Hard starting, Stalling with low fuel, Inaccurate coolant temp
06-28-2017, 01:41 PM
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Hard starting, Stalling with low fuel, Inaccurate coolant temp
Gents, need some help with this one. 2002 Audi A4 Quattro 1.8T 180K miles
1) For awhile, my coolant temp gauge has been inaccurate. The first time I drive the car for the day, the gauge reads that the motor is warming up normally, until it gets to the "25%" mark, (halfway between cold and normal temp). At that point it just stays there, sometimes It fluctuates a little. If I shut down the car for a minute and start it back, the needle goes straight to the "50%" mark, or normal operating temperature. I've tried replacing the Engine Coolant Sensor that is behind the motor, and nothing changed. Is there another sensor (maybe the one down by the radiator) that would fix this problem?
2) Next, I have had a hard time starting the car on the first crank for awhile. At first it was only every now and again, but lately it has been every time I try to start the car the starter engages but nothing happens, regardless of how long I hold it. As soon as I release it, and then try again, the car starts up, usually right there on the next crank. Thoughts?
3) Finally, about 2 weeks ago, my car shut down on the way home, without warning. It would crank back up to about 1200 RPM then go right back to zero. I had it towed to the shop and they replaced my fuel pump and filter. It went back to operating as before the incident until today. Leaving work, the car started to jerk and act like it was stalling as RPM fluctuated from about 2K RPM to 3K and back. Pulling into the gas station it actually stalled all the way and when to 0RPM. I had about 1/8 tank of gas and no gas light. It did start back up so I moved it to a gas pump and filled the tank. After putting gas in it, it ran smoothly and hasnt stalled or jerked since. I went to the shop, but without keeping the car and doing some diagnostics they have no idea.
I am not getting any check engine lights related to these problems. I am getting a check engine light for the catalytic converter, but just that the O2 level is below the threshold. I dont think this has anything to do with the other issues I am seeing. As I have already dropped about $4K on the car in the last year (all new hosing, oil and coolant systems and the fuel pump) I'm getting pretty frustrated at this point. Anybody else seen any or all of these things, and have any ideas? Any help is much appreciated. Thanks.
1) For awhile, my coolant temp gauge has been inaccurate. The first time I drive the car for the day, the gauge reads that the motor is warming up normally, until it gets to the "25%" mark, (halfway between cold and normal temp). At that point it just stays there, sometimes It fluctuates a little. If I shut down the car for a minute and start it back, the needle goes straight to the "50%" mark, or normal operating temperature. I've tried replacing the Engine Coolant Sensor that is behind the motor, and nothing changed. Is there another sensor (maybe the one down by the radiator) that would fix this problem?
2) Next, I have had a hard time starting the car on the first crank for awhile. At first it was only every now and again, but lately it has been every time I try to start the car the starter engages but nothing happens, regardless of how long I hold it. As soon as I release it, and then try again, the car starts up, usually right there on the next crank. Thoughts?
3) Finally, about 2 weeks ago, my car shut down on the way home, without warning. It would crank back up to about 1200 RPM then go right back to zero. I had it towed to the shop and they replaced my fuel pump and filter. It went back to operating as before the incident until today. Leaving work, the car started to jerk and act like it was stalling as RPM fluctuated from about 2K RPM to 3K and back. Pulling into the gas station it actually stalled all the way and when to 0RPM. I had about 1/8 tank of gas and no gas light. It did start back up so I moved it to a gas pump and filled the tank. After putting gas in it, it ran smoothly and hasnt stalled or jerked since. I went to the shop, but without keeping the car and doing some diagnostics they have no idea.
I am not getting any check engine lights related to these problems. I am getting a check engine light for the catalytic converter, but just that the O2 level is below the threshold. I dont think this has anything to do with the other issues I am seeing. As I have already dropped about $4K on the car in the last year (all new hosing, oil and coolant systems and the fuel pump) I'm getting pretty frustrated at this point. Anybody else seen any or all of these things, and have any ideas? Any help is much appreciated. Thanks.
06-28-2017, 02:58 PM
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Gents, need some help with this one. 2002 Audi A4 Quattro 1.8T 180K miles
1) For awhile, my coolant temp gauge has been inaccurate. The first time I drive the car for the day, the gauge reads that the motor is warming up normally, until it gets to the "25%" mark, (halfway between cold and normal temp). At that point it just stays there, sometimes It fluctuates a little. If I shut down the car for a minute and start it back, the needle goes straight to the "50%" mark, or normal operating temperature. I've tried replacing the Engine Coolant Sensor that is behind the motor, and nothing changed. Is there another sensor (maybe the one down by the radiator) that would fix this problem?
