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yup the 3.9 mounts should be the same; but which ever engine you use (the engine itself is the same 92-03 beside some years had EGR, sensor plugs changed throughout the years etc; look up a replacement long block and they all list them clumped together 92-03; Dakota full size or van. the differences are in the manifolds and the oil pan/pickup tube depending on what body you are putting it into. which when repacing an engine with the same size engine that stuff gets transferred from the old to the new engine.
Legally you need to keep all the smog stuff on it that an 01 with a V8 woud have had; in your favor is that in your year everything related to engine computer wiring etc would be the same for a Dakota as a Durango. though by then the base V8 was a 4.7 not the 318; but they did still put the 360 in Durangos and Dakota R/T's and everything taht will work on a 318 will work on 360. except the flexplate/flywheel' that's due to the internal/external balance difference between those 2 engines; but those are certainly NOT "one year only" type of parts! Your best bet would be to find a 97-00 Dakota or Durango that's been wrecked and being parted thatll give you everything you will need in one package; watch Craigslist and the U pull type yards.
 

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1988 Dakota 3.9L-TBI
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Discussion Starter · #42 ·
Also im not for sure about the computer i know it will need to be one for a v8 stanard but thats about it. Also what about the wireharness?
I THINK a computer for an V8 auto will work on a V8 manual transmission with minor errors but I'm not 100% yet. Thought I read something about using a non-overdrive transmission but I thought a 5-speed NV3500 HAS overdrive?
 

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Whether the manual has OD or not dont matter; they put plenty of 3 speed auto (the old 904) in vans with the 6 in later years; albeit with a few extra plugs the older trannys didnt have...
The older OBD 1 (older than 96) you could get by using an auto computer for a stick; IDK about '96> whether the same would hold true.
Wiring would have to be as close to the year of your truck as possible so as to mesh with the connectors that go thru the dash;
not sure about the little details of the Dakota but on my 97 cherokee I needed a wiring harness and it HAD TO be from another 97, I tried both a 96 and a 98 thinking "close enough" but it eas not. and figures 6 months later theres a fresh 97 in my local yard; I hunted all over and could find every year Cherokee but.
Also the Jeep Wrangler used the same 3 spd auto as the vans til about 2000; (different only in the outer case itself because the jeep inline 6 has a different bolt pattern from a 3.9/318) but that may provide "possibility" of wiring help;
the closest for sure, to what you need would be a same-year-as-your-truck get a harness from a 3.9 stick truck, adding in the 2 additional injector plugs the V8 needs is easy Lotsa people here have done that.
 

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1988 Dakota 3.9L-TBI
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Discussion Starter · #44 ·
I believe my 1988 has the 904 but I can't get a "close to year" harness since mine is 88 and 92' was the first Magnum in a Dakota and 94' for Rams. I'm leaning towards a 94-96' harness probably from a Ram of some sort then re-doing all my wiring through my firewall. I'm not going to want an auto, deff the 5-speed manual w/ overdrive but I have a feeling that will need to be pulled from another vehicle.
 

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I believe my 1988 has the 904 but I can't get a "close to year" harness since mine is 88 and 92' was the first Magnum in a Dakota and 94' for Rams. I'm leaning towards a 94-96' harness probably from a Ram of some sort then re-doing all my wiring through my firewall. I'm not going to want an auto, deff the 5-speed manual w/ overdrive but I have a feeling that will need to be pulled from another vehicle.
yuh 92 was 1st year for Magnum in a Dakota you might not be as far off as we think if you go 02-93 I think they still had cable driven speedo til then;
alot of interchange 87-96;
my last response was more towards the guy with the 01 that jumped in
 

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Awesome lots of good info. So if i found a 97-00 dakota or durango with the 5.2 the mounts (which would be the same as the 3.9),pcm, and wire harness would work with my 01 dakota? And what would be a good oil pan for my 318 since it wont fit?
 

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Awesome lots of good info. So if i found a 97-00 dakota or durango with the 5.2 the mounts (which would be the same as the 3.9),pcm, and wire harness would work with my 01 dakota? And what would be a good oil pan for my 318 since it wont fit?
I'd suggest making your own thread. it will be better and a lot less confusing for us all.
 

