What makes using OBD2 system, so much better than OBD1

[TT5.9mag]

The obd2 system is not nearly as complicated as most guys seem to think. If you’ve done a megasquirt setup already it will be no big deal to get one running. Get a factory service manual for a dodge truck. I used a 2001 takeout 5.9 and with the engine harness and PDC it was 5 fuses and 3 relays to get it to run standalone. Once you put power to the pdc all those systems are powered and it’s as easy as wiring an ignition switch and a starter button. The service manual had great wiring diagrams. The jtec ecu is limited but can be tuned with an SCT handheld, contact FlyinRyan performance he’s one of the best. Also, the 46re is controlled by the ecu in all obd2 systems. At my last check a stand-alone controller has not been perfected yet. I’ve been looking for a while. On the megasquirt website there is an instruction pdf on how to piggyback a megasquirt over the jtec and use megasquirt for fuel/ignition and jtec for trans control. Currently this is what I am doing but it’s all going to change.

 

[TT5.9mag]

My 5.9 and 46re on the run stand

 

[DionR]

Glad someone jumped in here and corrected the idea that the OBD2 setup somehow requires a bunch of other modules to run. The only thing more complex about the OBD2 stuff is more wires to remove from the harness and maybe a little more research to figure what the PCM triggers (e.g. does the fuel pump power off the ASD relay, or does the PCM trigger a separate relay).

The only reason I can think you would need stuff like the BCM and ABS module would be if you wanted the PCM to control the cruise control or something, and even then I think it is just the ABS module it needs. If you wanted to run the Ram IP, you would need the BCM since it controls many of the idiot lights. But none of that is needed to make the motor run.

There might be some complications with sensors as the PCM needs to see things like water temp which might or might not be the same signal as the gauge needs. The OBD1 stuff still used mechanical gauges so that is different.

The way I see it is, if you want to run a stock setup without mods, and want maximum simplicity, run an OBD1 system. If you want to tune it (even someday), need (want?) to run an RE trans, and aren't afraid of reading a wiring diagram, no reason not to run the OBD2 system.

I have projects where I am using both. My '91 Dakota is getting a 5.9 swapped in next summer using a '95 PCM for van and a '92 Dakota harness. I have to splice in a third wire for the speed sensor and repin/rewire the IP plugs so I can use a non-mechanical speedometer, and there are a few other tricks to it, but nothing huge. Also in the works is a Hughes EFI intake swap onto my Duster using a 2001 PCM with a '98 Ram harness I cut down and repinned for the PCM along with a custom PDC. That one might end up using a BCM and ABS module, but only because I have wild ideas of using teh built in security feature for the Ram, and the OE cruise control. Granted, neither system is actually on a vehicle and running, but I see no reason they shouldn't.

 

[TT5.9mag]

Dion, none of the other modules are wired in to the ecu. I suspect they run off of a body control module or something like that. I’ve never researched any further as I had no reason to want to use ABS or anything else. What I can tell you for sure is,on the stand, mine fires up and runs just fine without any of that crap. It threw a couple of trans codes at first because the insulation on the wiring on the plug was torn but once that was fixed the only code present was for evap because I don’t have a purge solenoid connected to my tank. I have maybe 2 hours of run time on the stand with multiple warm ups and all is well.

 

[67Dart273]

I think you guys are pretty much right "except." There seems to be a lot of griping that a chipped / key/ security system can screw with you. I guess in that case you need to get the computer flashed and may have to prove ownership of the components

If someone knows for sure, I'd like to hear

 

[DionR]

Dion, none of the other modules are wired in to the ecu. I suspect they run off of a body control module or something like that. I’ve never researched any further as I had no reason to want to use ABS or anything else. What I can tell you for sure is,on the stand, mine fires up and runs just fine without any of that crap. It threw a couple of trans codes at first because the insulation on the wiring on the plug was torn but once that was fixed the only code present was for evap because I don’t have a purge solenoid connected to my tank. I have maybe 2 hours of run time on the stand with multiple warm ups and all is well.

Agreed, they aren't wired direct to the PCM. They communicate off a pair of bus wires (drawing a blank on the exact name, but like a canbus). The PCM needs the ABS module only if it needs to know vehicle speed for something like cruise control, or to tell the IP what speed to display on the speedometer (the PCM controls it). The BCM is only useful to the PCM for the security measure as far as I can remember. But none of those are needed to run the motor or transmission.

