PCM help and monitoring water temp and oil pressure

[derotoreut]

I'm doing a 5.3L LM7 swap into my '70 K10. My PCM harness is installed and I'm getting ready to start my AAW harness install. I'm quite intimidated by all of this and apologize in advance if any of these questions seem silly or trivial.

There is a water temp sensor in the driver side head that is connected into the PCM. I assume the PCM uses the signal from this sensor to control the operation of my dual fans right? Anything else? So if I want to get a water temperature reading into my Dakota Digital gauges do I have to install another temp sender? Same for oil pressure? The DD kit has these senders included. Isn't it also possible to do some of this monitoring by installing another BIM module?

[mongocanfly]

Most of us drill and tap the pass side head, at the rear, to npt, for the water temp to the gauges...
The ecm needs the sender that's on the driver side..for fans and etc..
Oil pressure can come from the rear of the engine..same location as a sb..you need a metric to npt adapter...ecm doesnt need to see oil pressure...

[70c10resto]

You could use the BIM module to get a lot of your readings to the gauges. It will plug into your OBD-2 port and get a lot of your readings. You should be able to get speed/tach/temperature/check engine light for sure. Depending on how your harness was reworked you may be able to get oil pressure and gear indications as well. My BP harness doesn’t have the factory ls oil pressure Wiring so I had to use the supplied DD oil pressure sensor plugged into the factory location behind the intake.

[kipps]

The PCM needs to see a temperature sensor for a lot more than just fan control. It also changes the fueling rate based on the engine temperature.

[derotoreut]

Originally Posted by 70c10resto

You could use the BIM module to get a lot of your readings to the gauges. It will plug into your OBD-2 port and get a lot of your readings. You should be able to get speed/tach/temperature/check engine light for sure. Depending on how your harness was reworked you may be able to get oil pressure and gear indications as well. My BP harness doesn’t have the factory ls oil pressure Wiring so I had to use the supplied DD oil pressure sensor plugged into the factory location behind the intake.

So this would be a DD BIM module correct? Is that the only way to get that information into my DD cluster? My harness has loose wires for me to connect. The are labeled: speedo, tach, check engine, brake switch and 12V switched. Not sure how the OBD-2 connection would work with this stuff.

I also have the DD water sensor adapter. Looks like this would go into the passenger side head with no drilling or tapping. Not sure then if I need to use this if I used the OBD-2 port.

I think I read somewhere too that guys were using some kind of splitter. I think it was for this connection into the OBD-2 port. It sounded like it created some kinds of issues (worked or didn't work), I'm not exactly sure.

These are my wires from my harness. As you can see I had Tilden Motorsports/Pacific Fabrication do my harness.


Here is Dakota Digital instructions for installing the water temp sender. Not sure if I need that or not (if I went to the OBD-2 port BIM connection)

[mongocanfly]

That water temp adapter will work...the main reason I drilled and tapped mine is I run mech senders

[70c10resto]

If you use the bim module you wouldn’t need the extra connections on the engine harness. You could roll roll them up and tuck them away. You will still need the brake (tcc connection for lockup of the torque convertor) and switched power. You will just plug the wire from the bim to the obd2 port. You will still have power connections/ fuel sender/ that will need to be connected to the control box.


if not using the bim you could use the supplied sensors and fittings that came with the gauges and remove that plug like the pic shows on the passenger head. I had header clearance issues where I couldn’t go that route. I think the manual states it needs to be connected to the supplied sensors and not the wires from your harness.

I remember reading where there was an issue with the BIM module software that was causing issues, but I believe Dakota digital fixed the issue. I haven't had any issues with mine.

[70c10resto]

https://www.summitracing.com/parts/dak-bim-01-2

This is the BIM module you would need.

[First c10]

I used the DD BIM-01-2. I only had to add the DD oil pressure sensor as the ECM did not communicate the oil pressure to the BIM. The BIM can read more then what is displayed on the gauges. You can toggle through many other perimeters... I even see gear selection.

oh and the splitters for the OBD-II don't work. On my first swap I built a splitter and for my hptuners to see the computer I have to unplug my gauges.

On the second swap no splitter I just unplug my gauges when I hook up my HP tuners.

build is looking amazing!!

[TA_C10]

derotoreut, what is your fan setup(stock rad and fans or custom)? What is your fuse box setup(stock or custom)? Do you plan to have A/C? Stock A/C or custom standalone?

.

[LS short box]

When I do a LS swap I like to keep thing simple by not adding aftermarket devices. I haven't used DD stuff (Heard it's good but I like Auto Meter stuff) So I run the Auto Meter oil and temp senders directly to the gauges. Tach and speedo from the ecm. As said above tap the head or use the Auto Meter adapter for the temp and either use the oil pressure port on the back of the block or drill and tap fitting above the oil filter. I use the LS ecm to control the cooling fans.
Good luck with your swap.

