Hi, I find that my car (99 A6 2.8) is hard to start after sitting for a while. I will have to hold the key for about 5 secs every morning to get the engine started every morning; if I drive during the day ususally it takes 1sec to start it. I do find it seems to be easier to get it started in the Winter.
Just to make sure, you do wait for the car to stop beeping and warning lights to go off before you turn the key first time right? Can't positively say it's bad fuel pump because it's in the tank not under the hood and car is fuel injected... You should do regular maintence, replace plugs filters etc. Also, I would check fuel pressure if other things do not help.
< Message edited by SSn -- 4/23/2007 11:53:19 PM >
anyone has more ideas? I went through the forum and see people talk about coolent temp sensor and the o2 sensor, and even throttle body alignement. Would they relate to my problem? thanks.
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Joined: 2/24/2007 From: Sacramento, CA Status: offline
A bad coolant temp sensor definately, bad forward bank O2 sensors can cause starting issues as well. The throttle body alignment probably won't cause a starting issue as much as it would bucking or stumbling issue. Do you have any fault codes?
Thanks Auditech79 for your kind replay. Strange enough is that I don't have any fault codes in my ECU. I suppose that's where I should be looking at.
Generally my engine is easy to start when it is still warm.
can you also explain more about the bucking or stumbling issue? I feel my car's vibration is a little excessive when I stop for lights (e.g., foot on break paddle, gear is in D). I am not sure if it is related to the throttle body alignment.
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Joined: 2/24/2007 From: Sacramento, CA Status: offline
I would start with the coolant temp sensor, they don't always throw a fault when they go bad. Its easy enough to replace, its directly behind the engine on the passenger's side facing upwards to the hood of the car, you just pull the plastic clip out and pull up on the sensor. Install a new sensor and o-ring and see what it does. 75% chance thats what the problem is.
Today I started replacing the ECT sensor. But I noticed that the new green sensor is a lot longer than the original blue sensor where it is interfacing to the wire connector. Actually I don't think the green one can be plugged into the wire connector. Did I purchase the wrong one? But this is what the dealer says the right replacement.
BTW, I find the ECT is very difficult to be pulled out. I have not been able to accomplish this part yet.
Thanks Auditech79, that's extremely fast response. I just checked codes, there was nothing there. I tried to use VAG-COM to find out the O2 sensor readings, got some numbers but don't know if they are of any significance. When you say clean the intake, can you explain a little more? (sorry about my knowledge, just started learning and excited about fixing the car I like).
Also, if the O2 sensor fails, would it not give me a code?
A bad O2 sensor should throw a code and we don't typically replace O2 sensors in a '99 car (for the most part).
What acutally happens on a cold start? Do you turn the key all the way and nothing happens? Or does it crank but not turn over for 5 seconds or so?
BTW a faulty fuel pump can go anywhere from complete failure to intermittant to occasional failure. I have one customer that just banging on the fuel pump was enough to "fix" it for a little while longer (this is not our usual MO though we tend to do permanent fixes). On the other side you could have a fuel pump relay that's faulty but typically it would fail a little more often.
How long has this problem been happening? Where do you live, is it truely cold in the morning (we're in SoCal and it really doesn't get that cold here)? If you have a failing relay ambient tempurature could play a role.
Sorry for all the questions but I can't just replace parts to find a problem I try to ask as many questions that can help identify a problem and even little details can help. Like what if the car sits ALL day from after a morning commute and you work late into the evening does it start quickly or slowly?
Thanks for the input. When I went through the forum, I find people are complaining about engine hard to start when it is warm, mine is on the other side, usually takes longer time to start when it is cold. It will start, just cranks a lot longer time (say 4-6sec v.s. 1sec). This problem first started 3 years ago, where the car just would not start. Then it became somewhat OK, but it has not been as bad as it is this year. Even last winter was OK. Once it is started, it is fine.
Just in case it means anything to you, I can feel my engine vibrates through the steering wheel when it is idling (I mean significantly more vibration than my other cars). A couple of weeks ago, when I stopped at light, the engine stopped (or you call it stalling?), never happend before.
I live in Windsor, Ontario, where I don't consider it is really cold. I have a garage too.
Your last question, when I start the engine in the evening, it starts slowly. But if I restart the car within, say 30mins of last drive, it will start normally.
Posts: 5019
Joined: 2/24/2007 From: Sacramento, CA Status: offline
Thats some crazy stuff your describing, it almost sounds like you have carbon build up on the valves causing it to idle wierd and hard start up but it starts normally when its hot? I would still clean the intake and try to clean the carbon build up off the valves. The old school approch to cleaning it is have someone floor the throttle wide open and you spray chemtool carb cleaner down the intake until the can is empty, this will make the engine bogg down and cause miss-fires until the can is emtpy but it should idle better than it ever did after your done. Give it a try it will only cost you the price of the can.
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