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1988 Dakota 3.9L-TBI
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Discussion Starter · #48 ·
yuh 92 was 1st year for Magnum in a Dakota you might not be as far off as we think if you go 02-93 I think they still had cable driven speedo til then;
alot of interchange 87-96;
Not even worried about the speedo at this point, I'll convert to whatever the doner has. Bear with me here... if I got just the block/intake and wiring from an automatic van or pickup (94-96) and I used it with my auto I have now (just temporarily since it is my daily driver it will make my swap faster) will the 318 blow up my dinky 3-speed (possibly 904)? I know the torque converters are the same but I don't think a 904 ever saw a 318 in 1988 lol also I highly doubt the donor motor will have a 3-speed probably something a bit better so how will that work with the computer; do all automatic transmission models work with a "automatic tranny computer" for a different tranny?
 

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Got out of Dodge.
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First off Pink, yes, a 318 will blow up your 3-speed trans. "When" just depends upon how hard you drive the truck. I thought I read that you want to make the truck a manual? If so, a member here named Hahns5.2 recommended to me trying to search on Car-Part.com. I was looking for a replacement for my 5.2, but by that time one had been located for me.
 

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Not even worried about the speedo at this point, I'll convert to whatever the doner has. Bear with me here... if I got just the block/intake and wiring from an automatic van or pickup (94-96) and I used it with my auto I have now (just temporarily since it is my daily driver it will make my swap faster) will the 318 blow up my dinky 3-speed (possibly 904)? I know the torque converters are the same but I don't think a 904 ever saw a 318 in 1988 lol also I highly doubt the donor motor will have a 3-speed probably something a bit better so how will that work with the computer; do all automatic transmission models work with a "automatic tranny computer" for a different tranny?
yup, most 318s had 904s behind them in 88; even cop cars, full sized vans and 2WD pickups.... the only way to guarantee a 727 behind a 318 that year was to buy a full sized 4WD truck...
some may have had different numbers of clutch discs in each clutch pack but a 904 is still a 904 (even the "998" and "999" derivatives)
 

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1988 Dakota 3.9L-TBI
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Discussion Starter · #51 ·
I DO want it to be manual but for now at least I will use my 3-speed transmission to make it a faster "engine" swap process.

Good so the 904 three-speed CAN handle the 318 (when it goes it goes I will replace it with a manual).

So am I good then to use an automatic 94-95 (OBDI) Ram van 4-speed computer on my 1988 3-speed, will it shift right?
 

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yeah it can handle it but dont get crazy with it.... if it were "fresh"I would feel better about it but being used; it may not last with the stock motor either.... everything is relative.

what induction system are you using? TBI, or multi port of the magnum engine?
You may get codes related to "OD not working" but bcak then there were alot of "false codes" codes that would show up on vehicles not so equipped; like my son's Ramcharger gets a code about the lockup converter; the computer is made to "see" it but if the vehicle dont have it ( most 4WDs didn't get lockup yet by then) the computer will have a code; another is something about "not sensing A/C load" on something that did not come with air in the 1st place.

I know that there were many vans (mostly 3.9 powered) that came with that same 3 speed, through the 90s; I wonder if any V8 vans also did?

YES it should shift as even in 94/95 the shifting of the tranny was still 100% hydraulically controlled; the only thing not so those years, would be the lockup converter and the OD gear; but your 88/89 truck most likely had a computer controlled lockup anyway; I know my '88 D 100 full size w/ its 318, did. you may have to change a connector or swap wires to a different terminal or 2 leading to the brain box, but I doubt it; the best thing is to look at wiring diagrams for both your truck and also the year of computer you want to use and see what terminal controls lockup. I know at least til 93 they still used a speedo cable, the speed sensor had both a cable port and a plug in for wires... (just pulled a dash from a 93 Dakota yesterday)
does your current computer have 1 plug in or 2? (or are you using the 94/95 harness)
 

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1988 Dakota 3.9L-TBI
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Discussion Starter · #53 ·
The multi-port that comes with a 94-95 5.2L wiring is what I am using. I'm not familiar with "lock-up" if I had a computer controlled lock up and now the 94-95 is different sounds like something will need to be changed no way in hell am I using my old TBI V6 wiring and computer it's all going right in the trash.

The speedo will be upgraded anyway, that shouldn't be any problem. I have both a cable coming out of it with wires too, maybe the wires are for the shift position sensor.

As far as my computer goes..I would say a 2 plug? This is mine I took a picture of it just now, what does this tell you?
 

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yeah 2 plug in pic. Yes you have lockup in your trans (many people dont know they have or what it is)
Up til 93 they used the cable and electronic plug around 94 or 95 they did away with the cable. you should be able to retain your cable drive speedo just use the speed sensor off the truck *now* so you can run both that and the cable....
 

