[kevlarblue]

Exhausted of options I installed an MHD backend flash to see what effect that would have on my symptoms. It didn't change anything - still cranking very long occasionally. In doing more research I am now suspecting the fuel pressure regulator. This video I came across shows the same symptoms and mentions they could be sporadic like mine.

According to INPA the low pressure system is supposed to hold 70psi in the rail while the car is off. I was able to look at the fp_L with my JB4 and see that it runs up to 66psi with the engine on but after shutting down it falls below 10 within a few seconds and will actually settle to 2 or lower within a few minutes.

If anybody who doesn't have a long crank/hard start issue has the ability to give me another data point it would help me out. This is selectable as a guage in the JB4 or with an MHD monitor license. You don't have to make a log but it would be interesting to compare it to mine. I just want to know what your rail pressure / fp_L behavior looks like right after shut down. Does it hold ~70psi or does it drop to almost nothing within a few minutes?

[Sgop335]

Originally Posted by kevlarblue

Exhausted of options I installed an MHD backend flash to see what effect that would have on my symptoms. It didn't change anything - still cranking very long occasionally. In doing more research I am now suspecting the fuel pressure regulator. This video I came across shows the same symptoms and mentions they could be sporadic like mine.

According to INPA the low pressure system is supposed to hold 70psi in the rail while the car is off. I was able to look at the fp_L with my JB4 and see that it runs up to 66psi with the engine on but after shutting down it falls below 10 within a few seconds and will actually settle to 2 or lower within a few minutes.

If anybody who doesn't have a long crank/hard start issue has the ability to give me another data point it would help me out. This is selectable as a guage in the JB4 or with an MHD monitor license. You don't have to make a log but it would be interesting to compare it to mine. I just want to know what your rail pressure / fp_L behavior looks like right after shut down. Does it hold ~70psi or does it drop to almost nothing within a few minutes?

rl]

here you go about 5mins after shutdown:

[kevlarblue]

Originally Posted by Sgop335

here you go about 5mins after shutdown:

Thank you, that's a big difference from what I'm seeing. I have a new fuel pressure regulator on the way. I'll update once it's installed.

[kevlarblue]

I am happy to say that the Fuel Pressure Regulator solved the long crank / hard start issue I was having. It wasn't a very difficult DIY - took about 1.5 hours and a $135 part (VDO 16117163295). I did rent the special tool to get the tank cover flange off and that saved a lot of time (OEM 25156).

My lessons learned in this process:
::The hard start was not necessarily correlated with the engine being warm. This was probably my confirmation bias searching for a way to justify what was going on.
::The hard start symptoms with a failing Fuel Pressure Regulator can be intermittent and happen when the car is warm or cold or in a bad mood. It can also come and go over time.
::It is easy to diagnose this issue by reading the fuel pressure in the rail after shutdown (should be 60+psi). My bad regulator allowed the pressure to drop to almost 0psi right after shutdown.
::Being your own mechanic can be frustrating when you are chasing a problem without having empirical evidence to back up your symptoms - having the ability to create a log or monitor with MHD/JB4 saves time and money.

marcell1401 I recommend you check into this solution for your vehicle if your still having the same problem. Good luck.

[autoart]

So happy you found the issue. Questions was it the original and was it cracked? Thank you.

[kevlarblue]

Originally Posted by autoart

So happy you found the issue. Questions was it the original and was it cracked? Thank you.

Original unless it was replaced before I bought it at 65K miles - it's currently at 112K. I couldn't find any cracks and I looked pretty closely with a bright light. There was also no evidence of fuel ever leaking out on top of the regulator.

[swellengear]

Originally Posted by kevlarblue

I am happy to say that the Fuel Pressure Regulator solved the long crank / hard start issue I was having. It wasn't a very difficult DIY - took about 1.5 hours and a $135 part (VDO 16117163295). I did rent the special tool to get the tank cover flange off and that saved a lot of time (OEM 25156).

My lessons learned in this process:
::The hard start was not necessarily correlated with the engine being warm. This was probably my confirmation bias searching for a way to justify what was going on.
::The hard start symptoms with a failing Fuel Pressure Regulator can be intermittent and happen when the car is warm or cold or in a bad mood. It can also come and go over time.
::It is easy to diagnose this issue by reading the fuel pressure in the rail after shutdown (should be 60+psi). My bad regulator allowed the pressure to drop to almost 0psi right after shutdown.
::Being your own mechanic can be frustrating when you are chasing a problem without having empirical evidence to back up your symptoms - having the ability to create a log or monitor with MHD/JB4 saves time and money.

marcell1401 I recommend you check into this solution for your vehicle if your still having the same problem. Good luck.

Well done dude!!

[konstat]

Originally Posted by kevlarblue

Original unless it was replaced before I bought it at 65K miles - it's currently at 112K. I couldn't find any cracks and I looked pretty closely with a bright light. There was also no evidence of fuel ever leaking out on top of the regulator.

Originally Posted by kevlarblue

I am happy to say that the Fuel Pressure Regulator solved the long crank / hard start issue I was having. It wasn't a very difficult DIY - took about 1.5 hours and a $135 part (VDO 16117163295). I did rent the special tool to get the tank cover flange off and that saved a lot of time (OEM 25156).

My lessons learned in this process:
::The hard start was not necessarily correlated with the engine being warm. This was probably my confirmation bias searching for a way to justify what was going on.
::The hard start symptoms with a failing Fuel Pressure Regulator can be intermittent and happen when the car is warm or cold or in a bad mood. It can also come and go over time.
::It is easy to diagnose this issue by reading the fuel pressure in the rail after shutdown (should be 60+psi). My bad regulator allowed the pressure to drop to almost 0psi right after shutdown.
::Being your own mechanic can be frustrating when you are chasing a problem without having empirical evidence to back up your symptoms - having the ability to create a log or monitor with MHD/JB4 saves time and money.

marcell1401 I recommend you check into this solution for your vehicle if your still having the same problem. Good luck.

Nice job man thanks for updating the thread

[whyzee125]

If both HPFP and injectors are ruled out, I would look strongly at your FPR/filter assembly in the left side tank. I've been seeing more and more people have this be a problem lately and replacing it with a new unit resolved their warm start woes.

EDIT: I didn't realize this was already resolved. Nice job OP and now you have fresh injectors too! Yours was probably one of the threads I saw on this already and I just got confused lol