cold start question, sloppy idle

[speedtrapped]

Well its finally getting cold enough here, last several days after coming off train, the temps have been 25-30 degrees, car sitting 12 hours each time. last 2 starts(cooolllddd) the car initially idles poorly, sputters, revs 500-600, now usually i know the ecu understand temps, and sends more fuel and pumps more air resulting in hbigher idle on warm up. Btw, I can rev engine once and idles fine. No other issues, but I wonder and tonight i will check to see if secondary pump turns on, on my S8 the air pump is loud, i will have to check and see.....is this likely culprit? no CEL, but maybe I should pull the vagcom out?

[speedtrapped]

Well, I pulled codes tonight and cleared them.
18010 - Power Supply Terminal 30: Voltage too Low
*********** P1602 - 002 - Lower Limit Exceeded - Intermittent
16955 - Brake Switch (F): Implausible Signal
*********** P0571 - 008 - Implausible Signal - Intermittent
16814 - Catalyst System; Bank 2: Efficiency Below Threshold
*********** P0430 - 001 - Upper Limit Exceeded - Intermittent
16684 - Random/Multiple Cylinder Misfire Detected
*********** P0300 - 008 - Implausible Signal - Intermittent
16688 - Cylinder 4: Misfire Detected
*********** P0304 - 008 - Implausible Signal - Intermittent
16690 - Cylinder 6: Misfire Detected
*********** P0306 - 008 - Implausible Signal - Intermittent
Readiness: 0000 0000

Since Thursday it has warmed up and I have had no idle or start up issues. I will drive her tomorrow and pull codes to see if they return. Any thoughts?

[V8weight]

18010- this just means the battery has been disconnected, and the ecu observed a no voltage event at terminal 30 (the starter). Disregard this.

16955- this usually means you need a new brake light switch, although it seems you Eurocharged guys are all throwing this code? Does your cruise function, and are your brake lights staying on when the car is off?

16814- This means your bank 2 downpipe is no longer filtering properly, it doesn't effect the way the car runs. Both of mine were replaced around 65k, they live a hard life in this car. Disregard this for now.

16684- this is triggered by default any time you have a misfire, even if it's only in one cylinder, disregard this for now.

16688, 16690- You probably need these two coil packs, buy all 8, they're cheap. At your mileage, they've done their due diligence.

[speedtrapped]

Pat, Ty vm for the response, ok my brake light etc no longer on, pulled my cable overnight. Now I'm really stating to get pissed at the Indy that did my service, because I had him(paid for) replace all 8 coil packs when I did my 75k TB service. I caught that he did not replace my fuel filter by the tank. He replaced no questions asked, although he did try to tell me that the dirty filter on the back was replaced 'they get dirty quick'.....his tech standing next to me agreed with me and said nope, that's old. So pat if he did replace coil packs, any reason why they would fail so quick? Or did he hood wink me?

[V8weight]

Well, either he didn't replace your coil packs, or you have two bum injectors. I'm actually hoping for you that they didn't replace the coils. Having recently replaced an injector myself, the list price is over $300 a piece.

[V8weight]

This could be any number of things actually. If the coil packs are indeed new, they're going to have to test the wiring to the coils for continuity. If this checks out, they should check fuel pressure and injector pulse. If this checks out ok, then maybe pull the fuel rail and visually inspect injector spray.

[speedtrapped]

Ughhh, I found this guy by way of a very reputable reference and the guys quote was amazing, now I am starting to feel like I will be mouthing, ya get what u pay for.

[V8weight]

Ughhh, I found this guy by way of a very reputable reference and the guys quote was amazing, now I am starting to feel like I will be mouthing, ya get what u pay for.
You're saving money now. ;)

[speedtrapped]

Never time to do it right, always time to do it over.

[hahnmgh63]

If the coil packs were done what kind of plugs did they install? I would stick with the stock NGK's and stock plug gap. Running too wide of a plug gap puts extra strain on the coils.

[V8weight]

If the coil packs were done what kind of plugs did they install? I would stick with the stock NGK's and stock plug gap. Running too wide of a plug gap puts extra strain on the coils.
Good point. Especially when your tuned, the plug gap becomes very critical.

[speedtrapped]

Mechanic swears coil packs changed, they do look new, shiny and no dust. He said he used Bosch plugs, PFR7Q for turbo applications. Codes have not come back, will be very cold here in next couple of days, so it could be interesting. Could it be so cal car coming to cold NE?

[DHall1]

Is that the stock Bosch plug for the RS6?

I dont like to change from the factory plugs.

[V8weight]

PFR7Q is the NGK number for the factory plugs.

[speedtrapped]

Yes, they ate stock

[ttboost]

If the coil packs were done what kind of plugs did they install? I would stick with the stock NGK's and stock plug gap. Running too wide of a plug gap puts extra strain on the coils.


Good point. Especially when your tuned, the plug gap becomes very critical.


Yup. Should be squeezing the gap down on boosted cars with higher than stock boost levels. Stock is probably .032ish, close it up to .028 or more...I have mine at .026 on my other car. Haven't had the RS6 plugs out yet, but they will be closed up a smidge.

[V8weight]

Yup. Should be squeezing the gap down on boosted cars with higher than stock boost levels. Stock is probably .032ish, close it up to .028 or more...I have mine at .026 on my other car. Haven't had the RS6 plugs out yet, but they will be closed up a smidge.
I run mine at .028. There are a lot of discrepancies out there regarding the stock plug gap (probably due to the fact that they technically shouldn't be gapped). I've heard .032, and .029 as well.

