Hope it is okay for me to start a new thread - as the last one has begun to lose steam, and I am yet to fix my problem. Hopefully this helps someone else out at some point, too?
Still having the same issues - Disco will get harder and harder to start as fuel gets lower and lower. The car feels much zippier and more responsive with a full tank. The other week the car was starting quite easily, but the RPMs would be so low (<500) it sounded like it was going to die for a few seconds, before going up to normal 750rpm idle. Also the engine doesn't seem to chug away while I am coasting, and when I get right down in speed it will kick back to life with a few awkward chugs before starting a pleasant sounding throb at 750rpm.
So as of right now I have done the following, to try and correct the issue:
- New Fuel Pump
- FPR Rebuild
- New Injector Wiring Loom
- New Injector seals and washers
- New Air Bleed Valve
When I replaced fuel pump the old pump had a thick layer of snot-like black build-up on the base (which I assumed at the time to be diesel bug) that I was told was likely carbon from dud injector seals. I bought Liquimoly algaecide and my intention is to drain the tank and clean it out (do I have to drop the tank or can I go in through the fuel pump hole?) and then mix in algaecide.
Is it even possible/probable that algae is my problem? Could it be the non-return valve?
Assuming you cleaned the filter behind the fpr when you did it , and made sure the injector washer seats were spotless when those were done ( have done 2 cars in the last year where owners did washers with same problem and both because of carbon left on the sealing surfaces) , did you check cam timing when you had the rocker cover off?. If you have a nice quiet pump now even when tank is low then it might be worth driving around with the fuel cap backed off . is there a vacuum when you fill up ?. have you got a nanocom or similar?. Definitely no fuel leaks on the fuel lines?.
Cheers
Also the engine doesn't seem to chug away while I am coasting, and when I get right down in speed it will kick back to life with a few awkward chugs before starting a pleasant sounding throb at 750rpm.
I used to get this same scenario, usually accelerating up a short incline, and then jumping off the gas quickly and onto the brakes for a stop sign near my house.
I was/am also getting a similar sounding hesitation at startup, randomly, usually cold tho. Where it fires, and then "romp romp romp" followed by smooth idling at ~750.
I have put 3 tanks of fuel through with "Flashlube" diesel fuel system cleaner added, bottle says for "common rail systems" but thats all that was on the shelf at the time, so it it went.
SEEMS to have helped... although i only drive it every second pankcake day.
This symptom being so much fuel level dependent IMO it might be some trouble with the tank ventilation/breather system, when it starts to make the tricks remove the cap and concentrate if you hear some hissing or not, normally it's not supposed to be noticeable if the breather system makes it's job, i'm thinkig that if there's something wrong with that the pump's swirl pot misses fuel cos the non return valve of the pump doesnt close if the pressure in the tank didnt drop together with the fuel level, the gist is in the folowing description(it's about the pump not the filter head):
....
A non-return valve is located in the base of the housing. When the fuel tank is full, fuel pressure keeps the valve lifted
from its seat allowing fuel to flow into the swirl pot. As the tank level reduces, the fuel pressure in the tank reduces
causing the valve to close. When the valve is closed fuel is retained in the swirl pot, ensuring that the swirl pot remains
full and maintains a constant supply to the fuel pump.
so if there's ''parasitic'' pressure in the tank the fuel level drops but the valve doesnt close so the swirl pot doesnt remain full
to rule this out when the fuel level gets to the limit of that symptom unscrew partially(or completely) the filler cap to let excess of pressure out if that's the case and if it will start well this way you'll have to investigate the breather system... what i've seen once on a friend's car with similar issues is that the vent pipe(nr 23 in the attachment) was choked at that inflection(pointed with red) and caused trouble at low levels.... but it can be clogged as well, worth a try
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Originally Posted by Trolley
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