Tyrone Alcorn

<table width="100%" align="center" class="tborder" id="post24782584" style="table-layout: fixed;" border="0" cellspacing="0" cellpadding="3"><tbody><tr valign="top"><td class="alt1" id="td_post_24782584" style="border-right-color: rgb(221, 221, 221); border-right-width: 1px; border-right-style: solid;">So yesterday I'm driving down the highways and all of a sudden I lose power while driving, for 2 or 3 secs, then as I'm pushing the pedal frantically it gets power again. So I drive another 3 miles then all of a sudden it happens again so I get ready to pull to the side of the highways and the gets power again. Mind you, I don't lose electric power or anything just rpms fall and car slows. Then I drive another 5 miles then all of a sudden it does it again and does not start this time.
So call a tow truck and while I'm waiting someone helps. So we think its the battery and check that, even try to jump it and nothing. 2 hours go by and tow truck comes so I try to crank it and it starts for literally 2 secs then dies. not it just cranks but doesn't start. Although I've noticed that if you let it sit for a while it will start for 2 secs and die again before going back to just cranking and no start.


So far I've checked:


the battery
fuel pump fuse
fuel pump relay (all 3 good)


I think it might be the fuel pump or fuel filter(or both). Anyone have any ideas. Also does anyone know how to do a fuel pressure check on this audi. I'm new to audi's. I see the fuel rail and what may be two fuel hoses (one on each side) in the front of the rail but I don't see a Schrader valve for a gauge. Any help anyone.
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georgeb944

VCDS Scan?

With no knowledge whatsoever (year, model, engine, transmission, etc.), I would guess the Crankshaft Position Sensor.

If you don't have VCDS, take it to a dealer.

SloopJohnB@mac.com

If you haven't changed the fuel filter in 60K miles it should be done anyway.

Tyrone Alcorn

oh its a 2003 Audi A6 quattro 2.7. Georgeb944: but should have shot a code for the crankshaft postion sensor. I didn't get a engine code for that. I've been getting a P0172 code but that was long before this. This just all of sudden happen. My car hasn't had any driving issues, even with the system to rich code. I definitely agree though, it is time to change the fuel filter probably. I just bought this car a couple months ago and it has been running fine until now. Oil change, tranny fluid change done. the normal.

georgeb944

When my CPS went **** up, no codes, just died on the road... no warning.

If you have VCDS, you can monitor the output of the CPS while cranking... no output, bad CPS.

CRuby

No fuel pressure schrader on my 2000 A6, so unless they added it, you don't have one either. If bad fuel pump, it would crank but no start. Don't think you would get multiple brief start, then die. But could check fuel pump under passenger side rear seat. Get someone to listen to that area, turn key on (don't crank) & listen for pump sound. No sound...go further. Pull seat bottom & check voltage to pump when key turned on. If 12V & no pump noise...bad pump.

Airbag

this is true and its not just an Audi issue. I have had other cars ( ford ) that when the CPS fails there is absolutely no code )

jcman

I've mention this a few times too in the past about the CPS only have two listed codes or having none when acting up, I've seen this two times where the car would not restart when warm or just flat out cold.

Tyrone Alcorn

So before I go the computer route to check the cps I checked my pump, which is in the trunk and sure enough no sound. Turned the key numerous times and heard nothing. Check the wires going to it and it was getting power. So guess it's the pump. I kind of thought the pump would be under they back seat like the 2002 model but guess not.

SloopJohnB@mac.com

Often the fuel pump is just 2"X6" or so but the entire fuel pump assembly is often sold, including the fuel level sensor, etc. at a much higher price. ECStuning has a Walbro that I've heard good things about, somewhat higher fuel delivery rate than OEM. It's a little fiddly to change it out of the fuel pump assembly but not too bad. You might want to look carefully at any of the flexible corrugated tubing on your FP assembly and consider replacing it at the same time.

OTOH, replacing the entire assembly is a faster job.


https://www.ecstuning.com/Audi-C5_A6....7T/ES2189784/