Non-starting

I was wondering if you can help with a 2002 Renault Espace 2.2 dci ‘The Race’, with the G9T engine and 64,000 miles on the clock.

Basically it’s a non-starter. It cranks well and may occasionally cough a little with the smell of burnt fuel, but the engine will not catch. It will run on easy start, though. It failed gradually over a period of about four days/100 miles, getting progressively harder to start and running roughly when it did. Prior to this, it started instantly and ran beautifully, and had just passed its MOT.

So far I have carried out the following, but all to no avail:

1. Charged the battery and replaced the glow plugs. The glow plug supply was checked and each was drawing approximately 8 Amps with the key on. 2. Changed the fuel and air filters.

3. Fitted a different, fully-charged battery from a diesel Passat (even bigger than the original battery).

4. Tested the low-pressure pump –

supply OK and it runs at key on. 5. Plumbed the fuel supply to a separate 10-litre drum of diesel with transparent pipes to check for air in the flow and return: all OK. This was fresh diesel, not from the tank, which should rule out incorrect fuelling. 6. Removed and cleaned the crankshaft sensor. A viable-looking waveform was found at its plug with an oscilloscope when cranking. You can adjust its distance from the flywheel – I’ve tried it in various positions, but I assume it should be set to the minimal clearance possible. 7. Scoped an injector when cranking – a viable-looking waveform was present, so they are definitely being pulsed. 8. Carried out diagnostic tests with a Renault Clip tool; no codes present or stored. From live data, the cranking speed is approximately 200rpm with the battery well charged. The fuel gallery pressure at key on (electric pump only running) is 3 bar; when cranking, 300 bar plus. I don’t really know what else to try. To my mind, it really should now work, but this is the first common-rail diesel engine

I’ve owned, so I fear I may be overlooking something obvious.

I apologise for the long question. I’ve just worked through as much as I can from an old Electronics Diagnostics feature (CM, April 2011) which covers the exact vehicle, but I still haven't really come up with anything – unless it is fuel leaking off from the injectors, but I’m not sure how to check this. And if this were the case, surely the gallery pressure would not be so high?

Andy Green

There is no such thing as too much information – not on these pages at least!

As the vehicle runs on easy-start, we know that the compressions are pretty good and that we are looking at a fuel delivery problem. The given feed pressure should be between 2.5-4.0 bar, so, at 3.0 bar, you are within the tolerances.

Given the work you have carried out, I would first inspect the EGR valve.

These are prone to problems on the

2.2 dci engine and can cause the nonstart scenario you are suffering from. I would remove and clean the valve, then ensure it is operating correctly.

If there are no problems with the

EGR valve, I would then check the valve timing. While I do not suspect that the timing belt has jumped, it may be the case that the adjusting bolts on the cam pulleys have loosened, allowing movement in the pulleys.

Having confirmed that the valve timing is correct, further investigation into the fuel injection system will be needed. First, remove the fuel filter and ensure there are no tiny metal fragments present. As the filter is new, these should be easy to spot. The sign of any small metal particles (however small) will be an indication of a failing high-pressure pump, and probably a clue that the injectors have been compromised.