5.7L FFV to non-FFV ECM Swap Attempt

I pulled all of this out of another thread that I was filling up, figured I would put all of it here as it is turning into quite an odd journey.

5/2 - I haven't been having much luck with my truck doing the alcohol density reset. 2013 CrewMax, 175k miles ish. I did the relearn about a month ago with my bidirectional unit (Mucar VO7S). Data stream shows alcohol at 0 and both FTs around .078ish. It ran fine for a day or two but then the hard starts came back. Got hold of Techstream and a cable and figured I'd try it that way in case the other tool wasn't up to snuff, but results are the same. Mpg always sits around 15.3, according to the dashboard. Otherwise all the other symptoms are there - extended starts, misfires on some starts, rich fuel exhaust. I've got a fuel pump arriving this weekend (DeatschWerks DW300C) so I'll replace that and clean the tank out as well.
Beyond that I'm stumped. I've wondered if swapping to a non FF ECU is possible. So here we go.
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This ECU PN 896610CM34 replaces previous ECUs for 2012/2013 5.7L - the interesting thing being that Toyota states it is for both FFV and non FFV... Anyhoo, I figure if I can find one from a non FFV with 4x4, with Crewmax, with Tow pkg I'll give it a shot. I'd like to find a PN# for the one I want first though, would make it easier. - Note, I am unsure if CM vs other cabs makes a difference, it is unclear, as well as 4x4 or non. Tow pkg is the only differentiator I can confirm, but best bet is to find an exact match all the way around.
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5/11 - I purchased a non-FFV ecm on fleabay from a yard with a truck that was, in every way I could find, identical to mine.
My FFV ECM pn# is 89661-0CM74
The donor ECM pn# is 89661-0CM34

Steps taken so far -
1. Installed donor ECM
2. Via shorting OBD pins 4 and 13 I was able to get the immobilizer ecu and engine ecm to communicate. Without doing this you will get an IMMO DCT
3. Written my VIN to the donor ecm using Techstream
4. Attempted to start the truck. Will not start, sounds as if it is missing fuel, and it throws the generic P1604 startability malfunction code. This code can be thrown for dozens of reasons and really means nothing other than your vehicle won't start which we already know. However I have found cases of this code and scenario appearing when people replace their ABS ecu. So preliminarily I may still have an issue with all the ecus in the truck shaking hands with the new ecm.
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So basically Toyota in their infinite wisdom decided to handle the switching of relays related to the fuel system differently between the 3UR-FE and 3UR-FBE. So the root solution to this is to simply bypass it by running the fuel pump off of another switched source. I'm still a little confused on this though because with the ign on I am currently getting 12vish at the fuel pump relay.
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Here's the bit under the hood in question, note the asterisks in the top right that indicate fe vs fbe. I'm not very good when it comes to this part, but I'm trying to understand the differences between the two in hopes of finding a solution.

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Alright, I gave that a try but no luck. However it was interesting. Previously when trying to start with all normal things in place, I would get the extended starter run, where it keeps going for several seconds after you turn the key even if you let go. The cel light was also on. With the c/opn relay removed and 3/5 jumped the cel went out and the extended starter run went away.
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5/23 - Well, in the last several days I put the old ecm back in so the truck could be used. I also changed out the fuel pump and bypassed the internal filter using an external one. While I was down there I went ahead and tapped the power line for the pump so I could manually connect it if needed.Truck has run much better than it did before and I've seen noticeable increase in mpg. That said, I'm still getting random misfire starts here and there, just less often than before. I have a suspicion (like others) that the "lifetime" fuel filter in the tank is a crap idea and they figured oh well we'll just gouge them for pump replacements.

Today I decided to start again with the donor ecm and now the odd behavior has changed. Step by step I - disconnected the battery, removed old ecm, installed donor, reconnected battery, jumped 4 and 13 on obd, put key in ignition and.... when I turn the key to the on position(not start) the truck tries to start itself and the starter runs till I disconnect the battery (does not respond to key turning off). So I removed the paperclip and tried to turn to the on position again and it does the same thing. I'd say starter ran for 10sec or so as I hurried to disconnect the battery each time.