[ttboost]

I run mine at .028. There are a lot of discrepancies out there regarding the stock plug gap (probably due to the fact that they technically shouldn't be gapped). I've heard .032, and .029 as well.

I agree. And most people (mechanics included) don't even check them out of the box. Could've been dropped on the floor and have a plug closed up!!!

[ben916]

I agree. And most people (mechanics included) don't even check them out of the box. Could've been dropped on the floor and have a plug closed up!!!

I was waiting for this topic to come up as I was thinking of asking the gap on the sparkies as I have been looking, perhaps I am glossing right over it, but couldn't locate the OEM gap on them...

[hahnmgh63]

Stock calls for .032 gap and the same for the RS6+ which is running a touch more boost so it is probably fine, I round my gap down to .030" as I imagine the factory ignition has a bit of reserve power although I've pulled stock plugs out of the box before and checked the gap and 7 out of 8 were fine but but there was that one that was at about .040 ~ .044. I've changed the plugs twice in both my RS6 & in the tt among other cars and I check the gap of every plug. I could easily see a shop trying to hurry a job and either just dumping them all in or at the most checking the first one and finding it was close and dropping the rest of them in. Always check the gaps.
And yes Dave, the stock plugs for our cars are NGK, Audi went away from Bosch in most of their cars around 1998~2000 timeframe to NGK but on their newest cars many of the models are now returning to Bosch plugs again? NGK PFR7Q is the OEM plug for our car.

[ttboost]

I was waiting for this topic to come up as I was thinking of asking the gap on the sparkies as I have been looking, perhaps I am glossing right over it, but couldn't locate the OEM gap on them...

I've seen everything from .032 to .044. I'm pretty comfortable putting mine at .028.

[speedtrapped]

Ok I will check gap, question can any one lead me to a site, genuinevwaudi? I need a MAF plug for the harness with pigtail. The driver side plug is so loose, it's only a matter of time before the wires fray or split.

[hahnmgh63]

Go to www.worldimpex.com (http://www.worldimpex.com) and try each of these two part #'s and look at the pics that come up and see which on you need. Or you can try calling them or www.genuinevwaudiparts.com (http://www.genuinevwaudiparts.com) and ask them which will work. Genuine VW Audi tends to be a little cheaper usually: 1J0 973 775 A or 1J0 973 705 they are VW part #'s but the parts should be no different than the Audi version, and possibly a dollar or two cheaper.

[speedtrapped]

Go to www.worldimpex.com (http://www.worldimpex.com) and try each of these two part #'s and look at the pics that come up and see which on you need. Or you can try calling them or www.genuinevwaudiparts.com (http://www.genuinevwaudiparts.com) and ask them which will work. Genuine VW Audi tends to be a little cheaper usually: 1J0 973 775 A or 1J0 973 705 they are VW part #'s but the parts should be no different than the Audi version, and possibly a dollar or two cheaper.
Ty I appreciate it

[speedtrapped]

perhaps...ever since I removed my intake(3x) to replace vac lines and run vac line for manual boost gauge I seem to have the problem, cold start issue(again this am). MAF dtc...honestly I am going to replave both MAF connectors, driverside is so jammed in that where the wires meet the plug there frayed and exposed, the passenger side connector is crumbling interally.

[ttboost]

Vacuum leaks are a nightmare on these newer cars...

[speedtrapped]

true, but vac line replacement was just preventative, i had no leaks. the turbo gauge was a sloppy mistake i made so i had to go back under the carbon box 2x, so all in 3x...basically my driver MAF is wedged next to the harness that comes out of the firewall(either this is a really poor design by audi) or someone has been back there before and rerouted MAF line.....all my refitting carbon box back on brittle connections has screwed the connections up.

[speedtrapped]

car at my mechanics(indy), both MAF connections being rewired w/ new connectors, left side MAF had NO signal, wire was shorting, plugs all gapped .28....should solve cold start up issue.

[ttboost]

I bet you notice a difference...

[speedtrapped]

i would think as well, apikol rear diff holder going on, and just got my fedex tracking # from deutscheland..........

[JSRS6]

car at my mechanics(indy), both MAF connections being rewired w/ new connectors, left side MAF had NO signal, wire was shorting, plugs all gapped .28....should solve cold start up issue.

I think i will be removing my spark plugs and checking the gap very soon as well...

[JSRS6]

i would think as well, apikol rear diff holder going on, and just got my fedex tracking # from deutscheland..........

What do you have coming from the motherland? catless milltek dp's? wagners?

[speedtrapped]

cooler breezes.....seller's name rhymes with smarsten lagner......

[JSRS6]

cooler breezes.....seller's name rhymes with smarsten lagner......

You getting rid of your aux rads?

[speedtrapped]

i am going to remove them, but keep in case i run into issue in summer

[JSRS6]

In that case, you should be able to take a couple of short lengths of hose, the same id as the coolant hose, and simply connect the lower piping to the upper t-fitting on each side. Be sure and use a couple of hose pliers so you dont lose any fluid.

[speedtrapped]

Ty Josh....having fun driving your beast?

[JSRS6]

Ty Josh....having fun driving your beast?

Haha, is that a rhetorical question? Of course, it feels good to have her back.

[speedtrapped]

either or........oooppss wrong forum

[JSRS6]

Any chance you can make it down for the get together on the 15 of next month around dc?

[speedtrapped]

that might work, call ya offline

[JSRS6]

Cool, looking forward to the meet.

[speedtrapped]

Car is starting perfectly on cold starts, runs great. New MAF connectors did trick. Had to replace a torn boot, and worn tie rod. Back in the saddle and a happy man.