Engine Swap Leessons Learned, Do's, Don'ts & Wished I Would Haves

[Steve Mikkelson]

Blown 5.0 EFI in F250 4x4 1986 and planning to swap in a 5.8 EFI from 1995.   Before swapping them, I plan to enhance the 5.8L as it already needs a valve job before it goes in the 1986.   The '86 is more of a toy that spends more time cruising than anything else, but it will see more time pulling a trailer than throwing sand up in the sand dunes.  I would like to build the 5.8 engine with both thoughts of towing and throwing sand in mind.

Please share any thoughts, articles, past threads or your lessons learned.  I would love to hear them even if it is, "don't swap in that 5.8!"

1.  I would like the engine to rumble, sound good and impress me with its performance and durability.   Durability wins moderately over performance when performance could lead to repairing the drive train.

2.  I won't be machining or assembling any bit of the engine myself so please share your thoughts on upgrades from the stock engine.   I will be hiring a pro so throw your crazy ideas my way.

3.   Thoughts on the swap.  My gut tells me the wiring & emission differences will be troubling.

4.  Budget is $3,500, but I could be talked into to spending a much as $5,000 if I cut cost away for the aesthetic improvements.

[Rembrant]

Steve Mikkelson wrote

...planning to swap in a 5.8 EFI from 1995.  

Oh nice. Didn't the 351 have a roller cam in 1995 or 1996? That would be a nice engine to build up imho.

I've seen a couple 351 roller blocks pop up for sale around here and they sell so fast I barely get to read the ads before they're gone.

[Gary Lewis]

First, you need to figure out if the 5.8L's EFI system is EEC-IV or EEC-V.  If from a truck the odds are that it will be EEC-IV.

The difference is that most EEC-IV systems are speed-density, and those systems assume that they know how much air is ingested into the engine based on throttle opening, RPM, and load/manifold vacuum.  But, if you change much, like the cam, or heads, or exhaust then the computer won't know how much air is ingested and all of its calculations will be off and the engine won't run correctly.

The EEC-V systems are mass air flow systems, meaning they have a mass air flow sensor and the computer really does know how much air is ingested because it is measuring it.  On these systems you can make significant mod's and the engine will still run correctly.

Something in the back of my mind tells me that some of the late EEC-IV systems might have been MAF, but I don't remember exactly.  However, Bill Vose/85LebaronT2 should, so maybe he will chime in.

[Steve Mikkelson]

Thank you Gary.  

Looks like a blind squirrel found a nut.  Both the '86 5.0L & the '94 5.8L have 60 pin connectors, which my research tonight if it is correct showed a 60 pin connector is an easy why to determine an EEC-IV.   104 pin connector would equate to an EEC-V.    Now the question to me becomes,  is this now simply swap and use the existing '86 5.0L wiring harness for engine coming in from '94 5.8L.

[Steve Mikkelson]

Rembrandt, I will need to look at the engine block number above the starter for an indentifiaction number  to determine if it is a roller cam.   I read that some late '93 have it but it started in '94.  Being that this truck is a '94, I bet it could fall either way.   I understand if the identification number starts out with "F4TE...".  Here is a pic...

[Rembrant]

Well that's nice then. I believe the roller block 351 engines are fairly desirable as SBF's go.

Can't help you with the actual swap much though.

What transmission is in this truck? I don't think you can re-use the flywheel from the 302, so you'll need the one for the 351 (in case you haven't already sorted this part out).

You'll have to change the exhaust as well?

[Steve Mikkelson]

Thanks Rembrandt.   I didn't know about the fly wheel or the exhaust.  With the truck having lived it's life entire in California, there are quite a few catylatic converters that need to be gone so the exhaust is going to need some work.

I have the AOD tranny with no electronic shift.   I thought about the C6 swap, but I have been influenced that the AOD will be appreciated with the fuel savings.

[Gary Lewis]

Hopefully you have the ECU/ECM for the 5.8L as the firing order is different - I think.  But other than that it should work.  However, the wires to the injectors might be short as the 5.8L is wider, but using the '94 engine harness should fix that.

But you also mentioned eliminating the cats.  I'm not sure you can do that and keep the computer happy.  Is there an O2 sensor aft of the cats?  If so, I think it is going to detect that the cats are gone and throw a code.

However, I'm not an expert on this, so will let others guide you.

