Exhaust Header issues - Follow up of my emission issue thread

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grayvixen93

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Oct 15, 2020
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The FPR could be a issue. Check your fuel pressure with the vacuum line connected and disconnected. You should see about 40psi with it disconnected and in the low 30s with it connected.

My FPR tester arrived today as well as my vacuum leak tester.

Fuel pressure with key on:

IMG_3796.jpg

Fuel pressure after 15 minutes (key off), while idling, while accelerating, with connected and disconnected vacuum line on FPR:

IMG_3797.jpg

Vacuum test:


What do you think?

I would say I have issues with my fuel pressure as the gauge readings do not change as expected.
I tested the FPR with the vacuum gauge and it did hold the vacuum.
I have installed a new fuel pump incl. hanger and strainer. Maybe the fuel pump is not strong enough? It came up in the parts list of RockAuto so I assume it should be the right one...

Regarding the vacuum test:
The needle is vibrating once the reading is steady.
In this video it is said that this could be worn valve guides:


Could this be the case or are these vibrations "normal" on a 302?
 

grayvixen93

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Oct 15, 2020
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I was following the guide of @jrichker.
Exception: For the fuel pump test I removed the hose of the return line next to the tank as I don’t have a fuel line disconnection tool and the fuel lines around the gas tank are rubber fuel lines with some standard clamps.

Result:
The fuel pressure stopped rising at 48 psi. It was also rising very slow.

I reassembled all and tested the pressure again. No change with vacuum line on or off the FPR.

So I would assume the pump does not produce enough pressure.

What do you think?
 

grayvixen93

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Oct 15, 2020
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The hose from the pump to the hard line on the hanger has possible split, time to drop the tank.
Yesterday I did drop the tank and removed the pump.
I could not see any issues. Here some pictures from the hanger:

IMG_3862.jpg IMG_3863.jpg IMG_3864.jpg

The tank looks clean inside. No visible debris.
The grommet of the Fuel Tank Vent Valve is quite worn. It has a lot of cracks so I ordered a new one.

I had a new 255 LPH universal fuel pump at home so I installed it on the old hanger:
IMG_3868.jpg IMG_3866.jpg

On this hanger the rubber lip is missing on the return line:
IMG_3867.jpg

I could use the one from the new hanger but I still would like to know if this thing is important and what it does or if I even could run the pump without it.

So I will install this pump these days and hope it will deliver the required pressure.
 

90sickfox

Wasn't a pretty sight...and I've got big hands
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Mar 2, 2015
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That little red or orange thing is actually a drain back valve. It's common for high flow pumps to blow them off. Never seen a real issue because one is missing. May cause you to have to cycle the key....with my FPR I have to do that anyway.