OBII engine management ?

Performance mods and Advanced Stroker discussion.
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Zorm
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I made it to triple digits!
Posts: 151
Joined: March 31st, 2008, 9:51 am
Vehicle Year: 1983
Vehicle Make: Jeep
Vehicle Model: Cherokee

OBII engine management ?

Post by Zorm »

Has anyone built a stroker and have it running off a Jeep OBII system? I got an 83 Cherokee with my 4.6L right now I have been wiring in a OBI system. I came upon a OBII system out of a 2000 Grand Cherokee, cool thing is, it has only one O2 sensor, but an automatic. I picked up everything from the engine bay, harness, ecm, sensors, coil pack, dizzy pickup thingy, and the fuse box.

So my question is, anyone wire up a Jeep OBII system in a Jeep that did not have one initially?

thanks for thoughts
jsawduste
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Re: OBII engine management ?

Post by jsawduste »

Look around the forum and search using OBD2, SBEC, JTEC, tuners, Chris Jensen, Ryan Hogan etc.

This has been discussed to death.

To answer your question, yes many folks have wired up OBD2 engine management from something else, even myself..........
Zorm
I made it to triple digits!
I made it to triple digits!
Posts: 151
Joined: March 31st, 2008, 9:51 am
Vehicle Year: 1983
Vehicle Make: Jeep
Vehicle Model: Cherokee

Re: OBDII engine management ?

Post by Zorm »

OK, I did do a search, a lot of tuning stuff which i cool, but what about install.

1. Do I need to keep the VSS because I did not see on on the Jeep I removed the harness from, unless I did not recognize it.

2. Do I need the 3rd connector? two of them go to the engine bay, the other to the passenger compartment and fuse box?

3. Would I need to get a different flywheel for a OBDII system?

4. I would kinda like to keep the 130A alternator but the connections are way different from the OBDI and OBDII systems, is there a higher amp alt for the 2000 Grand Cherokee?, options?

5. If I run the OBDII system, I need the starter from the donner engine, if it was mated to an automatic, would that starter work for a manual tranny?

6. Would it be better to first run with the OBDI system then change to the OBDII?

7. I have the 4.6 mated to a NV3550 5 speed, the ecm and harness I got was from a automatic 2wd Grand Cherokee, can tuning resolve any conflict there?

7. When I install the distributor pick up sensor thing, does the engine need to be a TDC?

8. For later down the raod, for tuning, I have the 24lb injectors, stock 91 cam, and larger mustang TB, would I get better benefit from the OBDII system?
jsawduste
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Re: OBDII engine management ?

Post by jsawduste »

Zorm wrote:OK, I did do a search, a lot of tuning stuff which i cool, but what about install.

1. Do I need to keep the VSS because I did not see on on the Jeep I removed the harness from, unless I did not recognize it. Yes, the ECM needs a VSS signal and so does the speedo.

2. Do I need the 3rd connector? two of them go to the engine bay, the other to the passenger compartment and fuse box? Likely as that 3rd connector will have wiring for the transmission, and maybe the fuel system. Don't know what vehicle you have.

3. Would I need to get a different flywheel for a OBDII system? OBD1 and 2 share the same wheel.

4. I would kinda like to keep the 130A alternator but the connections are way different from the OBDI and OBDII systems, is there a higher amp alt for the 2000 Grand Cherokee?, options? Not sure what would be different other than the connector perhaps. Both use the same 2 wire alternator. Plenty of alt. upgrades to choose from.

5. If I run the OBDII system, I need the starter from the donner engine, if it was mated to an automatic, would that starter work for a manual tranny? Same starter

6. Would it be better to first run with the OBDI system then change to the OBDII? No, waste of time.

7. I have the 4.6 mated to a NV3550 5 speed, the ecm and harness I got was from a automatic 2wd Grand Cherokee, can tuning resolve any conflict there? Yes

7. When I install the distributor pick up sensor thing, does the engine need to be a TDC? Follow the procedure in the FSM.

8. For later down the raod, for tuning, I have the 24lb injectors, stock 91 cam, and larger mustang TB, would I get better benefit from the OBDII system?
Yes


I just did a quick and dirty answer session to your questions. If you search on my user name you will find recent posts answering your questions in greater detail.

Plus you don't mention what type or year vehicle this is going in. I am confused if the donor is a 2000 GC or your putting it into a 2000 GC. If its going into a 2000 GC then it already is OBD2.

Some assumptions have to be made. One assumption is that the vehicle is pre OBD2 and your using the non can-bus gages.
Zorm
I made it to triple digits!
I made it to triple digits!
Posts: 151
Joined: March 31st, 2008, 9:51 am
Vehicle Year: 1983
Vehicle Make: Jeep
Vehicle Model: Cherokee

Re: OBII engine management ?

