Fuel pump and pressure

Hi Thomas:
Sounds like it's not getting fuel right away.
I'd be checking the choke, and also perhaps try priming by pushing gas pedal all the way down twice, spin over 2 or 3 seconds, then pump gas pedal twice again, then try to start.
None of this is valid if it is a diesel.

run the fault codes
have a fuel pressure test done to check fuel pressure (45-65 PSI)
the codes may show problem crank/cam position sensor

Something is definitely wrong with this picture. It should only take 2 or 3 seconds for the pump to make correct pressure. Just turning the key to on turns the pump on to pressurize the system, then pump will shut off, maintaining pressure, until the computer gets an engine cranking signal, at which time pump should come back on, and stay running when engine is running.
The only way to check fuel pressure is with a fuel pressure gauge hooked onto the fuel rail. If you check and pressure is correct and doesn't drop right away, the problem is elsewhere, not in the fuel delivery. You said takes a long time before car will crank-is there a problem with the engine cranking over with key in start? That would be an ignition or starting circuit problem, not having anything to do with the fuel pressure.

If you have 100,000 miles or close to it you needed or would need a fuel pump anyway.Your mechanic sounds like a knowledgeable skilled honest one, he didn't even charge you for some items.
Stick with him/her as you both will get all the problems solved.
The work he has done is smart logical work so far.
Next time it does not start right away,keep cranking the engine to get the oil pressure up.If it starts when the oil pressure builds it may be you are not getting a prime cycle when you first turn on the key some times.

the only way to tell for sure is to have the engine anylized with a real time scanner, it could be a sensor or actuator that is not throwing a code so a scan for codes will not help, if all seems to be od start looking for vacuum leaks, air bubbles in the fuel, fuel pressure constant, etc

SOUND LIKE FUEL PUMP FAILING. REPLACE FUEL PUMP RELAY CHANGE FUEL FILTER.CHECK FUEL PUMP PRESSURE SHOULD BE 34 - 38 PSI.

Have you relapced the fuel pump and filter? Take it to a garage and have the fuel pump pressure checked. It very common for fuel pumps or a clog in the line to cause this.

Hi there again

Sorry to hear you are still having problems.If you are going to change the pump I would certainly not recommend you do it yourself.If it is the V4 motor I am thinking of, you would need to get to it by removing the rear seat ,remove access panel , and pretty much play around in the gas for an hour or so to get it off in the first place.

What I did find was this on the net on a recall by Audi to replace 2002/03 model fuel pumps as noted below.

RE: 2002 Audi A4 Fuel Pump Change:


I just had my fuel pump changed out by the dealer. Here is what the letter said-

"Safety Recall JL 2003 year Audi A4 quattro with 1.8L Turbo or 3.0L engine and 2003 Model year Audi A6 with 3.0L engine"
The fuel pump on some affected vehicles may contain a carbon brush set that is susceptible to premature wear.

On invoice it says-

JL12 Install fuel delivery unit and sealing washer.
1 8E0-919-133-G Washer
1 8E0-906-087-P Fuel Pump

No charge for unit or install. Just call them up and give the vin number to see if your car is affected. On the other note of your code error '1&3 misfire',try and have it re-set (it might be an old error)and see if it comes back. Hope this helps ,and I will research your problem further with pleasure if need more help.

You have mentioned that you replaced the O2 sensor. The oxygen sensor is completely ignored by the engine computer while the car is starting, and doesn't come into play at all until the engine warms up completely. Are you sure you have a fuel pressure problem? If so, replacing the O2 sensor would not have any affect.

To be sure you have a fuel pressure problem, you need to measure it. This car does not have a fuel pressure test port, so you need an inline fuel pressure test gauge. To test the pressure, connect an in-line gauge and switch your ignition switch to the "run" position. (Do not start the engine.) The fuel pump should run for two seconds. During this time when the engine is not running, you should have between 41 and 47 PSI of fuel pressure. If you start the engine, the fuel pressure should drop somewhat at idle (maybe somewhere closer to 28-35 PSI). Fuel pressure is regulated according to intake manifold vacuum, so at idle, it should be fairly low, while at higher throttle settings, it should be higher.

From what I gather, your car cranks for a long time before starting. If you suspect low fuel pressure, a defective fuel pump relay could cause that condition. The relay is located in a relay/fuse box under the hood on the driver's side of the car. If the relay fails, the fuel pump can still be energized by the engine oil pressure switch. This switch closes when engine oil pressure reaches ~4PSI. If your engine is not producing 4PSI of oil pressure while cranking, or if it takes a while to reach 4PSI, that would explain your problem.

Check your fuel pump pressure. You can rent a fuel pressure gauge from autozone and check pressure coming from supply pump. I bet its weak. Hope this helps.