HELP - Peugeot EP6 High Pressure Fuel Pump Failure

FourPot

FourPot

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Tadpole
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Hi all,

A few weeks back I had the high pressure fuel pump go on my 207 GTI. This pump was not the original that came with a car, but rather a genuine new replacement from a few years back. The usual story of rough cold starts and the P0087 - so was swapped out for a known working genuine HPFP (not re-manufactured) and a fresh fuel filter. Car was driving beautifully for a week, but then the LTFTs start slowly drifting out towards -4% until a cold start flagged the code P0087 again. LTFT had blown out to between 8 to 10%. Seems to be the same series of events as the first pump.

I've scoured the internet for info regarding successive failures of the HPFP, but a lot of it seems to be people having bad luck with remanufactured pumps, etc. Before I chalk it up as a coincidence and go out and buy yet another HPFP, is there any known external causes for pump failure? Could the low pressure fuel pump contribute?

Cheers
 
Of course it can - though usually in the form of a damaged/melted electrical connector on the low pressure pump.

This lives under the back seat under a black plastic cover.
 
With the ignition on, but engine not running, I do hear what I think is the in-tank fuel pump prime for a few seconds. Fuel rail pressure reads 5 to 6 bar (70 to 90 psi). Once started, the idles rough as expected. When driving, the pressure seems to be 6 to 8 bar (90 to 120 psi) or so.

First two starts this morning the car presented the same code and displayed the typical, ambiguous 'depollution system faulty' message. On the third start, the pump appeared to idle at 50 bar and increase with RPM as expected.
 
From what you've described it certainly sounds like there's no issue with the in tank pump and a "classic" issue with the HPFP.
 
Thanks SLC206 - it definitely does seem to be the case. Must have gotten very unlucky.

Just for reference, here is the fuel rail pressure on start-up. From 5 bar, slowly builds and overshoots 50 bar, then steadies.

Screenshot_20240130-1431552.png


Once I give the throttle a light blip, it goes haywire with spikes to 130 psi (that's not from throttle input) and then very unstable pressures sub 50 bar. I have not been game to drive it when fueling is so off.

Screenshot_20240130-1432322.png


I'll bite the bullet and buy another HPFP. Is it worth getting a re-manufactured or sourcing a brand new one? These things have gotten a lot more expensive since the last purchase.

Greatly appreciative
 
OK so we are looking at fuel rail pressure, which I understand to be the output from the HPFP. I note the vertical axis is labelled as Bar, not psi. Since 1 bar =14.5 psi your 130 bar max equals about 1900 psi. I'm thinking this is ok?
 
I looked up the French data concerning the camshaft driven HP pump. Roughly it says this:

Pump pressure varies between 50 and 150 bars (2176 psi) depending on engine speed. Flow regulation helps avoid losses, minimising fuel consumption as well as minimising fuel return, since this regulation is integrated into the pump.

Flow regulation is by an electrically controlled valve (called MSV in the French), which restricts fuel on the intake side but not on the high pressure side. High pressure is regulated by the timing of the start of delivery, using the MSV

There is then a page with diagrams showing the working of the MSV fitted in the pump housing. Basically it permits the pump cylinder to fill until sufficient flow has occurred, when the solenoid closes it on computer instruction.

I have an oscilloscope pattern for the solenoid. Like so much else it is pulse modulated.
 
gwest said:
OK so we are looking at fuel rail pressure, which I understand to be the output from the HPFP. I note the vertical axis is labelled as Bar, not psi. Since 1 bar =14.5 psi your 130 bar max equals about 1900 psi. I'm thinking this is ok?
Click to expand...
It's within range, but as you can see, the pressure drops below the 50 bar on multiple occasions and very slow returns.

seasink said:
Flow regulation helps avoid losses, minimising fuel consumption as well as minimising fuel return, since this regulation is integrated into the pump.

Flow regulation is by an electrically controlled valve (called MSV in the French), which restricts fuel on the intake side but not on the high pressure side. High pressure is regulated by the timing of the start of delivery, using the MSV
Click to expand...
Is the valve/solenoid on the underside of the pump module? I believe this is the only electrical connection to the pump. The main concern is that both pumps failed in the same manner, in a matter of weeks. My worry is that either the lift pump in the tank is not supplying enough pressure, leading to heat and wear, or that there is an issue on the return side. The trouble is the car runs fine until the pumps just die.