These things are baffling. I put the old ecm back in and everything works as expected but no starter now, so whatever the trouble was with the starter running is related directly to the donor. But the last few times I worked with it it did not have this problem. The only thing that has changed since then is the fuel pump. Weird.
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5/24 - Whatever it was that happened seems to have roasted the starter solenoid, lovely smell.
I got the starter out. Put it on the bench and broke it open. Turns out the solenoid seems to be fine but the starter itself is fried, stator is cooked, pretty nasty. I have to assume something shorted, no idea what though. It may have been on it's way out already, but this seems a bit extreme.
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9/25 - Now that the absurd Texas heat has departed I'm back to working on this. And of course mysteries abound. I now have the fuel pump wired through an external relay and fuse to solve that issue. I put the donor ecu back in today to fiddle and it did the same thing - as soon as the key goes to ON it tries to start, very odd. This time I disconnected the starter cable from the battery so I could get the ECUs talking. Unfortunately something is still trying to run power through the starter circuit and leaving the ECUs to talk for 30mins resulted in a hot, blown starter fuse. Also unfortunate is that although the fuel pump runs on its own now the engine still isn't starting. Totally baffled.

 

@e30cabrio successfully converted his ffv to non-ffv. Search through the supercharger thread around page 503-505. He also tuned out a lot of the ffv codes with hpt tuner software that we use to tune our supercharged tundras.

 

Yeah, I've talked to him a little bit about it, but it's all pretty hit and miss. I'm hoping to work out a working, documented solution. Or if nothing else just something to fill my time. Didn't expect to frag the starter tho, lol.

 

Still a work in progress. I'm currently trying to decide where to connect the fuel pump at. I want to add a new relay for it that is switched from key ignition ON as our oem design doesn't normally come on until start. In the process of this I noticed the stock fuel pump relay getting hot several times. I've checked the resistance a few times and all is within range. Had some trouble starting lately that seemed fuel caused so on a whim I changed out the fuel pump relay and lo and behold it it starts perfectly now, maybe better than it has in a long time. Very odd.

 

Well, the relay I put in the fuel pump socket was from the defroster, same relay type though. Over the last week I started having tough starts again. I had previously ordered some new relays so I went ahead and changed it out. Once again it starts up just fine. Since the first were old relays (probably the originals) I'm going to chalk it up to age and see how this new one does, but if the trouble returns I'll be baffled. I'd like to find a relay that goes in the same socket but can handle a slightly higher load, but that wouldn't make much sense as this fuel pump pulls 15.4amps absolute max and the relay is good for 20. Until I figure it out though there's no point in running the other fuel pump wire.

 

If you decide to hard wire the fuel pump you have 2 options. Hot wired from battery to pump but have the relay either trigger by ignition or fuel pump power from fuel module.

 

I'd like it triggered by the ignition, the ON position preferably, that way it will function correctly when I swap the ecm. Any ideas what I can use for that in the fuse box? I've thought about creating a new circuit in one of the empty relay sockets but that fuse box looks like a lot of trouble to get to the bottom side of.

 

Just use an add a circuit fuse tap and have it trigger by the 10amp ignition fuse believe it's number 29 in engine fuse box. We use that for our intercooler pump relay trigger.

 

Oh so use the fuse tap to run over to the existing fp relay? Never thought of that

 

May have misunderstood. I thought you wanted to run an independent line, hard wire or hot wire, and relay to the pump bypassing the oem wiring. But you could theoretically bypass the ign ON for the relay but you would have to bypass that part of the 12v trigger for the oem relay. May be too much trouble...

 

Oh you understood correctly. I have to bypass the oem trigger for the pump as the FFV and nonFFV ecms trigger the pump differently. I was thinking you meant I should use the IGN fuse as the trigger for the fp relay. Either way I appreciate the idea on the fuse tap. What relay do you guys use for the intercooler pumps, like a 567-0004?

 

Pretty much just a standard $12 Bosch 12v 4pin relay. It's external of the engine fuse block.

 

Update - Now that the Texas heat has finally departed I have the fuel pump wired up on its own relay and fuse. But when I put the donor ecu back in and turn the ignition to ON (not Start) it tries to run the starter continuously as it did before. I'm totally confused and baffled by this. Unfortunately it also did not start the engine even though the fuel pump is running on its own.
Hooking up Techstream shows no DTCs in the immobilizer, but is showing a P0335 in the engine ecu.