Odd issue with my 1994

[RonD]

1994 Ranger 4.0l 4x4, manual trans

All electrics are original except spark plugs/wires and O2 sensors, 400k

A few days ago it stalled after 2 min drive time so still cold, wouldn't restart right away, figured fuel pump time, 26 years, I got no complaints, lol
It did restart after about 2min, drove it back home, tested pressure, went to just above 40psi key on and off, 30psi running, held engine at 2,500rpm stayed steady at 30psi, and held at 25psi after 6 hours key off
Cleaned MAF at that time

So drove it again yesterday, seemed fine for a few hours, then it started stalling out, but didn't stall, but when stopped idle would go high and low
IAC Valve
And CEL came on and I got a code..............522 clutch switch fault????
IAC tests fine, but cleaned it

After doing the code retrieval, jumper removed, tried to start but CEL stayed on, aha Crank sensor
Cycled key off and on started fine??
Checked crank sensor anyway, its fine

Did a "sanity test" on computer, unplugged MAF, TPS, IAC Valve,, one at a time and got a CEL and a correct code for each

Pulled out all fuses and relays in the engine fuse box and plugged back in to clean connections

So today it seemed fine, but got CEL while driving, and no code just 1 1 1
Didn't reset/clear, and no CEL??

Have done a few engine running tests and always 111

Not sure what to think but leaning towards a computer issue

 

[Dirtman]

Uhhh no no no, we ask YOU questions. Not the other way around...

 

[RonD]

Uhhh no no no, we ask YOU questions. Not the other way around...

LOL, but I seldom have the RIGHT answer, just a good keyboard

 

[Guanfy]

You check the neutral safety switch? You mentioned you got a CEL for that.

 

[scotts90ranger]

I would point to power or ground to the computer, cycling connectors is a good start

Being a '94 it shouldn't have a neutral switch if memory serves. I know my trans from a '89 has one, later '89 ('90 model year) did not, both 2.3L manual trans pre MAF (mid '90 model year change) trucks... I don't remember on the '91 Explorer but I don't think it had one and haven't had any other M5OD's out...

 

[RonD]

You check the neutral safety switch? You mentioned you got a CEL for that.

Good call, no I haven't tested it, grey/red(5v) and light blue/yellow stripe(to pin 30), computer gets the 5v when clutch pedal is down

I guess I should but really can't see how it would effect the system overall and code hasn't returned, the starter part of the switch is working

Its the CPP(clutch pedal position) switch, on clutch pedals pushrod, it has 3 switches inside, one switch for starter motor activation, one for cruise/brake, and one for computer
All switches are open when clutch pedal is up, all switches are closed when clutch pedal is down to the floor

Some of the M5OD-R1s did have a neutral switch on passenger side top, but only saw them in early Explorers


I did get a another code: 511 - No power to PCM pin 1 or bad PCM (processor)
But that was after I had pulled all the fuses out of engine fuse box and put them back in
So it would have been correct code to get when I pulled computer's pin 1 30amp fuse out

Thinking I will pull the computer out tomorrow to have a look at connector and inside at the Caps, as said 26 years old
And test CPP

 

[Eddo Rogue]

Sounds like a computer issue, but they only do what they're told...something is making it be stupid.
Long shot but maybe a bad 02 sensor is telling the ecu to do weird things?
Also maybe a loose/old/bad connections somewhere? Have you jiggle tested all the connections? Sometimes you get 12 volts until you give it a jiggle.

 

[RobbieD]

The weirder the problem(s), the harder I look at grounds.

 

[Uncle Gump]

26 years old... they sure don't build them like they use to.

 

[RonD]

CPP switch tested OK on all 3 internal switches, so code most likely came from inside the computer...............another reason to pull it out

I though O2s at the start but had the original problem before O2s were on-line, and WOT(wide open throttle) didn't make engine run better, Computer ignores O2s for first 4-5min or so of warm up, and ignores them at WOT
I did unplug them, check connectors and plug them back in

Yes, intermittent grounds causes all sorts of odd issues

Another symptom this AM, turned on key and fuel pump came on and stayed on, turned off the key and turned it back on and fuel pump did normal 2 second thing
Repeated that a few times but only did the full time on that one time

Only 26 years old and having a problem...............darn disposable vehicles

 

[Dirtman]

Have you tried cursing at it?

 

[sgtsandman]

Throwing tools seems to help me.

 

[RonD]

I gotta hold my tongue in just the right place to get things to work

 

[Eddo Rogue]

Maybe just throw fuel pump at it?

 

[Dirtman]

Fuel pumps are a mysterious thing... some work for all eternity, some are broken out of the box. I keep a voodoo good luck mojo bag on top of my fuel tank to keep mine running.