Instant power loss, then snaps right back. Intermittent.

[Black Frog]

My 92 Ranger is SO CLOSE to hitting half a million miles- I'm at 490,000 now and want to get there if I can. But now I have another problem. She seems to be falling apart rather quickly this last year.....

About a month ago, one morning went to start the truck and immediately the engine rev's to 3000rpm. It never moves from there for idle. Never settles down or fluctuates from that 3k. I had this thread about it:

http://therangerstation.com/forums/showthread.php?t=106651

I tried a new TPS, MAF, and the IAC checked out fine. The truck would idle down if I unplugged the IAC, no vacuum leaks found. I was thinking the problem might be leading to EEC? Since I plan on getting rid of the old girl at 500k, I didn't want to stick any more money into it. So what I did was unplug the IAC and turned the idle set scew up a bit for a normal idle.

I know it isn't the correct way of doing things, but I only needed 10,000 miles out of her. Ran it like that for the last month.

Well now I have another problem that popped up this week. Driving along the highway one day, and it was like someone flipped a switch- loss of power and the engine heavily bogged down for a few seconds. And then just as suddenly it snapped right back to normal operation. It has started doing it more often the last few days, but there's no pattern to it. Hot or cold, under load or sitting idle at a stop- sometimes it does it for 30-40 seconds, sometimes just a second or two, or even a split-second "blip". Flooring the gas pedal makes no difference to bring it out of the "bogged" state or to keep it from bogging down. And there's no "ramping" down into (or out of ) the bogged down condition- it is instantaneous.

Thought it might be a fuel problem and replaced the fuel filter. Had good pressure in the fuel lines (didn't measure it though).

I'm wondering if this issue could be related back to my 3000rpm idle state? Does the ECC control idle and engine ignition, or does the Ignition Module do that?

Plugs and wires were replaced earlier this year. I just need 10,000 more miles...... A band-aid fix is good enough at this point. Could an oxygen sensor cause something like this?

Going to dump a can of Sea Foam in the tank later today and see if that has any effect.

 

[Black Frog]

I forgot to add on other tidbit that might all tie into this.

My tach isn't working anymore either. Reads zero all the time- never moves. I'm not sure if it stopped working right when this 'power loss' condition appeared or not, but it was close.

Trying to find more info on the wiring of the tach- doesn't that come right from the Ignition Control Module? That would be another thing pointing to that ICM going bad.....

 

[Black Frog]

This diagram is from a 1990 4.0, can't be a much different on my 92:

http://www.therangerstation.com/tech_library/EDiagrams/files/Diagram_Ignition1990_4_0.JPG

See on the left side where it shows the tach being tied into both the EEC and the Ignition Module?

 

[Black Frog]

Ummmm.... I think I found my problem:

 

[Black Frog]

Anybody have an EEC module for a 92 (or compatible) V-6 4.0L MANUAL trans?

I'm going to have to chop the wiring harness off as the current connector is toast- literally.

So somewhere I'm going to have to find the EEC module and the mating connector with about the first 6" of the harness included.

got some splicing to do I guess....

 

[BillupsOMally]

That's exactly what happened when I used my Ranger as a submarine one too many times.

 

[Black Frog]

2WD truck, never went subin'.... that must have been from a rain leak.

 

[BillupsOMally]

Mine was a 2WD when I went sub'n, haven't had a chance to abuse it since the 4x4 swap. lol

Every 2nd Gen Ranger I've ever looked at closely had a hidden rust hole below each corner of the windshield letting water that collects in the bulkhead for the wiper linkages leak into the cab. That may be your source of water. Another common spot is the roof, then it runs down the A-pillar and into the same spot and you'd never know it unless you had the trim off during a rain storm.

 

[Black Frog]

It's leaking above there for sure. If I can find a different module to splice in, ill tuck it up under the glove box to avoid any moisture.

Now I just need to find out what modules would work for my 92.

I know I need one from a 4.0 engine, but does it have to be from a manual trans?
Does it have to be from a 2wd? Anyone know what years would work with a 92?

 

[Black Frog]

My module is: F27F-12A650-JC

Anyone know what the last two letters designate? Looking around the net I can find modules similar, but different last two letters....

 

[BillupsOMally]

I've been told that when you do a manual swap you can keep the auto computer but you'll have a constant CEL giving you a tranny related code.

When I was butchering my Explorer harness to turn it into a Ranger harness the wiring for the push-button 4x4 seemed almost completely seperate except for a sensor on the t-case. I imagine it would cause the same constant CEL issue.

Any scrap-yard I've dealt with will let you return a computer within 14 days if it doesn't work.

 

[Black Frog]

Just looking in the Tech Library here about doing trans swaps going from auto to manual and it mentions that:

If replacing an automatic with a manual, you need a manual transmission computer to turn the MIL off. If not, the computer will send an error code complaining that it can't see the torque converter clutch. You also need to hook up the neutral switch to the computer.

So, if I find a auto 92 4.0L 2WD module from an auto transmission wouldn't that mean that my neutral switch is already there and connected?

 

[Black Frog]

Stopped by the yard and got the 92 Explorer harness, they charged $5 for it. Looks like new.

Sat there doing the brain surgery and spliced in the 38 wires into my old wiring bundle- not a very comfortable position to do that....

All set for the new box. I think she just might live again, and just might make that half-million mile mark...

 

[jhammel85]

Wow! Dude that's awful.

Is your windsheild or cowl leaking into the cab?

 

[Black Frog]

Wow! Dude that's awful.
Is your windsheild or cowl leaking into the cab?

There's a rusted out area at the lower corner of the windshield. Plus, when I had the windshield replaced several years ago I'm not confident they sealed it back up all that well.

See that white stuff on my ECU lid? Like yours but much worse. That moisture will work its way down into the main connector harness and you're gonna have a big problem like I did, so I suggest you fix the leak while you can.

I'm not that worried about the leak in that corner anymore, I'm simply going to fasten my new spliced-in ECU up under the glove box out of the way of the moisture.

....after 490,000 miles, she can leak where she wants to.