93 Ranger 3.0 problem...

[TomTom59]

Hi guys, My 1993 Ranger XLT has had random stalling issues for some time. The first go around when it stalled, usually while cruising 35-60mph, it would not restart anywhere from minutes to hours. I had a new fuel pump, sock, and fuel filter installed and I changed out the fuel pump relay, MAF sensor and inspected the wiring under the relay panel under the hood, finding no problems there. Stalling continued. I then changed out the Thick Film Ignition module, replacing the thermal compound under it, and later changed the electrolytic capacitors in the PCM and put it back in as it was failing to go into learn mode after the battery was disconnected, even after 24 hours. Replacing the caps fixed that issue. Also replaced the Idle Air Control valve and afterward when it stalled it was only at a complete stand-still and would always restart right away. New battery and new terminal posts, cleaned the throttle body. It has been running really well, better than ever and seemed fine for a couple of days but when I went to leave work it cranked and cranked but never offered to start. This was a new phenomenon. I fiddled with this and that but still no start. Finally I pressed on the coil plug (low voltage/excitation side) and it started right up. I replaced the coil pigtail with a new one. That was 3 days ago and it has seemed right as rain until tonight. I was on a interstate doing 60-65 and hit a good sized bump at the very end of a low-rise bridge. It has Gabriel Gas Charged shocks and doesn't take bumps well. The bump was hard enough to make me say, "Sxxt!" That's when it shut off and I immediately noticed the instrument panel lights seemed rather dim and so did the headlights. I coasted to a stop in the emergency lane and attempted to restart it. It reluctantly barely started but shut back off. I waited a minute and tried again and it stayed running (very poorly) and if I gently pumped the accelerator it slowly picked up RPMs but died again. I waited a couple of minutes and tried again and it did start, running unevenly but it smoothed out after 10 -15 seconds or so and I let it just idle for a couple of minutes. I pulled out into the road and proceeded to a gas station a couple of miles away so I could see under the hood and found nothing, letting it idle while I looked. I gingerly returned 8 or so miles back home without incident. I shut it off with the lights on and this time they were not dim. Could the dim lights and shut off have been caused by a bad regulator in the alternator? I have a brand new one sitting here in the box I can install. I've never known a regulator to cause a stall like this but I suppose it's possible. Has anyone had similar experience like this? I'm a bit baffled by it. As each of you know, it's uncomfortable driving any distance in a vehicle you feel you can't trust to stay running.

 

[basketranger]

The fuel pump shut off. passenger floor board. first bypass it with low amp mimi fuse see if problem returns if not (kind of expensive) replace. underneath carpet, peel carpet back just a bit and u should see it.

 

[TomTom59]

Inertia switch?

Thanks for your reply Basketranger. Are you referring to the Inertia Switch? If I recall that is supposed to to tripped in an accident normally, though I have read where people tapped a curb hard enough to trip it. I will check it but have a difficult time thinking it reset itself without me physically doing it. You may be right after all the truck is now 19 yrs old and the inertia switch could be operating intermittently or acting improperly. Would you know where (or if) there is some sort of oil pressure switch that can kill the engine for self-preservation? I know there is a oil level sensor screwed into the passenger's side fo the oil pan that initiates a light on the instrument panel (oil level, check oil level, or something along those lines) but that one doesn't sense oil pressure. One nagging thing is that neither the inertia switch (loss of fuel delivery) nor does a oil pressure switch account for the dim instrument panel and headlights. It was acting like (looked as if) I had lost the alternator and was running the battery down. That could not have happened in a distance of 1/16 th of a mile though. Unfortunately under the stress of the moment I didn't even glance at the voltmeter to see what it was doing. Thinking about what appeared to be an electrical drain on the battery, with the ignition switch off and nothing but the headlights on, there isn't anything connected (all electrical loads switched off) except the alternator and it's associated internal regulator are always directly connected to the battery. Anything else would be fused and any such fuse would have opened in response to any greatly added current draw through it's circuit, kind of self-identifying where that problem was. The regulator has no fuse. Does my line of thinking on the abnormal electrical load make sense to you? The regulator is the only thing I can think of that is still in direct connection to the battery when the switch is off other than the usual list of brake lights, cigar lighter, perhaps the under-hood light, and dome & glove box light, all of which have fuses. Thank you again for your thoughtful insight.

 

[TomTom59]

I dropped the tank this morning in my driveway. I found overheated power connections inside the top of the sending unit for the fuel pump, obvious melting of the insulator ring where the riveted connections pass through the top of the sending unit. The pump itself is OK. Since this is the fourth time this has been replaced, I have elected to just clip the red and black fuel pump wires just inside the top of the sending unit, soldering longer wires onto them and drilling a new hole in the sending unit for the longer wires to go through inside a rubber grommet. I'll seal the hole well with Black RTV for no leaks. I will retain the two connections for the fuel level sender connections. The new longer wires run to a terminal block for interconnection into the wiring harness coming from up front. I also attached a green 12 volt LED to the fuel pump connections for a tell-tale. When the LED is lit there is power at the pump. If it isn't lit, there is no power to the pump. I'll be able to tell if it has juice or not in about 2 seconds with just a quick look underneath. A considerable, cheap, and easy improvement. No more shall the winged Ranger stall because of poor connections to the pump. I consider the design of the Ford connector very poor. Out of necessity, and disgust with repeated failures I've bypassed it.
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[TomTom59]

I'm very happy to report that the addition of a canister fuel filter (SPECTRE 5965 from AutoZone), fits 3/8" & 5/16" fuel hoses, is keeping my throttle body clean as a whistle. It's been inline with the vacuum hose (that runs from the PCV valve to the throttle body), for several hundred miles. I located it close to the PCV valve. I took the inlet off the throttle body to spray CRC Engine Treatment for de-carbonizing using a pump bottle. The passageway from the PCV (easily visible in the lower right of the throat in front of the throttle blade) is completely clean as is the throttle blade, no discoloration from deposits of any kind, it looks exactly like the outside of the intake manifold's clean aluminum. I would have preferred a semi-transparent filter so I could see when it needed replacement but this one is chrome and I suppose it can withstand underhood heat well. The end marked "IN" faces the PCV valve of course. They are cheap and I'll replace it every 6 -8 months or so. If your throttle body keeps getting nasty I highly recommend this little mod. This is on a 1993 Ranger XLT 3.0 automatic.