2) Next, I have had a hard time starting the car on the first crank for awhile. At first it was only every now and again, but lately it has been every time I try to start the car the starter engages but nothing happens, regardless of how long I hold it. As soon as I release it, and then try again, the car starts up, usually right there on the next crank. Thoughts?
3) Finally, about 2 weeks ago, my car shut down on the way home, without warning. It would crank back up to about 1200 RPM then go right back to zero. I had it towed to the shop and they replaced my fuel pump and filter. It went back to operating as before the incident until today. Leaving work, the car started to jerk and act like it was stalling as RPM fluctuated from about 2K RPM to 3K and back. Pulling into the gas station it actually stalled all the way and when to 0RPM. I had about 1/8 tank of gas and no gas light. It did start back up so I moved it to a gas pump and filled the tank. After putting gas in it, it ran smoothly and hasnt stalled or jerked since. I went to the shop, but without keeping the car and doing some diagnostics they have no idea.
I am not getting any check engine lights related to these problems. I am getting a check engine light for the catalytic converter, but just that the O2 level is below the threshold. I dont think this has anything to do with the other issues I am seeing. As I have already dropped about $4K on the car in the last year (all new hosing, oil and coolant systems and the fuel pump) I'm getting pretty frustrated at this point. Anybody else seen any or all of these things, and have any ideas? Any help is much appreciated. Thanks.
1) For awhile, my coolant temp gauge has been inaccurate. The first time I drive the car for the day, the gauge reads that the motor is warming up normally, until it gets to the "25%" mark, (halfway between cold and normal temp). At that point it just stays there, sometimes It fluctuates a little. If I shut down the car for a minute and start it back, the needle goes straight to the "50%" mark, or normal operating temperature. I've tried replacing the Engine Coolant Sensor that is behind the motor, and nothing changed. Is there another sensor (maybe the one down by the radiator) that would fix this problem?
2) Next, I have had a hard time starting the car on the first crank for awhile. At first it was only every now and again, but lately it has been every time I try to start the car the starter engages but nothing happens, regardless of how long I hold it. As soon as I release it, and then try again, the car starts up, usually right there on the next crank. Thoughts?
3) Finally, about 2 weeks ago, my car shut down on the way home, without warning. It would crank back up to about 1200 RPM then go right back to zero. I had it towed to the shop and they replaced my fuel pump and filter. It went back to operating as before the incident until today. Leaving work, the car started to jerk and act like it was stalling as RPM fluctuated from about 2K RPM to 3K and back. Pulling into the gas station it actually stalled all the way and when to 0RPM. I had about 1/8 tank of gas and no gas light. It did start back up so I moved it to a gas pump and filled the tank. After putting gas in it, it ran smoothly and hasnt stalled or jerked since. I went to the shop, but without keeping the car and doing some diagnostics they have no idea.
I am not getting any check engine lights related to these problems. I am getting a check engine light for the catalytic converter, but just that the O2 level is below the threshold. I dont think this has anything to do with the other issues I am seeing. As I have already dropped about $4K on the car in the last year (all new hosing, oil and coolant systems and the fuel pump) I'm getting pretty frustrated at this point. Anybody else seen any or all of these things, and have any ideas? Any help is much appreciated. Thanks.
I can provide a bit of input on some of this.
1
I can't say for the temp gauge, older cars have separate temp senders but it could also be the gauge.
2 & 3 because they sound related
Sounds like problem hot starting, it could be plugs are worn or a fuel issue. I hate shops, my suspicion is that they changed your pump and filter because it "sounds right". I may be mistaken but I've had some bad experiences.
Do you have a code scanner? maybe you can get some info with that. If you stall at idle when the car is warm, I immediately suspect a dirty throttle, you can clean it yourself if you want to save a couple hundred. Then possibly vacuum leaks, temp sender, AFM or 02 sensors in that order. If you are getting some readings showing an 02 sensor acting up, listen to it. At this mileage if you have never changed them, you're lucky they have lasted so long. My inclination is that you are getting into old fuel system parts now, I recommend you do your own work at this stage because it is a hit and miss to some extent. I only have 80K miles and am having some issues similar to yours and this is what I'm doing.
- change AFM
- change fuel filter
- coolant temp sensor
- (you should change 02 sensors, cats sound like they are on their way out too, they are $$$ to replace)
So... up to you, the miles are up there and if you don't like working on your car you may want to cut your potential losses.
06-29-2017, 04:46 AM
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Thanks for the reply, I will start going down some of the rabbit holes that you mentioned.
I feel you on shops, I think I can trust these guys, but they have disappointed before...
