Almost there - first start rough idle

Cranked the car on Saturday with the plugs and coils still out after spraying WD-40 down the plug wells. After this we didn’t see any crud or anything in any of the wells so I proceeded to install the plugs and coils. I went to start the car last night and it turned over but it was running really really rough like surging violently, I only let it run for a few seconds. Keep in mind this thing hasn’t been started since December. I still need to connect the throttle bodies and air intakes but otherwise I’m assuming I have some codes from when I cranked it on Saturday - should I be clearing these first?

https://pastebin.com/pfzNKc05

What was done to it. The TB’ not plugged in would be cause for rough running I would have to say. As for codes I would clear all after plugging everything back in and go from there.

So i’m buttoning things up after doing the following major pieces of work:
-carbon clean
-water pump
-alternator
-new plugs & coils
-new intake manifold

A myriad of o-rings and seals were also replaced along the way. I had run it sans throttle bodies the last time I drained coolant - and wasn’t seeing this behavior. I was thinking the same thing but wanted to post just to see everyone else’s thoughts as well. It was quite alarming just how rough it sounded and felt.

Yeah so I connected the throttle bodies and hooked up my battery tender then cleared the codes - thing fired right up and was purring. Like night and day difference. Have an issue with 1 pin on the driver headlight connector that I’m trying to replace before I can get the bumper and cover back on. Should be on the road this weekend. I think I’m going to start another post specifically for my car with before, after and along the way pics.

This is not surprising. Throttle bodies at idle are almost all the way closed. You had them off creating a wide open condition. Assume you also had not connected a few things. No doubt the engine computer had no idea what the hell was going on. I’m surprised it ran at all.

So after what was essentially the first drive I took it for about an hour or so drive and had a CIL come on. There seem to be no drivability symptoms matter of fact the car seems to run noticeably better than before. But I’m again seeing these Ignition Circuit errors on every cylinder. This makes me feel like perhaps something with the ignition harness. What do you guys think?

https://pastebin.com/Nn4JDnMq

So these open Ignition circuit errors are not going away nor is my CIL but the car is driving fine. Even cold starts are pretty smooth. I’m not seeing much regarding these errors for the ignition circuit on here or the web but what I do see references a bad coil or plugs - both of which are brand new from JHM. Is is possible I could have not cleaned up any of the ground connections well enough particularly the alternator? Would plug gappings yield this error? Other people I’ve talked to have said if it runs well to just keep driving it and perhaps let the ECU relearn itself. I’m fine doing that but would love to hear from some of you guys as far as your thoughts.

What is the status of the battery? Your voltage seems low on those errors.

What is the condition of your wiring harness?

I think you are on the right track, you have an electrical issue of some kind, but the battery voltage looks funky to me. What does the battery show for health?

Ed

The battery did occur to me as well as I’ve seen other posts on here referencing odd behavior. I thought it was fine but I’ll double check when I get home. It was sitting for a month or two but I took it to Autozone and they tested it fine and then I put it on a tender for about another 2 months after that.

…the ignition harness wasn’t plugged in nor were the air flow sensors in the airboxes. At least it was something simple. In the meantime I’ve developed a nasty coolant leak that after pressure testing was able to track down to the front coolant pipe I removed for the water pump job. It’s where that pipe bolts up to the oil pan and I’m wondering if I didn’t quite tighten enough as it definitely appears to be streaming from that inner really hard to reach bolt. I’m also praying that I didn’t cross thread it as I really really took time with that bolt to ensure I avoided just that. Bentley spec was 8nm and then a 90 degree half turn I believe. Does that sound right?

The good news so far was the fix was just plugging things in.

Some of those smaller bolts you have to be careful. I would back the bolt all the way back before trying to tighten the bolt again. 8nm or 9 should be more than enough.

Rule of thumb on some of these. I use the snug then 1/4 turn.

So in trying to snug it in there a little more I ended up stripping out this bolt…again. Not as bad as the first time so hopefully getting it back out won’t be as troublesome. In doing so though I did get another quarter turn on it which did nothing to stop the leak. At this point I have to believe worst case is I had already cross threaded the damn thing. If that is the case how big of a problem am I looking at? I can’t imagine having to retap (or if that’s even possible) to where this appears to bolt into the upper oil pan.

Is this the bolt on the lower coolant pipe that attaches behind the oil cooler?

If so that is a real challenge to get to. I assume (if i remember correctly) you refreshed the O ring there?

Ed

Ed, yes & yes. Specifically the bolt that’s closer to the block, the PIA one. After pressure testing I have a steady drip that appears to be coming from that bolt. I did replace the o-ring on this pipe and this particular bolt is also new (stripped the original one) N 91032702. I’m gonna try and back this one out and see if what I can tell. Odd thing is I drove the car for 2 days prior to any leaks like this so I am not sure what may have happened at this point.

What psi should I be limiting myself to when pressure testing? I was hitting just below 15psi before the dripping started.

Would these bolts go into the water jacket?

After spending more time looking around today and doing another pressure test I was able to tell there is a spray coming from a hose on the oil cooler. I’m almost positive it’s the hose closest to the rear (# 2 in the diagram).
2020-08-12 22_34_01-eBahn_data_AUDI-C-C6-Front Coolant Pipe.pdf - Profile 1 - Microsoft​ Edge
It’s then running down and hitting that far screw on the coolant pipe. With that said the hose appears to connect into a Y underneath the passenger side headlight which stems off to two other places. I’m not sure if I need to replace all these pieces as one or what but I’m looking for part numbers now. if anyone has any quick links that would be much appreciatedt.

I ended up getting the part for this - 4F0 819 378 H - from ECS. There is also a third line that connects off of that part that runs back up to a black metal line right underneath the coolant res I’m going to replace as well. This should do it for any hoses that I would have to deal with on the front side. Stupid mistake not replacing this one to begin with when I did the oil cooler stuff. I suspect I got a little overzealous with my pick tool and punctured it just enough that I was actually able to drive it for a few days before the pressure finally sprung a leak in it.