help needed NJ

[FirstRanger86]

Hey,
I can't get my 86 Ranger started. I got it at auction. It had been sitting for 10 years in a barn, and it had some mouse houses. With a new battery, it started right up, so I put some money into a tuneup, new TFI and fuel pump relay, but I can't keep it running. It runs for a few minutes, pretty well actually, then dies, unless I keep my foot on the throttle, and then it dies a few minutes later anyway.

I am new to Fords in general, but I've been working on GM's and Jeeps for years. This OBD1 is driving me crazy. I'm a good wrencher. I could help someone in return for an hour or two of their time, or pay with some cash and/or food/beer. I have plenty of tools and space.

In Somerville, NJ

Tom

 

[dennis461]

need more data

engine size?
carb or fuel injected (motor may have been changed from original)

fuel lines in good shape?

If it can be restarted;
get a can of starter fluid, just when it begins to stall, spray fluid into intake.

 

[RonD]

Reads like a fuel problem.

New fuel filter for sure.

Could be the screen in the fuel tank is clogged up, long time sitting will do that, it is only allowing X amount of fuel in the pick up area per minute, so fuel is available until exhausted, then refills slowly.
Ford fuel pumps(you have two) are not on all the time, the computer turns the pumps on and off based on "need", so engine RPM, throttle plate position, feathering the gas pedal turns pumps on more, so sucks up limited fuel if screen is clogged.

The pump in the tank is a low pressure pump, same pump that was used for the carbureted engines, they added a second fuel pump in the frame rail when fuel injection was added, this is a high pressure pump.
If you have a pressure gauge you should see 30-40psi at the fuel rail with key on/engine off, then about 35psi at idle.
On the fuel rail there is a Fuel pressure regulator(FPR), it will have a vacuum line attached.
The engine vacuum is high at idle this opens the FPR and sends unneeded fuel back to the tank, at higher RPM vacuum goes down so FPR closes a bit to hold more fuel in the rail.
With engine off FPR closes all the way to hold fuel pressure for the next startup.
If you pull off the FPRs vacuum line while engine is idling you should see the fuel pressure jump up, this is fine to do, same as revving the engine to highway speed, 0 vacuum.
This tests if the FPR is working.

The high pressure pump has a check valve that prevents fuel/pressure from draining out when engine or pump is off.

Ford fuel pumps should run for 2 seconds each time key is turned on, that's the computers priming timer.

If you do change the fuel filter I would do a flow test.
Run fuel pumps output into a container for 30 seconds to see if there is good flow or it is tapering off.
You will need to put a jumper in the fuel pump relay to keep pumps running for 30 seconds, or run 12v to the inertia switch to run the fuel pumps.
This will tell you if fuel flow coming from the tank is the issue.