87 Ranger In-Tank Fuel Pump

[jaezzell]

I have an 87 2WD STD cab Ranger, 145,000 mi, it has started hesitating really bad when accelerating, feels like the engine is pulsating, like maybe it's not getting the fuel it needs. It does fine at idle. I have replaced most of the ignition system and pretty much every sensor on the engine. It tends to happen at random times....some days it will hesitate 2 times every minute, some days not at all.

I am starting to think that it may be my in-tank high-volume fuel pump. Since I got the truck, the fuel gauge has not read right, and I think the check valve is shot because it takes like 7 or 8 seconds to start the truck. But if I switch the key off and on several times first it primes and starts right up.

Does this sound to anybody like it is probably the in-tank fuel pump?

Also, the fuel pump top on my tank is located halfway under the cab and halfway under the cab/bed gap. So it looks like I will have to drop the tank to get it out, and that only removing the bed is not an option.

Any help would be greatly appreciated!

Relevant Parts Already Replaced:

Spark Plugs
Wires
Dist. Cap
Rotor Button
Ignition Module
Coil
TPS Sensor
O2 Sensor
ECT Sensor
EGR Pos Sensor

 

[jmcleek]

First try to pull codes http://www.therangerstation.com/tech_library/OBD_I.html

 

[jaezzell]

I did pull codes, but only got one for the A/C Compressor (which the PO removed)

This problem started a few weeks ago, and has steadily been getting worse.

 

[jmcleek]

When you say the fuel gage don't read right does it work at all? when the key is turned to the run position can the intank pump be herd running . It should run for afew seconds. I have seen these trucks run off the pump on the frame rail and pull fuel through the return from the tank.

Have you changed the fuel filter ?

 

[Insanejughead]

Check your fuel pressure. See how quickly it goes from 0 psi to 35+ psi.

My guess, as of now, is that you have a very weak pump. Or a bad connection somewhere.

 

[tomw]

If you have to cycle the key to get the engine to start, you have a bad check valve in the sender unit, leaking injector(s), or a leaky regulator. Any one could be letting the pressure drop as the fuel drained back to the tank or into the intake. You can try pinching the return line from the regulator, while checking to see if the pressure held, but I'd bet on the check valve in the pump/sender assembly being bad. I do not like the idea of pinching any fuel line, especially one that is old enough to drink. The black plastic lines get VERY brittle, and will shatter if impacted even just a little.
I have an '85 standard cab, and think I would check very carfully to see if you have enough access to the pump by tipping the bed. Raise the drivers side and support with some 2X4 chunks, a section of log, or whatever you have. Dropping the tank is not nearly as much fun, and getting the straps back into their original position is sometimes a difficult thing to do. The 'slack' always seems to be in the wrong place, yet the strap will not move back into position. It can be done, but I think it is more cumbersome than the bed. You are only have the 6 torkx bolts holding the bed to the frame, and the license plate & tail light connector. You still have to disconnect the filler etc.
Is it possible you have some contamination in the tank? I have recently gotten fuel that has water, and the engine will stutter and hesitate as it will not run on water. Seafoam seemed to help for a while absorbing the water, so maybe I have a problem with the filler neck allowing rain to enter. I've never heard this tank do the 'whoosh' as the filler cap is removed in the summer time that I have heard on my other car. The cap passed the emissions test, so should hold pressure.
I'd borrow or buy a fuel pressure gauge, and tape it to the windshield. Note if the pressure is dropping when it misbehaves. That would indicate a pump problem. You could also have a problem with the rollover switch getting intermittent contact. It can be checked and 'cleaned' by pressing the reset button on the top several times. Well, you'd have to use a meter to check...
tom

 

[jaezzell]

When I turn the key, I can hear a pump kick in, but I can't tell which one it is....it sounds like it is coming from closer to the engine, like it's the high pressure pump. I changed the filter today and will try it out later today. Black and brown gas came out of the inlet side of the filter and it was very hard to blow through even after all the gas had drained out.

I hope that was the problem because I am not looking forward to dropping this tank.

The fuel gauge works, but basically reads empty when the tank is half full.

 

[Insanejughead]

A new/good filter has almost no restriction when you try to blow through it with your mouth.

 

[jaezzell]

Well I took it out for a test drive. At first it was still hesitating bad, but after about 1 mile it stopped and was fine for the rest of the drive (6 more miles). If the filter was the problem, I can't figure out why it was still hesitating for the first mile. I will drive it to work on Monday and see how it does.

I already ordered a new tank pump, should be here in a couple days. I will probably still end up changing the pump out because I know the check valve is bad and the sending unit is off.

 

[jaezzell]

If the in-tank pump had died, would the truck still run and be driveable? Is the high pressure pump capable of delivering the fuel needed during acceleration?

 

[jmcleek]

I had a 88 That the fuel gage didn't work ,pulled the bed off and remove the sending from the tank. The float was missing and the electrical terrmenals where completely gone from the fuel pump. It still ran before that but not good. Had a tank of stale gas that I emptied out and alot of rust and settements that I also cleaned out. Ran off the return line.

 

[jaezzell]

I don't understand how the truck could run off of the return line? Couldn't the high-pressure pump just suck gas up through the supply line past the broken pump?

 

[jmcleek]

The bad pump acts as a plug. when the system is working right , the low presure pump keeps a resavor filled with fuel that is between it and the high presure pump . This small tank is there to keep the high presure pump from running out of gas during cornering at parshal tank when the enlet in the tank has no gas covering it. The return from the fuel rail goes back to this tank and a return from this tank goes back to the fuel tank and ends next to the inlet. Newer truks have baffles in the tanks to brevent the pumps from runniing out of gas at parshal tank during cornering. These tanks have no baffles.

 

[jaezzell]

Ohh gotcha. Well it is stumbling/lacking power about 90% of the time now and it seems to suddenly come and go, which feels like the pump is turning on and off randomly. I guess I will be replacing that pump as soon as it arrives.

It looks like about half of the pump top is below the cab, and angled toward the cab. Will I have enough space to disconnect the fuel lines and electrical connector and tilt the pump and slide it out if I take the bed off?

 

[chilsam]

90 4.0 pump

I put the pump from a 90 4.0 in my 87 had to mod the pick up SHORTN fuel line on pik up then just took the in line pump and resevoir off ,that's been over a yr ago and have no probs with full starvation until below E .THATS when I know to fuel UP!