3.0tdi fuel pressure too low P0087 (CCWA engine)

Hi,

I'm getting this code when I let the car slide on it's own (like when coming to a crossroad / traffic lights).

5215 - Fuel Rail/System Pressure: Too Low
P0087 00 [032] - Cannot Be Tested at this Time

In worst case the engine will cut off and needs to be restarted. I made some VCDS logging: in 1st one I let the car slide. Eventually automatic gearbox will change to 1st gear and speed slows down. And then pressure drops under 100bar engine cuts off and coil lights will start to blink --> error code P0087



2nd log is when car is idle:

fuel pressure is going up and down as well as deviation



What do you guys think?

When was the last fuel filter service?

Filter change about 7000miles ago. I had the error code happen few times before the filter change, so it didn't help

I'd be looking at the pressure-control valve (on the pump or rail), but for giggles check the clutch switch too.
Looks like either the pump can't keep up with the leakoff at low revs or the valve is leaking/opening too far, tho.

Yes, I'm leaning towards pressure regulating valve on HPFP. But is there any way to test the valve?

How about changing the valve from HPFP, is that straight forward job?

Hi. This thread is too old. As far as I know, the way to test the pressure valve is the following:

There is a hose that comes out from the valve (also, injectors's fuel output goes there too). Well, that hose need to be disconnected and closed someway (block it so it doesn't spills fuel). Now connect a new homemade hose into valve's output and put the other end into a recipient.

Now turn the engine on. The first 10 seconds there must NOT be any output. If it does output fuel, then your valve is likely to have a problem. After those 10 seconds you may see fuel output.

By the way, low pressure may be caused by man y kind of failures:

1) Leaking injectors.
2) Bad fuel pressure sensor.
3) Bad fuel pressure regulator (valve).
4) Not enough fuel coming from the filter.

Among others.

How did you solve this problem back then?

Hi,

my response is a few years late

This was due to HPFP (high pressure fuel pump) was bust. Inside of the pump was full of aluminum shreds. The piston inside the pump had rotated by itself on 90 degrees and then eaten off the insides.

Luckily the shreds hadn't broken anything else!

So I ended up changing HPFP and fuel filter. Cut open the old fuel filter to see if there is any aluminum shred, but filter was clean (what the eye could see).

Doesn't the HPFP pass unfiltered fuel directly to rail and injectors?