ok so i have a 99.5 a4 quattro and ever since a couple months ago when i had some mechanic try to replace my fuel pump my cars been takin like 5-10 seconds to finally start.. the pump i gave the guy to put in he said wasnt good enough so he put the old one back in so i left it alone but ever since he took it out and put it back in this is when ive been getting this extended crank problem... it use to start right up.. ive replaced all spark plugs.. im thinkin he fu*ked something up with the fuel pump it seems to work fine once it finally starts for the most part unless i let it sit for a couple hours then it cranks a little bit before starting again... so does anyone have any ideas of where i should start at to try to fix this problem im not tryin to mess up my starter. thank you

 

Sounds like maybe a fuel leak somewhere after the fuel pump. Try turning the key to "on" position but don't turn it all the way to the starter position. Wait a few seconds and if you have the radio off, you should hear the fuel pump kick on, pressurize the system, and shut off. After that, turn the key to start the rest of the way. If it starts right away, you have a leak somewhere. If it still does not start for 10 secs. the problem is elsewhere.

 

i tried that everytime so far ive gotten into my car and its seemed to work but this morning when i tried it, it didnt reallly seem to have worked... i mean its taken longer before but idk ill have my friend look around for a leak by the pump.. thanks

 

Could be your coolant temperature sensor, they are known to go bad on these cars. When the computer thinks the coolant is much higher or lower than actual it wont adjust the fuel mixture correctly when trying to start.

 

OK - so waiting the time before starting worked for a while and you did not have this problem before the mechanic worked on your fuel pump. It's most likely something he did while swapping out the pump as you suspected. You probably will not be able to visually see a leak, as the pump is inside the tank and the fuel could be leaking back into the tank. There is an O-ring on the connection to the supply line that must be changed every time it is disconnected. Possibly this was not replaced or tightened properly and it is leaking there. You did not say why you wanted the pump replaced in the first place? Did the mechanic perform any other work? fuel filter?

 

yea it was fine till he took it out.... but i tried to have him replace it casue my car just hit 105,000 miles so before it went out on me i just wanted to throw a new one in, but he snapped something on the new one so i took it back and told him to just put the old one back and and ever since in the mornings mainly it cranks for like 10 sec before it starts. i dont use that guy anymore so ill have me new guy check it out... but also how do i check my coolant temp sensor? and yea he put a new fuel filter in.. but until now hes been reliable he put in my clutch for only 300$ and theres no problems with it and my axles and **** like that but he messed up on this