lewismug

Check engine light came on the other day in my 2000 A4 2.8 Quattro. Checked the codes and P1296 was what I came up with.

Occasionally car is VERY difficult or impossible to start. Sometimes I have to wait an hour before retrying before I get it to start. When it does start it blows grey-ish smoke & has a VERY rich fuel smell. Seems to be flooding out during warm start. Starts fine every time when it is cold. Once the car is warm, the only way to get it to start is by removing the fuel pump fuse, turn the key for a few seconds until it starts, then put the fuel pump fuse back in. It is pumping way too much fuel into the engine during warm start. I'm thinking

Any one have a clue to what could be causing this?

Yippers®

coolant temp sensor

77'911

Well, you've caught me away from my factory manual but I'll do my best to help you. You might consider checking the fuel pressure , as well as the rest pressure. When is the last time you've changed the fuel filter? If it has not been changed within the last 30k, then its time to change it out. I would make sure you have the most recent upgraded coolant temp sensor as well. These cars are getting old enough, as well as higher mileage to warrant fuel pump and regulator replacement, but you should have some more diagnostics done.

lewismug

Well, I purchased the car in Feb. and have no idea as to when the fuel filter was replaced last. I will pick up a coolant temp sensor tomorrow, or at least order one along with a new fuel filter. Where exactly is that sensor located on my engine? I haven't noticed any fluctuation in my temp guage that would make me think to replace it though, but all the posts I have read on other forums all point to that particular sensor. The car has 107,000 miles, so I know it needs a little extra care, as it is no longer a spring chicken. Thanks for your responses guys. Maybe I will get it sorted out with your help.

77'911

The coolant temp sensor on the ATQ(eng. code) engine is on the back side of the passengerside head. Make sure you get a new washer and o-ring seal for that sensor, otherwise the ones tend to leak. VW/Audi has never put very robust sensors in their cars, I view them as maintenance items and change them out when replacing the timing belt/waterpump. You'll need new crush washers(one time use, or they leak) for the fuel filter if your ordering one.
You might search for the "B5 Faq link" here as well as the tech section on audiworld. There are a number of fairly informative articles there. Its no replacement foir the factory manual from Bentley but a great accessory. Hope you get the car fixed.

Yippers®

The Bentley manual lists a bad coolant temp sensor for the code you posted.

Rack 'em Willie

2nd. I had similar symtoms and this was the problem. Easy DIY fix for around $30

lewismug

Thanks a MILLION guys! I have ordered a Temp Sensor and a fuel filter for the car and will install them both tomorrow afternoon. Hope they get the car back to normal!

lewismug

I installed the coolant temp sensor tonight, and MAN WHAT A PITA! I really don't believe they could have put more stuff in the way of that sensor! Anyway, I have it anstalled and will see what happens tomorrow after my 1.5 hour drive to work. Thanks again guys! I have a Volvo and there are several sites that I use for repairs such as this one, but there aren't many Audi repair forums that I could find!

lewismug

Thanks Guys! You probably saved me several hundred dollars! The temp sensor did the trick!