All,
I just purchased a 1991 Ford Conversion Van (Mark III) that has very low miles but is having a fuel issue according to my fuel pump tester.

It has the dual tanks (3 pumps) but I am having some issues.

Here is where I am at;
The front high pressure pump engages and pumps the fuel to the mid to upper 30 pounds. Once the pumps are there the engine starts and runs fine until after a while the pressure just drops slowly. If I manually deprime the pump just a bit, with a tank draining attachment or increase the RPMs to say 3000 for a while, the pressure stays down until it finally stalls and after a series of key turns the front pump will get back up to mid thirty pounds. In short I felt the rear pumps were not pumping to the front pump. At the same time I noticed I had no fuel gauge if I selected either of the tanks using the tank selector thats under the tank. This made me question the tank selector switch, so I pulled the switch and tested it and it appears fine. So I thought maybe no power going to the switch. So with the key on I test with a voltmeter and I started first with the pink black wire. I tested no voltage. So I tried a few other wires in the switch harnes and still no voltage. I verified my voltmeter on the battery and it tests out fine.

So knowing the front pump is engaging, does anyone on the forum have the wiring diagram for my vehicle? (1991 Ford Econoline 5.0 Liter)

Also I have seen from a few other wiring diagrams out on the forum that many are very similar in nature. Many have a connector between the first high pressure pump and the low pressure pumps in the back tanks. Does anybody know where this connector is and if I can test continuaty on the pink and black wire?

Also are all the pumps 12 volt - i.e. can I run a wire for testing purposes to verify this is the issue 100%.

Thanks all,
Chris
Solomon_Man
1991 Ford F150
1991 Ford Econoline Mark III

 

https://www.ford-trucks.com/forums/8...ting-fuel.html Have a read here. Especially the posts by subford for wiring diagram.

 

Thanks for the reply.

I will make sure that I confim the one second on or ground out the #6 terminal as it will confirm whether I am getting power to the selector switch or not.

I have already verified that the Inertia switch is not flipped. Its actually, in this van, located on the passenger front panel not drivers front panel.

If I do have power to the switch then maybe the ground went bad.

I am having problems imagining both pumps and both ascending units going bad. I know its possible but I would be surprised. With the pumps on I will be able to verify whats operational and whats not.

Thanks for the information,
Chris
Solomon_Man
1991 Ford F15o
1991 Ford Econoline Mark III

 

All,
Now I am a bit confused.

I went out and grounded out the #6 terminal as suggested.

I have done this on my Ford truck in the past. I tested at the tank selector switch for voltage and I received voltage as expected.

I started the vehicle and it ran. So I went through a series of tests on the pump where I basically through my fuel test setup deprime the pumps. Once when running and once right after the key is turned off.

This time as one would expect, if the rear pumps were working, pressure to resume to the 40+ lb mark which it did on all occassions. So I removed the ground out wire from the #6 terminal and tried the test again which this vehicle has failed at least a dozen times previously. This time it passed the above tests and now has been running the longest it has been running in over 6 years.

The vehicle has been sitting as the previous owner experienced a series of health issue and the vehicle sat in front of a garage.

I have turned on and off the engine and ran the test now 4 seperate times. Each time it does what I would expect it to do.

So at this point I am not sure what to do...

Anyone have any ideas?

I have worked on a series of vehicles over the years and the computer checks usually RPM or oil pressure before enabling the pumps to stay on after the initial key turn. Could the issue be in the vehicles ECU or something along those lines or could this be I had a stuck fuel pump(s)/sensor.

Anyone experience this problem before?

Thanks,
Chris

 

I am curious, what is your VIN # without the last four numbers?
I have never heard of a 1991 E-series having this fuel set up.
As far as I know all E-series went to the high pressure pumps in the tank in 1991.

You also need to see if you have any codes in the computer memory. The PIP is what tells the computer to keep the pumps on and the pumps will stop one second after the last PIP. Post any codes and then we will try to help you more.

If you do not know how to read the codes go to this link:
Ford Fuel Injection How To Run a Self-Test

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All,
The vin minus the last 4 digits is;

1FDEE14N7MHB3

What is the PIP?

Anyways I did the STI test and I get a series of 11 codes followed by a 15. I reset the ignition and tried again and I get the same response. Please note the vehicles battery is disconnected every night as the vehicle has sat for such a long period.

I am not sure what the codes mean as my service Factory Manuals are on there way here but I did find this morning a fairly decent fuel leak coming from the rear tank lines. I mean a steady consistent squirt. I will have to climb under and investigate further but I am fairly certain that new lines have been installed from the front to the back of the vehicle as they are very clean (no rust).

So maybe the fuel ascending system (lines, pump,fuel level) is shot and it was plugged or something along those lines.

Anyways did the same tests last night and got the same positive result. Its running now but with a new leak.

Any Ideas?

Thanks,
Chris

 

PIP: Profile Ignition Pickup.
ICM: Ignition Control Module (TFI)

The PIP is a pulse train from the Distributor to the computer and the ICM.
This tells the computer the engine is turning (RPM) and the position of the engine (which piston is coming up).

 

All,
I did a little research and came up with the following link;

Ford Fuel Injection 2 Digit Self-test Codes 11-32

Which says the 11 codes are that the system passed.

The 15 may be the fact that the battery was pulled?

Really not going to get much considering the battery power was pulled.

Anyways I am not sure what caused the issue, but with the continuous gas leak I will more then likely end up dropping the tank and or replacing the assembly. I am surprised the engine will run with the stream its producing.

Unfortunately, I will not get to look at this more till the weekend (maybe Friday) as my work schedule is horrible the next two weeks.

Another issue that I have experienced is the Heating and cooling blower is not functioning. I have tested the blower and it functions. The fuses are all fine. So I guess there is a resistor pack... Where is this located?

