OBD2 to OBD2 questions

[driller]

I'm trying to help someone with their project which involves an engine swap and changing the PCM. The project car is a 96 Mark VIII and the project requires a 98 PCM since the new motor is COP. Since the 96 is technically OBD2, most everything seems to cross over easy enough and they plan on re-pinning the harness to be compatible with the later model PCM pinout.

The first of a handful of hurdles is the MLPS from the 96 vs the Digital Transmission Range Sensor from the 98. I have the EVTM from each and need to look at them but I was wondering if anyone had some insight to what needed to be done in this specific case. I'm thinking they simply need to purchase the DTR sensor and replace the MLPS and do whatever wiring changes need to be done?

Somewhere I have the required info to swap the coils and plug wires to the COP ignition setup.

What other unexpected surprises are waiting for them? Are the transmission shift solenoids and TCC solenoid the same? What about the BOO (Brake On/Off Switch)? Are there any differences in the MAF, IACV, TPS, IAT, crank sensors and cam sensors.

(I tried to talk them into using coils and plug wires, change the valve covers and just run the 96 PCM but they wanted to hear none of that. :fart )

 

[Mad1stGen]

Any details on the replacement engine ?

I would reconsider the PCM swap. It's rather complicated.

Each coil is fed separately, fuel system is different, MLPs is entirely different, VCRM vs VCLM, and all those will require not only repinning but also adding several wires.
However, pretty much all the other sensors are interchangeable. Still quite a feat.

Have they considered rewiring the waste spark system to just drive COP coils in pairs ? It's easy to do, and has been working great for years on multiple cars I know of.

 

[chris2523]

Have they considered rewiring the waste spark system to just drive COP coils in pairs ? It's easy to do, and has been working great for years on multiple cars I know of.

works ok on NA cars.
does not work on power adder cars.

 

[Mad1stGen]

works ok on NA cars.
does not work on power adder cars.

Thus the question about engine specifics.

While not the ultimate solution, it worked for us several times in the past.

Ask Jeff and his 1996 10:1 compression 12-13 psi Eaton car (original 1996 PCM).

Close the gap down to .018-.023 if you're having blow out issues on a boosted car.

 

[psychostang]

Best thing to do, would be to stay with all 96 parts. There is nothing wrong with a 96 trans. But, there is a schematic, somewhere that shows how to re-pin the vehicle harness connector, to use the 98 trans. Also, just rewire, solder the 96 engine harness to use the cops. Much easier solution. Two red power wires; 1 goes to each bank, and 4 grounds which split to 2 each opposite cylinders. Also, the VLCM for 96 is just a little bit different than the 97/98 VLCM. They removed the FPDM and moved it to the Trunk sidewall.

 

[driller]

Any details on the replacement engine ?

I would reconsider the PCM swap. It's rather complicated.

Each coil is fed separately, fuel system is different, MLPs is entirely different, VCRM vs VCLM, and all those will require not only repinning but also adding several wires.
However, pretty much all the other sensors are interchangeable. Still quite a feat.

Have they considered rewiring the waste spark system to just drive COP coils in pairs ? It's easy to do, and has been working great for years on multiple cars I know of.

If it were easy, everyone would be doing it. :fart

It's a confluence of cheap parts. My contribution was a spare PCM I had laying around.

I think the engine was out of a Mach One? I know it is a 4V and was rebuilt over the last 2-3 years with a forged rotating assembly but still needs a lot of details. Basically, at this point he has a parts car and an engine that needs parts. LOL

Looks like to start with, we need to get a DTR sensor and connecting harness pigtail. I was looking through the EVTM's and noted the MLPS has a 8 pin connector and the newer DTR sensor requires a 12 pin connector. Apparently the transmission bulkhead connection wiring pin-out is also different?

Looking through the PCM pinouts, besides the obvious ignition and DTR sensor issues, there are a half dozen or so differences we need to sort through but none that look like will prevent it from running? Things like the tach, fuel tank pressure sensor, fuel level input, etc...

 

[driller]

Best thing to do, would be to stay with all 96 parts.

Unfortunately, that boat has sailed.

But at least that would be a fall back if all else fails!

 

[Right on the mark]

Why don't you just get a COP harness from the dude that makes them? Plug and play.