My audi a4 is having hard start

[ponyboy]

My 1997 audi a4 is having a hard time starting I have to give it a little gas on cold start and it takes a while to start. When starting when the car is warm the starter turns for a while and then turns on. Once its running it fine for the most part. some times when stopping and going theirs a little hesitation sometimes almost like the car is going to stall. So far I have change the fuel pump, fuel filter, a fuel line, ignition wires, spark plugs, and I've had the fuel injectors cleaned. I just cannot figure out what is going on with this car and its frustrating and expensive. I'm thinking it could be the MAF or the fuel pressure regulator but I'm just not sure. I've also heard that it could be the coolant temperature sensor but I'm just not sure if some could help me out or give me there opinion on it this would be greatly appreciated.

[jvega21]

Since you already spent all the money on everything else, why not drop the $30-40 on a coolant temp sensor. Most everyone here would have told you to start with the fuel filter and temp sensor. Any codes?

[A1 A2 German]

A $11 coolant sensor resolved my problem 100%.

[JaysA4]

CTS as stated above. Like 99% sure. Had the same exact problem.

[Kromodus]

My 1997 audi a4 is having a hard time starting I have to give it a little gas on cold start and it takes a while to start. When starting when the car is warm the starter turns for a while and then turns on. Once its running it fine for the most part. some times when stopping and going theirs a little hesitation sometimes almost like the car is going to stall. So far I have change the fuel pump, fuel filter, a fuel line, ignition wires, spark plugs, and I've had the fuel injectors cleaned. I just cannot figure out what is going on with this car and its frustrating and expensive. I'm thinking it could be the MAF or the fuel pressure regulator but I'm just not sure. I've also heard that it could be the coolant temperature sensor but I'm just not sure if some could help me out or give me there opinion on it this would be greatly appreciated.

Check your fuel pressure at the rail. You may have leaky fuel injectors which would absolutely cause this problem. Clean fuel injectors will do nothing for you if they leak. Hook up a pressure gauge to your fuel line and check the pressure during ignition on (fuel pump on) and also after you turn off ignition (fuel pump off). After ten minutes there should only be a slight drop in fuel pressure in the line (I can't remember the exact tolerance but it's in your Bentley). If it drops more than the spec, you have a leaky fuel injector (or two). Replace the leaky fuel injector or all of them if you abide by the "if one has failed the others aren't far behind" rule.

[walky_talky20]

If you have access to a fuel pressure gauge, that is a good test. I don't think it is a common failure of our injectors, but possible.

If it were mine, I'd drop in a fresh CTS. They go bad over time anyway, so it's not really wasted money -even at such low cost. I'd also log the MAF to make sure it is reading well and look at long term fuel trims to make sure it isn't correcting too much at idle (indicating an intake leak).

[woolveren]

A bad IAT sensor can cause hard start.

It can also end up in lean or rich fuel mixture that causes driveability symptoms such as poor idle quality when cold, stumble on cold acceleration, and surging when the engine is warm.

[Kromodus]

I still say he has a leaky fuel injector or two. It is correct that they do not commonly fail, but that is precisely why he should rule that out. Three years ago I had the same hard start problem and the last thing I checked were the fuel injectors (pressure). Of course.

Here were my symptoms:
Morning: Engine would need to crank for 4-8 seconds before it would start. After engine started I could stop and start it again immediately. If my engine was off for as little as 5-10 minutes it would also start immediately. However, if I let the engine rest for 10 minutes or longer the hard start process would repeat every time (4-8 seconds to start). It baffled me. I replaced this sensor and that sensor, fuel filter, etc. In the end I decided to check my fuel pressure (I was actually trying to check if my fuel pressure regulator was maintaining the correct pressure to the rail). By accident I noticed that the pressure had dropped to zero after about 10 minutes. I knew the pressure was not holding at that point. I lifted the rail with the injectors attached and immediately spotted the two leaky injectors. Drip. Drip. Drip. I had two leaky fuel injectors. I replaced them all ($). Problem solved.

[ponyboy]

before I changed the fuel pump I had a fuel bank one and fuel bank two code afterwards it was gone. The the check engine light came on again and it gave me a coolant temp sensor. I didn't think that would have anything to do with it starting like that so I pulled the injectors and had them cleaned I still had the same hard start problem so I pulled them off again when I noticed two of them had a little fuel leaking from where the rail and the injector meet. One of them still looks a little greasy but I think I'm gonna try and replace the ctp sensor before I try and replace injectors because of the cost