 

[TT5.9mag]

Well I can only give advice from my experience and I have done 3 stand alone 5.9s with 46re trans, one for myself and 2 for other guys and not once have I had to do anything for security key issues. I have heard that though on the interwebs.

 

[DionR]

I think you guys are pretty much right "except." There seems to be a lot of griping that a chipped / key/ security system can screw with you. I guess in that case you need to get the computer flashed and may have to prove ownership of the components

If someone knows for sure, I'd like to hear

My understanding is, if the PCM has never been connected to a BCM that has the security measure (the lower tier BCM), then the PCM won't have the security measure. If the PCM does see the upper tier BCM with security on the twist pair, it will forever be looking for a code from said BCM to indicate all is well so it will start and run. Thus, no BCM, no start. All the BCM does is broadcast a code that says the security is off and if there is no code, the PCM assumes the security is active and attempts to start and run should be ignored.

Not sure if there is a work around or not, but it is a good thing to think about with the OBD2 system.

 

[DionR]

I should note that the above is related to Rams. Don't think the Dakota's have security, and I don't know what the Durango's have. Pretty sure the Jeeps did, but don't know much about them.

It should be noted that the OBD2 systems are pretty model specific. The language used on the twisted pair changed and didn't allows overlap between models so I wouldn't try mating stuff from a Dakota to a Ram and such. Might be overlaps, but not sure where/when.

 

[rustytoolss]

Glad someone jumped in here and corrected the idea that the OBD2 setup somehow requires a bunch of other modules to run. The only thing more complex about the OBD2 stuff is more wires to remove from the harness and maybe a little more research to figure what the PCM triggers (e.g. does the fuel pump power off the ASD relay, or does the PCM trigger a separate relay).

The only reason I can think you would need stuff like the BCM and ABS module would be if you wanted the PCM to control the cruise control or something, and even then I think it is just the ABS module it needs. If you wanted to run the Ram IP, you would need the BCM since it controls many of the idiot lights. But none of that is needed to make the motor run.

There might be some complications with sensors as the PCM needs to see things like water temp which might or might not be the same signal as the gauge needs. The OBD1 stuff still used mechanical gauges so that is different.

The way I see it is, if you want to run a stock setup without mods, and want maximum simplicity, run an OBD1 system. If you want to tune it (even someday), need (want?) to run an RE trans, and aren't afraid of reading a wiring diagram, no reason not to run the OBD2 system.

I have projects where I am using both. My '91 Dakota is getting a 5.9 swapped in next summer using a '95 PCM for van and a '92 Dakota harness. I have to splice in a third wire for the speed sensor and repin/rewire the IP plugs so I can use a non-mechanical speedometer, and there are a few other tricks to it, but nothing huge. Also in the works is a Hughes EFI intake swap onto my Duster using a 2001 PCM with a '98 Ram harness I cut down and repinned for the PCM along with a custom PDC. That one might end up using a BCM and ABS module, but only because I have wild ideas of using teh built in security feature for the Ram, and the OE cruise control. Granted, neither system is actually on a vehicle and running, but I see no reason they shouldn't.

Thank you, I could not see why I would need all of those electrical systems to run the OEM EFI system and an RE trans.

 

[DionR]

Ok, the twisted pair in a '96-01 Ram is a CCD bus. This does overlap with many others - here is a chart.

 

[rustytoolss]

Glad someone jumped in here and corrected the idea that the OBD2 setup somehow requires a bunch of other modules to run. The only thing more complex about the OBD2 stuff is more wires to remove from the harness and maybe a little more research to figure what the PCM triggers (e.g. does the fuel pump power off the ASD relay, or does the PCM trigger a separate relay).

The only reason I can think you would need stuff like the BCM and ABS module would be if you wanted the PCM to control the cruise control or something, and even then I think it is just the ABS module it needs. If you wanted to run the Ram IP, you would need the BCM since it controls many of the idiot lights. But none of that is needed to make the motor run.

There might be some complications with sensors as the PCM needs to see things like water temp which might or might not be the same signal as the gauge needs. The OBD1 stuff still used mechanical gauges so that is different.

The way I see it is, if you want to run a stock setup without mods, and want maximum simplicity, run an OBD1 system. If you want to tune it (even someday), need (want?) to run an RE trans, and aren't afraid of reading a wiring diagram, no reason not to run the OBD2 system.