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If you're wanting to run a Magnum 5.2 (EFI) you'll want a 92-95 OBDI computer and a 92-95 wiring harness to go with it. I'd suggest using the wiring harness from a Dakota in that year range so it will work OK in your engine bay. RAM truck and van wiring harnesses of those years use the same components, but the connections, including those for the computer, are in different locations. That could make wiring it up a little painful. You can use a V6 wiring harness. They're very common and modifying them for a V8 is pretty simple, just a matter of adding two injectors (4 wires). Just don't try to use a V6 computer in your V8 truck - that won't work.

As for the speedo, like donram360 said, easiest thing is to use the cable/VSS combo so you can use your cable-driven speedometer but still get the VSS signal the computer wants.

I'm in the middle of swapping a '92 5.2 Magnum into an '89 Dakota 4WD. Each swap has unique requirements I know, but I'll be glad to share what I've learned. Something else to consider: I plan on using the return-style fuel system from a 92-93 Magnum (93 on is return-less). You may find you need to get another fuel tank, pump, and/or fuel rail because the fuel systems changed 3 times from 88 to 93. 88-91 is TBI return-type, 92-93 is EFI return-type, and 93-on is return-less.
 

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1988 Dakota 3.9L-TBI
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Discussion Starter · #56 ·
Ragged89 you are the man! This is new information :) I will be sure to look closely at my fuel system, I have fuel return on mine I'm almost 100% but is there anyway to change what you have up front instead of everything down back? Are there safety perks in the returnless?

Sounds like I should just use a V6 wiring harness and add the wires, I can't use an LA harness on a Magnum can I?
 

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I haven’t been called the man in quite a while - LOL! By the way, I made the same mistake twice in my previous post regarding the return-less fuel systems; they actually go from ‘94-on, not ’93-on.

OK, here we go… As for changing everything up front, it still wouldn’t solve the fuel issue you’re going to have. The reason is because your ’88 Dakota, like my ’89, has a TBI return-type system which is a significantly lower pressure than the EFI return-type found in ‘92-‘93 Magnum trucks. All the various fuel system types have the fuel pump located in a module or canister in the tank, however, our late ‘80’s tank module is different than the others, and the pump itself is a lower pressure unit. No matter whether you decide to go Magnum return-type or returnless, you have to have the tank that accepts the ’92 through ‘95 fuel module (I’m pretty sure the ’92-’95 tanks didn’t change except for what’s in the module). So, once you know which year motor you’re going to go with (’92-’93 or ’94-on), you could drop the return-type or return-less module for that year motor in the ’92-on tank. Still with me?

The year of the motor matters because the fuel rails on the motor also differ, depending on whether it’s a return-type or return-less type. Return-type has the fuel pressure regulator on the rail, the returnless has it in the tank module. Another thing is the fuel lines themselves. This is sort of obvious but return-less systems have only one line, while return-type have two. While it might work OK, your ’88’s TBI return-type fuel lines aren’t really designed for the additional fuel pressure of the EFI return-type. I believe the older lines are also 5/16’s versus 3/8’s for the EFI (I might be a little off on this).

So, you can change the fuel rail on your motor, or the tank/module, to create whichever system you chose. Either way, the fuel line(s) on your TBI system will probably need to be changed. I know some people have used the older TBI return-type lines with Magnum EFI fuel systems successfully though.

In my research I haven’t found any significant performance or safety advantage with either system, except maybe in very high horsepower situations. Here’s a good link that describes return-type and return-less fuel systems:

http://www.aa1car.com/library/returnless_efi.htm

No, you can't use your LA (TBI) harness, it is different. It only handles two injectors max and requires the old, two-connnector PCM. You need a EFI Magnum harness to run a EFI Magnum 5.2/5.9 (modded Magnum V6 harness works too). The nice thing is the Magnum harness will still plug right up to the existing bulk connector on the driver’s side firewall of your ’88, which ties it in to the rest of your wiring.
 

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I haven’t been called the man in quite a while - LOL! By the way, I made the same mistake twice in my previous post regarding the return-less fuel systems; they actually go from ‘94-on, not ’93-on.

