04 Passat crank but no fire

LKN · Aug 10, 2017

Drove my 04 Passat yesterday, everything was completely fine.

Went to start it this morning, and it just cranks. No codes on dash. After 10 seconds of cranking, the oil pressure light came on and said stop.

Anyone have a clue where to start?

Windex · Aug 10, 2017

Can you hear the in-tank pump running when you turn the key to "on"?

LKN · Aug 10, 2017

Windex said:
Can you hear the in-tank pump running when you turn the key to "on"?

Yes and it's fairly new

LKN · Aug 10, 2017

Not my day!

Passat would start, so I took my motorcycle. It broke down a few miles from work, and I had to walk. It's only a few months old.

Windex · Aug 10, 2017

Sorry about your dual-failure...

If the in-tank pump is running, then check to see if you have fuel past the fuel filter.

Remove the line from the fuel filter to the tandem pump at the back of the cylinder head (at the pump) and place it in a clear container - turn the key and see if you have fuel coming out.

Silly question - what does the fuel gauge read?

If the issue does not end up fuel related, do you have access to a VCDS scanner to determine if the engine is seeing crank RPM? They are rare, but a bad crankshaft sensor can cause the same issue.

LKN · Aug 10, 2017

Windex said:
Sorry about your dual-failure...

If the in-tank pump is running, then check to see if you have fuel past the fuel filter.

Remove the line from the fuel filter to the tandem pump at the back of the cylinder head (at the pump) and place it in a clear container - turn the key and see if you have fuel coming out.

Silly question - what does the fuel gauge read?

If the issue does not end up fuel related, do you have access to a VCDS scanner to determine if the engine is seeing crank RPM? They are rare, but a bad crankshaft sensor can cause the same issue.

I will check that when I get home. It's a little above 1/4 tank.

Could this be a ignition switch issue? I bought the car less than a week ago from a member here, and it's been running completely fine. Zero sign of any issues.

I've never noticed the glow plug light ever on this vehicle.

Anyone here in the Charlotte/hickory nc area, willing to help assist? Obviously I will pay

afarfalla · Aug 10, 2017

crank it, see if tach moves

LKN · Aug 10, 2017

afarfalla said:
crank it, see if tach moves

I will check that when I get home.

Picking up an ignition switch tonight. Have a 219 relay and fuel filter showing up tomorrow....

Hoping one of those solve the issue... If not, then crank position sensor? No clue?

LKN · Aug 10, 2017

afarfalla said:
crank it, see if tach moves

The teach moves. Glow plug light works. I can hear the fuel pump.

afarfalla · Aug 10, 2017

I believe you lost pressure from the tandem pump to the common rail, (leaky injector) if you crank for 5 seconds at 10 second intervals it should start, double up on your battery.

Its happened to me a couple of times, takes awhile but it eventually starts

LKN · Aug 10, 2017

afarfalla said:
I believe you lost pressure from the tandem pump to the common rail, (leaky injector) if you crank for 5 seconds at 10 second intervals it should start, double up on your battery.

Its happened to me a couple of times, takes awhile but it eventually starts

I owe you a beer!

Took about 6 cycles, and it started.

What should I be looking at replacing?

afarfalla · Aug 10, 2017

My experience with this problem...I drove from Houston TX to Wildwood Fl, parked the car, the next day it would not start, I cranked and cranked, it started and the problem hasn't returned, been 6 months?? If you have a failure its the tandem pump one-way valve or a leaky injector

The lift pump in the tank delivers low pressure fuel to the tandem pump, the TP pressurizes the fuel thru the common rail to the injectors, (the TP works off the cam) from the TP to the injectors is a sealed system, when you shut down the engine this hi pressure is supposed to remain, if fuel its allowed to dribble out then you have to crank to get this pressure back to the injectors so the car will start. The TP also delivers vacuum to your brake boost.

afarfalla · Aug 10, 2017

carry an extra battery and jumper cables till you figure out what's going on.

You could probably find the problem with the vag-com with a little research

LKN · Aug 11, 2017

It started fine today, but pretty sure diesel is getting into my oil.

Looking like it's time to replace the tandem

whizznbyu · Aug 11, 2017

Injector seals.

LKN · Aug 11, 2017

whizznbyu said:
Injector seals.

