V9X Engine Failure??

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Old.Tony

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You're absolutely correct, the camshaft sensor must also play a part.

Number one trick to see if diesel is getting into the cylinders is to sniff the exhaust after cranking the motor (not while, just in case it fires!).

Have you checked the glows? Are they wet? Are they heating up?
 

Adhaul

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Thanks Old Tony you jogged my mind into action (I'm supposed to be a mechanic ha ha) no fuel was/is the issue, traced it to a "valve or sensor" photo attached. If I work from the diagram (also attached) it should be a fuel temp sensor, it sits just above the high pressure fuel pump and has stopped all flow of fuel to the pump, thus no start. The "switch/valve ??" has two terminals only, I'm thinking it's a shutoff valve but why? and what actuates it certainly turning on the ignition doesn't seem to atm.
All I know right now is that until this thing allows fuel through we aren't going anywhere.
Any Ideas?
 

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Adhaul

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Here's another photo of this "valve" which shuts off the fuel to the high pressure fuel pump. My issue is remaining closed when cranking, no fuel, no start. Any ideas what activates it and can it be bypassed? Nissan dealer can only advise it's a fuel line as per parts manual.
Circuitry of the ECU would be good Ha Ha - I live in hope!!

Well seeing as no-one could tell me; I decided to pull the bl....dy thing apart and it's not a valve it's a temp sensor for the fuel. Cleared line, well I didn't see any obstruction but now have attempted to bleed system, still plenty of air but now we have fuel at the pump, we might be making progress but bl..dy slowly, maybe it's just air in the system?? All clamps are tight, but there is a lot of air to clear and a lot of lines without real high level bleed vents. - Plodd on!!
 

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Old.Tony

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You have the same manual that I have, excellent!

Page 1245 indicates that the fuel rail pressure regulation actuator is the item responsible for fuel flow during vehicle start. It looks to be controlled by the ECM based on the inputs listed on that page. On p1246 there's a small section about a malfunction in the actuator and what's considered "fail safe" operation.

I can't see what's causing that to stop the fuel flow unless the filter is triggering a water alert or something?
 

Adhaul

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You have the same manual that I have, excellent!

Page 1245 indicates that the fuel rail pressure regulation actuator is the item responsible for fuel flow during vehicle start. It looks to be controlled by the ECM based on the inputs listed on that page. On p1246 there's a small section about a malfunction in the actuator and what's considered "fail safe" operation.

I can't see what's causing that to stop the fuel flow unless the filter is triggering a water alert or something?
Hey Tony
 
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Adhaul

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Update -
Have/had fuel at the injectors, quite a process just kept at it, however it seems that I'm not building up enough pressure to start. Had quite a reasonable flow at one stage, left it for about an hour, now we are back where we started, no fuel, can get some froth at times but no matter what I do the air is not clearing. Thinking that tomorrow I'll get a mate to assist with individual bleeding of each injector. Have checked all fittings which seem to be tight - all the basic stuff, no leaks etc:
Any ideas??
 

Old.Tony

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There's a bleeding technique described in the manual which requires a tool that attaches to the pump. I guess the tool is available at the local Nissan dealership, so if you have a friend ... ;)
 

Adhaul

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So I got a friend to assist with bleeding at each injector (got a lot of air out of the system, but clear )- now I am at a complete loss as to no start, will have to go back to basics I suppose.
I can confirm that I have some compression (yet to test that exact psi), I now have fuel and a limited amount of bubbles at the priming pump. On assembly everything regarding camshaft timing is as per the instruction manual, new timing chains and guides etc: On cranking I have air flow at the intake not hugh, but it's only cranking speed (ps and it's in the right direction) The timing sensors cant be wrong because they are fixed points that can't be changed on the camshaft and crank. I have no error codes on my OBD2 tester, I have removed all the "chip kit stuff". Replaced the battery which improved the crank speed, the fuel tank is 1/2 full. Double checked/triple checked sensor plugs etc:
To my way of thinking diesels require 3 things to run
1. Air - Checked Okay
2. Compression - ?? what should it be, i'm expecting around 350psi??
3 Fuel - I think we now have that, but the timing could be an issue?? I'll confirm that when I pull an injector out for compression test.
Any further ideas please add - PS the engine cranks over like it used to prior to the rebuild, some times it almost sounds like it's about to fire.
 

Old.Tony

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It will be interesting to see if the injectors are firing at all. A wet glow plug will tell that story. Also, pulling the glow will give you an idea if it's heating up (infrared thermometer aimed at the tip).

