Possible good news about cold start issues...
01-14-2009, 09:55 AM
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Possible good news about cold start issues...
After Todd/AWE suggested that fuel injectors might be contributing to the cold start issues, I went out and got a few cans of BG44K Fuel Injector Cleaner. I threw one can in a full tank last Sunday. After 150 miles, no detectable difference in cold starts. Suddenly, this morning (220 miles on this tank so far), it's 18 degrees out, the car started right up as if it was 80 degrees out! It's NEVER done this in cold weather before!
Don't take this for gospel yet, as I have no idea if it was a fluke or whether it's a band aid that will only last until after I burn through the tank with the fuel injector cleaner.
We've got a few very cold days coming, and my weekly driving is about 700 miles a week, so I'll post back in a few weeks and let you know how things go. Stay tuned...
Don't take this for gospel yet, as I have no idea if it was a fluke or whether it's a band aid that will only last until after I burn through the tank with the fuel injector cleaner.
We've got a few very cold days coming, and my weekly driving is about 700 miles a week, so I'll post back in a few weeks and let you know how things go. Stay tuned...
01-14-2009, 10:09 AM
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How many miles on it? (a little history about my car)
According to Todd, he has seen fuel injector issues on cars with mileage as low as 20K. The problem went away after replacing the injectors.
Since these are the first engines where Audi is placing the injectors in the cylinders, it wouldn't surprise me if there were longevity issues they haven't discovered yet. The BG44K was a long shot that might hold some promise.
I have 27K on my car right now...I'd say it had 25K by the time the weather got cold enough to notice the issue. I axquired the car last summer, so this is my first winter with it. Audi reflashed the ECU just after Thanksgiving '08 with the latest software, which had no effect on cold starting performance.
Since these are the first engines where Audi is placing the injectors in the cylinders, it wouldn't surprise me if there were longevity issues they haven't discovered yet. The BG44K was a long shot that might hold some promise.
I have 27K on my car right now...I'd say it had 25K by the time the weather got cold enough to notice the issue. I axquired the car last summer, so this is my first winter with it. Audi reflashed the ECU just after Thanksgiving '08 with the latest software, which had no effect on cold starting performance.
01-14-2009, 03:35 PM
#4
just passed 20,500mi
bought new, been through two very cold winters without so much as a hiccup on startup. I was concerned the startup settings on the APR software might cause issues in below zero weather, but I was reassured before purchasing and it still starts up like stock.
I'd have trouble believing Audi engineers didn't test this motor for potential startup issues in all conditions before releasing it. It would be interesting to find out exactly what was altered in the "new reflash" that was supposed to take care of this issue for problematic cars.
I'm guessing OEM injectors for this car don't come cheap, so if that's actually the issue hopefully a little injector cleaner solves it.
I'd have trouble believing Audi engineers didn't test this motor for potential startup issues in all conditions before releasing it. It would be interesting to find out exactly what was altered in the "new reflash" that was supposed to take care of this issue for problematic cars.
I'm guessing OEM injectors for this car don't come cheap, so if that's actually the issue hopefully a little injector cleaner solves it.
01-14-2009, 04:09 PM
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the new flash worked for me.. sort of
they made a new flash update end of nov, and i got mine flashed. now it starts up every day without a problem. however a new problem has arisen. it's not as frequent but VERY annoying, i'm taking it back to the dealer next week. Some cold mornings, i cannot shift out of 1st (manual), i turn the car on, still won't shift. i have to wait a few minutes before it will move. i don't know if this is due to the fact that they changed my transmission fluid or the flash, but one of the two has caused this lovely issue.
01-15-2009, 08:34 AM
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Prior to the IC, did your car fail to start every time or just sometimes?
I've only ever had a cold start problem on a few occations (maybe 5 total over several years)... so i've never really though about it. She started right up for me all this week- which has been very cold.
As for the injector cleaner... if you are driving 700 miles per week, I doubt your injectors are clogged, but perhaps the IC changed the combustion facors for the fuel making cold start eaiser on the car. What kind of fuel(brand) do you run and what octane? I'd be curious what else is different with the cars or our methods that gives different results.
As for the injector cleaner... if you are driving 700 miles per week, I doubt your injectors are clogged, but perhaps the IC changed the combustion facors for the fuel making cold start eaiser on the car. What kind of fuel(brand) do you run and what octane? I'd be curious what else is different with the cars or our methods that gives different results.
01-15-2009, 09:37 AM
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The history is incomplete...
I bought the car used last June, it sat in the garage until November, used occassionally in mostly warm weather. In a handful of instances the car was left in sub 40F temps overnight and it exhibited the cold start issue (stumble).