I had an issue with it not starting, and after 6 or so cranks it fired yesterday. Generally, isn't that the sign of the tandem?

fastcar4re · Aug 11, 2017

As noted above, it sounds like a pressure/fuel loss is causing the issue, so it could be injector seals, but it could be the tandem pump IF there is an issue with maintaining pressure on that end after shut down. Without more information, any conclusions are educated guesses. Keep us posted.

LKN · Aug 11, 2017

fastcar4re said:
As noted above, it sounds like a pressure/fuel loss is causing the issue, so it could be injector seals, but it could be the tandem pump IF there is an issue with maintaining pressure on that end after shut down. Without more information, any conclusions are educated guesses. Keep us posted.

What's the best way to see if the tandem is leaking fuel into the motor?

afarfalla · Aug 11, 2017

sounds like your dying to change something so change the tandem pump and coolant flange underneath it, you may want to include the sensor. Get torque values and sequence right on the TP so it doesn't leak oil. Grease up O-rings. The TP would be the likely suspect for your problem, make sure your in the right frame of mind when you start it. Now is the time to add a boost gauge.

LKN · Aug 11, 2017

Paper test.

This is fresh oil, it was changed earlier today.

This photo is under a minute from dropping on the paper

This is a few mins of sitting

LKN · Aug 11, 2017

Also note. The oil cap trick, mine dances about this much....

https://m.youtube.com/watch?v=hupIKBK0nro

It starts right up, and turns off instantly. I'm only familiar with older diesel Benz, and usually when the cap dances that much on them they shut off rather lazy...

Could this be the cause of fuel in the oil? Zero smoke out of the tail pipe.

whizznbyu · Aug 11, 2017

LKN said:
I had an issue with it not starting, and after 6 or so cranks it fired yesterday. Generally, isn't that the sign of the tandem?

My problem presented with difficulty starting when
1) Parked nose up
2) Fuel tank less than 1/2

Eventually, the problem progressed to difficulty starting even at 3/4 tank, and nose down.
I changed out the lift pump, changed out the tandem pump, the thermostatic T.
Problem persisted despite that.
Clear tubing was then placed somewhere along the fuel line and the car parked over a period of days, and it allowed for the ID of bubbles and where they came from. Narrowed it down to the injector seals. Replaced all four and I'm good now.

afarfalla · Aug 11, 2017

your oil cap is normal, post 22 appears to be another possibility, I've haven't experienced this one

where did you place the paper?

LKN · Aug 11, 2017

whizznbyu said:
My problem presented with difficulty starting when
1) Parked nose up
2) Fuel tank less than 1/2
Eventually, the problem progressed to difficulty starting even at 3/4 tank, and nose down.
I changed out the lift pump, changed out the tandem pump, the thermostatic T.
Problem persisted despite that.
Clear tubing was then placed somewhere along the fuel line and the car parked over a period of days, and it allowed for the ID of bubbles and where they came from. Narrowed it down to the injector seals. Replaced all four and I'm good now.

Im hoping it's not the injector seals ha

afarfalla said:
your oil cap is normal, post 22 appears to be another possibility, I've haven't experienced this one

where did you place the paper?

Just had it sitting on top of the motor.

afarfalla · Aug 11, 2017

normal blow by with the cap off. Like mine, you may never experience this problem again?

LKN · Aug 11, 2017

afarfalla said:
normal blow by with the cap off. Like mine, you may never experience this problem again?

That would be great, but there is diesel in the oil.

Going to bring it into a specialist, so they can determine if it's the injector seals, or tandem.

Appreciate all the feedback!

afarfalla · Aug 11, 2017

how did you determine there is diesel in the oil? Oil overfilled? smell?

LKN · Aug 11, 2017

afarfalla said:
how did you determine there is diesel in the oil? Oil overfilled? smell?

Smell, and you can see the fuel separate from the oil on paper.

LKN · Aug 12, 2017

Solid deal on a new tandem pump
https://m.eeuroparts.com/Parts/55077/Vacuum-Pump-724807170/

LKN · Aug 12, 2017

afarfalla said:
sounds like your dying to change something so change the tandem pump and coolant flange underneath it, you may want to include the sensor. Get torque values and sequence right on the TP so it doesn't leak oil. Grease up O-rings. The TP would be the likely suspect for your problem, make sure your in the right frame of mind when you start it. Now is the time to add a boost gauge.

Which coolant flange? There appears to be a few web searching.

Thanks

04 Passat crank but no fire

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