[derotoreut]

Originally Posted by TA_C10

derotoreut, what is your fan setup(stock rad and fans or custom)? What is your fuse box setup(stock or custom)? Do you plan to have A/C? Stock A/C or custom standalone?

.

I'm using a Northern radiator with their custom 2-fan set up. When Tilden did my PCM tune they used two relays to control the fans. I'm assuming this will mean either one fan is on full speed, or two fans on full speed, depending on the parameters. I'm also installing Vintage Air AC. Tilden told me to use the Vintage Air trinary switch and tie my trigger wire from one of the fan relays to the trinary switch. This will turn on one of the fans based off of trinary requirements.

Here are the details of my radiator and fans:
Northern Radiator 209603B kit; 31”x19”; final custom fabrications made by Tilden with 1-1/2” & 1-3/4” LS connections, steam port, overflow; no trans cooler. Electric fan shroud, model Z40003, with dual 12” Spal fans, 2066 total CFM.

My fuse box is American Autowire Classic Update kit for '69-'72 trucks. I would like to be able to modify the fuse box wiring to remove some of the unnecessary wires, but I'm unsure of some of it. There are VSS wires and others that I'm fearful of cutting out. I also want to add in my wires going back the rear of the truck, since I no longer have the factory bulkhead connector for the tail lights.

[derotoreut]

I'm tempted to buy the DD OBDII Bim module, but looking at my OBDII connection I'm surprised by the minimal amount of wiring. There are only 4-wires going into this connector. Is this correct?

Only 4-wires in the OBD-2 connector



This is how they're pinned.

[pcmcobra]

looks legit

[TA_C10]

On the fuse box I was asking about the LS harness fuse box. I didn't specify, my fault. I'm assuming tilden built this?

If tilden built the LS harness fuse box, and there is available slot to install another relay, you could most likely do the 3 relay setup if you want. There is a thread here I started in LS swap section called 3 relay fan + vintage air diagram. Check that out if you haven't already. It has the wiring diagrams to study for that setup. Otherwise, 2 relays work fine, just make sure your alternator is up to par voltage/amps wise. Your fans may draw more amps at startup with the 2 relay setup. I would think your fine though.

And you saw the other posts on the A/C transducer, so it's up to you if you want to go that route instead of the trinary. And again, contact tilden/tuner and find out if you PCM supports the transducer. If so you will have to install the wires needed in harness and pin them in the PCM plugs. Then when you take truck to tuner after truck is done to get your final tune completed you would also have him setup the transducer settings.

Otherwise, trinary will work, but like I said in other post, it's external components, a workaround, and the transducer is OEM. It's a preference

The OBDII connector only requires those 4 wires. Your good. And I will also recommend the BIM module for DD gauges. It's less wiring, no senders to install(usually, does your harness have oil sender plug), and you will get extra features like automatic trans gear indicator, trans temp, LS check engine light, etc. These depend on your PCM of course but you can ask your tuner about these options too.

And you mentioned removing wires from AA truck harness, shouldn't be a problem removing wires, just study that diagram they give you and trace them out and de-pin. My advice doing this for first time is research research research. Think about anything you want to add, research the wiring you need, and you should be fine.

Hope this helps

.

[First c10]

The OBD-II has a 12+ volt source a ground and the 2 CanBus/Data wires. When I assembled my harness I read that 2 places were needed to have a ground depending on what reader you were using. So added two grounds. My OBD-II harness has 5 wires. (its been a while).

[TA_C10]

Originally Posted by First c10

The OBD-II has a 12+ volt source a ground and the 2 CanBus/Data wires. When I assembled my harness I read that 2 places were needed to have a ground depending on what reader you were using. So added two grounds. My OBD-II harness has 5 wires. (its been a while).

Depends on year right? LS1 had the 2 data wires. Rest of them don't? I don't know for sure, I just follow LT1swap.com for this info. He mentioned he's doing a LM7 engine which is same engine I have so I assumed he was using same wire harness details of 99-07.

See very bottom of page:
http://lt1swap.com/fuseblock_obd2port.html

[derotoreut]

You guys are way above my head with this. I would not have attempted to assemble my own harness. I look at my AAW fuseblock and just shake my head. I don't even know where to start. I have it all laid out on a table, I walk out into my shop and try to figure it out, get frustrated and leave. I'm sure I'll figure it out eventually. I have to... I don't have a choice.

All I know at this point is... yes I have a LM7 GenIII Vortec engine, and Tilden built the harness for it. They already programed the PCM and ran it, so I assumed that I would not require any additional tuning. I was not expecting that one. We are on opposite sides of the country so I don't know how that would work. Nonetheless, you guys are great! I've followed your builds and enjoy reading about your trucks. I really appreciate the time you take to help out.