[Steve83]

The EEC has nothing to do with firing order - it doesn't control the ignition system directly.  And the injectors are bank-fired, so the firing order still doesn't matter.  The difference in distance between the injector banks is smaller than the slack in the harness, so it'll fit either engine.  No downstream HEGO until '96, so even though deleting the cats is a bad idea, the EEC wouldn't know about it.

[Steve Mikkelson]

With this being a California truck, what are he "bad" effects if the cats were eminated?

[Gary Lewis]

Good points, Steve.

As for deleting the cats, unless they are plugged they don't hurt performance, and they help the environment.  But, if you delete the AIR system then the cats probably won't work correctly.  And the ECU may detect the absence of the AIR system if you remove it completely.  I'm not sure what can be removed w/o the ECU detecting it.

Steve?

[Steve Mikkelson]

Thank you for sharing your knowledge guys.   I appreciate the willingness to collaborate and hope I can return some useful information when someone else needs a hand.  

My '86 is a California truck that has been certified and passed their inspection three years ago so basically up to California stringent emission standards

'94 is providing the engine and it is a Michigan truck with emission controls that I believe resemble the other 48 states.

Please correct my logic if it is flawed here, but from what I am piecing together here...

If I keep the '86 wire harness & computer and then plug into the '94 engine, I suspect there will be additional issues to address on top of the cats as mentioned.  

If I use the original '94 computer, wire harness with its married engine, there will likely be other unknown issues to deal with, but I suspect removing the cats would not be one of them?

As far as the wire harness length, I have suspicion about the relative length.  The '86 computer is currrently mounted inside the cab under the instrument panel just above the transfer case shifter.   The '94 computer is mounted in the firewall directly inline with the drivers side front tire.   I kept every wireharness from the '94 because I figured my ignorance would bite me if I threw it away.  

I probably should mention that every serpentine driven component from the '94 is staying with the engine when it finds its home in the '86.   Would that create additional concerns?  

Again group, much appreciated that you are willing to give up some of your time to transfer knowledge to a fella you don't really know.   Thank you!

[Gary Lewis]

I think the easiest thing to do is to just put the 5.8L in place of the 5.0L and run the original wiring and ECU.  As Steve said, the system is bank fire so the engine's firing order doesn't matter.  And, also as he said, the ECU doesn't determine the ignition's firing order.  It just figures out when to fire the ignition, not what cylinder to send it to.

But, the concern I have is the amount of fuel it will give the engine.  It is geared for a 5.0L engine and is assuming it knows how much air is ingested.  But the engine will be pulling in 16% more air than a 5.0L would have, so I'm wondering if the ECU will be able to properly compensate.

However, you may be able to plug the 5.8L's ECU in where the 5.0L's is and it'll be happy.  But, the question that needs to be answered before you attempt that is whether Ford changed something in the wiring between the two years/systems.

Fortunately Bill Vose/85lebaront2 has done quite a bit of work that should help in answering that question.  He's compiled in spreadsheet form the pinout of many of the different systems, and I have it on the website here: http://www.garysgaragemahal.com/efi.html.  But it is going to take some work to compare pinouts.  You need to go to the Pinout tab, then go to the 5.0L tab at the bottom and compare the circuit numbers for each pin with the same pin on the 5.8L tab for 1994.

It is a tedious process, but I would want to do it before I attempted to plug the '94 computer into the '86 harness.

And, speaking of harness, given the difference in mounting locations for the ECU, you are really stuck with the '86 harness.  That's because your body style doesn't have the mod's that allow the ECU to be mounted where it is on the '94.  

And the serpentine system shouldn't cause any problems.

[NotEnoughTrucks]

Couple of things you may want to consider.

The later model ECM may also have transmission controls, likely for an E4OD. If you use a non electronically controlled transmission, like an AOD or a C6, the ECM will not be very happy.

There are a few small changes between the 86 ECM's and the later EECIV ECM's. I did a spreadsheet some time ago, perhaps this will help?

Year_comparisons_SD_compatibility.pdf

[Gary Lewis]

Excellent points, Ray.  

[85lebaront2]

One item you will see right off, the 1985.5 and 1986 EECs did not use a speed sensor, the other is the relocation of some power and ground pins and the final is the change in EGR valve control in 1987 from the dual valves (vacuum and vent) to a "dithering" single valve that combines both vacuum and vent in one valve.

[Steve Mikkelson]

Thanks fellas!   I appreciate the guidance.   Makes me think the simplicity of a carburetor may start to challenge benefits the provides EFI.

