Renault Master difficult to start

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RYM6746
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Re: Renault Master difficult to start

Post by RYM6746 » Sun May 14, 2017 6:04 pm

I can see no diagnostic value in leaving the engine to idle for 10 mins and see if the pressure rises in the rail. The ECU would just adjust it to where it needs to be using the IMV.

Dcunning35
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Re: Renault Master difficult to start

Post by Dcunning35 » Sun May 14, 2017 6:17 pm

Exactly richard .
Danny

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Re: Renault Master difficult to start

Post by Technician » Sun May 14, 2017 8:44 pm

Technician wrote:I've seen it on VW's, I can't guarantee it will work on other makes but thought it might be worth a look while testing.

The coolant temperature should be minimum 80 degrees C, the rail pressure measured, then while idling allow the engine to continue running for around 10 minutes, the heat soak should see the fuel rail pressure rise, if it does the injectors are not leaking internally.
RYM6746 wrote:I can see no diagnostic value in leaving the engine to idle for 10 mins and see if the pressure rises in the rail. The ECU would just adjust it to where it needs to be using the IMV.
The other point I should make here is that what you can see while testing and measuring might be influenced by the software in the ECM!
Would the software not influence the pressure as I pointed out earlier, or am I wrong about that!

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RYM6746
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Re: Renault Master difficult to start

Post by RYM6746 » Mon May 15, 2017 8:32 am

I am really unsure what you are trying to get at. I am trying to get a test from someone that will have a test result that will aid me in an accurate diagnosis.

The pump noise that I initially heard was a pump in the tiptronic gearbox. Sounds exactly like a fuel pump and is activated when you open the drivers door. That explains why there is no change in pressure on the pre supply system, ha ha

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Re: Renault Master difficult to start

Post by Dcunning35 » Mon May 15, 2017 9:40 am

If it has no lift pump and the suction on the transfer pump was good as you first stated, and low pressure has no vacuum loss. The only thing I could suggest is that maybe there was a temporary restriction in pipework disturbed during testing or a kinked softened pipe .
Not much of a concrete conclusion but with no reproducable symptom to diagnose you have done all you can .
And as ever in this job we move on to more fun .
Danny

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