OM639 Fuel System Nightmare

pmnunes

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OM639
Afternoon gentlemen,


Bought a car to fix it up, came with some problems i fixed them all except this fuel issue.

The car fuel economy is very low. When going uphill or merging highway it turns off. Basically any situation that you need to accelerate its a problem.

The codes are 2634; 2637.

I replaced 3 injectors with OEM brand new. Replaced HPFP with a used one. Replaced fuel quantity control valve with brand new bosch. Replaced fuel filter.

The problem persists. I attached two photos with STAR data from the fault codes. The lack of fuel pressure is a problem. I removed the fuel hose to the HPFP and it ****es fine so i assume tank pump is fine. I'm leaning towards the DRV on the rail. Any thoughts?


Thank you.
 

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LostKiwi

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Looking at that it's suggesting you're drawing air into the fuel supply from somewhere.
 
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pmnunes

pmnunes

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Looking at that it's suggesting you're drawing air into the fuel supply from somewhere.
I thought that too but when I created a small leak by not clamping the fuel hose to the HPFP everytime I started the car I could hear the tank pump purging air.

When the car shuts off mid hill and I completely stop, it does not purge air.

Could it be the DRV can't handle big pressures anymore and is dumping the rail pressure to the return line?
 
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pmnunes

pmnunes

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So after 3 new mercedes injectors, used high pressure fuel pump and a used rail I finally fixed it. The DRV on the rail was the problem. Got new injectors for 90 Eur each off the black market, hpfp 35 off a 200 cdi and used rail from the local scrap yard 20 eur. Ez
 


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