Fuel pressure sensor replacement

[MrFancypants]

Merging on the interstate, foot on the floor, there was a very sudden loss of power like an intake hose after the turbo popped off. Car still ran but with loss of power, but no dash lights. Parked car, shut it off... tried to start again and it sputtered a bit as it tried to fire, then died. Now the engine just spins with the starter.

Checked codes and got p0087 and p119a. Fault within fuel deliver system and fuel pressure sensor, respectively.

Looks like the fuel pressure sensor failed in a pretty spectacular way and I still had enough fuel in the system to limp for a couple of miles.

Question to the technicians here... Is this a doable repair in a parking lot? It looks tricky to get to, but not impossible. Can I assume there's not much fuel left in the system at the fuel rail at this point or will I make a mess pulling the sensor out?

I'd rather not tow it, but I'll do what I have to.

 

[MrFancypants]

Thinking about this a little more... unless someone suggests otherwise I'm going to assume the sensor is fine and it's getting no pressure. Seems like if the sensor were bad and there was still fuel pressure the car would at least start and run in limp mode.

Given the very sudden loss of power I'm betting on a bad pump.

 

[BudgetPhoenix]

http://wiki.ross-tech.com/wiki/index.php/P119A/004506

There's a note about checking the resistance of the HPFP fuel metering N290 sensor & the N 276 fuel regulator sensor. The HPFP sensors should be easy to reach and test first. Idk how easy it will be to test the G247 fuel pressure sensor and/or remove it since its in a tight spot with the intake manifold on. I haven't heard of that sensor failing too often on these engines.

 

[MrFancypants]

http://wiki.ross-tech.com/wiki/index.php/P119A/004506

There's a note about checking the resistance of the HPFP fuel metering N290 sensor & the N 276 fuel regulator sensor. The HPFP sensors should be easy to reach and test first. Idk how easy it will be to test the G247 fuel pressure sensor and/or remove it since its in a tight spot with the intake manifold on. I haven't heard of that sensor failing too often on these engines.

I’d go test the HPFP now but the car is resting where it died, 45 minutes away in a parking lot.

Seeing that these engines have a history of failing HPFPs my money is on that.

 

[BudgetPhoenix]

That's rough man. Couldn't find any info about whether the fuel pressure is easily removable without pulling the Mani. Don't have elsawin on my PC anymore either

 

[MrFancypants]

That's rough man. Couldn't find any info about whether the fuel pressure is easily removable without pulling the Mani. Don't have elsawin on my PC anymore either

It looks like it can be done with the manifold in the car, probably worth a few scraped knuckles though. The HPFP looks super easy to change though… a couple of torx screws and fuel lines and it comes right out.

 

[MrFancypants]

Going to have it towed to a local VW shop. If I were able to limp it home I’d figure it out and fix it myself, but I don’t feel like driving around for hours trying to source the part only to have it not solve the issue and the car still be stuck where it’s at.

Made it nearly 12 years before it left me stranded somewhere. Not bad.

 

[MrFancypants]

Turns out I was partially correct. The high pressure fuel pump failed, but it looks like it failed because the in tank pump also failed. Theory is the HPFP was overstressed because it had to pull fuel without the in tank pump’s assistance. Had I noticed that it wasn’t priming (the noise when you turn the ignition to “on”) I probably could have replaced it before the HPFP failed.

 

[Joe_Mama]

I was thinking LPFP too. It sucks it doesnt have its own sensor.

 

[MrFancypants]

I was thinking LPFP too. It sucks it doesnt have its own sensor.

Yeah, if there was an in line sensor between the tank and the HPFP I’d have known there was a problem before it left me stranded.

I also thought it might have been the LPFP, and if I had noticed it wasn’t priming I’d have fixed it before it became a problem. Oh well.

 

[MrFancypants]

Turns out I was right, it was just the HPFP… mine was completely worn out. When the plugged the new one in the LPFP primed as it was supposed to.

 

[MrFancypants]

Got the car back, was running fine. Put my foot on the floor and… sudden loss of power, flashing check engine light (which didn’t stay on), solid EPC light, a steady misfire, and an exhaust that smells like someone dumped a gallon of gasoline into it.

Scan tool says cylinder #4 is misfiring and the O2 sensor is unhappy.

Wild ass guess: the new HPFP broke an injector and now it’s dumping a ton of fuel into cylinder #4, causing the misfire and dumping a lot of fuel into the exhaust

I suppose it could be a failed coil-pack, but I can’t overstate just how strong the fuel smell coming from the exhaust is. I just can’t imagine that cylinder dumping so much fuel into the exhaust that it makes it smell as intense as it does if it’s the coil pack.

Spark plugs have ~30k miles on them so they shouldn’t be the issue.

 

[BudgetPhoenix]

Same symptoms as my failed injector. It also gave me a low fuel pressure fault. If you pull the spark plug you can prob confirm it should be very wet with fuel

 

[MrFancypants]

I let the car sit for a week because I was tired of looking at it and now I'm ready to drive it again. Pulled a few pieces off this morning and thought to check the oil to see if it smelled like fuel and *yikes*... the dipstick smells like I dropped it into the fuel tank. So much for my freshly changed Mobil 1 and brand new Mann filter.

Question for those who've removed their intake manifold regarding that metal brace the bolts to the bottom of the manifold, in DIYs I see that everyone completely removes it from the car. Why not just unbolt it from the manifold and just leave the brace itself in the car and bolted to the engine? Is there a reason why the manifold won't slide out if I just leave it in there?

Also decided that because I'm ready for a new drive belt I'm just going to remove the alternator as it's held on by four very easy to reach bolts and looks like it'll free up an awful lot of space to make it easier to get my hands and tools under the manifold. Five minutes of extra work which could make the job that little bit less frustrating.

I'll get back at it tomorrow. I think I've disconnected nearly everything other than the coolant temp sensor, that metal bracket, and the injector harness connectors that I can't figure out how to get my hands on with the manifold bolted down.

 

[Sspcivic31]

The brace connects to a rubber isolator on the bottom of the manifold. It has a threaded stud the brace bolts to with a flange nut. Take the brace off the block. It’s held on with an xzn/triple square. Brace should kinda wiggle out. The injector harness et all should come off with the manifold. It “starts” on the manifold side by the flapper motor on driver side. Once the car side harness is disconnected you should be ok. I wouldn’t fart with the alternator. Your biggest worry should be if an injector is stuck in the motor.