Hey guys and gals,

I picked up a 93 f150 with a 351w, and an automatic. It has head gasket issues, but runs well.

I have a 93 shortbox 300 6 cylinder with a 5 speed manual that is begging for a 351w.

I've done a fair bit of reading about the swap, but for me when I read, it gets cloudy when it comes to ECU's.

I'd like to use the automatic trucks ecu in the manual swap. All the wiring and harness are the same style (no idea about the actual pin locations yet).
I'm assuming the auto ecu will be searching for the automatic transmission in one way or another which may throw a transmission code.

With a 5 speed swap, behind a 351w, using a ecu from the same year but from an automatic, will this work? Anyone know for sure?

 

From digging around, mostly here, it will function.

But the PCM from an auto will be really grumpy that there's no transmission attached.
Practical side effects range from no cruise control to some reports of drivability issues.
More will chime in- I've stuck with manual PCMs from other vehicles...

Also, you will want to be a bit gentle on the M5OD, especially in 1st gear, as it's not technically rated for 351 torque...

t

 

Thanks for the reply.

Yeah I've read a bunch, and I haven't had anyone say for sure that their cruise control didn't work, or anything else really that has actually happened. Most of it was speculation. I was hoping to find someone that has tried it and can give some more non speculative answers!

I do appreciate it though, and appreciate any dialog on it. If I had a manual ecu I would use it, but unfortunately I don't have one. Would like to see if I can use this one first.

 

I have not swapped auto/manual computers but have done computer swaps.

You need to compare the pin outs and the components. As an example some computers will be set up for sequential fuel injection versus batch fire. Early computers will use a different style IAC valve than later units.

You set up the harness and components to match what the computer expects to see. Do your homework before you purchase a computer. Finding a computer that closely matches the harness and components you plan to use will your life easier.

 

An E4OD computer could probably be tricked into "working" with a 5.8/M5OD combination by setting a mlps in neutral or drive but I would expect it to be quirky at best. I would think you could get a 5.0 or 5.8 manual computer pretty easily or a 5.0/5.8 C6 or AOD and it would run better than with the E4OD computer.

If I was going to the trouble of swapping the powertrain around I would probably plan to rework the harness to put in a MAF mustang computer.

Or go aftermarket.

 

Another F150? What axle ratio does it have?

With both trucks beiung the same year you have some options. I think the best move would be to swap in the 5.8 engine harness with the motor and go find an early 5.8 computer for a manual or non computer controlled auto(C6) to use, that computer should be plug and play in your truck.

The reason I asked about axle gearing is that the 5.8 will put more load on the transmission but lower gearing(higher ratio) in the axle will aleviate some of that load which will help the trans live longer. And because the I6 manual 1/2 ton trucks were more often equipped with those rediculous 3.08 and 2.73 axle ratios.

 

Thanks for the reply. What do you mean by quirky? That's the part I've been really trying to figure out, but everything I've read it seems like everyone is speculating what it would do, but doesn't really know for sure. You'd be surprised how difficult of a time I've been having trying to acquire a 351w manual computer. I cannot find any from any year of truck with a manual.

I'm not interested in going aftermarket or maf swapping it either. I'm not really building a super nice truck or anything, just playing around with the stuff I have.

I haven't read about the 5.0 mustang ecu being compatible yet, I will look into that as those I seem to be able to find. Especially the speed density ones.

 

The shortbox I have (that I'm considering swapping) has the 2.73. I have 6? Parts trucks though, and at least one has the 4.10 ratio in it. Think most are the 3.55s.

I'm not too concerned about that part yet though, same with the m5od. I just need to figure out the whole junkyard/solution to the ecu problem.

 

The missing inputs may put the computer into limp mode. I would expect idle quality issues. I don't know if the transmission inputs are integrated into engine management beyond idle strategies and shift management.

Speed density mustang computers will be sequential injection, so will require some additional work. They are easier to find and cheaper.

 

3.55's with 29-31" tires is a good all around driving ratio with the M5, go 4.10's if the tires are bigger and/or you plan to work the truck.

Yes a PCM may be the toughest part to source, what I suggest is just searching for a PCM for an early F250/350 5.8/C6 truck just to get the catch code and engineering number, and then order one from an online distributor.

 

So what we're really saying is 'try it and see, but don't be shocked if it does weird things with idle'

t

 

Yeah I will likely end up going that route as nobody really seems to know for sure.

Was still hoping someone out there would have tried it and came across this post to share their experiences though!

Appreciate the dialog so far everyone.

 

Any update? I have a zf5 that I installed in my 1992/93 econoline with a 5.8/E4od run by speed density obd1. Finishing up little items this week to hopefully fire it up in park/neutral. I have been in the same boat as you researching, except there isnt a manual EEC option for the van that all the truck posts suggest to get.

If not, I too will wing it and see what happens.. hopefully to report back somewhere with the experience for others to reference.

 

Thanks for the reply. Honestly my project is a few projects down the line. I'm a high school shop teacher and this is a project for my students. Hoping to get them on it in the fall, was more just researching than anything. Let me know of you end up trying it though!

 

have some updates.. I thought I had a fuel problem, fought and tried to diagnose an issue where my van (auto eec with manual trans) would start fine and idle but under any load or reving of RPM would stumble terribly or stall. With a new fuel pressure gauge and going through all the wiring and plumbing issues I could think of including finishing the dual tank setup.. I realized the fuel pressure gauge was too tight and thats why it would only register 3 psi or so but still start and run fine. So on a whim I stuck a 1990 f250 manual trans EEC in to see if it would run. It did, it revved fine and would not die under load, started and idled drove down the road and back. So now I have delved into the wiring of manual vs auto EEC. some wiring diagrams show a simple pedal circuit, which lead me to believe the auto being in park attained the same results. But then looking further into it and finding someone finally mention that the EEC/manual setup does more.. apparently it will bump the idle or prepare for load each time you press the clutch, Similar to when the Auto is put in gear it tells the engine to prepare for a load on the engine. I kept digging and found the switch/harness and some diagrams that show more detail. I will upload them here, I have not wiried any of it in yet. I need to source the switch and pigtail but want attempt to find them in a junk yard before dropping 150 or so on some new ones, especially if finding them used gets me more harness to utilize. When that happens, I will splice it into the extra Auto harness and hope it all works out. The second or third time starting the van to run some other tests after the initial ride around the block, the idle has been a bit high and surging. May be learning, but I assume it is more to do with the clutch pedal circuit that thinks the clutch pedal is depressed and doing whatever it does for the engine to prep for a shift by having the auto harness in park.