I admire you for tackling this conversion, but here is one reason, among many others, I don't have the knowledge or patience to pull this off. I really hope you find the problem and it's something simple.

I'll try that, specifically. I'm afraid, as many times & ways I've tried to clear the codes, I'm sure I've done that. Plus both ECUs are doing the same thing, and both have been unplugged/off battery for long periods of time, but still show the same codes. I understand 15 will come back every time the battery is disconnected. Thanks.

Tonight was frustrating.

I made no progress trying to clear my error codes.

First I made sure to clear my codes according to Viper's suggestion. No difference.

Then, I replaced & soldered my ring terminal connecting the battery connection of the RJM harness. No improvement.

Then I checked female spade terminals on the relay block, and made sure the connections for the battery to #1 wire was good. Everything checked out ok. Same codes.

I even checked the continuity & ohm'd the ground connection of the RJM harness to the negative battery post. I got a closed circuit, and .4 ohms between the intake post/RJM ground & negative battery post.

Worse, I realized the barb I had installed in the gas tank 15 years ago, was leaking, not the hose. So, now I need to remove the main tank. I think I'm going to close up the barb hole I had installed in the fill neck, and use one of the factory barbs that use to run to the charcoal canister or EGR system(I pulled & capped them many years ago, can't explain why, just thought simpler was better). My tank is well vented with the 1/2" hose @ the filler neck, and another 5/16" hose I ran a hartford loop up high in the body. Wish I could afford a new EFI tank, but right now is not the time to drop $400+ on my truck.

Oh yeah, I replaced my F250 IAB with my Explorer IAB and my idle still hangs. I can still reset the idle rpm, and then check the TPS setting, but I doubt that will cure anything.

After a few hours reflecting (and a few drinks);

I'm out of ideas how/where to look for problems causing the 2 error codes. Other than the hanging idle issue, the truck is running great, the CEL is not lit. The idle problem is not at bad as it was this winter with the faulty alternator. I'm considering ignoring the error codes, and just driving my truck. What are these codes going to do to my system? I'm guessing the 15 code is preventing the adaptive programming/learning from taking place. Possibly causing the hanging idle problem?

What's next?

I don't know. It's strange that you have 2 code issues that shouldn't be happening.

Fuel pump obviously runs so you should have 12V on the FPM wire. I get this code occassionally when I forget to turn off my fuel kill switch and turn the key on. That's all it takes to set it.

KAPWR (keep alive power) should be attached directly to constant battery power at the solenoid. Should be no reason for a break in the voltage unless the battery positive or ground is disconnected.

I'm not sure if you've tried this but I would check continuity of the FPM wire from the fuel pump relay to the ECM pin #19 and KAPWR from the ring terminal to ECM pin #1. The only other thing I can think of is maybe dirty battery terminals or poor cables that may allow voltage to drop below about 10V during cranking.

I can see code 15 preventing the adaptive learning. Code 96 shouldn't hurt anything as long as the pump is running.

Hanging idle. This is how the ECM works idle strategy. Cold start will set idle high for at least 30 seconds. Then speed should slowly drop. Hit the throttle and let go. Speed drops to near fast idle speed then slowly drops after about 5 seconds.

Thanks,

I'll check the FPM wire, which relay is the fuel pump relay? I think one of the relays had the inertia switch wire on it, that is probably it right? I thought I had a diagram with the RJM harness, but can't find it. I feel like I may have misplaced a pack of paperwork included with the harness. Stupid things happen when you don't work on something for 2 months, and move all your stuff from work to home, during that break.

I've been thinking of ohming/checking continuity of the battery wire to pin #1 too. And from the intake ground to pin #60. Pin #40 is listed as a ground too, where does it pick up the ground on the harness? There isn't a 2nd ground, only the intake terminal right? I've checked voltage from the #1 pin to the #60 & #40 pins (with ECU removed) and always shown good voltage.

I was playing with a volt loss test across the fuse block, with the 20a (#1 wire) fuse removed, and not getting the results I expected. I was getting 0v loss, but I expected 12v loss. The ECU side of the fuse showed no voltage, the battery side of the terminal showed 12v. The ECU was plugged in. Does volt loss not work with 12v (I used the test on millivolt boilers a lot)? I'm going to keep playing today. I've kinda got the day off work.

Two odd things are happening. I can see the voltage rise and fall with my RPMs, the belt is slipping on the alt pulley with higher rpms for sure(volts actually drop w/higher rpm). When I start my truck the voltage is close to 12v and takes some time to get to 14v. I don't ever see it below 12v, but that doesn't mean it isn't happening during cranking. But my battery is fairly new, good condition, gold plated high end bat terminals, good-n-tight. The battery checked out good on our charging system analyzer when I was checking my alternator back in January.

Second, since I started running the truck again this week, my fuel gauge is acting weird. It is rising and falling dramatically. On my first test run I pulled over because I thought I might be dumping fuel. The gauge fell almost 1/2 a tank in a couple miles. Yesterday, the gauge went to E and didn't come back up on the whole drive. I got under the truck and check the wires @ the sending unit and everything looked good. I wiggled the wires, turned the key back on and the gauge was back working. Probably unrelated, but thought I'd throw it out there.

Inertia sw wire goes to fuel pump relay. Diagrams are here: http://www.oldfuelinjection.com/?p=6

As I recall the only ground is at the intake. Don't know where it breaks off for pins 20, 40, 49, 60. Probably close to the ECM.

Your alternator is slipping. It slips just after startup because it has to charge hard to replace electrons used during cranking. Get that fixed and it will instantly jump to 14V after starting and stay there. There's a reason all the car manufacturers went to serp belts when electronic EFI began to be used.

Thanks that's what I was missing. I'll check all the grounds, fuel pump wires, and power leads. Maybe temp an extra ground from the intake to the battery, just for good measure.

Yep, now that my alt is actually working, I can watch the voltage rise and fall when the belt slips. It doesn't squeal, but the volts jump around a bit. It never acted like that before I sent it in, so I really think there was something wrong, despite what SVA told me. Looks like my dual pulley will be here soon, maybe tomorrow, but probably Monday, knowing USPS. Part of me hopes that a fully functional alternator will fix things, but again, its probably wishful thinking.

I'm done for a while with this. In the last week or so, I've added extra & redundant ground straps, swapped batteries, swapped ECUs, switched where my "battery" line on my EFI harness attaches, ohm'd out grounds in the harness, and nothing has cleared the codes.

My truck runs nice, and gets good gas mileage (don't have exact figures, but judging by my trips to Blue Mesa with the dogs and how much I fill the tank), so I'm just going to ignore the codes, and pretend they aren't there. I have to dedicate some real time to my house project, get my electrical & framing permits closed, and empty my garage of all the building materials I have.

I'm going to squeeze some small projects into my schedule, wire a pump & momentary switch from my Aux tank to my Main (so I can get back 8 gallons of capacity), and some other nit picky stuff I have on my "list". But big projects, and trying to trouble shoot my codes are off the list for a while. I'm considering adding a VSS to maybe help with my hanging idle, it is liveable, but I don't think its right.

I don't know what my next big Bronco project will be, rewire & new dash? new roll cage? new suspension? they are all on the list, but since the truck is running, they are low priority. I guess the new suspension would be first, if the parts become available, I think I'm sold on Battlements new stuff. That would make the most sense to do before, or early in the summer.

Maybe if I make some real progress, I'll drive my Bronco to Denver for a "Fix Chad's EFI" tech day some weekend, if a few gurus wouldn't mind helping out.