Long drive after using fuel treatment, now got EPC light on

**A4B6Cab** · 12-09-2018,07:42 PM

Drove about 150 miles yesterday in the 3.0 V6 petrol Audi, and put a can of Cataclean in before we set off. Went like a dream. Returned to it last night to drive home, and it took ages to fire up. Turned over at full speed (not like a flat battery sound) but took 10 or 15 seconds to start, and didnt feel right on the journey home. Idle revs sat now sitting 1200rpm instead of the usual 800 ish.

Going to scan it over the weekend when i can borrow a scanner, but any ideas please guys? Could the can of cleaner highlighted an issue?

Used her today and now the engine management light is on as well.... help

**calum** · 13-09-2018,07:12 AM

Originally Posted by glenbat

Drove about 150 miles yesterday in the 3.0 V6 petrol Audi, and put a can of Cataclean in before we set off. Went like a dream. Returned to it last night to drive home, and it took ages to fire up. Turned over at full speed (not like a flat battery sound) but took 10 or 15 seconds to start, and didnt feel right on the journey home. Idle revs sat now sitting 1200rpm instead of the usual 800 ish.

Going to scan it over the weekend when i can borrow a scanner, but any ideas please guys? Could the can of cleaner highlighted an issue?

Used her today and now the engine management light is on as well.... help

Check the pcv valve, they usually break and stick open, resulting in high idle, lumpy running. It basically upsets the fuelling, I think the cataclean is unrelated.

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**A4B6Cab** · 13-09-2018,07:10 PM

Originally Posted by calum

Check the pcv valve, they usually break and stick open, resulting in high idle, lumpy running. It basically upsets the fuelling, I think the cataclean is unrelated.

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Thanks Calum, sorry, whats the pcv valve and how would you check it?

Also, drove it to work this morning and the EPC light no longer on, but the engine management light is still on. Car seems to be starting better again too, not sure if related or not?

**Crasher** · 13-09-2018,09:24 PM

Try taking the oil cap off with the engine running. Cataclean has been known to melt cats, does it pink when you accelerate?

**A4B6Cab** · 14-09-2018,02:56 AM

Originally Posted by Crasher

Try taking the oil cap off with the engine running. Cataclean has been known to melt cats, does it pink when you accelerate?

Thanks Crasher, took the oil cap off while it was running and you could hear the vacuum change and compensate for the cap being off.

Had no idea about the cataclean, I'll avoid it in the future. Will let you know about pinking when i use it in the morning. i managed to get it scanned tonight and came up with:

16805 Warm up catalyst Bank 1 Efficiency Below Threshold P0421 Upper Limit Reached

16706 Engine RPM Sensor - G28 No Signal P0322 No Signal/No Communication

17772 Cylinder 4 Ignition Circuit Open Circuit P1364 No Signal/No Communication - Intermittent

**Crasher** · 14-09-2018,11:49 PM

So it did not try to rip the oil cap out of your hand and it looks like the right hand cat is not happy, it could be burnt out due to an ignition problem but that says bank 2 not bank 1.

**A4B6Cab** · 19-09-2018,11:05 AM

Originally Posted by Crasher

So it did not try to rip the oil cap out of your hand and it looks like the right hand cat is not happy, it could be burnt out due to an ignition problem but that says bank 2 not bank 1.

It did try to suck the cap back into the hole, yep. Guess that means thats working as it should?

I swapped coil pack 4 for a spare i had indoors (because of the 17772 code) and it was fine for a few days, but today its a bit lumpy again. No warning lights on dash though. I did notice a little oil in spark plug 4 hole, so cleaned it out best i could, unsure if it comes from the mrs being a bit messy when topping her up with oil (there was a little in the rocker cover securing bolt recess nearest the oil filler too), or could it of comeup from the sparkplug hole itself??

**Crasher** · 19-09-2018,11:52 AM

The cap should not have much suction behind it, just a gentle pull. If it is a high vacuum it means the crank case breather has failed.

**A4B6Cab** · 19-09-2018,01:31 PM

Originally Posted by Crasher

The cap should not have much suction behind it, just a gentle pull. If it is a high vacuum it means the crank case breather has failed.

Thanks again, was more of a gentle pull as the cap was 1/2" from being located fully, certainly didnt require any effort to keep it out the fill hole

What do you think about the oil in sparkplug hole 4 (front pass side)? New rocker cover gasket?

**Crasher** · 19-09-2018,04:25 PM

Yes, common problem. I did a service on something VAG (been to bed since) a few weeks ago and I had to use the vac pump to drain the plug bores and then blow the holes out with an air line and brake cleaner before I could take the plugs out.