Hi all,

I'm hoping that someone can help me diagnose this non-starting problem with my car. Here's the info:

Model: 2000 Audi A6 2.8L (C5)
Milage: 142K

**Symptoms**

When functioning car gives off smell from engine area in first 5-10 minutes of driving.
Loosing coolant slowly.
Currently engine won't turn over / start.

**Recent History**

12/4/2012 - Notice low coolant during fluid check (note: coolant expansion tank and tubes were replaced 2 years ago)

12/6/2012 - Topped off coolant with G12 50/50 mix (continued to check over next few weeks - appears losing coolant slowly)

12/22/2012 – State Inspection - passes - no problems.

12/22/2012 – Oil change (at Valvoline) Valvoline Oil Filter V093, 5W30 SynPower Oil

12/23/2012 – Drive Boston to NY (5+ hours) – no problems

12/26/2012 – Notice strong smell, open hood to look for any smoke or noticeable signs of leak, while looking I snap brittle vacuum hose that leads from top of engine to the reservoir on drivers side (oops!)

12/27/2012 – Patch vacuum hose with a new piece and rubber sealing tape - seems ok.

12/28/2012 – Drive from NY back to Boston – no problems, even better than normal gas milage, no CEL.

12/30/2012 – When starting car idle very low, inconsistent, car won't go without revving. Stop car, rev in neutral for a while, let warm up. Idle seems to return to normal – drive to store and back no issues.

12/31/2012 – Car cranks but won't turn over or start - battery meter reads 12V with key in. Tried jump anyhow, unsuccessful. Weather fairly cold. Note: last replaced spark plugs and wires 2-3 years ago. Note: Valve cover gaskets replaced 1.5 years ago

1/5/2012 – pulled plug coil packs to check – noticed some burned oil in wells – worst in #4 near the oil fill hole. Cleaned carefully with shop towels. Replaced CP (no effect)

1/5/2012 – Connected VAG-COM – no error codes, observed measuring blocks 001-009 (http://www.ross-tech.com/vag-com/m_blocks/001-009.html) for a while. Engine coolant temperature (group 001#2) read around 30C (was 2C outside). Cooling temperature (group 004#3) read upwards of 45C (again was 2C outside). Engine load shows 73.7% not sure if this is normal, but the engine wasn't running.

Does anyone have a suggestion as to what I might try next? Is the high coolant reading indicative of a bad sensor – would this prevent starting? My goal is just to start the car so that I can get it into the shop. I like to fix things when I can, but given that it seems like multiple issues at the same time I'd like to get it into a pro.

Thanks so much for your help!

 

I ordered a new ECT sensor - will update once I know if that fixes the problem. If anyone has ideas in the interim please let me know. Thanks!

 

I would suggest changing out the ECT. I have heard of weird stories in which they don't throw any codes, but are still on their way out. They will cause all kinds of weird problems.

Do yourself a favor. Visit your local dealer and try to get one or two extra C clips that hold the ECT sensor before doing the job. When I did mine, mine broke and I had to order a new one. They are very cheap. So if you can make it to the dealer before doing the job, I'd highly recommend spending the 5 dollars or so to get one or two.

 

Thanks Nebunchadnezzar. I did replace the ECT sensor. Took advantage of some great tips in this thread: Replacing Engine Coolant Temperature Sensor (ECT) - Long - AudiWorld Forums

A few things I noticed... the sensor can be very hard to fully seat - adding some vaseline to the O-ring and sensor helped a great deal. I also put a quarter on top of the sensor and pushed on that to apply pressure (saves your thumb). The mechanic who last replaced used a zip tie as an extra mesure to hold things in place - not sure if that's a good tip or not.

In any case, now the temps all look great in VCDS, BUT car still won't start. Now I'm receiving some engine codes:

17831 - Secondary Air Injection System (Bank 1) Insufficient Flow
17819 - Secondary Air Injection System (Bank 1) Insufficient Flow

Any thoughts my next diagnostic step here? Should I check fuses? Could this be caused by the vacuum line that I patched?

Thanks a bunch.

 

im having the same problem i have 55 psi for fuel good spark and i did get it to run for a day so i know i have compression i have no idea what is going on i need help oh and there are no codes any ideas or did you find a fix for yours

 

Replace your vacuum lines. Especially the ones from the rear of the engine combination valves to the solenoids. There should be a vacuum diagram under the hood. Get 5 feet of vacuum hoses and replace one section at a time.

 

Thanks hxgaser - this makes sense. My patch seemed pretty good, but it might not be perfect or there might be other leaks - I'll replace the hose.

I also noticed where someone else had patched where the breather system connects (by the coolant tank) with a piece of heater hose and zip tie. That had come loose. I cleaned and used a metal clamp to seal more tightly. The code hasn't come back, but I'll replace (or have it replaced at the show) when I can.

 

For anyone following my saga. I was able to get the car to start. Here were my next steps and the results:

1) Replaced spark plugs with new NGK Iridium IX (BKR6EIX) - followed this helpful guide Audi A6 (1997-2004) 2.7T Spark Plugs Replacement DIY | AutoDIYOnline On the 2.8, however, I was able to get away with less disassembly. Still found more oil in the wells and cleaned (will have valve cover gaskets checked at dealer)

2) Very very rough start, but after 30+ seconds of cranking and feeding some gas car turned over.

3) After a short drive CEL came on with:

16684 (P0300 - 35–10 Intermittent) - Random/Multiple Cylinder Misfire Detected
16689 (P0305 - 35–10 Intermittent) - Cylinder 5: Misfire Detected
16690 (P0306 – 35-10 Intermittent) - Cylinder 6: Misfire Detected
16518 (P0134 - 35-10 Intermittent) - O2 Sensor Circ. B1 S1: No Activity Detected
17521 (P1113 - 35–10 Intermittent) - Oxygen (Lamda) Sensor; B1 S1: Internal Resistance too high

4) Cleared the codes (figuring that they might be related to the hard start). Took the car for a 30 minute test drive with VAG connected. No CEL, but code 16514 (O2 Sensor B1S1 Malfunction in circuit).

So, now that it starts I'm off to the shop for more diag. I did have all 4 O2s and both CATs replaced 2-3 years ago, but seems worth getting B1S1 looked at.

Thanks everyone for your help.