I have projects where I am using both. My '91 Dakota is getting a 5.9 swapped in next summer using a '95 PCM for van and a '92 Dakota harness. I have to splice in a third wire for the speed sensor and repin/rewire the IP plugs so I can use a non-mechanical speedometer, and there are a few other tricks to it, but nothing huge. Also in the works is a Hughes EFI intake swap onto my Duster using a 2001 PCM with a '98 Ram harness I cut down and repinned for the PCM along with a custom PDC. That one might end up using a BCM and ABS module, but only because I have wild ideas of using teh built in security feature for the Ram, and the OE cruise control. Granted, neither system is actually on a vehicle and running, but I see no reason they shouldn't.

Sounds like that OBD1 would be far easier for me, and then use an RH series overdrive. This is all about low cost, simplicity, I'm at appoint were going fast is less important, than cruising in a good looking vintage mopar (with modern creature comforts and modern engine controls)

 

[TT5.9mag]

Rusty, I wouldn’t shy away from an obd2 system for sake of complexity. neither one obd2 or obd1 are any more or less difficult than the other. The obd2 system once working will have much greater diagnostics that you can read with a modern scanner once you have it running and that alone makes it worth using over obd1.

 

[pt70]

Somewhere between 2006 and 2008 the CANBUS/TIPM system was put in Chrysler models. Avoid this system for changeovers.

There is a security key ['chipped key'] to prevent a car from getting stolen. It reflects a specific signal from the transponder located inside the steering housing. I bought a plain $2 key that was cut to my existing 'chipped' key. The car would start and run for 2 seconds and shut off. After 5 tries without the chipped key, it will shut down the system for several hours.

If a car has the factory security SYSTEM, when you lock the car doors with the key button, a light flashes on the dash [the alarm is set]. You have to open the car with the other key button. If you open the door by turning the key in your door lock, the alarm [horn] will blast.

An ABS code will appear and a dash light will go on if the ABS module doesn't receive a proper signal. But the car should start and run.

The easiest way, I think, would be to find a 318 or a 360 with throttle body injection [smec computer] and overdrive/lock-up from a van or truck without a security key, ABS, or remote door locks, etc. ------1989 to 199?

 

[TT5.9mag]

Pt70, why recommend the TBI? IMO they are junk and no better than a carburetor. All of the same wet flow problems are present and they typically do not run any better. Again IMO the benefits of this swap and the work involved come from the use of tuneable mpfi. Rusty find a 5.9 ram truck 2000-2003, unbolt the PDC and cut every wire that goes in to the cab. Save everything going to engine and trans. Take the harness, PDC, engine, and trans. Once you run battery power to the PDC and a ground you are an ignition switch source and a starter button away from a running standalone, modern MPFI system. It really is that easy.

 

[DionR]

Somewhere between 2006 and 2008 the CANBUS/TIPM system was put in Chrysler models. Avoid this system for changeovers.

Why? There are plenty of G3 Hemi's running around on '06-'08 wiring harnesses that where cut down to just the PCM with no issues. The CANBUS system has little to do with the swap.

I would add that I was under the impression that the OP was looking at a Magnum/LA swap, not a G3 Hemi. Might be me just reading into it something that wasn't there, not sure. But if so, the Magnum was out of production by '06 and you would be talking about the G3 Hemi.

Looking back, I get the impression the OP is talking about a Magnum swap due to his questions about the RH/RE transmissions. The new Hemi PCM won't run an RE, so I guess in my mind it cuts out a motor swap from a vehicle later than '03. This would limit it to the more common Magnum swap that just makes more sense for what he is talking about.

There is a security key ['chipped key'] to prevent a car from getting stolen. It reflects a specific signal from the transponder located inside the steering housing. I bought a plain $2 key that was cut to my existing 'chipped' key. The car would start and run for 2 seconds and shut off. After 5 tries without the chipped key, it will shut down the system for several hours.

If a car has the factory security SYSTEM, when you lock the car doors with the key button, a light flashes on the dash [the alarm is set]. You have to open the car with the other key button. If you open the door by turning the key in your door lock, the alarm [horn] will blast.

Not certain on every model, but pretty sure the Ram didn't use a chipped key in the years that had a Magnum. The BCM recieved a signal from the key fob to unlock the doors and turn off the security, or you could use the key to manually unlock the door which also signaled the BCM to turn off the security. But there was no chipped key or reader in the years that I am familiar with.

