Dakota Durango Forum banner
1 - 13 of 13 Posts

·
Registered
Joined
·
11 Posts
Discussion Starter · #1 ·
I've got a 91 Dakota 4WD with the 318 TBI motor in it with 220K miles. Not only is the motor getting long in the tooth, but it didn't start out as the best when compared to a Magnum. So, decided I would do a Magnum swap and improve it both in wear and design.

When I bought the motor, I though it would be as simple as using a 93 Ram PCM to run the 5.9 with a 92 Dakota engine compartment harness. Then I discovered that the Rams went to a 3 wire speed sensor in 93 while the Dakota's waited until 94. Add to that, the Ram had two O2 sensors while the Dakota only one. Now, neither of these is all that hard to figure out, unless I am missing something.

My plan is to:

1. Rewire the harness to use a 3 wire speed sensor by splicing in a sensor feed from the CPS. The other wires should be good to go.

2. Splice a wire into the speed sensor wire circuit and run it to the bulkhead connector and into the cab and up to the instrument cluster.

3. Re-pin the instrument cluster plugs to match a 94-95 instrument cluster and swap in an electronic speedo cluster.

4. Splice in a second O2 sensor plug and run a wire back to the PCM.

I have an early return style fuel rail, so I think fuel is covered, plus most of the rest of the OBD1 stuff (intake, TB, exhaust manifold, etc.) minus the 5.9 injectors.

I have printouts of the wiring, still working on verifying everything though.

My question is...what don't I know I don't know? Am I missing something that will make this a huge science project? Am I correct that the engine compartment harness from the 92 should plug into my 91 without issues?

Been all over the internet looking for a similar swap and came up blank so thought I would ask.

Thanks.
 

·
Registered
1988 Dodge Dakota LWB RC 3.9V6 3 speed auto
Joined
·
1,628 Posts
Since the donor motor is a OBDII generation motor, that's why it has two O2 sensors for it. I'd grab some 1996 parts (Y pipe, intake, exhaust manifolds; wiring; ECU).

The other choice is to grab a 92/95 OBDI harness and ECU and work off of those, IMO.

I'm not sure if the engine bay wiring plugs right in; I'd want to cross between the 92 and 91 factory service manuals. They'll be CLOSE in any case.

RwP
 

·
Registered
Joined
·
11 Posts
Discussion Starter · #4 · (Edited)
Test

Cool!! I can respond now. I responded to RalphP the same day he post, or at least the next day, and got a response that my limited posts meant I had to have it verified by an moderator and never saw it show up. Even sent a message and didn't hear back.
 

·
Registered
Joined
·
11 Posts
Discussion Starter · #5 ·
Since the donor motor is a OBDII generation motor, that's why it has two O2 sensors for it. I'd grab some 1996 parts (Y pipe, intake, exhaust manifolds; wiring; ECU).
After some investigation, I believe the only time a 94/95 5.9 has two O2 sensors is when it is an HD motor. Looks like most of them are just a single O2 sensor like my '91 and the '92 harness I have.

The other choice is to grab a 92/95 OBDI harness and ECU and work off of those, IMO.
That's what I did. Grabbed a harness off a '92, as well as the manifolds and y-pipe. Also found a ECM from a '94 van for a 5.9 that looks to be a direct plug in (pin to pin) minus the possibility that because the van harness doesn't include a tach wire the ECM might not have a tach output, and the '92 harness is missing the 3 wire speed sensor input.

I'm not sure if the engine bay wiring plugs right in; I'd want to cross between the 92 and 91 factory service manuals. They'll be CLOSE in any case.
Been a little while since I compared them, but going off my memory, the harnesses swap fine. I have some wires for fog lights that are missing from the '92 harness because I think the Sport with the fog lights was a 1 year only deal.
 

·
Registered
Joined
·
11 Posts
Discussion Starter · #6 ·
dbl check the converter or flexplate counterweight differences the 360 will need weight somewhere compared to a 318
what trans three wire OD? lockup?
Weights are on the flexplate, and the 5.9 I bought came with one, so I should be good to go as far as the balance is concerned.

Truck has the A500/42RH with lockup right now. Tranni has a 1-2 flair when it is cold, so I am expecting to do some transmission work when I do the swap.
 

·
Registered
Joined
·
11 Posts
Discussion Starter · #7 ·
Oh, and I ended up with a '98 5.9 OBD2 motor, but plan to swap sensors and injectors to a 94/95 OBD1 setup. Probably swap the intake at the same time so I can run the EGR valve and avoid lighting up the check engine light.
 

