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As above, the tank itself will never be pressurised as it has to work with changes in volume as fuel is used. Many vehicles vent from the fill tube just down from cap, so if you keep pumping in there, it'll ultimately go out through the breather in most cases.

Fuel pressure, pump is suspended from top plate of tank and sits on a stem reaching down to tank base with pickup resting on bottom of tank (else you'd not be able to use all the fuel). From here it just pressurises the outflow line, via the fuel filter and then straight to the fuel feed rail going round the injector circuit.
Pressure is held up to required level by the regulator above which pressure it bleeds off in return line back to tank.

Fairly simple really but tank is always open to atmosphere.
 

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On my rovers gas cap
If I tighten it
I get vapor lock
.., after a while...
it stops
Then it won’t crank
So I loosen the cap
And it fires right up
Now I just leave it loose
 

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Discussion Starter #23
I'm really starting to suspect my fuel pressure regulator is bad. This morning I went to start the truck and did the thing where I cycle the ignition on and off 4-5 times before I crank it.
It fired on the first crank, but stalled immediately.
Second try was a little more cranking, and then fired on a few cylinders then stalled.
Third try it cranked for a while, then slowly fired up with some help from me on the throttle.

I can't find any definitive information on the interweb about the Rover V8 fuel pressure regulator, but a lot of general articles make me think I could be sniffing up the right tree.

The way I understand it is that the vacuum from the manifold decreases the fuel pressure, and as vacuum decreases (and engine speed increases) the fuel pressure increases as well. If mine is faulty it could be giving too much pressure at idle/startup, but higher in the rev range it's less of an issue because the engine requires higher fuel pressure anyway.
I have tried running the engine with the vacuum line (to the FPR) removed and it has a noticeable detrimental effect on the way the engine idles and revs, so I know the vacuum diaphragm is doing something.

I really don't want to disassemble the plenum AGAIN, but I'm getting pretty good at it by now and a new FPR can be had for ~$60 so I'm thinking it could be worth the effort.
 

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Discussion Starter #25
After some more head scratching and talking to my dad, I don't think it is the fuel pressure regulator at all. I believe that since I get better (not great, but better) starting when I cycle the key on and off 4-5 times before cranking, my fuel system isn't holding pressure. Pressure is held in the system via a check valve which is internal in the pump.
I believe mine is allowing the fuel to leak back into the tank, thus when I go to crank I am not getting the fuel pressure I need to start and idle right away. When I blip the throttle, more fuel pressure is being added by the FPR which allows everything to run happily.
To test this theory I bought a 5/16" fuel check valve. I am going to try to install it either right behind the fuel filter or directly out of the pump itself. This should allow the system to prime and then hold pressure in the lines.
I'm planning on getting this installed tonight and will report if I had any success.
Question, on the fuel pump can anyone tell me which pipe is the output and which is the return? I believe the pipe closer to the outside of the housing is the feed, but I don't know for sure.
 

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Discussion Starter #26
On second thought, I decided to go ahead and order a new fuel pump after pulling off my access panel to reveal this mess.
fuel pump.jpg

I had always known that it didn't look great, but I never realized how poor the wiring situation was. I got an Allmakes kit for about $110 shipped and it includes the sealing ring and wiring harness.

I was going to try to salvage this one, but the ground connector broke apart when I looked at it and everything else just looked past it. All the rust on the top was not confidence inspiring. Hopefully this helps my starting issues, or at least improves them.
 

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That may be more typical of condition than many realise.

Our current one came to us in similar state, with previous owner hacking into insulation to try and effect a repair. I stripped it out, remade by soldering the wires to pump connects, then recast insulation in epoxy resin to make it competent. Probably started slightly better than your situation though, so more chance of salvaging original.

That plastic retainer ring will hold any water there during use as there appears no way to drain out easily, I've covered the top of assembly with marine grease to try and prevent so easy a deterioration in future.

Guess we'll soon see if the pump is affecting your starting, but good to eliminate it though as ours had random non-pumping incidents that left it stranded a couple of times until fixed.

We await your verdict.
 

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Discussion Starter #28
So I finally had some time this weekend to pull the old fuel pump.
It was in pretty bad shape, and the return line actually broke off while I was removing it. I got the new one installed without issue.
My cold starting is definitely better. The engine fires right away, like less than a second of cranking.
The bad news is that the bad idle is back as is the code 48 CEL. There is a distinct whistling sound that sounds like a vacuum leak. I cannot tell where it’s coming from and I’m unsure where to go next.
Oh, and my right front brake caliper is Seized and is causing my brake fluid to boil or something. I noticed it driving yesterday then I got a spongy brake pedal.
This truck is such a pain. I can’t imagine what’s gonna pop up next. It’s literally been one thing after another for 3 years.
 

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Once you get it sorted out
It will be smooth sailing
You will just have to contend
With the not trusting how good it’s running syndrome
Hang in there
It’s worth the effort
 

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on the brake issue, I just replaced all 4 calipers on my lwb cost about $270 for rebuilt units from rock auto plus pads. on the intake whizzle, mine does the same but I have traced it down to alternator wine.
not sure if it has been covered before but how is your intake rubber hose? they deteriorate and with the vibration of the engine you get false air.
have you spayed gum out around the intake? false air or air leaks will increase idle as you spray faulty area, how is your belly pan (intake gasket)? are the intake manifold bolts tight?
your idle and idle code issue is the out come of other failure.
 

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@Razorbeam
Like I mentioned in an earlier post, my RRC had a lot of the same symptoms yours has, namely the recurring Code 48.
If you suspect a vacuum leak, spray carburetor cleaner near any gaskets, joints, and hoses while your engine is idling. If you spray somewhere and the engine surges, then you've found a potential vacuum leak.
I had the same suspicions, but never found any vacuum leaks on my engine when it was giving me a Code 48.
While replacing your fuel pump was probably a good thing, it's unlikely your fuel system would pull up a code; it's more likely too much air, not enough air, or an issue with the ignition system.
To make sure, pull the spark plugs one-by-one. It'll tell you what's going on in the combustion chamber, and whether the engine is running to rich or too lean (or burning oil, coolant, etc.) Eric the Car Guy has a great video to help you out!
Some things to consider are how new the stepper motor, spark plugs, spark plug wires, ignition coil, distributor blast shield, distributor rotor, air intake hose, and vacuum hoses are. I replaced all of these things on mine, and it ended up being the distributor rotor and base idle that were causing a Code 48 to appear.
You might also want to consider cleaning the MAF sensor (with MAF sensor cleaner ONLY), and checking the distributor pickup air gap.

As for the brakes, do you know when were last serviced? If not, or even if the problem with your front brake sticking persists, you should replace the brake pads and their oil seals; trust me when I say that it makes a world of difference. Replacing the pads is a really simple job, but if you can spare the effort then replacing the oil seals will do you a lot of good in the long run.
https://www.roverparts.com/Parts/9976F

Like Mikieman said, once you get these things sorted out it's smooth sailing. I spent the last year working on mine, and it runs better than my commuter car.
 

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Discussion Starter #32
Quick, and possibly final update on this thread.

After driving the car a bit more I noticed a leaky fuel line (yikes) from the hose that connects the fuel filter to the hard line. I guess the old pump wasn’t putting out enough pressure to make it a big deal.

I got that tightened up and she runs perfect. Starts with the smallest bump of the key and idles super smooth. Time will tell if the code 48 comes back. For now I’m chalking it up to a failing fuel pump and sketchy earth points on the pump.

Thank you to everyone who chimes in with helpful advice. Hopefully this thread can help someone else out someday.
 
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