OBD2 swap in older car

[3100 MPFI]

1999 was the transition year from the small port 3100 SFI (L82) to the large port 3100 SFI (LG. The L82 upper intake is held on with 12 bolts, but the LG8 is held on with only 6 bolts.

This is the SMALL PORT 3100 SFI (L82)



This is the LARGE PORT 3100 SFI (LG



This is the OLD STYLE 1996-1999 L82 and late 1999 LG8 EGR. They all use the LINEAR EGR, but the mouting is different. This is why the 1999 LG8 is rare.





This is the NEWER LG8 intake manifold with an ADAPTER PLATE to use an older DIGITAL EGR.

[1994KlrWhaleOlds]

I see.......And the J code 3100 seems to be most prevalent in 1999 in Malibus more than Luminas, Centuries and Grand Prixs that which the engine was offered according to the Wikipedia.

[3100 MPFI]

yup. In fact, it was a 1999 Malibu that my 3100 came out of.

[IsaacHayes]

Not all 99 cars got it though. Some got 98 small port 3100's. There was a wrecked 99 malibu at a friends place and it had a 98 cast on the LIM and it was small port.

[3100 MPFI]

Please read the first sentence of post number 46.

And I QUOTE:

"1999 was the transition year from the small port 3100 SFI (L82) to the large port 3100 SFI (LG."

Transition meaning EARLY 1999 cars got the SMALL port (L82) and LATE 1999 cars got the LARGE port (LG.

[1994KlrWhaleOlds]

Yes, you want to find a car with J for the 8th digit and X for the 10th digit.

Too bad the 3.4 DOHC wasn't available in 1999. You could have a car with the check digit an X and have "XXX" in the VIN.

[3100 MPFI]

well. I had to pull the dash back out. There are some differences between the 1988 one that I had in there, and the 1994 one that I needed. I also didn't have the proper airducts, so I had to remove the carrier. I also wanted to do some more minor things under there, and finally had all the parts. I figured that I would show comparison pics for all the world to see. This way if anyone else goes to do this, they will not make the same mistakes, and have to redo it all like I did.

First of all, here is a side by side of the 2 IPCARRIERS. 1988 is on the bottom, and 1994 is on the top:


At first glance, the only real difference appears to be the passenger side lower cover, but there is really a LOT different.

Here is the passenger side ends. 1988 is on the left, and 1994 is on the right. The only real difference is that the 1994 one is more rounded, and goes out a little further. In the 1988, the vents stick out at an angle, and they are flush in the 1994.


This is where the AC controls go in the 1988. As you can see, there is 4 mouting screws for it.


This is where the AC controls go in the 1994. As you can see, there is only 2 mounting screws for it. If you try to use the 1994 AC in the 1988, or the 1988 AC in the 1994, it does not sit, and goes either too low, or too high. I will get a comparison of the 2 different AC units as well.


This is the 1988 dash where the radio sits.


This is the 1994 dash where the radio sits. The difference here has to do with routing the wiring harness. It has a larger hole cut in it for the thicker wiring harness. Also, the back part has an indent in it for the routing as well.


This is the drivers side speaker area in the 1988.


This is the drivers side speaker area in the 1994. It has a larger cutout for the wiring to go down through, and also, it is missing those extra hole/tabs for the older foglight switch bracket.


This is the area where the steering column goes through on the 1988.


This is the area where the steering column goes through in the 1994. It has the rounded indent for the round steering column.


This is a comparison of the 2 different airducts. 1988 is on TOP, and 1994 is on BOTTOM. The only real difference is where the ducts meet up with the BRAKE PEDAL BRACKET. 1988 has the window vent on the LOWER part, and 1994 has it going OVER the bracket.


This is the end that meets up with the steering column area. As you can see, it has something added.


here is a closeup of the 1994 end piece.


this is that added airduct that 1994 uses. In 1988, it goes under the steering column, but in 1994, they needed more room for the AIRBAG stuff, so they moved it to OVER.


This is the end piece at goes through the brake pedal braket. If you do this dash swap, you will want to get the 1994 bracket anyways, and it will have all of that stuff already on it.


I read somewhere that the 1996 PCM might need to get a signal from the airbags, so as a JUST IN CASE, I decided to add in the airbag sensors. If I get a service engine soon light with the unit unplugged, then I will go ahead and make the airbags functional. Adding the sensor in there means that if I want to run airbags, all I will have to do at this point is plug in the module under the dash.


closeup of the airbag sensor.


Finally, this is one of the last major differences. This is my 1988 IP CARRIER with a 1994 foglight bezel on it. As you can see, they don't line up. The 1994 is more curved, and goes lower than the 1988 one. 1988 also has a removeable cover piece, and the 1994 does not.

1988 corner


1994 corner





The only other real difference has to do with the HUD mouting. The car that I got the carrier out of had a factory HUD, so it had a weird bracket that goes UNDER the IP CARRIER for the rear 2 bolts of the HUD BRACKET to screw into. I am going to get pics of it later on, but the 1994 HUD mounting is more secure than the older style.

[3100 MPFI]

I used the bolt clips in the older ones, but for the 1994 carrier that I just installed, I used that metal bracket.

Here are some pics. I didn't get a pic of the bracket out of the car, but here you can see it installed.





This is a comparison of the older and newer climate control units. 1994 is on TOP, and 1988 is on BOTTOM.


The 1988 has 4 mounting bolts, but the 1994 only use 2 in the middle. I have tried to use a 1994 unit in my 1988 in the past, but it didn't line up right. When I installed the front cover, there was a gap and the buttons were being pushed by the opening.


