Citace:GC 2.7 CRD and P1130 fault code
Hello mates.
A couple of months ago a posted some notes related to contaminated diesel and the subsequent failures in my 2.7 CRD engine.
After a very short period of rattling, the engine stopped (ussually at the moment of decreasing rpm, like when comming to a trafic stop ligth) and then the engine will not start for hours. Then the engine started perfectly and run OK for some period (sometimes minutes, sometimes days. No other simptoms were present (correct power and idde, no smoke, no engine ratling).
After a lot of assembling and disassembliong of the whole fuel system (including both fuel pumps serviced at a Bosh agent and a new fuel pressure solenoid fitted to the rail), the cause seemed to be a faulty (possibly cloged) return fuel valve (the "T" shaped hose connector on top of the fuel filter).
The tentative explanation for this is as follows:
The valve is a bimetallic temperature sensitive one, wich in normal operation directs the return fuel (ussually with some air in it) back to the fuel tank but if the fuel is cold, the valve closes and re-direct the cold fuel back to the fuel filter and from there to the pumps again. If this valve locks in the fuel recirculation position, then the air bubles will get trapped in a "pump-rail-filter closed loop" until the amount of trapped air is enough to cause a drop in the rail fuel pressure (hence P1130 code) and consequent engine stop.
The problem with code P1130 is that it has a so general meaning that actually means almost nothing. To help with the diagnostics I fitted two electrical cables to the connector pins of the common rail fuel pressure sensor and routed them to the cabin where I used a cheap voltmeter to monitor the fuel pressure in the rail by myself. I learned that the voltage (pressure) varies from 1.3 to 3.5 V deppending on the engine regime. For a normal start up, the minimum voltage (pressure) necessary to start the engine was 0.8 V.
After a few days of voltage reading the failure showed up and I could verify that it was effectively a negative drop in the rail pressure what caused the engine shuts down. I saw that if the engine was cranked just after the shut down, the voltage (pressure) couldn´t rich more than 0.6 - 0.7 V and hence the engine didn´t start.
The voltmeter tip if very simple, it may help to better understand what is going on inside the common rail, at least in terms of fuel pressure, whitout the use of a DRBIII scanner.
By the way, the dealer (stealer) had said that is was the common rail pressure going "too high" the reason for the engine shoot down (). How could they know this if the scanner just read a stored P1130 code
Best regards,
adrian