OK, here we go… As for changing everything up front, it still wouldn’t solve the fuel issue you’re going to have. The reason is because your ’88 Dakota, like my ’89, has a TBI return-type system which is a significantly lower pressure than the EFI return-type found in ‘92-‘93 Magnum trucks. All the various fuel system types have the fuel pump located in a module or canister in the tank, however, our late ‘80’s tank module is different than the others, and the pump itself is a lower pressure unit. No matter whether you decide to go Magnum return-type or returnless, you have to have the tank that accepts the ’92 through ‘95 fuel module (I’m pretty sure the ’92-’95 tanks didn’t change except for what’s in the module). So, once you know which year motor you’re going to go with (’92-’93 or ’94-on), you could drop the return-type or return-less module for that year motor in the ’92-on tank. Still with me?

The year of the motor matters because the fuel rails on the motor also differ, depending on whether it’s a return-type or return-less type. Return-type has the fuel pressure regulator on the rail, the returnless has it in the tank module. Another thing is the fuel lines themselves. This is sort of obvious but return-less systems have only one line, while return-type have two. While it might work OK, your ’88’s TBI return-type fuel lines aren’t really designed for the additional fuel pressure of the EFI return-type. I believe the older lines are also 5/16’s versus 3/8’s for the EFI (I might be a little off on this).

So, you can change the fuel rail on your motor, or the tank/module, to create whichever system you chose. Either way, the fuel line(s) on your TBI system will probably need to be changed. I know some people have used the older TBI return-type lines with Magnum EFI fuel systems successfully though.

In my research I haven’t found any significant performance or safety advantage with either system, except maybe in very high horsepower situations. Here’s a good link that describes return-type and return-less fuel systems:

http://www.aa1car.com/library/returnless_efi.htm

No, you can't use your LA (TBI) harness, it is different. It only handles two injectors max and requires the old, two-connnector PCM. You need a EFI Magnum harness to run a EFI Magnum 5.2/5.9 (modded Magnum V6 harness works too). The nice thing is the Magnum harness will still plug right up to the existing bulk connector on the driver’s side firewall of your ’88, which ties it in to the rest of your wiring.
Actually you can use any year Magnum engine; at worst, you may have to swap manifolds to accomodate EGR.... whether you go returnless or return, below the intake manifolds the remainder of the engine itself is no different in these years. .I have swapped magnum engines across that single line/dual line threshhold before. also though 94 and 95 are EGR years, as are 92-93, (no EGR '96+ exc maybe california models) between 92 and 95 all you'd be switching is the rail itself with injectors, to go between single and dual line fuel systems.
when you cross OBDI/II in years 95 and< (I) 96 and > (II) you also "lose" the EGR too.... so any OBDI is gonna basically be an EGR motor... (meaning no manifold swap needed between any of these years)


yes tanks from 92-95 are the same and there are 2 sizes available; a 15 gallon and a 22 gallon; I put a 22 gallon from a 93 return style system into my 94 returnless, and put the original 94 fuel pump module into the 93 tank; whether 15 gallon or 22 gallon the module is the same for a given year.
 

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and; ragged; not quite; the dual line went newer than 94, IF you have a 4 cyl truck;IIRC the dual line went to 95, on 4 bangers. I know that we are not talking 4 bangers, but thought I'd toss that out there; and the 4 bangers w/ dual line used the same pump as the 92/93, V6/V8 dual line trucks did.... so if he goes dual line, that will expand the possibility of finding something in a boneyard that would work, that is set up that way if he's having to get parts from more than 1 truck.
 

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1988 Dakota 3.9L-TBI
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Discussion Starter · #60 ·
So I will need a 92-96 tank and internals (92'-93' / 94'-96').

I replaced my fuel lines with rubber oil lines designed for high pressure but I think they are 5/16. If my motor comes out of a Ram van or pickup the fuel system might be different within those years.

"The nice thing is the Magnum harness will still plug right up to the existing bulk connector on the driver’s side firewall of your ’88, which ties it in to the rest of your wiring."
^ This is something I have been trying to determine for a while! However I do not have a temp gauge and oil pressure gauge, I just have temp and pressure "lights" in my cluster. Did they change from a voltage line to a data signal line for a gauge? (variable values) that might be a problem when trying to plug a Magnum harness into my firewall bulk connector?

The whole swap seems like it's going to be a long planned out process of acquiring components, so until then, I think it would be wise to drop my 3/4-speed for a 5-speed to save on gas and brakes along with harness the 3.9's power (I'm always too low in a gear when I need RPMs or too high in a gear when I need to come to a stop or slow down) I don't have to use an AX-15 on my 3.9-TBI do I? I would rather get the transmission I want now for the 5.2L (NV3500)
 
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