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Discussion Starter · #1 ·
This has been a long ongoing pita with my fuel issues. First the issue started when my primary passenger side pump died. Ran for 30 seconds and then would stall. Fixed it easily with a new oem pump. Drove it for a month without issue when I realized that the fuel pump to tank gasket was a one time use item. CEL for "large evap leak detected".

Purchased a new gasket for $12 at the dealer. Put it in this Sunday. CEL gone. Fires right up. I drive to the gas station right afterwards. Fill up and start the Touareg. After 30 seconds of idling it stalls out.

Luckily I was across the street from home. I walk home, get tools, and pull the passenger side pump thinking maybe the electrical connection is loose. Everything looks good so I inspect the pump in the tank. The female spade connection deep in the fuel pump itself came off of its connection. This requires bother pumps to be pulled out to remove the pump and reconnect the connection. I assemble everything and she fired right up. No issues, no CEL, no stalling.

She runs fine for 2 weeks when I need gas again. I put half a tank of fuel in. Starts up fine. Then stalls at 30 seconds.........

Without playing around I pull the fuel pump covers, inspect both connections, all external fuel fittings and use a stethoscope (I'm a medical resident) to listen to the priming pump and make sure that's good. It works properly, for 30 seconds, then turns off and the treg stalls shortly after.

I listen to the passenger pump at 31 seconds. Nothing. Doesn't turn on. So I unplug the passenger fuel pump. Start the treg and as soon as I hear the priming pump turn off, I plug in the passenger pump at 32 seconds. And it turns on........

Fuel gauge doesn't work when I had to do this. So, I turn off the treg. Restart it and I have fuel gauge, but again, it stalls at 30 seconds.

Once more, I pull the passenger plug. Start the treg. And plug pump in at 31 seconds. Works perfectly with no fuel gauge.

At this point I drive it home. Leave it home. And get a ride to work.

I'm thinking its a fuel pump relay. I'm essentially creating a negative feedback loop by unplugging/ plugging in the pump while the treg is running. I think. Tried to swap around the two 404 fuel relays. No difference at all.

Anyone ever hear of any such issue like this?!

Is it possibly I burned out a relay when the spade connection to the fuel pump inside the tank was loose and flopping around? Short the circuit?

Are there other fuel system relays I'm overlooking besides the two on the drivers side firewall?

Thank you!
 

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Bummer. VCDA/Vag-Com would be really useful right about now.

I'd recommend getting one yourself. It's $$$, but well worth it for the diagnostic ability, not to mention all the other fun things you can customize with your Touareg.

In the meantime, if you want, you can try new fuel pump relays. They're reasonably inexpensive.
 

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I messed around for almost 2 weeks, trying to figure out my no fuel pressure issues. It ended up being a cracked filter housing on the driver's side. It was bleeding all the pressure back into the tank.

Maybe check that...?
 

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Discussion Starter · #7 ·
Thanks for the tips guys! Turned out to be the passenger side fuel pump. Again. I think when the power wire inside the tank came loose it may have shorted the motor. Bench tested the pump and got nothing.

Used a test light on the harness entering the fuel pump. Passenger side pump gets power 5 seconds after the drivers side pump turns off.

1 year warranty paid for itself ??
 

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Hi, I am curious to this scenario and could be related to my dilemma. My Treg starts no problem. But I am getting an intermittent shutdown during the times I back out of my garage or when I slowdown. I am getting a CEL now with all cylinders misfire. What was your CEL code show? when your pump did not work? I am wondering if it's my fuel pump or the relay.When I turn on the Treg I hear the humming sound only sometimes, but will hear it after around 30 seconds. This (I guess it's the fuel tank priming) sound sometimes turns multiple times. I hear this sound also sometimes when the Treg starts to shake right before it shuts off. Could it be possible the relay turns on and off itself? Or I am not getting any signal to the pump or get signal ON and OFF resulting the fuel pump to keep priming? Or could it be my primary fuel pump getting bad?
I have already changed the crank position sensor a week ago, but it was not the OEM one, it was from Rock auto brand name Beck/Arnley could that be it? I've also changed the spark plugs and one of the damaged coil, the other 5 looks OK, so I left them.
I don't have Vag-Com so I really cannot diagnose it.
 

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The Beck/Arnley crank sensor should be fine so long as it was in fact the right one. It's also possible your Treg is having a problem with the correlation between the crank and the cam sensors talking to each other. Most likely this is not the case, the bad news however...


Depending on how many miles you have on your vehicle and if it's even been done yet, is that you may need to look at a timing chain. (If this is the case, just get the kit and replace the water pump, thermostat, etc. all at once)

Could be as simple as a vacuum line getting knocked loose or busted during crank sensor replacement, etc.

Also, not sure what you put in there for plugs, just make sure they have the correct gap on them.


I fear you're really going to need to just try and hook up with someone who has a VCDS and knows how to use it and find out what's really going on.
 

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Mine is at 133K now. Yea, I made sure I got the right crank sensor on mine. So far that P0016 code didn't come back since I replaced it. I may find around one close by or order the VCDS soon.
 
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