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John L

PI Fuel Pressure

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I have just rechecked my fuel pressure out of interest after my adventure, and the change of the battery, with just the key on engine not running I see 125psi.

I know the pressure should only be 110psi max.

I haven't had any problems, car runs fine, no extra fuel consumption, I think it even starts better.

Suppose I should put it back to 110psi max or leave?

This is just with my new battery, I must say I'm impressed with the Russian item so far, its showing 13V with nothing connected,  I didn't think the old Bosch battery was that bad, as I had set the pressure a few weeks before my departure.

John

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125 is a bit high and potentially shortens the life of your pump, damaging to the metering unit and greater potential for leaks.

The recommended is 105-110 psi.

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I agree with Andy 125 (assuming your pressure gauge is correct) requires the pump to work much harder drawing more current and thus running hotter. As heat in the pump is a problem and needs to use the fuel in the tank as a cooling reservoir more heat cannot be good.

As the system is designed to run at 10% lower pressure than you are using it will not bring any benefit, only the potential for grief and expense.

Strange though if a pressure relief valve "moves" its adjustment and is probably more likely to be stuck closed and the pump will be running at its maximum.

Alan 

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Hi Both 

Given all the problems with the pumps Lucas or Bosch has anyone run a modern in tank pump where it will be cool along with adjustable external pressure regulator/gauge similar to a modern EFI set up?

Andy 

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Having the pump submerged in the  petrol won't result in cooler fuel- which is the cause of most pump problems. My PRV has been set at 680 kPa (gauge) with air and the PI system has worked perfectly since I had the MU and injectors rebuilt and recalibrated a few years ago. The PRV setting has been unchanged since I bought the car in 1998- it works with my PI system so I see no point in changing it.

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2 hours ago, PodOne said:

Hi Both 

Given all the problems with the pumps Lucas or Bosch has anyone run a modern in tank pump where it will be cool along with adjustable external pressure regulator/gauge similar to a modern EFI set up?

Andy 

With a proper Bosch pump set up, a clean fuel tank and the metering unit/prv/injectors/throttle bodies  reconditioned by someone like Raven Smith there really are not a lot of problems to be honest...and I speak from experience...and we are talking a 50 year old vehicle here too

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I agree, my Bosch set up works fine. However  I guess a pump in the tank would remove any inlet piping restriction problems.

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Is there such a thing as a high pressure in-tank pump? I have only seen low pressure pumps for carbs, but I have never researched other pumps as my Bosch works well (chassis mounted).

Alan

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44 minutes ago, barkerwilliams said:

Is there such a thing as a high pressure in-tank pump?

Bosch 044 can be submerged. 

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The part no of the Bosch submersible pump is 0 580 254 040 ( runs at 100 psi )

 

                                               Harvey S. Maitland

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