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Discussion Starter · #41 ·



I can graph the fuel rail pressure using the torque app on my phone. What your seeing is three attempts at starting the car. Pressure begins at just under 2000, slowly builds and finally starts on the third attempt when it gets up to around 3000. I don't have the test IMV unit like you say so I cant test pump functionality on its own. The cheapest way would be to swap out pressure sensor but still seems like a stab in the dark. I have ordered one anyway for about £65 off ebay. Not too shabby if it does fix the issue.
 

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that's the high side of the pump and that's showing you have pressure on the high side, the pressure sensor giving the codeis on the low side
 

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Discussion Starter · #43 ·
Please correct me if I'm wrong but I can't get a reading on the low side from the odb as far as I know. I do have a manual gauge but there is no port that I can find either. I was thinking about making an adapter with a port in the middle and a male quick connector on one end and a female quick connector on the other side to be able to attach and remove the gauge.
 

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Discussion Starter · #44 ·
flash22 said:
that's the high side of the pump and that's showing you have pressure on the high side, the pressure sensor giving the codeis on the low side

When you say that's showing I have pressure on the high side, there still doesn't appear to be adequate pressure to start immediately until pressure builds up.
 

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Check the crank sensor and the neutral/reverse switch next
 

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Oil burners need 2 things only, enough compression and fuel at roughly the correct time. If the engine runs fine when warm/hot and easily restarts in the same conditions then a cold leak down test needs doing, I have known diesel engines with bucket shim cam systems be rottten starters but above a certain temp be absolutely fine due to shim cam lobe clearances being less than zero when cold.
 

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k9k is dci akacommon rail, the ecu still needs to know where the crank and cam is, so it knows when to fire the injector or micro inject as needed - no crank or cam signal = no fuel

long gone are the days of old mechanical pumps what are nice and easy to diagnose
 

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have you rescanned for fault codes since you fitted the new part ??
 

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Discussion Starter · #50 ·
I've cleared the codes and haven't rescanned it yet. I did take another graph of rail pressure while starting, still taking around 40 seconds to start but strangely this time it seems to start with less rail pressure.



My next step will be compression test, leak test and to take a look at the other things you mentioned.

I have a couple of questions though.
Firstly what should correct starting pressure be?

Also is it possible to have a starting issue caused by the injectors? Why would they only cause a problem starting and not when running warm?

Just to clarify the symptoms are hard starting, taking 40-60 seconds to start when cold. Engine stalls out a few times when running cold. Runs well once warm. It it is turned off then its back to hard starting but not as bas as when its cold.



Edited by: evilmrkipling
 

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From you early posts I thought it didn't start at all

Forget the crank sensor and neutral switch

Do a Compression test and a leak down test, check the heater relay (pop the cap off it an make sure its operarating correctly or hold it closed while starting it

If you have a nackerd injector it will either flood the cylinder or not deliver any fuel, you could try unplugging 1 injector at a time and see how it starts
 

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Fuel rail pressure at idle is 230bar (3250psi) with a warm engine, this rises to 450bar @2000rpm, so I would expect the cranking pressure to be significantly lower. things to check in order would be cylinder compression ( no diesel will start easily without adequate compression), injectors for spray pattern and delivery volume, fuel rail pressure and filter system for air/water/leaks. If your engine runs reasonably well once started you can more or less eliminate the crank sensors etc and focus on the starting conditions.
 

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Discussion Starter · #54 ·
Ok compression test done and its not looking good for cylinder 4

Cylinder 1 - 400 psi
Cylinder 2 - 400 psi
Cylinder 3 - 400 psi
Cylinder 4 - 200 psi - jumps around between 200 and 380 psi
 

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Discussion Starter · #56 ·
I have also took out the EGR valvue and it was full of black soot, I cleaned it and but it back but there was still a load of soot in the cooler pipes.
 

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Discussion Starter · #58 ·
Cylinder four though is no where near 400. The neadle jumps around like crazy. I retested it a few times same result. Also carried out a wet test on cylinder 4 and same result.
 

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Should start on 3 though, does it attempt too? Possible remaining faults are leaking injectors (this stops the rail pressure achieving correct value) lpfp and hpfp, air leaks into the fuel lines.
 

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Discussion Starter · #60 ·
It does start but only after a 40 to 60 second cranking session! Or if given a spray of easy start then it fires up.

Do you not think I should address the compression issue before moving onto the fuel?
I'll accept I could have multiple issues here. Possibly exhaust valve, EGR, injectors and HPFP.

I don't think the note has a LPFP though.
 
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