An ABS code will appear and a dash light will go on if the ABS module doesn't receive a proper signal. But the car should start and run.

I doubt any year swap would have a dash light unless the stock IP was being used, but it if was maybe you could see a light on the dash if the ABS module wasn't present or incorrectly configured. Most motor swaps, and the one I think the OP is asking about, wouldn't include the original IP and so I really doubt you will see a light.

I wouldn't be surprised if a code was stored in the PCM if the ABS module was missing, but I haven't heard of anyone having issues with the way a Magnum runs if so.

The easiest way, I think, would be to find a 318 or a 360 with throttle body injection [smec computer] and overdrive/lock-up from a van or truck without a security key, ABS, or remote door locks, etc. ------1989 to 199?

I see the same amount of work to swap a TBI or a Magnum into a rig, both will require a higher pressure fuel system, wiring, PCM, etc., but a 318 TBI will be down like 90 HP to a 5.2 Magnum and be much less efficient. Why go through all the same work and not use the better motor?

And the SMEC was used until '95 on the OBD1 stuff. The 5.2 Magnum was released in '92 and the 5.9 the following year, and both were still on the SBEC.

Rusty, I don't disagree that the OBD1 system is probably the easiest to swap in, but only marginally. The later OBD2 systems didn't gain any power, so I see no advantage to either system performance wise if you stay stock and the OBD1 system would avoid any potential issues with vehicle security. My only reservations for your situation is that is seems like the RH transmissions are getting harder to find, and I would worry that the old SBEC PCM could be hard to replace if it ever went bad.

And if you went OBD2 and did want to put a bigger cam in it, you would be able to.

Just some thoughts.

 

[rustytoolss]

Why? There are plenty of G3 Hemi's running around on '06-'08 wiring harnesses that where cut down to just the PCM with no issues. The CANBUS system has little to do with the swap.

I would add that I was under the impression that the OP was looking at a Magnum/LA swap, not a G3 Hemi. Might be me just reading into it something that wasn't there, not sure. But if so, the Magnum was out of production by '06 and you would be talking about the G3 Hemi.

Looking back, I get the impression the OP is talking about a Magnum swap due to his questions about the RH/RE transmissions. The new Hemi PCM won't run an RE, so I guess in my mind it cuts out a motor swap from a vehicle later than '03. This would limit it to the more common Magnum swap that just makes more sense for what he is talking about.



Not certain on every model, but pretty sure the Ram didn't use a chipped key in the years that had a Magnum. The BCM recieved a signal from the key fob to unlock the doors and turn off the security, or you could use the key to manually unlock the door which also signaled the BCM to turn off the security. But there was no chipped key or reader in the years that I am familiar with.



I doubt any year swap would have a dash light unless the stock IP was being used, but it if was maybe you could see a light on the dash if the ABS module wasn't present or incorrectly configured. Most motor swaps, and the one I think the OP is asking about, wouldn't include the original IP and so I really doubt you will see a light.

I wouldn't be surprised if a code was stored in the PCM if the ABS module was missing, but I haven't heard of anyone having issues with the way a Magnum runs if so.



I see the same amount of work to swap a TBI or a Magnum into a rig, both will require a higher pressure fuel system, wiring, PCM, etc., but a 318 TBI will be down like 90 HP to a 5.2 Magnum and be much less efficient. Why go through all the same work and not use the better motor?

And the SMEC was used until '95 on the OBD1 stuff. The 5.2 Magnum was released in '92 and the 5.9 the following year, and both were still on the SBEC.

Rusty, I don't disagree that the OBD1 system is probably the easiest to swap in, but only marginally. The later OBD2 systems didn't gain any power, so I see no advantage to either system performance wise if you stay stock and the OBD1 system would avoid any potential issues with vehicle security. My only reservations for your situation is that is seems like the RH transmissions are getting harder to find, and I would worry that the old SBEC PCM could be hard to replace if it ever went bad.

And if you went OBD2 and did want to put a bigger cam in it, you would be able to.

Just some thoughts.

Doing a Gen 3 hemi would be nice, but installing a Magnum will be cheaper and easier, and will be all the power I need. but can't say a 5.7 wouldn't be cool.