Thanks for your insights
 
It would be interesting to monitor both the low pressure supply from the tank and the high pressure fuel rail at the same time when the HP output falls below the 50Bar limit and when the car runs out of puff. I mean, just make sure you take your mobile phone and a cut lunch.
I did a quick check on my DS5 THP but my Launch diagnostic tool seems very confused about the units and terminology it is using. I should drag out my Diagbox to see what it comes up with.
 

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Thanks for checking that - legend! Always good to have some reference data.

I'm a bit too worried to drive it as it's running so rough - like shaking the car. I have not seen the petrol rail pressure value in any of my scanners, but can make sense the other two. Reference value is what that ECU is expecting and fuel pressure measured is what the sensor is actually seeing. Good idea with Diagbox - forgot about that!
 
If I had done my homework I would have learnt that there is only one fuel pressure sensor on these engines, and it is in the high pressure fuel rail:
https://www.aussiefrogs.com/forum/i...el-rail-system-pressure-too-low.132335/page-2.

Dmccurtayne: “….there is a fuel pressure sensor on the fuel rail if you check the pressure with the engine off that will give you the low pressure pump value. “
So when interrogating the car with a scanner, ignition on, engine off, the value for fuel pressure is that being produced by the in-tank pump. When you start the engine the pressure reflects that produced by the HPFP. So there is no way of monitoring the low pressure side with the engine running.
My Diagbox vsn 7.58 tells me that with the ignition on, engine off, petrol rail reference pressure is 5 bar. On my DS5 the fuel pressure measured in the high pressure rail was 6 bar. With the engine running Diagbox sais that the petrol rail pressure reference value should be higher than 30 bars. My measured value was 46 bars.
Have you checked the connectors on the low-pressure supply pump as SLC206 suggested?
 
Yeah, connectors are all fine. Pump primes when key is placed into ignition. Haven't removed the pump as it'd be a messy job and require a new seal. Something I will have to look into, however

My car displays a fuel reference value of 17 bar with ignition on, engine off, and a pressure of 5 bar. Seems to be far off what your car is measuring.
 
I will attach the file I generated from screen shots from Diagbox- it's a pdf so I'm not sure how it will come across. Given Seasink's observation that : "Pump pressure varies between 50 and 150 bars (2176 psi) depending on engine speed." I was a little surprised to see a reference value of 30 bars on mine. Your 17 bar reference value sounds odd? It would be interesting if you can record data for both the actual pressure and reference value together.
 

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There is an interesting parallel to yours in a diagnostic video by LM Autos:


Mini Cooper S R56 running rough... Error 2880, high pressure fuel system faults

It mirrors the observations by dmccurtayne above : “ I have never needed to replace a fuel pressure sensor on a ep6 motor but done a heap of hp pumps and burnt connectors at the lift pump..”
 
Thanks for linking the vid - very in-depth!

I guess checking the function of the electrical components won't hurt. The replacement pump ran fine and was driven pretty hard, but gave up the ghost only after a few 100 km. I would have thought, if it was electrical, I'd see consistent issues right off the bat.

Once I get my new pump (ordered from UK), I'll perform a few more checks and see how it runs. I love these cars and thankfully I haven't had a lot of issues throughout my ownership (regularly change oil every 5000km), but the economics of buying a new pump every so often doesn't add up (third time's the charm?). Might be time to move on, unfortunately...
 
My DS5 THP had its HPFP replaced at 69k km (now at 91k). I don't know the history of my DS3 THP which has done 132k, but on the way down to pick up the chicken katsu I recorded some fuel pressure data- actual and reference values. All very regular looking. I should do some reading up on how these pumps fail and how to ensure you buy a good one - I can see why they would fail under load but why when cold? It has obviously created some doubtful reconditioning enterprises in China.
 

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Awesome! Cheers for that - I'll have to compare with my new one. Looks spot on and no strange dips below 50 bar. What tool are you using to chart?

Bought a new, non-genuine one be SMP Europe. So far, so good in terms of running, but early days.

I almost picked up a pump from a DS3 at the wreckers, but once removed, I could tell it was China-sourced variant. Might be fine, but like you, have heard bad things about them.

Sorry for the delay in response - been experiencing power outages since a storm blew through.
 
My apologies for not replying- I lost track of this thread. The tool I am using is a Launch 123E - I think it cost close to $300 and in its favour is that they keep on updating the software for the manufacturers it covers for free. And you can send them queries when you find something wrong with their software. It can log live data and plot it, but it only exports the initial diagnostic file and the images you can snap while inspecting the results. And on multi-variate plots it scales the Y-axis in ways that are often unhelpful.
 
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