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P0087 (Fuel Rail Pressure Too Low) & P2294 (FP Reg Valve N276 Open Circuit) *EPC Warning*

MagicMK

Go Kart Newbie
Location
PA
It's been a while, but I'm back with a problem if anyone can help. Here's the background --- I have a 2008 MKV with a little over 100K on it, newer cam follower, original HPFP, original timing belt, no previous cam follower issues (replaced multiple times), and it's a dual clutch. I've been the owner since 2010, and I'm the only one that drives the car as well.

Just a few days ago, I noticed that the car lost a lot of performance and would not seem to rev much on my way home from my local gym. An EPC CEL Warning light came up for the first time on the car, as well. I shifted the car into manual shifting, and that seemed to fix it for a few more miles until I started having same issue in manual shift, as well. So, I hooked the car up to my Autel MX808 and reviewed the CELs (they're in the title) and also monitored the live data.

Based on my research, I'm thinking it's a HPFP issue, but could be as small as just an $11 + N276 Pressure Valve. I haven't had a chance, with the holiday and all, to remove the HPFP, but wanted to ask for some opinions and experience from the forum. Have any of you had similar CELs, and, in particular, has anyone found that it was as minor as the $11 pressure valve - or did you have to replace the entire Hitachi HPFP... or, was it something else, entirely?

Thanks in advance!
 

ROH ECHT

K04 PLAY
Location
PDX OR
Car(s)
2007 MKV GTI
The link is for the Pressure "Limiting" Valve not for a N276 pressure regulating valve...the N276 being on top of the HPFP, and is not on the fuel rail.

Check the N276 to see if it is cracked through the plastic. Its two codes say the rail pressure is not being met and it has a signal issue to the ECU. If you were only seeing the rail pressure issue, then it could possibly be the pressure limiting valve (the part you linked) was allowing fuel to go back into the low pressure delivery feed to the HPFP. But the data would show the actual pressure for the rail to be low, and the actual pressure in the delivery side to be higher than specified.


 

MagicMK

Go Kart Newbie
Location
PA
The link is for the Pressure "Limiting" Valve not for a N276 pressure regulating valve...the N276 being on top of the HPFP, and is not on the fuel rail.

Check the N276 to see if it is cracked through the plastic. Its two codes say the rail pressure is not being met and it has a signal issue to the ECU. If you were only seeing the rail pressure issue, then it could possibly be the pressure limiting valve (the part you linked) was allowing fuel to go back into the low pressure delivery feed to the HPFP. But the data would show the actual pressure for the rail to be low, and the actual pressure in the delivery side to be higher than specified.


Gotcha - was having trouble getting pics of the N276, but that makes sense, thanks. I just pulled the HPFP and checked the follower just to make certain before I progressed and the follower is in perfect condition. I used my scanner to save the Live Data, and I'm looking at it now - 230-1 Rail Pressure Spec is showing 36.26 bar, Rail Pressure Actual is showing 7 bar, so 230-3 is 27.8 bar difference. On another reading I saved, it was 50, 7, and 43, respectively.

After a quick look, I did not notice any cracks - but I'll examine it more closely. When I was looking at FCP Euro's website, I noticed some of the comments mentioned that at least one of the persons seemed to have similar issues, and he noticed that his part seemed "worn out," and the replacement of it fixed his low rail pressure issue.

Let me ask you - have you ever had similar problems? Did you ever replace your Hitachi HPFP? I saw a website that had a sale on it reducing the price from over $270 to around $210. $200 isn't a big deal when it comes to car parts, but I guess given the Pressure Limiting Valve is only $11, which is a big difference, it's worth just trying the $11 part by itself. Also, what are your thoughts on on the pressure readings I was getting?

Thanks!
 

GTI's

Drag Race Newbie
Location
MD
06D133400A is a bleeder valve has nothing to do with pressure regulation.

You have a code for open circuit for N276, check the wiring or do an output test on N276 with engine off and see if you hear it.
 

ROH ECHT

K04 PLAY
Location
PDX OR
Car(s)
2007 MKV GTI
Was also going to say if the N276 regulator isn't damaged...then it's communication to the ECU needs checking. I didn't even catch that you linked the bleeder valve on the HPFP before, as GTI's noted. The Pressure limiting valve on the fuel rail I spoke of is PN: 06D 130 757 C ...not 06D 133 400 A.