 

[Ottmundr]

OBD means On Board Diagnostics. OBD II has far more system diagnostics than OBD I. Most OBD II systems can be flashed via a programmer (if supported by the aftermarket) where as OBD I needs a chip, reprogrammed, or replaced with a different ECU if major modifications are made like a larger cam, larger injectors, added engine displacement, etc. On the trans side I don't know, some manufactures the ECU controls the trans (if electric) and some have a Transmission Controller (TCU). If you have a donor, use all the stuff from it. Mismatch is when you get into trouble.

This is why the LS cookie cutter stuff is so adored, the aftermarket made it like playing with Playmobile instead of a used Lego set with no instructions. But, I'm a Lego guy.

Careful with them Legos.

 

[67Dart273]

DAMN Dion, what you say sounds reasonable. This is optimistic LOL

 

[pt70]

TBI in pick-up trucks came out in 1988 and 1989 [360]. There was a horsepower increase -- about 25HP? over the carb engines. TBI eliminates cold start problems. It has been a fine running truck for me for many years. The fuel pump system runs at 16 PSI. [The pump puts out more pressure but is regulated down to 16 PSI at the throttle body, and then returned to the tank.

I don't know when the overdrive trannys were installed. When I got my truck [used], the key dance showed a problem code for the lock-up converter. After some digging, I found a wire and plug hanging from the back of the trans. Ah Ha! Just plug it in. Nope. The 727 doesn't have lock-up that year, but the SMEC was designed for one.

Going from Dion's specs, a 1992 to 1995 Magnum with a SMEC would be a good choice for more power. But I question the 90 HP increase from a TBI. Also, find a donor vehicle without a chipped key and without the factory security system.

Stay away from the TIPM system. It requires a vehicle wired differently.

 

[DionR]

DAMN Dion, what you say sounds reasonable. This is optimistic LOL

I am actually planning to use the top tier BCM at some point so I can make use of the built in security. I plan to either set up a fob so I can turn on or off the security (and maybe lock/unlock the doors someday), and/or use the switch on the lock cylinder from the door to to enable/disable it.

The switch on the door is pretty simple, just used a variable output based on the direction it is turned. Just two tires is all. Already grabbed one, would have been two but I broke the second one trying to get it off the lock cylinder.

I am also half planning to use the ABS module and try and get the PCM to run the cruise control. Only trick I haven't scienced out yet is how to feed the correct speed signal to the ABS module. Ram's stopped using a speed sensor in the trans and used the tone wheel in the rear diff, so I have to figure out if I can trick it into thinking it is reading the diff when I don't have a tone wheel or sensor there.

 

[DionR]

... I question the 90 HP increase from a TBI.

Yeah, guess I was a little overly optimistic there, was going off memory. Based on data from Wikipedia, a 1991 Dakota with a 318 was rated at 170 hp, I though it was more like 145. A 1992 Dakota with a 5.2 was rated at 230 hp for an increase of 60 hp.

But 60 or 90 hp, either way I would jump up to the Magnum rather than mess with the TBI. It's not going to get you into G3 Hemi territory, but it's nothing to sneeze at. Plus, my Dakota runs out of breath at 3-3.5K RPM and can't pull a hill without kicking out of OD. Pretty sure a '92 with the Magnum 5.2 would kick the snot out of it both in driveability and efficiency.

Funny thing is, a 1992 Dakota with the 3.9 v6 was rated at 10 more than the 318 in the previous year.

 

[DionR]

I feel the need to clarify or acknowledge something.

I know Mopar used a SKIM (chipped key) system on some vehicles, but I don't know exactly when or on what vehicles. I know that the 2001 Ram FSM I have only mentions SKIM in a trouble code listing, but the vehicle security talks about the VTSS. That is what I have been talking about.

What I have to be clear about is, I don't know if Mopar added SKIM to the Rams in 2002 or not, and if so to what trim levels. Nor am I clear on the what other models might have used SKIM.

So, while I am comfortable saying that a 2001 Ram and older probably doesn't have SKIM, I can't speak for other models or years. If I were to guess, the GC got SKIM before anything else and the Dakota was the last. But Ram or Durango??? No idea.

 

[TT5.9mag]

Dion, I can help slightly. I’ve done 3 standalones using factory ecus and harnesses. A 2001 from a Ram 2500, a 2002 ram 2500, and a 2003 ram. All three are 5.9 and 46re combos. None of them had any security key features. Not to say it wasn’t available but these didn’t have it.