Ongoing, frustrating, thought I fixed but didn't, EEC-IV problem

I'm not saying that it is necessarily cheap, but it is possible.

Having to buy 5-figure scan tools for every manufacturer is why OBD-II is so nice.

ebonyandivory wrote: So since MAF and SD use different data to ultimately adjust fuel can an MAF ECM run an SD engine? Why am I having a problem seeing how 1993 technology has no problem running 2000 technology? Hell, I was under the impression that the ECM even needed to be from a very similarly-equipped truck (engine, trans etc.) let alone the same decade in these generation Fords.

The engine itself isn't what defines how it runs, it's the sensor/actuator set. The inputs and outputs have to be compatable withe EEC. SD and MAF inputs are totally different, and are calculated totally differently.

Besides, a 1993 and a 2000 5.0 are pretty much the same engine. From the late 70's.

This is a SD module that came with the truck, so it has to use a MAP sensor. And for this car, it's a pretty unique MAP sensor, too. If you want to run a MAF ECU, you need to add a MAF sensor (and all the other sensors that change)

Seems like the logical answer is that the 5.0 is just wondering where the carburetor is

There's old Snap-on scan tools that you can get off of ebay to read the data stream. I think I paid about $100 for the setup I got for my Mustang (and never ended up needing to use). Without a look at live data I don't think this is going to be very easy to fix.

alfadriver wrote: The engine itself isn't what defines how it runs, it's the sensor/actuator set. The inputs and outputs have to be compatable withe EEC. SD and MAF inputs are totally different, and are calculated totally differently.

No, I know they are virtually the same engine (I daily one and owned several).

It's just looking at what you said above, are we saying the 1993 EEC and 2000 sensors are totally ok with each other?

Is a previous gen EEC getting confused by model-year 2000 sensor set? Or even by trying to read differing data?

If one were to upgrade an MAF truck to Speed Density, the EEC will just act like nothing changed?

ebonyandivory wrote:

alfadriver wrote: The engine itself isn't what defines how it runs, it's the sensor/actuator set. The inputs and outputs have to be compatable withe EEC. SD and MAF inputs are totally different, and are calculated totally differently.

No, I know they are virtually the same engine (I daily one and owned several). It's just looking at what you said above, are we saying the 1993 EEC and 2000 sensors are totally ok with each other? Is a previous gen EEC getting confused by model-year 2000 sensor set? Or even by trying to read differing data? If one were to upgrade an MAF truck to Speed Density, the EEC will just act like nothing changed?

Some of the sensors and actuators won't change much from 1993 to 2000- temp sensors, injectors, engine position sensors, etc. So they should fully be compatable.

But the MAF vs. MAP sensors- they need to move with the controller. From what I'm reading- the truck may have a 2000 engine in it, but it's still has most of the 1993 senors and actuators- just the injectors have changed. Or if the sensors didn't change- it won't matter- ECT, ACT, throttle position, etc.

I'm not aware of an EEC that can swap between SD and MAF.

Humor me. What temp is the engine actually running at?

I'll get you that info streetwiseguy. I can't say for certain, just been watching the un-indexed factory temp gauge.

I'm using all stock sensors for 1993, the ECM for 1993, all the ignition is 1993(design, not actual production date), the wire harness is 1993, etc. The ONLY things from the 2000 explorer are the bare longblock and intake manifold.

In reply to alfadriver:

That's why I'm wondering if the problem isn't a 1993 EEC trying to make a 2000 engine run.

In reply to ebonyandivory:

Since he's telling us that it's the 2000 long block- which is pretty identical to the 1993 long block, plus the intake manifold- but all of the rest of 1993 sensors/actuators- I think the answer would be no, it's not a problem making it run.

It's something else.

I'm still leaning to the O2 sensor- trying to run closed loop before the heater is allowed to turn on. Something that would be masked by the original manifold letting the sensor be hot enough.

logging the data would, indeed, tell us that.

In reply to alfadriver:

Did I miss where he wrote he used all the sensors from the '93?

I probably did but I couldn't find it.

I've used Alex Peper's ODB-II solution with great results, works on just about anything.
Easily handled the EEC-IV on my 93 Escort. You need a computer to run the software, the cable hardware interfaces from ODB connector to computer. (NFA, etc.)

http://www.obd-2.com/#order

I looked at that link, and I have no idea what's going on there.

ebonyandivory it's true, I had not specifically indicated whether I mix and matched components or used all of either system.

So stupid question but don't the 5.0 in a 93 truck (non-roller cam 302) and the 5.0 in a 2000 explorer (lagit 5.0 HO) actually use a different firing order? Any chance its something as simple as some muffed up plug wires?

So I guess my question still is: is the '93 EEC getting confused by getting inputs that it's not supposed to (from the 2000 engine hardware/sensors)?

alfadriver wrote: I'm still leaning to the O2 sensor- trying to run closed loop before the heater is allowed to turn on. Something that would be masked by the original manifold letting the sensor be hot enough.

