2.0 BHW Swap starting issue

[Smittyzz]

Evening all, I have a 2000 a4 with a 2.0bhw swap with the euro driveline and s4 bits, I call her my tds4
Anyways she's been a great trustable vehicle but the last year she's started having a few crank no start issues..

Crank no start meaning I can crank it 10 times for 4 seconds and it won't start, or I can crank it for 20 seconds straight no start.

It will ALWAYS start within a few minutes, sometimes a random key turn, sometimes I let it sit a sec and it starts right up..
When this happens the glow plugs light flashes, no cel, but I will scan next time with vcds.
It's not the hpfp. As it's done this a straight year sometimes it's months without doing it sometimes it's the next day.. always comes out of it and starts everytime after.
I am going to see about letting it sit with the key on after the first try again and see if that makes a difference, but I'm looking for some guidance.
Maybe someone who knows these motors well.. maybe a tech?
Aside from the start issue she runs strong at 190k pushing 22.6 psi runs strong just annoying to start sometimes

Thanks in advance

 

[MEgearhead]

It doesn't have a real HPFP as it's a PD not a CR engine so I assume you mean the tandem pump at the rear of the cylinder head. What checks did you do to rule out the tandem pump?

Can you hear the lift pump in the tank run for a second when you turn the key on?

Have you checked for leaks at the hose connections to the fuel filter?

Check rpm and volts with VCDS while cranking.

 

[Smittyzz]

It doesn't have a real HPFP as it's a PD not a CR engine so I assume you mean the tandem pump at the rear of the cylinder head. What checks did you do to rule out the tandem pump?



Can you hear the lift pump in the tank run for a second when you turn the key on?



Have you checked for leaks at the hose connections to the fuel filter?



Check rpm and volts with VCDS while cranking.

Yes no leaks anywhere.
I don't think it's a prime issue.
I'll have to check if I can hear the lift pump in tank, I haven't checked. But I have read that won't stop them from starting..
When it fires it fires before it finishes its first revolution as soon as I turn the key

I haven't checked the tandem pump honestly because I don't know how, and I can't find much info on this stupid motor... I'm used to alhs...
How can I go about testing it?
As for volts, it's pushing 15.6 running and 13.2 to 12.8 not running regulator went but hasn't bothered anything in the months it's ran like that.. and the issue was long before this,
I'll check rpms next time it does this, what Block should I check? Idk this motor at all and thank you for the reply

 

[MEgearhead]

You test the tandem pump by connecting a pressure test gauge to a port on the pump with a banjo fitting. I wouldn't worry about that until you rule out some easier things first.

While yes it has been stated online that they will start and run with the in-tank lift pump inoperative, I can tell you mine will not. I fought an intermittent stall and no start for around 5 years. After a new lift pump, no more issues. I recommend you rule that out. If you can hear the pump, then the next step is to disconnect the fuel feed line to the filter and direct it into a container. Turn the key on and you should get a short shot of fuel out the hose. If that all checks out, you can put a pressure gauge on the fuel feed hose to the filter and use VCDS to run the pump. I'll have to fire up the old Windows XP machine to look the spec up in the Bentley manual, but I think it should be at least 10 psi. You can also run the pump for 30 seconds and measure it's output in a container. Just make sure you have at least a two liter container. There's no published spec for that, but my bad pump only put out around 0.35 L in 30 s, and the new pump put out over 1 L in 30 s.

To check for air leaks on the suction side of the tandem pump you can put a short section of clear hose between the filter thermo tee and the return line to the tank. Watch for air as you idle it. I wouldn't drive it like that unless you make sure it's secure so it doesn't come loose and spray fuel on the hot cat.

Check volts and rpm WHILE CRANKING. I don't remember the block numbers. Just go to advanced measuring values and look down the list. The labels on the BHW are pretty self explanatory. Both engine speed and voltage are near the top of the list. Put a check in the little squares and watch the numbers while you crank it.

 

[Smittyzz]

You test the tandem pump by connecting a pressure test gauge to a port on the pump with a banjo fitting. I wouldn't worry about that until you rule out some easier things first.

While yes it has been stated online that they will start and run with the in-tank lift pump inoperative, I can tell you mine will not. I fought an intermittent stall and no start for around 5 years. After a new lift pump, no more issues. I recommend you rule that out. If you can hear the pump, then the next step is to disconnect the fuel feed line to the filter and direct it into a container. Turn the key on and you should get a short shot of fuel out the hose. If that all checks out, you can put a pressure gauge on the fuel feed hose to the filter and use VCDS to run the pump. I'll have to fire up the old Windows XP machine to look the spec up in the Bentley manual, but I think it should be at least 10 psi. You can also run the pump for 30 seconds and measure it's output in a container. Just make sure you have at least a two liter container. There's no published spec for that, but my bad pump only put out around 0.35 L in 30 s, and the new pump put out over 1 L in 30 s.

To check for air leaks on the suction side of the tandem pump you can put a short section of clear hose between the filter thermo tee and the return line to the tank. Watch for air as you idle it. I wouldn't drive it like that unless you make sure it's secure so it doesn't come loose and spray fuel on the hot cat.

Check volts and rpm WHILE CRANKING. I don't remember the block numbers. Just go to advanced measuring values and look down the list. The labels on the BHW are pretty self explanatory. Both engine speed and voltage are near the top of the list. Put a check in the little squares and watch the numbers while you crank it.

I did have it happen again today in town away from equipment though so I didn't get to check anything at all...
I cranked it for like 10 plus seconds again after 4 crank no starts and it started the next start again like last time...
Zero issues when it is running
First time ever doing it after it's been started (usually only first thing in morning then fine all day)
I want to test an inline pump up by the fuel filter like my alh has with a clear like so I can see what's going on when it happens

 

[PickleRick]

Have you verified your in tank pump is working yet?

After a tandem pump R/R it usually to take about 10 tries to get it primed for restart?


Also since you're swapped into an Audi, did you swap out your in tank pump for a lower psi on? I believe the stock BHW in tank pump will also sent out 40 plus psi if the regulator found in tank with it is also swapped with it.


Or are you running a fuel return TEE to bleed off the excess pressure?

Another note, since your fuel tank is below your motor, when you power down the diesel can slowly drain back to the tank. I believe in the BHW Passat there is a check valve in the fuel pump assembly that prevents this.

Another poster here has a leak down issue with his car when he sits for extended times. His temporary fix has been to park on a hill nose down.

 

[MEgearhead]

Have you verified your in tank pump is working yet?

+1

Can you hear the pump when you turn the key on?

 

[Smittyzz]

+1

Can you hear the pump when you turn the key on?

Yesim leaning towards crank position sensor and have one ordered
Where is it located?
Sorry the the time between responses I've been doing a water pump and rear coolant flange on the wife's 2010 a4 premium plus 2.0
Also mid swapping an alh into a b5 sedan lol