Air, fuel and compression are generally it. The V9X runs what, 15.5:1 or something like that? I don't know what psi to expect, I think the last guy I spoke to who was testing his was talking somewhere over the mid 300s, but I can't recall clearly.
 

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should be zero bubbles when primed , can you pressure check the rail while cranking or remove an injector, connect it and see if you get a strong fine spray patern with each compression stroke , dont put your hands any were near tip. a friend pumped up his hand with fuel.. following clip shows pattern at slow cranking to high engine revs , in your case if they were working before you would expect your pump delivery or air.. second clip shows back leakage test,(should be minimal) to much is faulty injector
 

Adhaul

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Thanks for all the input, I really appreciate the help. In total frustration and advice from elsewhere I used "start ya bastard" to see if it would actually fire - we have combustion in fact I actually thought it might start running on it's own accord at one point. So it comes down to fuel delivery. Had the clearest fuel bleed this morning so will keep trying, I am fully convinced it's a bleed problem as a result of the intricate web of pipework making it very difficult to remove all the air, and of course every time I do a "bleed" at the injectors there's a possibility of more getting in.
 

Adhaul

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Update - still no start on diesel, process was to fully bleed the system via the primer which gave a pretty clear fluid flow, certainly good enough to provide some real pressure from a good pump. I then attempted to rebleed the system at the injectors, little or no fuel resulted, we are supposed to have 145psi in this area of supply according to the manual. It seems that the high pressure injector pump is not operating. Given that there are no fault codes reading on my OBD2 reader it would indicate that the fault is with the pump. Am I wrong or is there another issue I'm missing? Obviously I'm assuming all is okay with the ECU side of things.
 

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on my qd32 i have had trouble with a partially blocked filter in the inlet line at the high pressure pump. could pump fuel by hand to injectors but wouldnt supply enough fuel when cranking.. can you supply fuel to pump using a can and hose by-passing any shut off valves , disconnecting lines at injectors to see that you have good squirt. check you havnt got a blocked flow control in pump.. if pump has shot itself there should be some shiny metal parts on flow control valve
 

Adhaul

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Further update - Hand primed, now the interesting part is that there is a valve between the fuel filter and pump that ensures that air & fuel is bled out of the fuel supply lines and fuel rail prior to any incoming fuel from the filter (this is the 3 way connector), so given that, we should fairly quickly get a clear bleed. As soon as you open any injector line air is able to enter when bleeding (I've checked = true) so once you have a clear bleed via the manual prime and the pump has pressure, there is no place for the air or fuel to go except out the injectors. My test this morning was 1. clear bleed, 2. open the injector line and crank the engine with the Fuel Rail Pressure Regulator Actuator (FRPRA) unplugged. This resulted in No fuel, I then connected the FRPRA and we had supply, but in my opinion not enough. Re-bled the system, engine crank and a limited amount of fuel.
Now here's the big question - does this mean the fuel pump is defective? Remember we should have 145psi of fuel pressure in the rail & I also tried the process with one injector open, which if all is well should provide some minor pressure to the Fuel Rail Pressure Sensor certainly enough to allow a prime flow of fuel. (Note -Info on the operation is contained on Pge 1234 of the workshop manual, for those who are following)
Given that the pump has done 220,000 km and it's quite possible that something has entered the pump, it looks like I need to replace it - ouch $1000+
Interested in comments before I take the leap of faith in my diagnosis.
 

Cowboy550

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Wow Adhaul, it’s been a mission for you, start you bastard is wonderful in my opinion and is great for bleeding Diesals.
I couldn’t comment on the pump.
following your trend and wishing luck to you !
:)
 

Old.Tony

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I'm pretty sure during a start that there's not an enormous amount of fuel injected into the cylinder, so the actual flow rate of fuel shouldn't be really high.

The fact that it started (with the spray) indicates that mechanically speaking, the engine is in good order. So it must come down to either the amount of fuel metered into the chamber, or the timing of the spray.

If the timing is poor, you would think that if it's being sprayed in during the evacuation stroke (exhaust valve open) you'd have some diesel entering the exhaust in raw form, but a little left in the cylinder on the top of the piston which should be combusted on the compression stroke (and even though it's not a full amount, it's some, and should at least give some indication of firing).

So I agree that it must be the amount of fuel. Now is that the pump failing, or is it the SCV? Is it the system just returning fuel to the tank? There's a valve on the far side of the rail that maintains pressure in the rail prior to returning the fuel to the tank, if this valve is open the rail pressure can't rise very high and the amount of fuel delivered through the injector won't be very high.
 

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