94 Ranger Computer Location and Misfire Question
 

I have a 94 Ranger 2.3 (8 plug) that I'm having some misfire issues with. It seems to miss at lower RPM's.

So far, I've replaced the plugs and wires, coil packs and fuel filter as they all were looking pretty rough. This did seem to help out some, but I still have a slight miss at idle and cruising along in 4th or 5th gear at low RPMs.

I am pretty confident that the CEL is blown or removed as it never comes on, even when starting the engine, so I went to Advance Auto Parts and picked up a code scan tool (Actron CP9015) to try to see what codes are being thrown, if any.

For the life of me, I can't seem to find the computer connector to hook up to so I can get the codes.

Can someone point me in the right direction as to the proper location of the computer so I can test it? Also, if anyone has any ideas as to what might be causing the misfire, I'd greatly appreciate any input there as well.

Thanks!
Nick S.

Have read it's in engine compartment. This is the quote from someone else who had a 94 with a V6. Might be worth checking out.

"on my '94 its next to the fuse panel under hood on drivers side hanging under a little cover".

The Haynes Manual puts the DLC under hood, on the passenger side inner fender wall.
It'll be marked EEC Test.

Do the KOEO & KOER tests & post All of the code Numbers found & see what they suggest for a suspect list, as you may have more than one problem.

A good suspect for an under load, low RPM, or idle miss, is a spark problem.

I know you said you've replaced nearly all of the ignition related parts, but that doesn't mean their automatically good just because their new, I've seen plenty of bad new parts right out of the box. Or that you didn't damage something on the install.
My Dealers lead Tech cracked a #6 outer plug insulator on a head change & it would randomally miss at idle, or really act out in a heavy rain storm. So they performed a "wet down test" & located the culprit.

If you suspect bad, or damaged secondary ignition parts, you can perform an ignition wet down test with a spray bottle of water at night & look for arcs & sparks, or rough idle, while wetting down one plug, wire & coilpack at a time.

The plug wires resistance should have been measured from end to end before installation, to make sure it's within range. It should be a steady reading of about 1K ohm/inch of length when flexed, 30k ohms max, no matter the length.

Given the vintage of your ride, maybe also consider having an electrical system load test done, ( most autoparts stores will do this at no cost), to make sure the vehicles electrical system can take the electrical load & output the voltage needed to properly operate the computer, it's sensors & actuators, like the fuel & ignition systems.

Check the fuel pressure, if it's suspect, disconnect the fuel pressure regulators vacuum line, if it's wet inside with fuel, suspect the regulators diaphragm is leaking fuel into the vacuum system, so replace the regulator.

The fuel pressure, at warm idle, with the vacuum line connected, should be 25-35 psi, with the vacuum line disconnected, 35-45 psi, if the latter number is low, since you've replaced the fuel filter, suspect a weak fuel pump, or low operating voltage to it, or clogged pump prefilter sock, crimped or clogged fuel line. If the first number is bad, suspect the regulator.

There is a how to, for replacing the dash lights in our Tech Info thread, atop this forums thread listing page.

More thoughts for consideration, let us know what you find.

Thanks Papaw. I'll get to work on it tonight when I get home if the weather holds out and post the results.

On my 94 2.3l, the computer connector is in the engine compartment, drivers side, attached to a plastic cover on the bottom of the fuse box.