imp

How well do codes thrown with the old '90s system compare with those of OBD-II, '96 and up? Seems II has many more to work with. Also, more emphasis on the PCM taking over control of the vehicle. My '04 Explorer has gone into "Forced Limited Power" (limp mode), "Forced Engine Idle" and "Forced Engine Shutdown", due to various malfunctions.


I cut my teeth on EEC-IV, mid-90s. Found it to be forgiving, easy to work with. The new stuff is B.S. IMO. ABS Module failure shut down my truck. Try replacing one of those buggers!


So, now, I've reverted back to the old, bought a '94 Mustang GT (5.0, of course!), 5-speed, which runs incredibly well for it's age & mileage (161,000). But, I don't agree with how the electric fan works...... imp

TrimDrip

the foxes have a lot of 'separation of concern' in the workings of the eec. The higher you go up in years, the more one thing will affect another.

mongolchuck

Obd II is a much more thorough diagnostic system with more codes and tools like misfire counters and live engine management. Being more thorough though also makes it more involved in how the engine is running, which is a double edged sword.

imp

My understanding was OBD-II was mandated by govt. I don't see that it improved emissions by much, but rather watches more carefully for issues not addressed by OBD-I. Added O2 sensors, smog pumps disappeared w/OHC usage. Certainly, that CEL shows up a helluva lot more often, and folks getting their emissions test turned down generate more dough for repairers. Was it all about money? Hate to think that.


I had far fewer problems with EEC-IV than V. imp

TrimDrip

It did make it a helluva lot easier to pull codes on various cars, with a few imports being the exception.

I do like the injector balance and wiggle test of the old foxes. But having a built-in wideband sensor would be sweet as well.

imp

Easy, you'll bury me! Wiggle tests to me involve locating bum harness connections! Been fighting a "HO2S Heater Resistance, Bank 1 Pos 2" code for months now, 2004 Explorer 4.0. First, replaced all 4 sensors, even though heater resistance right in middle of spec range. P0054. Next, continuity checked, OK. Next, ran all new wires for that sensor, from fuse to sensor and back to PCM. P0054. Desperate, had wife run engine @ 2500, while I whacked the cat 10 or 12 times with a hammer.


Code went away! For over 1,000 miles! Back again. Cat beat up again, no go. Guess I will just have to replace the cats. Rough job, 160K, bolts and nuts at muffler flg. and headers so rusted, they have no corners left. No longer enjoy using torch under vehicle w/o a lift. Scars to prove it! imp