I've got the diagram in front of me, and the O2 heater gets power from a fuse in the underhood fuse box, and grounds to either G100 or G101. In other words, any time the ignition switch is in "run" the O2 heater is active. We're all old-school in this setup, no fancy computer control of anything.

I personally go back to the injectors, if they are the same flow as the ones the computer is expecting AND if they have the same opening/closing characteristics. But first, yeah, unplug the O2s when cold and just drive the car and see if the issue remains.

ebonyandivory wrote: So I guess my question still is: is the '93 EEC getting confused by getting inputs that it's not supposed to (from the 2000 engine hardware/sensors)?

I'm not being clear enough.

There are no sensors from the 2000 explorer being used. All of the sensors are correct for a 1993 F-250. Yes, I'm using the GT40p intake manifold, but it's just a chunk of aluminum. Air temp/coolant temp/TPS/etc are all the original(or replaced equivalents at this point).

93GSXTurbo is correct about the firing orders. When I plugged in the fuel injectors(which I'm led to believe are batch fired), and wired up the distributor, I was careful to reroute them to take into account the differences.

Knurled wrote:

alfadriver wrote: I'm still leaning to the O2 sensor- trying to run closed loop before the heater is allowed to turn on. Something that would be masked by the original manifold letting the sensor be hot enough.

I've got the diagram in front of me, and the O2 heater gets power from a fuse in the underhood fuse box, and grounds to either G100 or G101. In other words, any time the ignition switch is in "run" the O2 heater is active. We're all old-school in this setup, no fancy computer control of anything.

Man I'd love to open that hood and find the fuse for the O2 heater popped.

ebonyandivory wrote: In reply to alfadriver: Did I miss where he wrote he used all the sensors from the '93? I probably did but I couldn't find it.

The reply just prior to your one before this one...

That will send one searching..

Knurled wrote:

alfadriver wrote: I'm still leaning to the O2 sensor- trying to run closed loop before the heater is allowed to turn on. Something that would be masked by the original manifold letting the sensor be hot enough.

I've got the diagram in front of me, and the O2 heater gets power from a fuse in the underhood fuse box, and grounds to either G100 or G101. In other words, any time the ignition switch is in "run" the O2 heater is active. We're all old-school in this setup, no fancy computer control of anything. I personally go back to the injectors, if they are the same flow as the ones the computer is expecting AND if they have the same opening/closing characteristics. But first, yeah, unplug the O2s when cold and just drive the car and see if the issue remains.

The reason I don't think it's the injectors is how the issue is intermittent- it's not there cold when first starting, and not there when it's warm when first starting at all. But it comes from a sub 65 F ambient start for a brief amount of time (normally stalling the car).

If it were the injectors it would be a problem all the time- as would firing order, most sensors, etc- it's a very specific type of an intermittent problem.

BTW, I don't think that the heater is on all of the time- at cold temps it would not be on to prevent cracking the heater from drops of water in the exhaust. I'm not 100% sure what year that went into production.

belteshazzar wrote: I think the MAP-sensor is one part I haven't thrown at this bloody situation. It's mounted up on the firewall. I've unplugged it while the engine is running and the truck instantly stalls, but that's all the more I've done with it.

I'm not entirely sure it's supposed to do that. I would think it should fall onto some limp home table running off the TPS, but I could be wrong.

In reply to alfadriver:

I agree that the injector differences shouldn't matter. But it's not something to rule out until after everything else is ruled out. And the problems ARE too gross for it to be a simple injector deadtime error.

I repeat that there is no computer control of the O2 heater. It's strictly powered up by the ignition switch (or whatever is powering up "hot in run" in the fusebox, and it is apparently fuse E, but it has been literally over a decade since I've had to dig into a Ford of this vintage electrically and I am used to Fords using numbers, not letters, to identify fuses. And then give you no clue what the fuses actually do) and it is grounded straight to... wherever G100 or G101 are. There was an asterisk attached to that and true to Murphy there was no footnote to explain the difference.

Now, mind you, there are also two or three connectors in the circuit from the fusebox to the O2, and another couple connectors between the O2 and ground, so lots of opportunity for loose pins or chafed and corroded wires thanks to unsecured harness connectors.

Assuming that they aren't getting power or ground, of course.

Another dumb question: Are there any exhaust leaks upstream of the O2s?

nope.

But I'm definitely going to check the harness to the O2 sensor for the heater's power and ground

Update:Power and ground for the O2 sensor's heater are okay. Should the body of the O2 sensor become warm? It remained stone cold on the outside. Just curious.

Anyhow. It ain't progress so much as checking off one more possibility.

I've never tried a narrowband O2. Widebands get too hot to touch within a couple seconds.

What's the resistance of the O2 sensor across the heater circuit? Should be in the single-digits ohms when stone cold. I wouldn't worry about an exact number, 5 ohms plus or minus a few is okay, 3000 ohms is not.

Also check for continuity between the heater circuit wires and ground, and heater circuit and signal. Chrysler O2s love to fail by jumping current from the heater circuit to the sensing side, and it happens sometimes on other cars too.