You have two routes you can take; replace parts and cross your fingers, or diagnose the problem first.
 
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MagicMK

Go Kart Newbie
Location
PA
06D133400A is a bleeder valve has nothing to do with pressure regulation.

You have a code for open circuit for N276, check the wiring or do an output test on N276 with engine off and see if you hear it.
Thanks for the response - you're right... that is just a bleeder valve, I agree. I thought that maybe it could be leaking, but it doesn't make sense due to the fact that when I disconnected it, there was fuel coming out of it and it wasn't leaking gas. You were onto the right thing... the N276. I'm going to respond to ROH's post next, since he nailed it... I'll explain in my next post. And thanks, again.
 

ROH ECHT

K04 PLAY
Location
PDX OR
Car(s)
2007 MKV GTI
Don't disregard GTI's input....he knows more than I do and I have often sought his help for my own issues.
 

GTI's

Drag Race Newbie
Location
MD
No Sir I think you know a lot more than I. Just wanted to point out that Op links was not for what Op thought it was. I suspect OP found the issues based on your statement "Check the N276 to see if it is cracked through the plastic"
 

ROH ECHT

K04 PLAY
Location
PDX OR
Car(s)
2007 MKV GTI
LOL....mutual respect then.

Yeah, just before I opened the link I read "$11 pressure valve" and my mind was on the pressure limiting valve. And it resembles the raill limiting valve...if you only glance.
 

MagicMK

Go Kart Newbie
Location
PA
Was also going to say if the N276 regulator isn't damaged...then it's communication to the ECU needs checking. I didn't even catch that you linked the bleeder valve on the HPFP before, as GTI's noted. The Pressure limiting valve on the fuel rail I spoke of is PN: 06D 130 757 C ...not 06D 133 400 A.

You have two routes you can take; replace parts and cross your fingers, or diagnose the problem first.
Hey, you were right - and thanks! Here's what happened... it WAS a crack in the N276... so for that matter, the recommendation in the MX808 was correct, as well. When I first looked for a crack, I was looking for a C-R-A-C-K. After both you and GTI's (as well as my Autel) were pointing to the N276 (and I realized what part it actually was), I did a Google Image search and found this: https://www.mk5golfgti.co.uk/forum/index.php?topic=113298.0 ---- now that's a CRACK. I grabbed a flashlight and ran back out to my car after seeing that image, because I thought I had originally seen a plastic "mold line" that you might see in molded plastic parts. On closer inspection, it was in fact a crack in the exact same spot as that picture.

In addition, I noticed that my factory electrical connector clip to the N276 was damaged as well (I noticed that earlier, but wasn't sure how the hell it happened). I actually have the special VAG tool to take off those fiddly VW connectors (a great investment, btw, esp since I own 2 GTIs). So, I was pretty sure I did NOT break it taking it off of the HPFP. According to that other thread, apparently those dumb-as-fuq-engineering-design GTI MKV plastic engine covers can hit the top of the N276 sensor (ie - mine mysteriously broke) and cause damage to the N276. Regardless, upon closer inspection, it's clearly cracked... and that explains the "open circuit" reference on my MX808.

So, again... thanks to both of you. Just in the future, if you ever have somebody (like me) tell you they didn't see a crack on a low fuel rail pressure DTC code along with an EPC MIL on the instrument panel, ask them to double-check with a flashlight. That picture really helped as well, because, again, my crack was a hairline crack, but it was definitely a crack. Now I gotta figure out next steps as far as what I want to replace. I can get a whole new Hitachi HPFP for about $210 - which includes the N276 - and it does not appear you can purchase the N276 separately. So, if I buy the Hitachi HPFP, it seems like a good idea to also replace the low pressure sensor, as well. ECS had an OE VW low pressure sensor for $62... so, altogether, it's going to cost me a little over $270. Fingers crossed, hopefully this will fix the issue. I'll follow up once I have the new parts installed.
 
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ROH ECHT

K04 PLAY
Location
PDX OR
Car(s)
2007 MKV GTI
No problem. Yes, when one struggles to remove the engine cover they are often damaged. But also when one struggles to disconnect the wiring the same may happen. It may have been that way, cracked, for some time and just now got bad enough to cause the issue.
 
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