Where is the PCM to ground located on a 87 Ranger 4x4

[greaseyfingers]

Got a Code 95 - Fuel pump secondary circuit failure - PCM to ground

Where is the PCM ground located on a 87 Ranger 4x4?

 

[low_five]

powertrain control module - the computer or 'brain' inside the cab on the passenger side behind the kick panel where the passengers feet are. its probably not bad though. they rarely go bad.

 

[AllanD]

Got a Code 95 - Fuel pump secondary circuit failure - PCM to ground

Where is the PCM ground located on a 87 Ranger 4x4?

Low_Five: you are placing the emphasis the wrong way around "PCM to ground"
the emphasis should be: "PCM to ground"



It's the grounding screw right next to the computer.

It's a common cause of fuel pump relay (and for that matter the EEC power relay) malfunction.

One thing that is often misunderstood is that EEC-IV does most of it's switching
on the ground side of each circuit, so if the PCM grounds are questionable not
much of anything will work correctly or reliably.



AD

 

[greaseyfingers]

Low_Five: you are placing the emphasis the wrong way around "PCM to ground"
the emphasis should be: "PCM to ground"



It's the grounding screw right next to the computer.

It's a common cause of fuel pump relay (and for that matter the EEC power relay) malfunction.

One thing that is often misunderstood is that EEC-IV does most of it's switching
on the ground side of each circuit, so if the PCM grounds are questionable not
much of anything will work correctly or reliably.



AD

Being the inside cab's metal panel is painted that the PCM's ground wire is suppose to be grounded to.

It must only be grounded through this small type screw's threads and the underside of this screw's head that contacts the PCM's ground wire terminal end, as this metal panel is painted where the ground wire terminal end makes contact contact with this metal panel.

This doesn't seem like a very reliable way to make a good ground, if the threads on the screw, or the threads in the metal panel aren't making good contact from rust, or any moisture.

Would it be better to scrape all of the paint off this PCM's grounding mounting area, down to the bare metal, before screwing the PCM's grounding wire to this metal panel for making a more reliable ground contact surface?

Could a Code - 95 Fuel pump secondary circuit failure - PCM to ground, be caused by a malfunctiong fuel pump relay, too?

Is the Code - 95 Fuel pump secondary circuit failure - PCM to ground, affecting both the primary and secondary, in tank, fuel pump's operation and possibly the fuel injectors, too? Besides, maybe, affecting the PCM's ability to function properly for maintaining reliable engine management from it's sensors, if the PCM isn't receiving a good ground?

Is it possible to replace the low pressure secondary, in tank, fuel pump and fuel sending unit, with a high pessure fuel pump and sending unit that will fit in the fuel tank of a 87 Ranger 4x4, STX, without having to make any modifications?

Will a fuel pump and sending unit from a 89 to 92 Ranger or Bronco 2, work for doing this?

 

[adsm08]

Try sanding the paint off around the ground screw. I've seen that work many times.

 

[greaseyfingers]

I read this information at, http://www.fuelpumpinfo.org/page.php?mode=privateview&pageID=11&navID=27, that says this..

Running into a circuit failure in the fuel system?

Typically, circuits fail because of excessive resistance.
Excessive resistance limits current flow. Excessive resistance
is commonly found at the ground point where the fuel pump ground attaches to the frame rail ofthe vehicle.

Another common source of excessive resistance is pitting of the
secondary contacts of the fuel pump relay.

According to their information, another cause of excessive
resistance comes from spread fuel pump power and/or ground terminals at the fuel pump connector. When meter and test light leads are forced into terminals, the female terminals may spread and create a high resistance connection. Terminal tension can be verified by performing a “drag test” on female terminals. Poor terminal retention should be addressed by replacing
any spread terminals. The bottom line is that excessive resistance causes a decrease in current flow. When there is a decrease in current, the pump will not operate as designed.
http://www.fuelpumpinfo.org/page.php?mode=privateview&pageID=11&navID=27

Have any of you replaced a malfunctioning fuel pump relay, before, that had excessive resistance from pitting of the secondary contacts of the fuel pump's relay, with a new fuel pump relay and discovered that it improved your Ranger's engine's running performance, even though your Ranger's engine was still running while you were using your old fuel pump relay, but not as good, until after you had replaced it with new relay.

 

[adsm08]

Yeah, and that paint on the ground and you hypothetical "poor contact on the threads" would both constitute resistance.