Alright, I have a 1988 Audi 90 Quattro that I had just bought. It ran a little cooky so I took it to the shop and had emissions done on it to have it pass good at high RPM, fail on the low RPM because of HC limits (limit is 220 in utah and mine was a whopping 4900), in turn I changed the sparkplugs, wires, oil and oil filter, and it ran a little better but my buddy suggested we change the air filter. This is where we get a smack in the face, it was a pain to get to the air filter as its under a bunch of stuff, but we get to it and change it. Put everything back in place, crank it over and boom no start. it will start on occasion when i give it TONS of gas but as soon as I let off, it dies, and wont start even if i give it tons of gas again... So we again take everything off to see what the problem is and my mechanic friend told me to go crank it while he held this flappper thing about 3 centimeters up and the engine started. Its connected to a "Bosch" fuel pump, and to the looks of it, it requires a massive amount of air to push the "flapper" up. We checked all the fuel lines and they all get fuel. Only when the "flapper" is up it starts and runs. Please help!

peace

 

I figured out what the fuel pump is. Its the Bosch CIS-E III... if that helps any.

thanx

 

check that all hoses conected, a vacuem leak will make that you wont start.

 

sounds like a vacum leak ... make sure that all hoses are in place filter housing is closed

 

Alrighty Its fixed. Thanx you guys! Turned out to be the Boot right above the flapper had a hole in it so it has been replaced!

peace