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View Full Version : Constant thin white smoke? Limp mode? Car flooding itself?



JaysA4
02-19-2013, 06:38 PM
I have a constant thin white smoke coming from my 97 A4 2.8Q 12v Auto. I'm pretty sure I'm stuck in limp mode, I posted a thread a couple days ago with all the info on the Trans. I'm getting a constant thin white smoke from my exhuast, smells mostly of gasoline. Car will sometimes, after sitting a short period (5-30mins) will not start, I can crank it a few times and it wants to start but I'm pretty sure it's flooding itself out because when I do get it to start it will blow a few big clouds of black smoke which reeks of gas and will kinda "chug" for a minute before I can drive off. Also with the "limp mode" car will sometimes stall when taking off and I cannot take off in Drive gear I have to use gear '2' to take off and then shift through drive. A) What is the culprit? B) Could this be fuel pump, fuel pressure regulator, fuel filter? C) Could this be the cause of my 'limp' mode? D) Ordered VAG-COM, if I do find the problem will VAG-COM be able to take me out of limp mode? I'm getting about 12mpg in town, oil and antifreeze levels are full and never fluctuate.

Corrado_Guy
02-19-2013, 06:54 PM
Limp mode can be caused by many things, dead coils, sticking injectors, bad MAF, or other mechanical issues on the car. Pull the plugs and check their condition and clean/replace and see how things run after that. I would also go over the entire intake and make sure there are no intake leaks and if you have a oil-based air filter make sure it is not really dirty or over-oiled. Unplug the MAF and see how it runs then unplug the CTS and see of this makes a difference. Do you have a CEL? I'm not much on the issues with the V6 but the above would be a good start.

JaysA4
02-19-2013, 07:18 PM
Sorry I also forgot to mention that I think the thermostat is bad. I'm getting no heat and my top temp gauge stays like one notch above C. As far as CELs, I have none and OBD showed no codes as well. MAF sensor, I'm not sure exactly where it's located but if its the sensor directly on top of the stock air filter housing, I do have a crack right next to it and also a few more cracks on top of the box. I'm also not sure what the CTS is. I haven't had to do much work on these, but I picked this one up for a complete steal and my 98 5 speed has been fantastic (knock on wood). Could it be possible because the thermostat is bad that I'm feeding too much fuel to it? I mean I will defiantly be replacing thermostat but I also don't know of this is just coinciding with the other issues?

wretchedwrench
02-20-2013, 04:57 PM
CTS = coolant temprature sensor. If your cts is bad the ecm will think the engine is cold when it is not. It will cause an over rich condition, with some of the symptoms you describe. So will a bad thermostat. A massive air leak post MAF will also cause issues. Vacuum leaks can also cause similar issues. Leaky fuel injectors can also cause issues as mentioned.
Best to find out what the ecm is seeing and doing. Should be seeing coolant temps of 200 degrees or so. The fuel injectors can be checked by a fuel pressure leak down test. .
I'd definatly check your coolant level, a cooling system pressure test might not be a bad idea either and if ok then do a thermostat. White smoke is usually associated with an internal coolant leak. Black smoke is usually indicative of an overly rich fuel mixture. You could have both.
My 2.8 auto averages right around 20 mpg so 12 is way off IMO.

JaysA4
03-16-2013, 11:50 AM
Sorry I haven't been able to respond for a while, work has been crazy. Anyway, I oredered a third party cable and running it on vcds lite. Scan came back with excessive Common HVAC codes, tried running HVAC test but it says too many connections. I did, at one point, pull up fault codes, but was showing nothing. As far as the thermostat goes, I have noticed when it is 35 degrees or warmer it seems to warm right up and heat is working fine, oil temp only stays a notch above cold. I'm still having a thin white smoke/ I would be confident to say this seems more like vapor than smoke. The 'vapor' just reeks of gasoline. I will order the CTSs and replace, and try to diagnose a little further. Now as far as my transmission, what the heck is going on?? I don't believe I am in limp mode seeing that I can accelerate over 3000rpm in 2-3-4-Drive. But it seems like first gear is non-existent, it will not take off in any gear but '2'. Sometimes even if I slow down enough in 3 it will go into almost a 'neutral' feel? My mechanic is in his late 50s and has the flu, so extensive troubleshooting is somewhat out of the question at the moment. Also, I know this alot all into one post but, as far as my starting issue I've noticed if I just keep cranking it will finally chug to start. Too much fuel? Not enough fuel? I'm lost. Thanks for all the help fellas!!