charlie711

I was driving around town,was at a stop light to enter freeway and stepped on the gas, won't accelerate and ced p087 came on. Got home and next day started the engine and everything was fine until it happened again after 3 days. I noticed that it loses fuel pressure after driving around 20 to 30 miles around, get to a stop light and low fuel pressure. So what I did was when the car went into a limp mode, I turned off the engine when I got to a stop light, turn it back on, pressure came back on and car will run fine. No issues in starting the engine. Sometimes car runs fine for 2 to 3 days without losing fuel pressure. Is my fuel pump going bad?
Thanks in advance for any help or ideas what might be causing this problem

kajtek1

You might want to move the topic to diesel section for more exposure.
What's mileage? Those pumps can go for at least 1/2 million miles, so start with checking injectors for leaks.
Leak testers are easy available and I remember members building their own.
Than when ignition cycling restores the pressure - the regulator comes to mind.

charlie711

Thank you, 150,000 miles

AmirChouaieb

hi i have the same trouble !! all is fine the car is 100 % and when i accelerate limp mode ..same as you could you help me please what was the issue with you ? i tested the injector changed the rail pressure sensor ..and still the same trouble everything is ok and limp mode ....

84 GTI

Did you check the fuel frequency valve at the high pressure pump?

AmirChouaieb

thanks for reply....
no i will do and let you know
..thanks there are other things that i have to check ?

PSDCampervan

Limp mode can be triggered by multiple issues... EGR, swirl flaps on intake have caused it for me in past. Scan for codes to start with but ideally a scanner with live data capabilities will display rail pressure & injector contribution while engine is running. I do this with Star DAS but icarsoft mbII can do it too.

AmirChouaieb

thanks for replying and for your attention and help :
i have egr off swirl flaps like new (changed all the collector) with scanner in live everything is ok rail pression at 1600 bar max and after time limp mode and message rail pression is to low stop the engine restart everything i ok
since 2 months im in this case and i dont know where to go ...
help please ...

rapidoxidation

How many miles on the injectors?
Full tank of fuel or nearly empty when the problem occurs?
What is the ambient temperature when the problem occurs?
What engine load are you seeing before it happens?

AmirChouaieb

thanks for reply the car have 140 000 km (92584 miles) quarter tank or plus when the problem occur ambiant temperature 80 90 generally happen in low tr min 3000 4000 trm
thanks for your time

INDYbenzes

I had this issue on my CDI back in February on a road trip.
Come to find out it was just a bad sensor at the front of the fuel rail that just needed replaced.
Ordered it from FCP Euro for $120 and had my local Indy mechanic fix it.
No problem since.

AmirChouaieb

it was the rail pressure sensor ? or the fuel sensor ?

INDYbenzes

it was the fuel rail pressure sensor. It’s right at the front of the fuel rail. If you take the cover off it’s that wire connected to the sensor at the very front of the rail. Can’t miss it.

AmirChouaieb

i changed it but still the same...
thans for your reply and interresst

INDYbenzes

then it could be your high pressure fuel pump but it’s rare for those to fail unless you are running really awful fuel.
run live data with the star diagnostics. If it’s from the EGR or swirl flap device then just delete those systems.

AmirChouaieb

hi
egr deleted and swirl flap ok i tested ...i think i will also delete
have question please any relation between egr , swirlflaps with low pressure fuel on ramp ??
thanks for your time and attention .

Talal Al Hadidi

I have same issue in my ML350 Bluetec 2010
I change injectors , fuel pump , hoses , fuel filter , check the fuel regulator valve , fuel relieve valve
and still code P0087 😶

AmirChouaieb

fuel pump changed today and still the same problem anyone have a suggestion ?

Talal Al Hadidi

only God knows

Talal Al Hadidi

I thing it because the pressure sensor socket
see this video


I did mine and I think it works 😃

84 GTI

Have you tried doing an injector leak off test? You can get all the necessary material to test at Home Depot relatively cheap.

AmirChouaieb

injectors tested and cleaned

diesel315

Amir, Did you fix ?
Having similar mysterious Rail Low pressure on E320 CDI, after replacing Y74, Y94 and Rail Pressure sensor. This is all 3 rail components.

Talal Al Hadidi

it's really a mysterious !!
I did change the engine and still 🤔