I do have a code reader, the only code its popping is the one for the catalytic converter being below efficiency threshold. It could be the O2 sensor, but my guess is that the converter is bad, I've never changed it (and since I live in Florida, I dont really have any plans to). I did replace the O2 Sensors a few years back.
I hope I dont have any vacuum leaks since I just spent $3K about 7 months ago to get almost all of the hoses replaced.
What is a temp sender?
AFM may be something to look at
Yeah, I would like to do as much work as I can on my own. As I've said, I've dropped about $4K on the thing in the last 7 months or so and I just need it to limp through about another year. I'm leaving the country for awhile and dont feel like buying a new car before I go.
Again, thanks for the help, I'll chase some of these leads and see where it gets me.
I feel you on shops, I think I can trust these guys, but they have disappointed before...
I do have a code reader, the only code its popping is the one for the catalytic converter being below efficiency threshold. It could be the O2 sensor, but my guess is that the converter is bad, I've never changed it (and since I live in Florida, I dont really have any plans to). I did replace the O2 Sensors a few years back.
I hope I dont have any vacuum leaks since I just spent $3K about 7 months ago to get almost all of the hoses replaced.
What is a temp sender?
AFM may be something to look at
Yeah, I would like to do as much work as I can on my own. As I've said, I've dropped about $4K on the thing in the last 7 months or so and I just need it to limp through about another year. I'm leaving the country for awhile and dont feel like buying a new car before I go.
Again, thanks for the help, I'll chase some of these leads and see where it gets me.
06-29-2017, 10:27 AM
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That's good, so long as you don't need to worry about cats I wouldn't bother either. Even bypass but I'm not suggesting that. If you changed the 02 sensors recently it's probably ok unless you are burning oil or something to foul them.
There could be vacuum leaks other than hoses, for example the PCV valve or EGR if you have one. I have the 3.0 engine so I cannot say for sure what you have on your engine so I'm keeping my description general.
For the temp sender, try go to RockAuto.com for pictures and parts for your car. The temp sender reports the engine coolant temperature to your ECU to regulate fuel flow. When the engine is cold, the mixture is usually richer to help start the engine, when it heats up it is leaned out for better combustion.
You can also try cleaning your throttle body, those get kinda nasty around the edges of the butterfly valve and can cause hot idle issues. It's not too complex in my opinion to clean that and a shop probably charges $150-200ish around my area, easy money saved.
After a bit of thought, I also seem to recall fuel tank ventilation being a possible ghost culprit, fuel cap problems or vapor purge can do some weird things and may be fuel level related.
There could be vacuum leaks other than hoses, for example the PCV valve or EGR if you have one. I have the 3.0 engine so I cannot say for sure what you have on your engine so I'm keeping my description general.
For the temp sender, try go to RockAuto.com for pictures and parts for your car. The temp sender reports the engine coolant temperature to your ECU to regulate fuel flow. When the engine is cold, the mixture is usually richer to help start the engine, when it heats up it is leaned out for better combustion.
You can also try cleaning your throttle body, those get kinda nasty around the edges of the butterfly valve and can cause hot idle issues. It's not too complex in my opinion to clean that and a shop probably charges $150-200ish around my area, easy money saved.
After a bit of thought, I also seem to recall fuel tank ventilation being a possible ghost culprit, fuel cap problems or vapor purge can do some weird things and may be fuel level related.
06-30-2017, 04:24 PM
#6
Change the engine speed sensor, aka the crank position sensor. It only costs 40 or so, and is the first thing to do when the 1.8 is intermittently hard to start. Install is easy, or cheap if you use a mechanic. I have 3 cars, all with the 1.8T, and it's happened to all of them.
07-24-2017, 05:24 PM
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Is your CEL on? I had a similar issue with mine, it was pretty much like cranking over a diesel engine. The other day it threw the EPC light and started stalling out on me. Engine speed (crank position sensor) and coolant temp sensor apparently decided to throw codes at the same time so I replaced both at the same time. No more starting issue and coolant issue. Never noticed but when I did the coolant sensor, it made the fans kick on and they seemed rather loud but apparently before they wernt kicking on at all.
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07-30-2017, 05:24 PM
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Thanks all for the information. Unfortunately I never got to try any of the suggestions, as someone did me the favor of rear ending my car and pushing me into the truck in front of me. So, my beloved car is totaled and I now have a new car. Thanks again for the info guys!
07-30-2017, 06:24 PM
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Will end up being about $2,900. Crappy part is I had a mechanic put about $1600 in parts and another $2500 in labor into replacing pretty much my entire coolant and oil system, as well as the fuel pump all within the last year. The insurance company was gracious enough to give me an extra $85 for that...
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