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Motor swap, and now fuel electrical problems

Hello. I have a 1995 Ford Taurus, and I just swapped in a new engine from a donor from 2000. The engine is a Flex Fuel 3.0L Vulcan OHV.
I’ve got a wealth of background knowledge as a mechanic [5 years+] and an electrician [4 years+]
I have swapped over everything required to make this work, in theory. I swapped exhaust, fuel system, and computer/harness and all the relays to go with it. I also made a custom gauge cluster from a 2000 Taurus as well.

Well everything works just peachy, all the wiring for the most part is correct minus a few buzzing relays that I just need to work out. The main issue this [now monster in my eyes] has is the PCM is not telling the FPDM to tell the Fuel Pump to start. Turn key, and no 3 second startup. I’ve checked the fuel pump, and it’s fine. I replaced the PCM and that didn’t solve it. I have the security system from the 2000 in there as well, thinking that was an issue. I also have the emission sensors and canisters installed, just like you would see in the 2000.

I’m at my wits end trying to figure out why the PCM isn’t sending voltage out to the FPDM. I had to of missed something along the way but I double checked and still can’t find anything. I would love if someone can steer me in the right direction to get this working properly. Any help is appreciated!!!

If there is a crankshaft or camshaft position sensor that isn’t working, I could imagine that the computer doesn’t know the engine is turning. That’s just my imagination and also, but probably not the problem; a good ground between engine and body sometimes helps out with things on the body of the car. Hope your luck is better than my imagination.

So you are using the MY2000 PCM, I hope?

May I ask why you didn’t just drop in a MY1995 engine to keep everything comparatively simple?

I can tell you this: There are some differences between 3.0 regular vulcan engines and 3.0 flex fuel vulcan engines.
Can I assume you have access to ALL of the factory wiring diagrams for the MY2000 flex fuel 3.0 vulcan Taurus? You may be overlooking something.

I am using a 2000’s pcm. I used a 2000’s engine because I had the donor car already to do so with. It’s crazy but I got this far already!
I do have Official Ford wiring diagram books for both the 2000 and 1995 to help me with this. I feel like I’m over looking something but I just can’t figure what. I will check the crankshaft and camshaft sensor just to have one more thing off my mind. Thanks.

Something just occurred to me.
Do you have to get the car smogged or inspected?
If you do, the inspector could view it as having been tampered with. A lot of those guys are extremely sharp and will quickly realize that you’ve been “messing around”

Check to see if the 95 has a fuel shut off for the fuel pump. It will be under the dash Rt side or Rt side in the trunk. I have had this switch turn off the fuel pump when I was working the vehicle. Its for when the vehicle get in a crash it turns off the fuel pump. I don’t why working on a car sets them off, but it does and it never comes to mind right away. Then its the doh! head slap! LOL

The fuel pump has an inertia switch, I did check that and it’s correct. Lol I did think that at first too.

In my state only 96+ needs emission tests.

Also, the only thing that isn’t wired in right now is the cooling fans. Going from a CCRM to a single relay takes some thinking to get the fans working. That wouldn’t by any chance cause the PCM to not send a signal to the FPDM would it…?


You still didn’t the question as to why you didn’t just drop in another 1995 engine and keep things simple.

Yes he did, it’s because he had a free 2000 engine.

Did the 2000 engine happen to come from a car with PATS?

Yay I get to ask a dumb question. What’s PATS?
[My assumption is it’s the security system?] lol

Roach, had you asked us about this BEFORE you started this project we would have warned you to steer clear of it…It’s almost IMPOSSIBLE to get these computer car engine swaps to work without MAJOR problems…Stop beating your head against the wall…

Yes, it’s Passive Anti-Theft System. In Ford’s system, a transponder key is needed to energize the fuel pump. I could be wrong, but it’s possible that ECU in the 2000 engine is looking from a signal from a receiver (which the 1995 model won’t have) that in turn is looking for a signal from a coded key that the 1995 model won’t use.

Believe it or not, I thought of this too. So I swapped the key, tumbler, and that device that goes around the tumbler that I believe goes to the anti-theft. It had 4 wires, two going to the PCM and two somewhere else. [Power/ground if I recall]. I think there was one other part of the security system that I never did swap over, I’ll look into that.

For the most part I’m trying to make it think it’s still in the other car. So far this is the only “major” problem I’ve come across. I’ve already fixed the minor relay problems as well.

Thanks for all the help so far though!

FPDM? I’m not sure what that does. I’m assuming it is part of the fuel injection circuitry which controls the fuel pump.

hmmm … well, have you probed the signal that should be turning on the fuel pump relay? If it isn’t active, how far have you traced it back? All the way to the PCM, and the PCM isn’t sending it there either? Let’s see, what’s needed for thePCM to start the fuel pump? The engine must be turning (as mentioned above, check the crank sensor, and check for spark at a spark plug during cranking), the crash (inertia) safety switch must be in reset mode (per comments above), and it may be necessary for the fuel injection system to have good readings of intake airflow and nominal engine operating environment, from the MAF and/or MAP, coolant temp sensor, intake air temp sensor, and possibly also one of the O2 sensors. Any check engine light on?

I think this could also be a software compatibility problem. Is there any software remaining from a computerized component used on the engine/car you are trying to get to work? Or is all the software now from the donor car? What you want is for the powertrain, transmission, and body control software to be all from the donor car, and none from the car you are putting a new engine in.

Why not wire the fuel pump relay directly to the ignition switch?

@TaurusRoach did your original engine fail?

@Caddyman, being a single line returnless system, I do not believe I can do that without getting even more problems. I wouldn’t know how it would work exactly, and I even thought about swapping in a return system but that goes back to custom wiring and it seems like it’s the longest yard approach. The PCM [in theory] should tell the FPDM to cut on and off the fuel pump in very rapid succession to maintain the fuel pressure without any of it returning to the gas tank.