P0087 fault Help needed!!

[Dennisdyer]

I have a 2010 Peugeot petrol 1.6 which faults P0087 and comes up depollution system faulty, To date I have replaced coil packs, plugs, High pressure fuel pump but still I have this fault. When cold the fuel rail pressure is showing 80 PSI which I believe this is where the fault lies but when you press the accelerator and give it some revs after about 20 seconds the psi raises to between 800 and 900 on idle and then the car runs perfect. Has anyone any advise please.

 

[drdino]

80psi fuel pressure with engine running at idle?

 

[RCZ-R]

So, after you bump up the pressure by stepping on it and then release the pedal for the engine to return to idle, does it stay at about 900 PSI?

 

[Dennisdyer]

When cold the psi will stay at around 80 PSI - If I leave the accelerator alone and warm the car up, It takes approximately 8 minutes (Engine shows 65 degrees) then the PSI rises to 800 PSI on idle.

If I use the accelerator from cold it kicks in in a faster time.

 

[RCZ-R]

So you are sure the high pressure fuel pump is OK? It has been replaced from what I read above here. What about the fuel pressure sensor? Is that OK?

 

[pete.garratt]

Your P0087 code is definitely low fuel rail pressure.

Since you’ve had the HP pump replaced, the obvious culprit is now the sensor. Is P0087 the only code logged? Does your code reader/dongle have the capability to log data to a file? If yes, you should be able to log and plot fuel pressure data over time. That way you could spot anomalies. That’s how I diagnosed mine.

As an aside, plugs and coils can often be a red herring here, since absence of fuel can cause missfire.

My HP pump issue started the same way - missfire & limp mode.

 

[Dennisdyer]

Thanks for your reply Pete,
I'm sure the fuel rail pressure sensor is sensing correctly as I am using the Torque app and it shows the Fuel rail pressure which I believe to be correct.
I believe the High Pressure fuel pump to be ok as on replacing this with a new pump the fault is still the same.
I don't have any more codes apart from P0087 - The only other thing I can think of is the low pressure fuel pump in the fuel tank which I think I will be stripping down over the next few days.

 

[pete.garratt]

What makes you think the sensor reading is correct?

 

[Dennisdyer]

Hi Pete,

The Torque app is showing 80 PSI on the fuel rail pressure when cold, If you give it revs it does increase up to 120 psi then idles at 80 again. This is when the depollution fault appears and P0087 - But once warmed up and running ok the sensor shows 800PSI on idle, If you clear the code it stays off as does the depollution fault. If the sensor was faulty I wouldn't expect a reading.

 

[pete.garratt]

I know you’ve had your pump changed, but when I was looking for my fault I managed to catch the event with my data logging OBD dongle and app (I use Dash Command).

There, the drop that caused the code was only momentary. I wonder if the way you’re looking at it doesn’t allow you to see the detail?

Does your setup log data real-time data? Can you clear the code, go for a drive and have the code come back, so you can see what’s happening when the code appears?

Having said all that, if you’ve truly had the pump changed, why has it come back?

I’ll dig out the files I captured when my fault was present and see if I can share them. Might have to be tomorrow now, though.

 

[Dennisdyer]

Ok Thanks Pete. Just downloaded Dash Command and will have a look. Thanks for your reply, Appreciated.

 

[pete.garratt]

Clearly, didn’t manage yesterday - sorry. Will try again tonight.

 

[pete.garratt]

Clearly, didn’t manage yesterday - sorry. Will try again tonight.

 

[pete.garratt]

Here is a graph I created from my captured Dash Command data. I believe this shows an event that triggered an EML and P0087 code.

The sequence is start from cold, where the fuel pressure is about 55psi (left hand scale), which I believe is the pressure provided by the LP pump in the fuel tank.

The graph also shows engine RPM (right hand scale), which you will see is 0 initially, peaking at nearly 1800psi at just over 1 1/2 minutes into the run. Note this peak occurred just after a dip to around 120 psi. This is not much above the LP pump pressure and is what I think triggered the P0087 code in my case.

Hope you can read it - let me know if you can't.

 

[Dennisdyer]

Thanks for this Pete,
Hopefully get time over the weekend to look into it more,
Its definitely fuel starvation though. I've just started the car up with the foot straight down o the accelerator and its coughing and spluttering for a few seconds before the high pressure PSI kicks in and runs fine.
All seems to point to the High pressure pump but with renewing it and having the same effect I am confused.
The only thing I am thinking now is if the throttle housing is sticking.

Thanks again and I will let you know when I found out what the problem is.

 

[pete.garratt]

If it was sticky throttle, why a low fuel pressure error.

It sounds terrible to say this, but are you sure it’s really been changed?

Did you see the old one?

 

[Dennisdyer]

I know it was changed as I changed it myself - quite an easy job really and the pump was bought new.
I understand what you saying with regards to the throttle but I don't know what else it can be.

 

[pete.garratt]

Maybe it is the sensor, then. Would you consider changing it, on the basis it’s the cheapest option?

If you can catch some plots of when the code next appears after you clean it, that might help.

 

[pete.garratt]

Remember there’s closed loop control going on. If the sensor feed is bad, it would affect the rail pressure, through a regulation effect.

 

[pete.garratt]

Remember there’s closed loop control going on. If the sensor feed is bad, it would affect the rail pressure, through a regulation effect.

Might also mean it never was the pump itself.