It is helping me to realize where my line of ignorance begins and where I need to gain more knowledge to tackle this project.  I enjoy learning new stuff, but when it goes outside of my core compotnecies, it takes a bit longer for this guy to catch on.   Like the old saying goes, "you don't know what you don't know."   Keep it coming please.  

[Steve83]

Gary Lewis wrote

I'm not sure what can be removed w/o the ECU detecting it.

I prefer to look at it from a different perspective: how many things can I keep working the way the engineers engineered them to work?
This is an article I wrote about emissions systems.

Steve Mikkelson wrote

If I keep the '86 wire harness & computer and then plug into the '94 engine...

I'm not sure where exactly you're talking about plugging in, so I'm not sure what you're imagining is even possible.  Many connectors changed shape between those years.

Steve Mikkelson wrote

If I use the original '94 computer, wire harness with its married engine, there will likely be other unknown issues to deal with...?

I think that will result in the FEWEST issues to deal with.  That's how I've always done engine swaps, and all mine have been very reliable & maintainable.

Steve Mikkelson wrote

The '86 computer is currrently mounted inside the cab under the instrument panel just above the transfer case shifter.

That was one of several early EEC locations.

Steve Mikkelson wrote

The '94 computer is mounted in the firewall directly inline with the drivers side front tire.

That's the standard '87-96 location.

Steve Mikkelson wrote

Would that create additional concerns?

Again: I think it will minimize your problems; both during the swap, and in the years of driving to come.

Gary Lewis wrote

...I'm wondering if the ECU will be able to properly compensate.

I've never run the wrong EEC, but I've heard from many people who have that they run OK.  The EEC will default to its (now-incorrect) baseline the first time he powers it up, but it will learn & adapt as the engine runs, and always try to achieve stoicheometry based on the HEGO.

Gary Lewis wrote

...compare the circuit numbers for each pin with the same pin on the 5.8L tab for 1994.

I made this diagram, but it's actually based on '87-96 trucks:



It may NOT be correct for older EFIs.

Gary Lewis wrote

That's because your body style doesn't have the mod's that allow the ECU to be mounted where it is on the '94.

I found that was pretty easy to fix when I put the '95 engine, EEC, & wiring into my '83's '82 body tub:

NotEnoughTrucks wrote

If you use a non electronically controlled transmission, like an AOD or a C6, the ECM will not be very happy.

Many people think that, but I helped a local friend switch his '94 Bronco from E4OD to stick, and he didn't want to buy another EEC, so he just drove it.  We found that, although the EEC does set DTCs for the missing trans, those don't turn on the CEL, and it has no effect on how the EEC manages the engine.  So it ran fine for many years.  Eventually, he sold it to his brother (still running fine), so IDK what its current status is.

Steve Mikkelson wrote

Makes me think the simplicity of a carburetor may start to challenge benefits the provides EFI.

Not even close.  EFI is the way it always should have been done.  Carbs suck.

[Gary Lewis]

Steve83 - Please tell us more about how you put the ECA in the kick panel on your '82.  I'm going with EEC-V on Dad's '81 and have been thinking through where to put the ECA in it.  So I'm interested in how you did it as it may well be the way to do it for mine.

It brings up questions like:

Was the '95 EEC-IV or V?

Did you have to dimple or cut into the kick panel?

Were you able to put the plastic trim panel on?

Did you have to lengthen the later wiring?

[Steve83]

Gary Lewis wrote

...tell us more about how you put the ECA in the kick panel on your '82.

I saw that's where it belonged on later trucks, so I tried to cram it in there from inside.  But the e-brake was too close to the lower A-pillar/kick, so I slotted its firewall holes & slid it over.  Then I cut the firewall near the A-pillar, and folded the steel back to make the size & shape hole to fit the EEC.  Then I cut the bent steel flush with the firewall & slathered it with fiberglass (or Bondo - whatever) to seal it, and to give the EEC seal something to seal against.  Hose it down with paint, and stick the EEC in.

Gary Lewis wrote

Was the '95 EEC-IV or V?

EEC-V (OBD-II) started in '96 for these trucks.

Gary Lewis wrote

Did you have to dimple or cut into the kick panel?

Not the steel A-pillar/kick, but I cut the plastic kick trim.

Gary Lewis wrote

Did you have to lengthen the later wiring

No, the truck is the same size, and I put the EEC where it was supposed to be, so the wiring fit fine.