Here is the LAST BIT of my update. I decided to install the digital gauges cluster. I know a LOT of people say that the connectors between the BASE CLUSTER, and the GAUGES CLUSTER are the SAME, but they are NOT. They are keyed TOTALLY different.

I was reading something over on w-body.com about the swap, and they state in the writeup that the connector is the same, but it is completly different.

Here is a comparison of the 2 connectors.
The BLACK connector is the BASE CLUSTER/ANALOG CLUSTER, and the GRAY connector is the DIGITAL GAUGES CLUSTER.


The BASE cluster has 2 alignment pins BEFORE 1, and AFTER 16 on one side, and BETWEEN 4 and 5, and BETWEEN 12 and 13 on the other side.


The DIGITAL GAUGES cluster has 2 alingment pins BEFORE 1 and AFTER 16 on one side, and BETWEEN 3 and 4, and BETWEEN 8 and 9 on the other side.


This means it has now been PROVEN that that the connectors are NOT plug n play between the 2. We have known that the wiring was different, but now we know that the connector itself is totally different as well.




Last pic of the day, this is my interior as of when I stopped working on it tonight. I removed the center console to install the airbag sensor, and had to pull the passenger seat to route the wiring for it.

[CobraCDR]

Christ Tat that is a lot of fugging work....I'm pretty sure no one has ever done this before........this looks like more work than my 2.8 turbo project.....

[3100 MPFI]

it is not too bad. The only thing that makes it hard work is the fact that if anyone else HAS done this, they have not posted any information on this, so when I make a mistake, I have to undo everything and correct it.

To my knowledge, no one has done a 1994 dash swap (they mostly just update what they have, or go to the newer dash). I don't think anyone has done an OBD2 converions to a older W-body that didn't already have a 3100 in it (A lot have done it to the 1994 and 1995), but I have not seen it done to a 1988-1993 W-body. I have seen it to other cars, but not a w-car.

[geldartb]

i applaud all the work you have done with this car. thats definately a ton of work almost like building a new car.

congradulations though i bet you will be very happy when its all done.

[IsaacHayes]

yeah when it's all together and you are driving it around you'll be like "damn it's nice to have this car running"

[3100 MPFI]

EVERY DAY I miss driving this car. I don't like that it is not going to have as much power as it did before I blew it up, but this will give me the opprotunity to get into some new area's with these cars.

My STE is nice and all, but I really need a COUPE.

The funny thing is, it seems like I still might get my TWIN CAM finished before this one. Next week, I am going to Austin to help Jay swap out the twin cam in his 1994 Cutlass Supreme, and the one that we are taking out of his convertible, all it needs is a freeze plug, then I am going to drop it in my 1995 Cutlass Supreme

To be 100% realistic with this, even after I get everything together, I am going to have a LOT OF SMALL THINGS TO WORK OUT!!!!!

First of all:

the COMPLETE interior wiring is 1994 OLDSMOBILE.
the ENGINE MANAGEMENT to C100 is 1996 PONTIAC.
the drivers side fuse block is 1995 BUICK.
the front light harness is 1988 Cutlass Supreme.

I am going to have a LOT of minor issues to work out with this car. I have basically rewired the ENTIRE CAR!!!!! I am going to have LOTS of bugs, so I think I will get the engine in my 1995 Cutlass Supreme first. That way I can drive it until I get all these little bugs that are going to show up.

[3100 MPFI]

picture of the engine compartment as of today. I have done EVERYTHING that I can until I can get around to getting to the parts store for some new parts. I need an EGR gasket, spark plugs, and wires before I can put it the rest of the way together. The interior just needs me to get in the airbag sensor, then reinstall the center console, and passenger seat.

[3100 MPFI]

OMG. I actually worked on the GOLD car today. I really don't have that much to do, but I decided to replace the front light wiring harness, and then to install the forward airbag sensor.

The light harness is nothing special. It is just a 1994 Cutlass Supreme harness that is pretty much the same as the older harness, but it has the AIRBAG sensor wiring.

First of all, here is the air cooling duct for the PCM box. Since I was working in that area, I just cut a notch in the inner tire well liner, and ran the airduct out.



Now onto the AIRBAG sensor.

First of all, in the 1994 Cutlass Supreme, the airbag sensor is attached to the metal bracket that the hood latch is attached too. The 1988-1993 latch area is small, and does not have the provisions for the airbag sensor. 1994 was the only year to get an airbag sensor, and in 1995 they combined ALL the sensors into one unit (instead of having 3 individual sensors).

The 1994 hood latch that I got from the wrecked car of Jays was too mangled to use, so I had to get creative.

After looking around the front of the car, I figured out a good place to mount this thing. The first thing I did was dig out my 1994 book to be sure that the sensor didn't need to be grounded to metal. It does not. It has a ground wire, and that was all I needed to know.

What I came up with is this. The area behind the PASSENGER SIDE grill has nothing behind it. It is just a big empty area. I have plenty of room there to install the sensor.



Here is a closeup of where I mounted the sensor, and the 2 holes I had to drill to mount it.



And here is the sensor installed.



Another pic of it installed.



And lastly, here it all is with the grills back in place.





My main reason for doing this is for inspection later on. If the 1996 PCM needs to see an airbag sensor, and it is not there, then it might turn on the SES light. If that is the case, the car will fail inspection. This way, I can just install the DERM if it is needed, and after it passes inspection, I can then remove it.

A friend is sending me some TAYLOR 8mm spark plug wires for my 3100. I am going to get new plugs, and an EGR gasket, and then I can put this car back together, and see if it runs.