Hi guys, this is my first post here, hoping someone can help me out a bit.

Basic idea, have a 93 150 xl, reg cab short box, 4.9, m5od, 1356 on 410 gears. Pulled engine 7 years ago, just unplugged from ecu and around firewall so rest of truck still good. Now looking to put a motor back, have a nice 94 5.8 in a 250 at the u pull it up the road, just wondering about wiring diferences. I left the harness on the 4.9 since i figured i didnt need it for a 5.8 swap. If i pull the complete 5.8, harness and ecu then what am i looking at as far as plug and play with the rest of the truck? Not worried about hooking up trans etc, mainly concerned with the ecu and engine and dash. If its too much of a pain im gonna follow through with the swap but make a new harness to run the 5.8 stand alone with maf based on 5.0 ecu.

Thanks for any help, Eric

 

Did the 5.8 use an M5OD? I think your only choice of auto would be an E4OD. But regardless, you'll need the 5.8 harness, and PCM. Not to mention reworking your exhaust, new engine mounts, transmission mount, etc.

 

The 5.8 did NOT come stock with an M5OD but from my own findings if its a stock 5.8 with no power mods just stock as stock can be all he needs is a new clutch and flywheel for a 351W and it will all bolt up and work. Just uh don't put 1000 pounds of dirt in the bed and expect the trans to be happy afterwards if you thrashed on it the whole time.

 

Ok guys, got a bit off topic. M5od did not come behind the 5.8, but it does bolt up to it so im not worried there. Scrounging yards for a decent zf5 but all ive seen is 2wd lately, as for trans mounts anyone whos done the swap knows the factory crossmember works with factory perches, and sill works with the zf swap as well.

Im in no way worried about shoehorning the engine in and hooking up the mechanical aspects, if all else fails i have a full shop at work (where the old truck currently resides) so its going in. My only question was regarding running the 94 sd motor mated to the chassis harness of a 93.

Again thanks for the replies thus far.

 

93 and 94 both share the same wiring scheme so no insurmountable problems there of any kind, should be plug and play using the 5.8 engine harness.

Can't think of any circuits off the top of my head you'd have to add or relocate in the engine harness connector, I'd have to look it up to be sure but it be one or two tops I'd think if any at all.
Easy to figure out if it came to it with a simple diagram for both engines, one for 5.8 and 4.9 a basic haynes manual would be the most you'd need nothing more.

Simplified as both motors irregardless of cylinder count use all the same sensors and both are batch fired and those are the same pin numbers for example.

As stated you will need a 5.8L computer and one for a manual transmission would be preferable.

You won't have any trouble, worse you have to do is chase down a couple circuits add in or remove and or swap a couple wires around to make it right. But if so that will be done in the engine harness to main harness connector.

 

Thanks danr1, i figured it should be same 93-94. I was ready to go ahead and pull a motor this past weekend but i started reading about wiring differences post 92 and 95-96 specific so i held off. If it was going to be complicated i was just gonna grab the maf harness and ecu to do the stand alone swap but if its plug and play ill just keep sd and get rolling. I can get a chilton or haynes manual from school tomorrow to make some copies and search through.

Any idea what i would be dealing with putting an auto ecu in it? Ive heard main difference was the idle circuit and using clutch interlock instead of pnr switch on auto. Seems 5.8 std trans trucks are somewhat rare around here for this vintage. Lots of 89-91 but not so many newer.

Thanks much, ill update this with some pics of the project as i get it going, Eric

 

Take the computer from the truck you get the motor from, if its there and it's "good" it will work at least until you can source one from a manual.

Issue with using one from a auto trans model is that it will throw codes due to zero connection with the transmission it expects to have a connection with.

Not sure on the idle I'd really have to look into that but I do know my trucks auto and manual trans both idle at very near if not exactly the same speed so doubt you'd run into any issue there. You'd get MLPS (PNR) codes along with those for the trans itself but shouldn't be a problem say for example the truck you get the computer from has a E4OD, that is if I follow your questions.

As an example you might have to jumper a circuit with a 733 ohms resistor in line so as the computer thinks the auto trans that isn't there is in "neutral", not a big deal if comes to that.

 

Thx dan, thats what i was looking for. Was told idle issue is with how the pnr and clutch interlock work, basically auto raises idle if its on gear to compensate for torque converter drag. Hence the interlock would be wired in so when clutch depressed it thinks trans is in neutral if its running an auto ecu.


Again

 

Yea the computer is going to maintain a given idle speed regardless, it's constantly working to do so.

If using a computer for a auto trans with a manual you're not going to want to plug in the neutral safety, plug it in so it functions but remove its feed from at PCM connector? its output would be wrong for the auto trans computer. If it comes to it and at this point I still have doubts it'd be necessary letting the computer believe the auto trans is in neutral would be the proper? simplest? thing to do. Not that it wouldn't start without it but it may effect how the computer perceives load based on the MLPS's input. Must be a reason for it, shifting manually and or selecting a gear manually it wouldn't need that input for any kind of shift schedule based on ground speed/rpm/engine load under that condition. The operator has made gear selection so nothing to change as far as that goes but making some assumptions there/best guess based on what I do know.

For comparison the computer has no idea what gear the manual trans is in at any given time, doesn't need to know that so again shouldn't be an issue even in use of an auto trans especially if it thinks its in neutral.

Getting a computer from a truck with a manual trans would be the better option, can work around it but the correct computer for engine and trans combo if you can swing it would net you the best results and at the same time simplify your swap.

One item did come to mind, you'll want to get the transmission section of harness too depending on O2 sensor location differences for those two engines. 5.8L model over 8500 gvwr for example the sensor plugs in on top and just forward of the trans extension housing. Where its located on the half ton model and the straight 6 I couldn't say for sure and might be in the same vicinity as the 4.9L but it might not be, wanted to mention it just in case locations do differ by quite a bit.

If so you wouldn't need the compete trans harness but getting it while you're there will get you what you'd want for an overlay style addition to the harness it already has now. Extending the existing harness changing its location if necessary with factory results. Its easy to add in pins to any connector where required but need the wires from a donor to do it.

Myself I'd even take a few feet from the donor while I was at it just to be on the safe side, some taken from the PCM connector and the truck side of the engine harness connector. Easy enough to change length by soldering in more wire if necessary for solid reliable connections so getting full length isn't really necessary.

Again I doubt you'll need to do much but having what you might need on hand if or as something comes up would make the job go smooth.

 

Thanks dan, im gonna hit the pull n save tomorrow to start collecting parts so ill see what i find. I have several dash harnesses and a couple engine from 6.0 power stroke laying around for salvage wire n such but for the simplicity of keeping colors constant i will keep ur advice of looking for the trans harness as well. After all around here a complete truck harness goes for 20 bucks, but gotta get them quick before people start clipping off connectors.

Ill keep you guys posted.