·
Registered
Joined
·
697 Posts
You can do most of the tranny yourself except for the OD spring without some help
rebuilding
is the A 500 original?
your 91 318 has an a-500 my 92 has a 518
a 500's came with various numbers of clutches (especially 4 cyl so upgrade to more (there may be two snap ring slots in the shell)
or get an A998/A999 core and get even more
any number of clutches can be made to hold more lasts longer
you have a 4wd do you can't put the whole A999 trans in like you could a non 4wd and the dbl wrap band will not work on most (or any) a500 I've worked with) (comments from trans experts welcome) but your 4wd may be using the case with the holder for the dbl wrap band IDK
dbl wrap band gives you more hold in manual low and reverse if you are doing activities that require more hold
use atf+4 it's good stuff only better is Citgo Quatrosyn
 

·
Registered
Joined
·
11 Posts
Discussion Starter · #9 ·
is the A 500 original?
Pretty certain the A500 is not original to the truck. I have seen JY paint pen marks on it.

Truck led a pretty hard life before me. When I got it the rear diff was exploded, front diff was gone and only the stubs in the spindles left, TC had been swapped to some late 80's unit and the motor had to come out to replace the rear freeze plugs that had been replaced by rubber squeeze ones (mucked out several inches of stop leak out of the block when I did that). Didn't check the numbers, but pretty sure the only original piece of the drivetrain left is the motor, and I am working on swapping that.

So, based on how the truck was beat up, and the paint pen numbers I saw, I am concluding that the trans is not original.

No idea what it should have come with, either.

My plans are just to drive this thing. Makes a decent winter rig, and parts hauler, but not looking for a hot rod. Only putting a 5.9 in it because that is what I found, would have been more than happy with a 5.2. So, whatever I do to the trans will be to fix it, no plans for any real upgrades.
 

·
Registered
Joined
·
697 Posts
check your vin for oem trans and chk build sheet for trans and diffs
check the vin on the trans
if you are unlucky it will be a V6 trans ):
just build stock
put in as many clutches as your sell will hold with the snap ring all the way out
of no out to the end snap ring groove get a different shell they are cheap
inspect the planetary trust washers in the od closely
doing the cooling upgrades can be cheap
find a big Ford cooler at the wrecking yard and some half inch hose

run 0W x oil
fullsnthetic is inexpensive at wally world
 

·
Registered
Joined
·
11 Posts
Discussion Starter · #11 ·
I know it's been a year, but this isn't dead. Thought I could build a pole building shop by myself last summer and get the motor swapped after that, all before winter hit. Still working on building the shop......

I had started looking for a 5.2 PCM so I could sidestep the dash/VSS issue as I had heard that the 5.2 PCM would run the 5.9 ok. This would save me doing a bunch of rewiring to get a working speedometer making the swap that much easier. I figured that if the 5.9 ran ok on the 5.2 PCM, then I would leave it alone, but if not then I wasn't out anything but the cost of the PCM.

But recently I tripped over this info. Looks like a 2 wire speed sensor should still work on a 3 wire system. Sounds like the VSS pin on the PCM is powered and if you wire it to a ground through the 2 wire sensor, it will function just like it did using the hall effect 3 wire sensor. Only downside (I can see) is that the 2 wire sensor is probably mechanical in nature which means it will wear out while the hall effect sensor probably didn't have any moving parts and might last longer.

If so, this means I don't need to add a wire for the 3 wire sensor, nor run a wire into the cab for it and I don't have to rewire my dash for the '94 Dakota IP. And I can run the PCM I have that already matches the size of the motor.

So I might already have almost all the stuff I need to make this kind of plug and play. Now I just need to time to get moving on it.
 

·
Registered
Joined
·
11 Posts
Discussion Starter · #12 ·
I know it's been awhile, but I haven't given up. Was going over the wiring again, updating my notes and thought I should comment here just so the thread is kept kind of alive.

Biggest issue I have run into recently is the need for a radiator and with the shipping issues, seems no one has one in stock. Hoping to find a decent one at the JY.

The other thing I have worked on is the accessory drive setup. The 91 318 used a different power steering pump than the later Dakota and Ram, one that bolts to a wing on the timing chain cover. I am going to swap my original TC cover onto the 5.9 so I can use the current pump. This brings up the question of an alternator mount (I don't have AC) and will the existing one put the alternator in the wrong place and interfere with anything. I suspect it will so I snagged an alt only bracket from a Magnum motor and it appears that should bolt up to the TC just fine. Feeling like that is solved.

I think the only thing standing in my way (besides parts shortages) is getting off my duff and doing the swap.
 

·
Registered
Joined
·
11 Posts
Discussion Starter · #13 ·
Well shoot, still another year down and no swap. I am still moving forward, putting the motor together and such, but not going to happen until next spring as I need it for winter driving.

I need to fix a thermostat housing leak, so will probably swap the Magnum radiator in to fix that leak at the same time. Plus the belt tensioner looks to be on it's last legs again, so will probably swap in one from a Taurus just to keep it simple.

Don't expect anyone cares, but makes me feel better that I am updating the thread.
 
1 - 13 of 13 Posts
Top