[TA_C10]

Well in that case, hearing what your saying, I definitely recommend the BIM module for Dakota Digital gauges. It will make your life much easier. You don't need the senders from the AAW kit. You don't need most of the wires coming off the LS harness(only the ey+, Bat+, grounds, starter, fuel pump, and TCC wire for torque converter(auto trans). And all the wires needed in AAW harness are there.

For A/C, I can't tell you which way to go, I can only recommend what I would do, but if you don't want to break into that LS harness or get a re-tune, the trinary route would be easier in this case.

There are a ton of more knowledgeable people here than me, so just keep researching you will find your answers, and if you don't keep asking because someone will have the answer here.

Good luck!!

[First c10]

Originally Posted by TA_C10

Depends on year right? LS1 had the 2 data wires. Rest of them don't? I don't know for sure, I just follow LT1swap.com for this info. He mentioned he's doing a LM7 engine which is same engine I have so I assumed he was using same wire harness details of 99-07.

See very bottom of page:
http://lt1swap.com/fuseblock_obd2port.html

i said it had been a while LOL! ok so maybe i had the years backwards My swaps are GEN IV's so its just 1 data wire and 2 ground an 1 12+ wire like he has. sorry for the confusion.

Originally Posted by derotoreut

You guys are way above my head with this. I would not have attempted to assemble my own harness. I look at my AAW fuseblock and just shake my head. I don't even know where to start. I have it all laid out on a table, I walk out into my shop and try to figure it out, get frustrated and leave. I'm sure I'll figure it out eventually. I have to... I don't have a choice.

All I know at this point is... yes I have a LM7 GenIII Vortec engine, and Tilden built the harness for it. They already programed the PCM and ran it, so I assumed that I would not require any additional tuning. I was not expecting that one. We are on opposite sides of the country so I don't know how that would work. Nonetheless, you guys are great! I've followed your builds and enjoy reading about your trucks. I really appreciate the time you take to help out.

sorry I hope I didn't confuse you. I have no doubt you could have done your own harness you do great work. i do have to say the BIM made my life much easier...

Originally Posted by TA_C10

Well in that case, hearing what your saying, I definitely recommend the BIM module for Dakota Digital gauges. It will make your life much easier. You don't need the senders from the AAW kit. You don't need most of the wires coming off the LS harness(only the ey+, Bat+, grounds, starter, fuel pump, and TCC wire for torque converter(auto trans). And all the wires needed in AAW harness are there.

For A/C, I can't tell you which way to go, I can only recommend what I would do, but if you don't want to break into that LS harness or get a re-tune, the trinary route would be easier in this case.

There are a ton of more knowledgeable people here than me, so just keep researching you will find your answers, and if you don't keep asking because someone will have the answer here.

Good luck!!

^^^^

[bigmoe]

Bim module and Dakota digital gauges are the way to go for simplicity sake. If your 5.3 is a Gen III I think you can't get oil pressure through the ecm though. You can put a sender just above the oil filter with the use of an adapter plate. Lots of vendors for these. You mount Dakota's sender in it and run the wire to the Bim.

[TA_C10]

I rebuilt my factory harness on my LM7 5.3 GENIII and it has the factory oil sender plug. My DD gauges with BIM-01-2 module pulls oil, water, speed, tach, 4l60e gear indicator, and check engine light from PCM. It also pulls trans temp that I can see on my phone using DD Bluetooth app(connects straight to gauge cluster via Bluetooth) via the PCM as well.

DD then gets all other info from truck harness wiring like battery voltage, high beam and turn signal indicators, etc.

If your harness has the oil sender plug, it can pull that data via BIM because if the PCM reads it, it can be pulled for gauges. DD or OBDII apps. Torque PRO is a good app btw.

.

[bigmoe]

Originally Posted by derotoreut

These are my wires from my harness. As you can see I had Tilden Motorsports/Pacific Fabrication do my harness.

So if you're going with the Bim module you won't need some of these, ie. tach,
speedo, check engine. (as someone was saying). The Bim will read them from the ecm via the obdII. Have you got an LS conversion brake light switch like I have pictured? You need to run that brake wire to it.

I recently did a whole truck wiring LS conversion on my 65 C10. I'm just as intimidated by wiring as you are. One step at a time. Divide it in sections. Make notes. Tape and mark the wires as you go so you can go back and remember what you did and what for. You can remove the tape after. I had a lot of unneeded circuits in my fuse box I was able to borrow for other things.

[First c10]

Both my Gen IV swaps I had to put the DD oil pressure sensors as I didn't get that lucky for my DD gauges to read Oil pressure via the BIM.

[bigmoe]

Originally Posted by First c10

Both my Gen IV swaps I had to put the DD oil pressure sensors as I didn't get that lucky for my DD gauges to read Oil pressure via the BIM.

Lots of inconsistency with this. My Gen IV LMG 5.3 IS able to get oil pressure through the Bim. I heard the Gen III would not but others on here HAVE been able to get it. I guess the op and others will just have to try. At least it's easy to add an oil sender afterward if it's needed.