Since November I have been driving this car exclusively and it is routinely parked outside for now. When the temps are below ~40F, the issue appears. As the temps drop below 30F, it's even more consistent (99% of cold starts).
As for my observations, anything is possible. Even the starting results are seemingly inconsistent now (I initially posted after the first time it started flawlessly, hoping the injector cleaner actually did something). It's just too early to know...gotta give it a few weeks, run through a few tanks of gas, and see what it does.
As for the gas, it varies. I'm not brand loyal, I just choose whatever is cheapest along my commute (93 octane), which is often a choice between the following brands:
Exxon
Hess
Shell
Sunoco (albeit infrequently)
This could all be the result of something else entirely. Somehow it does feel like some kind of fueling issue. Maybe it's not clogged injectors, maybe it's leaking injectors? In that case, I'm not sure why it would be so temperature dependent, but it's possible that there is a connection. This might also explain some of the fuel dilution issues people have noted. I can tell you when it doesn't start on the first try, it has always started on the second attempt, with a little hesitation. BTW, I'm not one to crank the engine until the starter burns out. If the starter turns more than 4-5 times, I'll give it a rest and try again.
For now I'll finish with the fuel treatment and observe for a few weeks. Either it works or it doesn't, either way, I'll know in a few weeks and at a minimum, cross one more thing off the list.
Since November I have been driving this car exclusively and it is routinely parked outside for now. When the temps are below ~40F, the issue appears. As the temps drop below 30F, it's even more consistent (99% of cold starts).
As for my observations, anything is possible. Even the starting results are seemingly inconsistent now (I initially posted after the first time it started flawlessly, hoping the injector cleaner actually did something). It's just too early to know...gotta give it a few weeks, run through a few tanks of gas, and see what it does.
As for the gas, it varies. I'm not brand loyal, I just choose whatever is cheapest along my commute (93 octane), which is often a choice between the following brands:
Exxon
Hess
Shell
Sunoco (albeit infrequently)
This could all be the result of something else entirely. Somehow it does feel like some kind of fueling issue. Maybe it's not clogged injectors, maybe it's leaking injectors? In that case, I'm not sure why it would be so temperature dependent, but it's possible that there is a connection. This might also explain some of the fuel dilution issues people have noted. I can tell you when it doesn't start on the first try, it has always started on the second attempt, with a little hesitation. BTW, I'm not one to crank the engine until the starter burns out. If the starter turns more than 4-5 times, I'll give it a rest and try again.
For now I'll finish with the fuel treatment and observe for a few weeks. Either it works or it doesn't, either way, I'll know in a few weeks and at a minimum, cross one more thing off the list.
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01-28-2009, 12:16 PM
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Update...mixed results
Previously, weather in the 20's and below would result in two attempts needed to get the car started, or at the very least, 4-5 cranks on the first attempt before it was catch, stumble and run. Holding the key in the ON position made no difference (nor would I expect it to).
1/28 - So far, one treatment of BG44K, and well over 1K miles later (not keeping track). I've noticed the cold starting performance has improved. Sometimes it will fire up right away, sometimes it won't. Seems to be a crapshoot, but when it has an issue starting, it's exactly as it was before using BG44K. Putting the key in the ON position for 5 secs before a cold start virtually guarantees that it will start without issues. I can't explain this at all. The in tank pump might prime when you hold the key in the ON position, but the HPFP drives off the cam, not electrics, so this makes no sense to me. More updates to follow (in this post)...will run another can of BG44K through to see if there are further improvements.
2/9 - Last update. I finished running a second can through. No difference noted since I ran the first can through. The car is still better than it once was, but the issue remains unresolved.
Next step, check the plugs... No more updates will be posted in this thread.
1/28 - So far, one treatment of BG44K, and well over 1K miles later (not keeping track). I've noticed the cold starting performance has improved. Sometimes it will fire up right away, sometimes it won't. Seems to be a crapshoot, but when it has an issue starting, it's exactly as it was before using BG44K. Putting the key in the ON position for 5 secs before a cold start virtually guarantees that it will start without issues. I can't explain this at all. The in tank pump might prime when you hold the key in the ON position, but the HPFP drives off the cam, not electrics, so this makes no sense to me. More updates to follow (in this post)...will run another can of BG44K through to see if there are further improvements.
2/9 - Last update. I finished running a second can through. No difference noted since I ran the first can through. The car is still better than it once was, but the issue remains unresolved.
Next step, check the plugs... No more updates will be posted in this thread.
