92 4.0 swap wont run

[RobbieD]

It does sound like a fuel delivery issue to me, but there are much better minds on here than I on troubleshooting fuel injection systems.

A suggestion. Please give a description of how you have set up the fuel system. If I'm not mistaken, this a 1985 Bronco II with a 1992 4.0 and engine wiring transplanted in.

The '85 2.8 would have a mechanical pump on the engine, but the 4.0 runs an electric high pressure pump in-tank, with feed and return lines and a pressure regulator. Knowing how you've set up the new fuel delivery would be very helpful to know, and yes a fuel pressure test gauge would be a huge help in the trouble shooting and diagnosis.

Hang in there. I know how much it sucks to be getting a leg cramp when you're so damn close to the finish line.

 

[RonD]

On the main wiring harness in the engine bay is the OBD1 connector

Looks like this: https://www.therangerstation.com/tech_library/images/eec-iv_testing2.gif

In that drawing the Fuel Pump Slot is labelled
That's the GROUND for the fuel pump relay
Computer grounds that slot/wire for 2 seconds with key ON to prime the system
Then grounds it full time after engine starts, above 400rpms

With key on, use a jumper wire in that slot to battery negative or a good ground
You should hear the fuel pump relay "click" closed and then the fuel pump in the tank can be heard running, its not quiet

If you hear the pump start the engine, if it still stalls out check/replace fuel filter if you haven't already

If engine starts OK and stays running then there may be a problem in the computer, you will need to open it up and have a look

Fuel pressure regulator(FPR) is a maybe, certainly possible for it to fail open, but usual failure is leaking fuel, you can check its vacuum line for gasoline
It has the Return line to the gas tank, you can CAREFULLY pinch this hose with pliers to stop the flow back to the tank, which is what the FPR does
And see if engine stays running

(gas tank)Pump-----filter-------fuel rail/injectors-------FPR----gas tank

 

[Acgallen]

It does sound like a fuel delivery issue to me, but there are much better minds on here than I on troubleshooting fuel injection systems.

A suggestion. Please give a description of how you have set up the fuel system. If I'm not mistaken, this a 1985 Bronco II with a 1992 4.0 and engine wiring transplanted in.

The '85 2.8 would have a mechanical pump on the engine, but the 4.0 runs an electric high pressure pump in-tank, with feed and return lines and a pressure regulator. Knowing how you've set up the new fuel delivery would be very helpful to know, and yes a fuel pressure test gauge would be a huge help in the trouble shooting and diagnosis.

Hang in there. I know how much it sucks to be getting a leg cramp when you're so damn close to the finish line.

My fuel system consists of a brand new 86' fuel tank with a 86' in tank high pressure fuel pump. I ran all new bronco graveyard fuel lines with an inline fuel filter. I have the fuel pump hooked up to a switch next to the key. I prime the engine for 2-3 seconds before starting.

 

[Acgallen]

On the main wiring harness in the engine bay is the OBD1 connector

Looks like this: https://www.therangerstation.com/tech_library/images/eec-iv_testing2.gif

In that drawing the Fuel Pump Slot is labelled
That's the GROUND for the fuel pump relay
Computer grounds that slot/wire for 2 seconds with key ON to prime the system
Then grounds it full time after engine starts, above 400rpms

With key on, use a jumper wire in that slot to battery negative or a good ground
You should hear the fuel pump relay "click" closed and then the fuel pump in the tank can be heard running, its not quiet

If you hear the pump start the engine, if it still stalls out check/replace fuel filter if you haven't already

If engine starts OK and stays running then there may be a problem in the computer, you will need to open it up and have a look

Fuel pressure regulator(FPR) is a maybe, certainly possible for it to fail open, but usual failure is leaking fuel, you can check its vacuum line for gasoline
It has the Return line to the gas tank, you can CAREFULLY pinch this hose with pliers to stop the flow back to the tank, which is what the FPR does
And see if engine stays running

(gas tank)Pump-----filter-------fuel rail/injectors-------FPR----gas tank

Sorry, i did not describe the system i have set up for the fuel system. I described it above this. Its a 86' EFI setup with the fuel pump hooked to a switch. The fuel pump relay still clicks when key turns. The regulator had no gas coming out of the vacuum line. The truck will start on the initial fuel prime, rev to the normal starting 1200 rpm ish and then die immediately.

