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fuel pump.


handmedownreatta
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On 12/31/2020 at 8:59 PM, Ronnie said:

You must have just tested the pump pressure. There is also a load test for the fuel pump on my website that will tell you if the pump is capable of maintaining pressure as well as a test to see if the system will leak down with the pump off.

 

 

i did all three tests.i had to go back and read them to be sure.

Edited by handmedownreatta (see edit history)
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5 hours ago, handmedownreatta said:

i did all three tests.i had to go back and read them to be sure.

If you don't have an extension hose for a regular fuel pressure gauge, I made my single purpose setup with a -4 SAE flare female swivel, 90*, to a barbed hose nipple, fuel injection hose to another barbed fitting and a low cost pressure gauge from a hardware store. 100 psi would be about perfect so approx. center dial pressure, 60psi would do in a non-boosted application. You must remove the little tire valve core, similar to a tire valve, on the fuel rail as the female swivel has no release mechanism to depress the core. Of course the fuel pressure must be relieved before connecting or disconnecting. Keep the gauge outside the car.  

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Sorry but for a Reatta the fuel rail pressure should be 40-50 psi to run properly. At 20 psi it will idle but not have power.

BTW is all pressures are good, are you certain that it is gasoline and not much water ?

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9 hours ago, padgett said:

Sorry but for a Reatta the fuel rail pressure should be 40-50 psi to run properly. At 20 psi it will idle but not have power.

BTW is all pressures are good, are you certain that it is gasoline and not much water ?

its been through several tanks of gas.i did have to replace the fuel pump relay to get it to idle right.

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What is the fuel pressure reading you got?   if it is low, Padgett is correct. 

Other problems could be dirty or clogged intake...and/or a plugged converter. 

Exhaust pressure can also be checked by pulling the O2 sensor and attaching a gage.... at idle they should be close to "0"

I don't know exactly what it should be at lets say 2000 RPM but I would think less than 5 psi.

I am sure others will have an opinion. 

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I made the assumption that the actual fuel pressure had been checked, as per the original post of having passed the ROJ fuel tests? Just to clarify my experience with low fuel pressure which has been touched upon in another thread: I had an '89 for my grandson that had what appeared t be a recent fuel pump, but the hose installed to eliminate the factory pulsator was left loose without clamps. It had great difficulty starting, if it would start at all without the aid of ether. Once started, it would idle smoothly and could be driven moderately. Rapid acceleration caused it to fall on its face. I found the running fuel pressure to be 33psi, with or without vacuum hose attached to the regulator. It was low enough that it was below the minimum setting of the regulator and the return line could be disconnected completely, while running, and it would not leak a drop of fuel. I suspect upon initial fuel pump replacement the short hose in the fuel tank fit tightly enough that it held better fuel pressure but gradually it lost its grip and would lose prime almost instantly. I know it is an apple and orange comparison, but many decades ago, a friend with a '66 GTO had a similar problem. Under hard acceleration the short hose connecting the fuel tank to the main steel fuel line to the front would suck flat under demand and do the exact same thing, and was a devil to find.

 

By the way my experience with the exhaust backpressure as Barney mentions should be essentially zero at idle, and 2000 rpm while parked will be one psi or less. Maximum backpressure I have measured under hard acceleration has been in the 6-7psi range.

Edited by 2seater (see edit history)
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