Hi All
I'm a previous subscriber from the UK, and have returned to the fold after a long absence.
Let me give you as much info as possible to my issue. A friend bought a Van, its a 2005 Renault Master, 2.5 Ltr, 120DCi, it was an ex Ambulance. It was sold as a runner but when my friend and I went to view it the seller (Garage) said that they tried to pull it out of the yard and it wouldn't idle, we tried a few times and it would fire but as soon as you let go of the key it would stall instantly, if we gave it some revs (1,500 - 2,000) it would run but would stall once we took out foot off the pedal, after a few attempts It idled absolutely fine, a solid, even revs, no fluctuations, no noises.
I said it seemed fuel/pressure related, and we did find a new fuel filter in the back. The garage said they would get it looked at........ after a few weeks they still hadn't got round to it so they agreed to knock a good chunk of money off the van and would deliver it for free so my friend took a risk a bought it, it was a really low price compared to other similar spec/age vans.
Once delivered, I plugged my Diag machine in (Snap-on Verus Pro) We saw Injector Circuit codes for cylinders 1, 3 & 4 (Codes: 18E2, 1830, 1831). We changed the fuel filter, which was really black and clearly hadn't been changed in a long time, cleared the codes, we primed the system using the priming bulb and fired it up. ran great, we ran around in it doing a few chores and all was good.
The next morning it was back to not starting/idling, it would die as soon as you felt go of the key, we primed the system again and still the same. however, it i constantly pumped the priming bulb then it would idle fine until I stopped pumping. We decided to change the priming bulb after some research said this was a possible cause, it ran fine after priming using the new bulb....... for a few minutes, then it would die as it someone flicked a kill switch. each time we checked the DTC's it would be Injector circuit codes again, sometimes 2 cylinders/injectors, sometime 3 and occasionally all 4.
We carried out a good visual inspection of the injector wiring as were told the wiring under the Airbox sometimes would chafe the cause issues. All looked good!! I cracked each of the fuel lines at the Fuel Rail to ensure fuel delivery, then cracked the the lines at each of the injectors in turn and all were getting diesel. We got it started again and it ran for a good 20-30 mins while we pottered around cleaning the inside of the cab and back then went for a much deserved pint. an hour later returned to try and start it again and it wouldn't start/idle.
Live Data showed that the rail pressure was fluctuating quite a bit so decided to change the Fuel pressure regulator.... not the easiest job when they used Torx Bolts that are rusted, but we got there in the end and it seemed to run and idle fine, fuel pressures were a lot more stable at around 280-320 bar which is the expected pressure according to AutoData.
But after a few successful attempts start it and let it idle up to temp, then leaving for several hours or overnight and trying again, we even took it for another spin around the area, but the issue returned, still showing injector Circuit Codes, next we swapped out the fuel pressure sensor, this was because we followed the Testing procedures from HaynesPro:
1. Measure the voltage on pin 3. Is it between 4.8 and 5.2 V? - We got 4.9v
2. Measure the voltage on pin 1. Is it between 0 and 0.2 V? - We got 0v
3. Measure the voltage on pin 2. Is it between 4.5 and 5.2 V? - We got .4v, however if I unplugged the sensor and took a measurement, I got 5v so thought it was a faulty sensor. As I got 5v I am assuming that the wiring integrity is fine, however under load we are getting voltage drop. (the only thing I'm not sure of is if this voltage will only show if there is pressure in the rail.
I'll admit it was a secondhand one from a 'working' van that was scrapped, I checked resistance between the pins and it was the same as the one already in the van so suspect that it’s not the sensor. At this point we experienced a flat battery when trying to bleed the air out of the fuel lines so are going back at it tomorrow but I'm not holding my breath as the 'New' sensor is giving the same voltage readings.
Would everyone agree that the next step would be to remove the injectors and get them tested?
Is there anything I can view/record using the diag machine to catch the live data at the point that it dies/stalls?
Would it be worth putting an amp clamp on the injectors to view the waveform?
I'm getting frustrated with it now and need a direction to head in, I would rather not remove injectors as they can be a nightmare to get out and if they break its a head off job which I would rather avoid.
Let me know your thoughts.
Thanks
Derek
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