If I end up at the parts store I might as well correct that as well.

I will keep everyone posted,
Chris

 

Yes pulling the battery will cause a 15.

If you select HI on the blower you will bypass the resistor pack.
You might have a bad blower relay.

 

All,
If my back fuel ascending unit and pump assembly unit is bad (rusted out) does anyone have any idea where I can get one new at?

Is there a online source?

I have called my local parts stores (napa, autozone, o'reilleys, and advance) and all say not available. Call the dealership and they said it take a few days but at just under $400 with tax seems a little pricey considering the front tank assembly can be had for under $100.

I am going to try and climb under it tonight after work - 10pm.

Thanks,
chris

 

What size tank is it?
Maybe you can just put the replacement Fuel Delivery Module on the fuel Hanger.
Most just use the old fuel hanger anyway.

 

All,
I believe the tank is 22 Gallons.

Everything I am finding from Auto parts stores suggest the rear is 22 and the front is 16 gallons. Can anyone confirm that is what is in my van?

The problem, I am anticipating is the fuel lines are rusted out... just the reason for the severe leak. If thats not it, then something either popped loose or this is some kind of recirculating line etc gone awry. As you can tell I am fairly anxious to see whats going on!

I hope tonight to get under the vehicle and take a look and possibly pull the tank, if necessary. At this point, I just want it fixed and on the road.

What I am finding is no where does anyone sell the complete rear pump/ascending assembly except for the dealership. Even though the pumps began to work I still do not have working fuel gauges.

If I find out a rusted mess, I have no problem replacing tanks and fuel pump/ascending assemblies, if available, for both tanks. I got the van for the right price so if I have to sink a few bucks into the van, to make it dependable for my wife and my toy hauler, that is OK.

I went through a similar issue on my F150. Sometimes the extra $150 for a new tank and fuel pump/ascending gauge is worth the piece of mind. Do they sell just the fuel ascending unit? (asking as if the dealership is my only option and I end up at a yard (worse case))

I assume to test the fuel ascending unit its best to do once out of the tank. Then how do I test it....Ohms test?

I am hoping something popped loose and the fuel ascending units are gummed up and a full tank of good gas in each will correct any issues.

Thanks,
Chris

 

Most auto pars stores only sell the FDM to be installed on the Fuel Hanger so the size of the tank is not that important. The fuel hanger is made out of stainless steel so it should not be rusted.

Most just test the Fuel system while the FDM is still hooked up by turning on the key and shorting pin#2 to pin #6 of the EEC Self-Test plug. With the selected pump running they check the pressure with a fuel gauge that they put on the fuel rail before turning on the key. The pressure should be 45 PSI.

The fuel gauge has nothing to do with operation of the FDM, it is a separate system. They just use the same fuel selector switch and tank.

Fuel Pump & Fuel Hanger:


/

 

All,
I am able to get the complete fuel delivery system from both Advance and Autozone for the front tank.

Fuel Pump Sender Assembly by Airtex - Part E2147S - Advance Auto Parts

Airtex Master/Fuel Pump | Fuel Pump | 1991 Ford E250 3/4 ton Van 8 Cylinders N 5.0L FI | AutoZone.com

I was hoping for the same for the back tank. I have located and confirmed after about 4 hrs of research that the rear pump (FDM) and hanger assembly can be had separately with lifetime pump (BOSCH) for around $120.00.

Sender; Includes Fuel Sender, Float and Strainer (Fuel Pump Not Included) by Spectra Premium - Part FG90A - Advance Auto Parts

I was actually able to reduce cost for both complete Fuel assemblies for less then $150.00 to my door and it is original Motorcraft. I could also purchase both tanks new 5yr warranties and fuel assemblies to my door for less then $385.00.

After what Subford has said I believe my issue may not be the rusted out hangers as they are supposed to be stainless. The leak was a large even flow not a spray. Maybe the return line? Vehicles, non fords, I have worked on in the past... I have not been so lucky and usually are spray leaks in nature do to rust. So it may be just a popped off connector. Which will make me wonder.... why...Has this been a on going issue for the previous owner or just a coincidence? Not a big deal either way

Subford your statement of "The fuel gauge has nothing to do with operation of the FDM, it is a separate system. They just use the same fuel selector switch and tank." I 100% agree with but don't they use the exact same ground? Can anyone confirm where the ground from the tanks are connected at either at the frame or a connector returning to the negative battery connector\other ground source. I hope to figure that out later tonight as well.

A ground issue may help explain some of what I have been experiencing. For explanation point lets assume the common ground used on both tanks have corrosion and resistance is high at that connection point. When the ignition is turned on, the split second voltage/amperage is sent to the pumps to prime the front external pump. I would assume the in tank pump(s) would not function always 100% properly and explain maybe why it would run some times and not others.

There is some clear problems with this answer as the solution, mainly why grounding out the ECM seemed to have corrected things. I assume that the rear tank pump(s) once the PIP senses the proper RPM are on continuously until the engine is shut off. So I would figure it would have a problem sooner or later again.

I think the only way to 100% remove the tanks and fuel assemblies from the problem picture may be to trace everything from ground forward and thoroughly test. Its tempting to replace the whole mess to avoid frustration and quickly and blindly do an R&R procedure. (Remove and Replace).

The lines on the frame, when I was replacing the brake lines appeared to be very clean in fact could still read lettering on the lines.

I think I just need to get my A$% under the car and see whats going on more. Thanks for listening to my rambling.

And Thanks for the help,
Chris

 

Yes the fuel pumps and the gauge both use the same ground at the drivers side radiator support.

Please disregard my post above as you do not have the FDM
I will edit and make changes to that post.
For the rear tank you need the pump for the fuel hanger and the AirTex number is E2008.