1995 3.8L OBD1 complete swap to OBD2

[ShaneAustin]

I need to know what it would entail to swap out the complete OBD1 emissions system for an OBD2 emissions system. I have all the under hood sensors from a late 96 mustang. I know I'll need the following: OBD2 computer, complete computer wiring harness. Not completely sure about what else. Also I'm not quite sure about where all the complete computer harness runs. I have a few things in mind... fuel pump, gauge cluster, engine harness, transmission. I am in the process of trying to get my hands on the wiring diagrams for 95-97 3.8L's. I figured I would throw this out here and see if anyone knows anything about this kinda swap and if it requires a total rewire of the whole car. If that's the case I'll forget all about it!
Thanks for any insight you can bring on this endeavor.

 

[MustangLX-5.0]

Hate to say it, but 94-95 3.8 Mustangs ARE OBDII. They are one of the very few models that came with an OBDII PCM. 1996 is the primary year where nearly all models switched over to the OBDII system... aside from the Mustang. It's the 94-95 Mustang 5.0 that had the EECIV systems on them still. One of the couple of things in 94-95 3.8 that are different slightly from the 96 up, is that they have a separate ignition module, while the 96-up 3.8's use the PCM to control ignition.

 

[ShaneAustin]

What Communications Protocol does my vehicle use?
As a rule of thumb, GM cars and light trucks use SAE J1850 VPW (Variable Pulse Width Modulation). Chrysler products and all European and most Asian imports use ISO 9141 circuitry. Fords use SAE J1850 PWM (Pulse Width Modulation) communication patterns.
There are some variations among captive imports such as the Cadillac Catera, a German Opel derivative, which uses the European ISO 9141 protocol. If you have first hand knowledge of other such variations, please send them in and, together, we can build a more complete listing.
On 1996 and later vehicles, you can tell which protocol is used by examining the OBD II connector:
J1850 VPW--The connector should have metallic contacts in pins 2, 4, 5, and 16, but not 10.
ISO 9141-2--The connector should have metallic contacts in pins 4, 5, 7, 15, and 16.
J1850 PWM--The connector should have metallic contacts in pins 2, 4, 5, 10, and 16.
If your vehicle has this style connector, but doesn't have these pins populated, you probably have a pre-OBDII vehicle. To add some confusion, even having the connector with the contacts shown above is not a guarantee of OBD II compliance. This style connector has been seen on some pre-1996 vehicles which were not OBD II compliant.


I found the above write up @ OBDII - On-Board Diagnostic's System - Does My Car Have OBD-II? The Connector and Communications. I cannot get an OBD2 scan tool to successfully establish a connection with my computer. I started looking into it more and found that write up. My buddy's scan tool had a book saying my mustang was pre obd2 I have tried 4 types of scan tools, last being a $2000 Genisys USA 2007 Deluxe Scan Tool Kit. . . still no connectO!
I want to install a Diablo Trinity T-1000 Performance Tuner but the vehicle has to be fully obd2 compliant.

 

[MustangLX-5.0]

That's digging in a bit deep. I never heard of that happening before. You should be able to get a basic Actron, MAC, Snap-on code scanner to connect and pull codes. If you cannot, then there is a problem with either the connector, or the PCM itself. I can't recall how many countless times I've had other members in here go to a parts store and get the codes pulled via a cheap scan tool. And many of these members have 94-95 V6's. No problems there. Regardless of the ISO compliance, a basic OBD II scan tool should be able to connect, read data, and pull DTC's. Are you having any problems with the way it's running? Any CE lights? You may wish to take it up to a Ford Dealer. Have the service dept. look into it. If the tech working on it can't get a connection, then there is definately a problem with either the connector... or the PCM itself.

 

[393strokervert]

the 94-95 v-sixxer's are definently OBDII ,a few years back I owned a 95 v6 stang. pulled the codes with a OBDII scanner. as already mentioned, it definently sounds like you have either a connector or ECM problem.
you probably don't want to hear this but why go through all of the hassle of swapping everything over to a 1996+ system..only to still have a v6? I have a 393 in mine & still get 26+ mpg's hwy. I got 29mpg a few weeks back. + I have all that extra power & torque at my disposal not trying to be a jerk, just putting in my .02

 

[ShaneAustin]

Well you have a point there 393strokervert. I was not aware you could get those kind of MPG's from a hopped up 8. That was the whole reason I was keeping the 6r . . . Thanks for the insight guys! 393strokervert what kind of power gain did u get making it a 393??

 

[393strokervert]

Well you have a point there 393strokervert. I was not aware you could get those kind of MPG's from a hopped up 8. That was the whole reason I was keeping the 6r . . . Thanks for the insight guys! 393strokervert what kind of power gain did u get making it a 393??

I have never dynoed it but the previous owner had it tuned when the shop built the motor & it put down measly 310rwhp/383rwtq. very low ##'s IMO but the reason being is the crappy heads he put on it. he ported/ put bigger valves in the stock E7's...... I plan on getting some real heads & probably a little bigger cam soon. then I will get it tuned & see what it does. I have never checked mileage soley in town but I get a consistant 20-22 combo city/hwy. thats with the 5spd & 3.27 gears. It had 3.90's on the rear when I bought it & I never got any better than 24hwy with them.

 

[ShaneAustin]

I did some looking around... I think a 97 cobra would be a good mustang to own. It would have alot more power being stock than my V6. The diablo electronics would also work great with the cobra. Your right that would give me a good base to build from rather than a V6.