoal canister would fill up to the point of overflowing? This is my wife's car and she says once the gas pump clicks off she stops filling the tank.

At home I let it run a bit but never saw more fuel coming out. I did notice if its running a while, taking the gas cap off I hear the pressurization equalizing more than I've ever heard before. Does it for a couple minutes or so.

Thanks again

Yes the charcoal canister can fill up. Indicated by gas coming out from right rear fender as thats the drain tube location for the charcoal canister...



The gas needs to be shut off before the pump clicks.

The internal system inside the tank is flooded. I have pictures of this system I can post later...

Only fill the tank to half until the system clears out.

Removing the gas cap allows the gas vapors to escape that normally go thru the charcoal canister...however since its flooded(gas coming out right rear fender) the vapors are trapped...

You can remove and or replace the charcoal canister...if you remove it...allow it a couple days to dry out.

I replaced mine...drove it for a couple weeks only filling to 1/2...it cleared on its own.

[MikTip]

This is inside the fuel tank. Its a system of hoses and boxs that are part of the vent system...somehow it gets flooded...not sure how but it seems to if the tank is filled to the max.

Same thing your experiencing happened to me. I stopped filling the tank for a couple of weeks. Ran it to empty. The system self-fixed itself.

[sled14]

Thanks, I'll try that next. Regarding the original issue I had, could this have been a cause of the check engine light for the P2188 "system too rich at idle" and then later the various cylinder misfires?