1999 A4 1.8T Quattro Rough Engine
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1999 A4 1.8T Quattro Rough Engine
So i'm new to Audi and driving one has been a blast until now. I have a 1999 A4 1.8T Quattro. (B5 platform)
A few months ago I started to have the engine sputter a bit on me. As a matter of fact, it got to the point where I would loose responsiveness even when I pressed the gas pedal all the way down. I did a bit of research and found that the MAF sensor could be to blame. I tried to clean it and it didn't work so I tried replacing it and it worked well for a two weeks or so and then it went bad again. I thought that since it had worked for a good while it could have just been a faulty sensor so I replaced it again. This time the car worked for a whole month. I thought that I had found the issue but its up to its old games again. I tried to disconnect the sensor in hopes that I could at least drive the car to a repair shop but now it seems that even telling the computer to go to baselines isn't working (it had worked previously and was what pushed me to believe that the sensor was at fault in the first place)
Since then, I have been noticing that the issue isn't exactly what it had been before. For example, I couldn't keep the car on before because it would not respond when pressing on the gas. I've found that now I can press the gas to keep the car on but if I let it drop below 1000 rpm it has a good chance of stalling. Also, If I let the car idle right after I turn it on from a cold night it will stay on until I press the gas after that it'll idle fine for about 30 secs and then it'll almost stall or actually stall. If the car doesn't stall, it'll cycle every 30 secs between a rough idle and normal idle.
I just bought the car back in August so I don't know much about it's history. One note that may be useful is that it does have a 900w system working off of the battery. (600w to the speakers and 300w to a sub) I have tried to turn the car on with everything off.
Sorry for the long post. Any help will be greatly appreciated!
A few months ago I started to have the engine sputter a bit on me. As a matter of fact, it got to the point where I would loose responsiveness even when I pressed the gas pedal all the way down. I did a bit of research and found that the MAF sensor could be to blame. I tried to clean it and it didn't work so I tried replacing it and it worked well for a two weeks or so and then it went bad again. I thought that since it had worked for a good while it could have just been a faulty sensor so I replaced it again. This time the car worked for a whole month. I thought that I had found the issue but its up to its old games again. I tried to disconnect the sensor in hopes that I could at least drive the car to a repair shop but now it seems that even telling the computer to go to baselines isn't working (it had worked previously and was what pushed me to believe that the sensor was at fault in the first place)
Since then, I have been noticing that the issue isn't exactly what it had been before. For example, I couldn't keep the car on before because it would not respond when pressing on the gas. I've found that now I can press the gas to keep the car on but if I let it drop below 1000 rpm it has a good chance of stalling. Also, If I let the car idle right after I turn it on from a cold night it will stay on until I press the gas after that it'll idle fine for about 30 secs and then it'll almost stall or actually stall. If the car doesn't stall, it'll cycle every 30 secs between a rough idle and normal idle.
I just bought the car back in August so I don't know much about it's history. One note that may be useful is that it does have a 900w system working off of the battery. (600w to the speakers and 300w to a sub) I have tried to turn the car on with everything off.
Sorry for the long post. Any help will be greatly appreciated!
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1st Gear
Joined: Nov 2012
Posts: 4
I did unplug the battery at one point after I stopped driving the car so that may be to blame for the power supply error.
Also, I do remember the that driving at night with the music plying would often cause the lights to dim in tune with the music. I thought about the battery then but I didn't do anything about it. Could the radio be to blame? (900w)
But then I still don't know why I keep getting MAF sensor errors.
Thanks in advance for the help!
Also, I do remember the that driving at night with the music plying would often cause the lights to dim in tune with the music. I thought about the battery then but I didn't do anything about it. Could the radio be to blame? (900w)
But then I still don't know why I keep getting MAF sensor errors.
Thanks in advance for the help!
P1602 is common when your battery dies or you disconnect it for any reason. It's just saying that the power terminal to the ECU experienced lower than normal voltage. You might try adding a power cap to your system to see if that helps.
If the MAF was bad, unplugging it would make the car run better. Sounds like you tried that already.
As for the idle problems, that makes me think primary O2 sensor. At idle the engine isn't pulling enough air passed the MAF to give accurate readings, so the timing and fuel are calculated using readings from the primary O2 sensor.
Do you hear any tapping or weird noises at idle? Does the bouncing idle problem go away when the car is at operating temperature?
If the MAF was bad, unplugging it would make the car run better. Sounds like you tried that already.
As for the idle problems, that makes me think primary O2 sensor. At idle the engine isn't pulling enough air passed the MAF to give accurate readings, so the timing and fuel are calculated using readings from the primary O2 sensor.
Do you hear any tapping or weird noises at idle? Does the bouncing idle problem go away when the car is at operating temperature?
Thread Starter
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1st Gear
Joined: Nov 2012
Posts: 4
P1602 is common when your battery dies or you disconnect it for any reason. It's just saying that the power terminal to the ECU experienced lower than normal voltage. You might try adding a power cap to your system to see if that helps.
If the MAF was bad, unplugging it would make the car run better. Sounds like you tried that already.
As for the idle problems, that makes me think primary O2 sensor. At idle the engine isn't pulling enough air passed the MAF to give accurate readings, so the timing and fuel are calculated using readings from the primary O2 sensor.
Do you hear any tapping or weird noises at idle? Does the bouncing idle problem go away when the car is at operating temperature?
If the MAF was bad, unplugging it would make the car run better. Sounds like you tried that already.
As for the idle problems, that makes me think primary O2 sensor. At idle the engine isn't pulling enough air passed the MAF to give accurate readings, so the timing and fuel are calculated using readings from the primary O2 sensor.
Do you hear any tapping or weird noises at idle? Does the bouncing idle problem go away when the car is at operating temperature?
i'll look into a capacitor for the sound system. I think its a great Idea. Do you think that if I replace the battery for an optima yellow top it would help? It's pricey but I think it might be better in the long run.
I'll also look into replacing the primary O2 sensor tomorrow.(by primary I'm assuming that you mean the pre-cat sensor. let me know if i'm wrong)
The rough idle does settle down a bit once the car has warmed up but it'll still almost stall. Just in more prolonged intervals.
As for noises, I did just notice a very soft slight metallic rattle but I'm not sure if that has always been there or if its a result of what is going on.Other than that, I did not hear anything else out of the ordinary. Either way, i'll lift the car up to see if I find anything, (sounded like it came from under the car) hopefully its not the cat.
Thanks again for your help! I'll keep you posted if the issue gets resolved or if anything changes.
Last edited by RUA; Dec 8, 2012 at 12:44 AM.
Correct, primary is pre-cat. Sorry about that, I should have been more descriptive. The rattle is probably a heat shield or your valves, nothing to worry about. Replace the primary O2 sensor and see if that helps.
The Optima certainly couldn't hurt, but I would exhaust as many less expensive options as you can before you go drop $200 on a battery that you may not need.
The Optima certainly couldn't hurt, but I would exhaust as many less expensive options as you can before you go drop $200 on a battery that you may not need.
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