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Discussion Starter · #1 ·
Question for the Brains Trust - I have fully rebuilt my V6, all the lines and bleeder lines were clear and empty. I have attempted to bleed the system using the primer pump and continue to get amounts of air. I then attempted to start the engine, hoping that the small air would be forced out, however no start, not even a wimper. After several repeats of the process (as per the manual) I then cracked several fuel connections on the injectors, froth, eventually a reasonable amount of fuel which I thought would give us a start but no go, I think the air is compressing and no fuel is making it into the cylinder.
To my way of thinking, if there were loose lines for air to get in, surely there would be a leak under pressure (which there is not) and it would be visible. So if I leave the primed system for a while (say 1/2 hr) the priming needs to be redone as the system is full of air again. I'm at a loss as to my next move, is there an issue or special process for the initial "charge" of fuel, and anyway, where does the fuel go? (there is a check valve/one way valve in the system which has been replaced, because it was broken on engine removal)
Here's an interesting note - If I leave the primer connected with a hose attached and dropped into a bucket the fuel syphons into the bucket, still need to re-prime, but not nearly as much as if the primer is disconnected.
I've also noted there is no way for the air to be removed from the system except via the primer or mix with fuel and exit via the injectors, as the return fuel goes back to the pump to be recycled. I not aware of a primary pump from the tank as it's not shown in my workshop manual (wouldn't need a primer if there was one), ironically there is a fuel return line on the high pressure pump going back to the tank.
Any suggestions would be helpful, I've got time to investigate thanks to COVID
 

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Only thing I have to offer is they are a complete [email protected][email protected] to prime even if you're only changing the filter. I didn't clamp the pipes and so spent a good half hour pumping, thinking it was done and then seeing air. I used a jar and pipe, similar to you. The only offering I can give is use an electric pump, to get it to the filter and then crack the injectors to get it the rest of the way.
Good luck.

Sent from my SM-G950F using Tapatalk
 

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Same here. I bled a couple of litres with pump.
According to the manual, you may have to crank the engine for at least 30 seconds to get it to fire. 30 seconds is a long time!
I think I cranked it for 45 seconds, all of a sudden it fired up.
 

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Discussion Starter · #4 ·
Thanks for the input,
update - my friend gave me a hand and we bled each injector individually, actually got a clear run of fluid & the primer ran clear as well. The engine has been cranked for all of 45 sec several times, sounds like it wants to go but nothing real. Even installed a new battery (thinking low voltage may be an issue) which helped with crank speed. There are no fault codes, engine light remains on. Given that the rebuild included new rings and a hone, they were installed with plenty of oil so we should have compression, we do have some (not measured) and we do have air flow on cranking at the inlet manifold, the camshaft & crank were installed as per manual and you can't change the timing except via the ECU in my humble opinion it should start.
Anyone got some magic I think I need heaps right now!!
 

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Back to basics I suppose.

First check is to make sure the mechanical stuff is right. Squirting easyStart or similar into the intake (not sure where on the V6}. It should fire up which will eliminate (or not) a mechanical issue
 

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Discussion Starter · #6 ·
Thanks for the advice, quite frankly I should have thought of that before, but that's what happens when you're so entrenched into a project - miss the obvious - using "start ya *******" I managed to get the engine to run a few seconds, this stuff frightens the **** out of me as it has a reputation of breaking top rings, however desperation makes you do weird things, got a very clear fuel bleed this morning, so will keep trying, at least I'm on the fuel track. Any further ideas I'm listening.
 

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Discussion Starter · #7 ·
Thanks for the advice, quite frankly I should have thought of that before, but that's what happens when you're so entrenched into a project - miss the obvious - using "start ya ***" I managed to get the engine to run a few seconds, this stuff frightens the **** out of me as it has a reputation of breaking top rings, however desperation makes you do weird things, got a very clear fuel bleed this morning, so will keep trying, at least I'm on the fuel track. Any further ideas I'm listening.
With assistance we attempted to bleed the system again at each injector, no pressure, even though we had just had a good clear fuel flow at the primer. My diagnosis is that we must have a problem at the pump, could be ECU signals or simply a faulty pump. ECU has "No Codes" on the OBD2 reader, which would tend to indicate faulty pump. Am I correct or is there other possible issues, I'm certainly very adverse to start pulling a pump apart?
 

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Ok, so good news that the engine is set up ok. That easy start stuff will damage engines if used a lot as it washes oil off the bores.

Next check, are the injectors spraying?

Take one out, tape it into a small coke bottle and crank the engine while somebody looks at the bottle. If you are getting fuel it would indicate a problem with timing (a sensor)

If no fuel, by pass the filter and tank by providing a fuel supply directly to the output of the fuel filter. Another soft drinks bottle will help.
 

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Discussion Starter · #9 ·
Injectors were checked by a diesel specialist as part of the rebuild process, so no concerns there.The main issue has been no fuel rail pressure which should be around 145psi. Today I have checked fuel flow at the high pressure pump with & without the Fuel Rail Pressure Regulator Actuator connected and at best have a small flow which would not provide enough to run the engine. I have now reached the opinion that the fuel pump requires replacing (220,000 km or some foreign particles). I have managed to get a clear bleed at the priming pump, but am thinking that the high pressure pump does not have enough draw vacuum to pull fresh fuel through the check valve. Interested in anyone's thoughts before I take the leap and spend the big$'s
 

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Discussion Starter · #11 ·
Did you try feeding the fuel pump directly from a fuel can?
Well; we have ignition & the V9X purrs like a kitten!! How?? It would seem that the primer "cap" is critical as it acts as a seal to stop air being drawn back into the system. I thought it was just a cap, but if you note; the manual instructs us to replace the cap before attempting a start after bleeding. It's been a challenge in the detail.
 

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Discussion Starter · #13 ·
Good result, a bit of a school boy error though!
Yes but who would have thought that "so called quality vehicle" would use a "condom" as a check valve or seal, particularly on an important and critical piece of the engine. Minor leak and wham you have hard starting issues etc:
 
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