 

[RonD]

Then one if the fuel pumps is shutting off
IF.......like you said it can be kept running by spraying fuel in manually, so spark is still on

Do you still hear the pumps after engine stalls?

What about the fuel filter?

 

[RobbieD]

Do you still hear the pumps after engine stalls?

It sounds like he has one high pressure pump in the tank. I think a test pressure gauge will tell a lot.

 

[Acgallen]

Then one if the fuel pumps is shutting off
IF.......like you said it can be kept running by spraying fuel in manually, so spark is still on

Do you still hear the pumps after engine stalls?

What about the fuel filter?

Yes fuel pump hums until i turn the switch off, with no change in tone. Fuel filter is brand new with the fuel lines. I pretested the lines by using the FP to push gas into a can through the feed line. I can also immediatly start the truck again once it dies.

 

[bobbywalter]

Sounds like one of the pumps is not working or something is packed off. As said....gauge and volume test. Could just be a bad connection at sender.

 

[Acgallen]

This may be pertinent to the running issue. I found my code reader and was able to produce some codes.

114 : Idle Air Temperature out of range

Not sure this would hinder the truck from staying on.​

522: Park/ Neutral Position

Truck was an auto before, i took the park wires (blue/black) and spliced them together. That may be wrong.​

542: Fuel pump secondary circuit failure

I have the fuel pump on my own circuit. My 5.0 ranger is the same way with no issues.​

Only got these codes 1 time out of the 3 scans. These may make the truck not stay alive
157: MAF signal low or grounded
528: MAF signal under .4 at some point in 80 key cycles

I also will test the fuel pressure in the next few days. It does seem like a fuel issue but at this point I have no idea what the computer could be doing to the system. Thanks again yall, driveshafts just came in, last step in getting this B2 moving for the first time in 10 years

 

[RobbieD]

Just an observation.

What sticks out to me, is that you're using an "86' fuel tank with a 86' in tank high pressure fuel pump". If it's a stock-spec pump, in the 1986 through 1988 models the in-tank pump was just a "lift" pump to get the gas out of tank, and to get it to the high pressure pump on the frame rail. The PSI rating for a replacement (Delphi) '86-'88 in-tank pump is only 5 PSI.

The 1989 and 90 models did change to the one high pressure pump in tank design, and a replacement pump (in-tank, and again Delphi brand) for these years has a 45 PSI rating.

In any case, doing a pressure test with a gauge will be a good step, and either rule out fuel pressure or confirm that it could be the issue.

You'll get it; hang in there.

 

[Acgallen]

Just an observation.

What sticks out to me, is that you're using an "86' fuel tank with a 86' in tank high pressure fuel pump". If it's a stock-spec pump, in the 1986 through 1988 models the in-tank pump was just a "lift" pump to get the gas out of tank, and to get it to the high pressure pump on the frame rail. The PSI rating for a replacement (Delphi) '86-'88 in-tank pump is only 5 PSI.

The 1989 and 90 models did change to the one high pressure pump in tank design, and a replacement pump (in-tank, and again Delphi brand) for these years has a 45 PSI rating.

In any case, doing a pressure test with a gauge will be a good step, and either rule out fuel pressure or confirm that it could be the issue.

You'll get it; hang in there.

You hit the nail on the head with that one. My rock auto purchase history says 1986 pump with a 5 PSI output. You're awesome for being able to put the all the context clues together. Going to buy a 90 model pump and send it, (no space for an inline pump with new fuel lines)

 

[RobbieD]

Good; I hope that it's the final hurdle.

One thing to be aware of; if you get a complete later pump and sending unit assembly, I'm not sure if the later model ('89-'90) fuel level sending unit is compatible with the '85's dash gage.

Anyway, good luck!

 

[RonD]

1983-1988 Gas tank level senders are different than 1989-2011 senders

Later model sender will NOT work with earlier gauge in the dash

So just get the in-tank high pressure pump and swap it with old pump

 

[Acgallen]

1983-1988 Gas tank level senders are different than 1989-2011 senders

Later model sender will NOT work with earlier gauge in the dash

So just get the in-tank high pressure pump and swap it with old pump

Im going to just replace the pump to keep the guage working. Any suggestions to what year and size i would need for it to fit well? or are they pretty much the same based on looks.

 

[SenorNoob]

In my experience, there are very few variations on the aftermarket pumps. You can usually buy just a pump to put in your sender cheaper.