Post by Zorm »

Sorry for that, the donor is the 2000 Grand Cherokee, what its going in is a 83 Jeep Cherokee (last year for the big ones) and yes, non can bus gauges.
I have been trying to splice the OBDI system with the 83 harness.
jsawduste
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Re: OBII engine management ?

Post by jsawduste »

Now that we have a baseline we can move forward.

The ECM is going to be looking for emissions inputs/outputs that the 83 doesn't have. You would be wise to have them tuned out.

You will need to find the ignition and starter inputs (crank, run and off) in the 83 harness and tie those into the OBD2.

Gages will be the same as you currently have. IE non can bus hard wired directly.

On the OBD2 harness only what is needed to run the engine. Everything else can be (needs to be) eliminated.

Grounds are your best friend. The factory OEM harness grounds are adequate at best. Do what you can to make sure the connections are right. On both the vehicle side and the new harness side.

Use the SCI, powers and grounds for the underdash ALDL to read codes. The can bus can be cut away.

That 3rd plug your talking about is likely for the TCM. You will find the VSS wiring in there.

This is enough to get you started.
Zorm
I made it to triple digits!
I made it to triple digits!
Posts: 151
Joined: March 31st, 2008, 9:51 am
Vehicle Year: 1983
Vehicle Make: Jeep
Vehicle Model: Cherokee

Re: OBII engine management ?

Post by Zorm »

thanks jsawduste, I already have almost all of the OBDI harness spliced in but want to go OBDII. I need to pickup a 2000 GC FSM for the wiring schematic.

As if dancing between the 83 harness and the 91 OBI harness was fun, now its 83, 91, 2000. Nice challenge but I am hoping to be happier with the OBDII especially if I can get the ecm to a tuner and get all that junk I don't need tuned out of it.

Trying to maybe get the same, or close to the HP as a 351w or maybe a 360 without the weight of those engines. The NV3550 mated to the NP208 should do well also. :D
jsawduste
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Re: OBII engine management ?

Post by jsawduste »

You will find the ECM side of OBD1 and 2 to be VERY similar. Meaning you could repin an OBD1 harness to OBD2 with a little imagination. Of course with the coil pack you have will have 2 additional coil drivers.

Where your going to find the biggest differences in OBD1/2 is the connectors for the sensors. In early 96 they were the same as OBD1 but mid year and later harnesses are pinned different.

Say OBD1 A/B/C AND EARLY OBD 2 A/B/C changes to C/A/B or something similar after mid 96 production run. What that means to you is that your OBD1 sensors will not be compatible with the OBD2 2000 harness as the pin outs are different.

From your donor you will want to take the sensors as well as the harness.
Consider also if the donor has the anti theft. That will need to be called out if it does.

If you look at the OBD1 FSM and the OBD2 FSM you will clearly see what I am mentioning. Its all fun and doable but does require a little extra work and verification with continuity.

One thing you might consider is replacing the 2000 PDC with a couple of Bussmman RTMR`s. That way to can make your own PDC. Add circuits, relays and up wire gages as you desire. For example you may find the fuel pump runs on a 14 gage wire. It certainty works but I`d like to see 12 gage. Or the ability to run both high and low beams off relays instead of being hard wired.

I use 2 RTMR`s. One that internally bussed for the relay grounds....Headlights, horn etc and the other that is not bussed so the ground wire can be run directly to the ECM.

I like this wiring stuff........LOL :banana:
Zorm
I made it to triple digits!
I made it to triple digits!
Posts: 151
Joined: March 31st, 2008, 9:51 am
Vehicle Year: 1983
Vehicle Make: Jeep
Vehicle Model: Cherokee

Re: OBII engine management ?

Post by Zorm »

I also have been looking at maybe adding / modifying one of these to work on the jeep.

http://www.ebay.com/itm/162327939092?_t ... EBIDX%3AIT

I have been trying to find a air flow diagram and how much boost these put out. I know at idle, the air does not really go through the supercharger, there is a "bypass valve" I think but its controlled via ecu. I have been looking at maybe making the bypass valve mechanically connected to the throttle linkage on the intake, the more the throttle opens, the more the bypass valve closes, thus allowing more boost as you step on the gas. Would also need to see if these systems have a blow off valve and how to work that.

thoughts welome
Zorm
I made it to triple digits!
I made it to triple digits!
Posts: 151
Joined: March 31st, 2008, 9:51 am
Vehicle Year: 1983
Vehicle Make: Jeep
Vehicle Model: Cherokee

Re: OBII engine management ?

Post by Zorm »

Flywheel question. For the OBDII systems I see that the flywheels have 3 separate sets of notches where the OBDI flywheel has notches all around. Does anyone know if the OBDI flywheel will work with the OBDII system?
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