Vipermn1961

Fuel pump fuse is good. When I jump fuel pump relay 87&30 I get I thunk sound from the back (fuel tank) not a click from the fuse panel. Almost like fuel pump wants to turn on but doesn't, should be humming but isn't.

namasgt

I had that happen to an 84 that sat for 2 years with old fuel, Pump was stuck and a new one fixed it, The old pump was new but was stuck, just made a clunk sound every time I jumped the relay. Try to reverse flow it, see if anything comes out. How did your internal tank screen look like?

jcorenman

Sounds like fuel pump, happened to us exactly the same way, same "thunk" ... thread here

Vipermn1961

I called my tech and he's going to pick it up and look at it next week. Was hoping it was a fuse or relay issue. Thanks for everyone's help, you all are the best! Will update you all with the outcome. Who all is coming to the Frenzy, can personally thank you there!

WallyP

Don't assume that a new fuel pump will solve the problem. If the hose between the internal fuel pump and the fuel tank outlet has disintegrated, the pieces will jam the external fuel pump.

namasgt

Its a 86, so it shouldn't have the internal pump just a screen.

WallyP

It shows on the '86 wiring diagrams.
Easy to check - look for the wires going into the tank fitting. If the wires are dead-ended near the external pump, you don't have the internal pump. If the wires connect to the tank fitting, you should have the internal pump.

Vipermn1961

To all that sent diagnostic tips thank you. As promised i would update everyone with the actual problem when found, it was a defective fuel pump. The fuel pump was just replaced a few months ago (Bosch unit), doubted it could be the problem but it was. So i'll now have my tech replace the fuel gauge sending unit at the top of the tank since my fuel gauge isn't reading properly. By the way my tech covered the pump labor and tow bills. First class operation!

jcorenman

So is there an in-tank pump? See Wally's note, above. Check the tank fitting, if there are electrical connections then there is an in-tank pump which needs to be pulled and checked. The most common failure of an external pump is an internal pump with a broken hose, allowing debris in the tank to get pulled into the external pump and jam it.

FiveElements

It may be a good idea to put a fuel pressure gage onto the front fuel loop so you can see pressure or not. They are $20

jeff spahn

You might want to hold off on the permanent fuel pressure gauge. There was a fire this past year due to a pressure gauge failure. Leave the cap and ball there. If you need to check fuel pressure, hook up a gauge to this fitting, test it then remove the gauge. Non-boosted cars don't need a fuel pressure gauge sitting on there all the time.
I removed mine the day I saw the thread about the failure and subsequent fire. It looked cool, but a non burned up 928 looked even cooler in my garage.