E38 ECU Wiring Help Needed
05-09-2011, 06:28 PM
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E38 ECU Wiring Help Needed Hi Folks, Great website, probably the best site for hooking up an E38 ECU on the web. However, I am taking a bit of an odd turn with my E38 as I am using it to control a 2009 LZ4 3.5L V6 and I have a few questions. I have the complete wiring diagram for the donor car, as well as the harness, pedal, ECM and TCM. What I don't have is the BCM and Electronic Brake Control Module.
1. From reseach on here I don't need the BCM after the computer is flashed to get rid of VATS and other stuff I don't need. Can the same be said about the electronic brake controller? The 2500 and 2501 data bus lines run into and out of the brake controller. Can I jumper those wires without a problem to the bus?
2. Looking at the schematics the ECM sends a signal to the BCM to energize the crank run relay in the BCM. The BCM then sends a 12V signal to the Main IGN and Main PWR Relays which supply 12V to the ECU. Can I just run a switch on that wire going from the BCM to the ECM with 12V to trigger power to the ECU? (VATS of course will need to be disabled).
3. I would like to run a push button start. As I under the E38 offers starter latching, i.e. push the button and the starter engages automatically and disenages automatically, this is controlled by the ECM through communication with the BCM. I don't need this and I was hoping to just split wire 52 from the X1 ECM connector and hook this to a push button. Wire 52 goes to the starter relay coil control which will energize the starter. This creates a conventional starter curcuit. Any adverse affects from doing this?
4. The ECU appears to control the fuel pump. Can I just wire the fuel pump directly to a switch or will the ECU control the pump without feedback from the fuel tank pressure sensor or fuel level gauge? I have an aftermarket pump/filter and regulator assembly capable of putting out 80+ PSI to the rail. I have read that 55-60 is about what I need.
5. VE/Speed Density seems to be a fairly common modifcation. Are there any negatives with this setup? The GM computers are fairly high speed and have very dense tables so I think it should be fine.
I also need some advice on anyone who can do the computer tuning. I really don't want to spend 800 bucks on EFI Live or HP Tuners. However, I want a good reputable shop that will suppor the tune and help me through issues and do retunes if needed.
I've attached a picture of the car so you can see what I'm attempting to accomplish. The engine is mated to an F23 Getrag from a 2001 Cavalier with a custom designed Tilton 5.5" clutch on a button flywheel. I have a set of individual throttle bodies and headers also in the works but those are on the back burner for now. I would have used a V8 but with the transverse layout it just wouldn't fit without using a narrrower set of tires (305's on it now with Z06 rims). I am hoping that the short stroke of the motor coupled with no flywheel will make this thing scream.
Thanks!
Andy
1. From reseach on here I don't need the BCM after the computer is flashed to get rid of VATS and other stuff I don't need. Can the same be said about the electronic brake controller? The 2500 and 2501 data bus lines run into and out of the brake controller. Can I jumper those wires without a problem to the bus?
2. Looking at the schematics the ECM sends a signal to the BCM to energize the crank run relay in the BCM. The BCM then sends a 12V signal to the Main IGN and Main PWR Relays which supply 12V to the ECU. Can I just run a switch on that wire going from the BCM to the ECM with 12V to trigger power to the ECU? (VATS of course will need to be disabled).
3. I would like to run a push button start. As I under the E38 offers starter latching, i.e. push the button and the starter engages automatically and disenages automatically, this is controlled by the ECM through communication with the BCM. I don't need this and I was hoping to just split wire 52 from the X1 ECM connector and hook this to a push button. Wire 52 goes to the starter relay coil control which will energize the starter. This creates a conventional starter curcuit. Any adverse affects from doing this?
4. The ECU appears to control the fuel pump. Can I just wire the fuel pump directly to a switch or will the ECU control the pump without feedback from the fuel tank pressure sensor or fuel level gauge? I have an aftermarket pump/filter and regulator assembly capable of putting out 80+ PSI to the rail. I have read that 55-60 is about what I need.
5. VE/Speed Density seems to be a fairly common modifcation. Are there any negatives with this setup? The GM computers are fairly high speed and have very dense tables so I think it should be fine.
I also need some advice on anyone who can do the computer tuning. I really don't want to spend 800 bucks on EFI Live or HP Tuners. However, I want a good reputable shop that will suppor the tune and help me through issues and do retunes if needed.
I've attached a picture of the car so you can see what I'm attempting to accomplish. The engine is mated to an F23 Getrag from a 2001 Cavalier with a custom designed Tilton 5.5" clutch on a button flywheel. I have a set of individual throttle bodies and headers also in the works but those are on the back burner for now. I would have used a V8 but with the transverse layout it just wouldn't fit without using a narrrower set of tires (305's on it now with Z06 rims). I am hoping that the short stroke of the motor coupled with no flywheel will make this thing scream.
Thanks!
Andy
Last edited by Datsun1973; 05-09-2011 at 06:49 PM.
05-09-2011, 09:44 PM
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I speak from experience with V8 E38's, I assume it applies to the V6.
1. You can run without the BCM and EBCM. Your bus chain will go ECM-TCM-DLC. The ECM has a 120 ohm terminating resistor, be sure to add a 120 ohm resistor at the DLC. Total bus resistance 60 ohms.
2. Run a 12V wire to the crank/run-PTR relay from the ignition switch in run/crank position. Must be hot in crank or no start, if hot in accessory engine will continue to run.
3. Don't do that, pin X1 52 is a critical wire. This wire energizes the starter relay when a valid crank signal is received from the BCM. In most cases the output is 12v and the other side of the trigger is ground. The ECM receives feedback from the starter relay through this wire and if it is not valid shuts off noid, your engine will not run. 2009 OS should be able to flash out the starter check, in 2007 it cannot be flashed out and a 100 ohm resistor must be used between this wire and ground. Then use whatever button/switch/relay you want to energize the starter solenoid.
4. Most E38's I worked with run a Fuel Pump Control Module which controls fuel pressure. Flash out the FPCM and use a Corvette fuel filter/regulator if your desired pressure is 58 psi. Use the fuel control wire from the E38 to trigger a fuel pump relay.
5. I've run with and without MAF, it's a toss up for me. With a MAF things seem more stable, idle, cold start; but speed density seems to have a little better response.
HPT or EFI Live is a good investment with a project like yours and the retunes are free.
1. You can run without the BCM and EBCM. Your bus chain will go ECM-TCM-DLC. The ECM has a 120 ohm terminating resistor, be sure to add a 120 ohm resistor at the DLC. Total bus resistance 60 ohms.
2. Run a 12V wire to the crank/run-PTR relay from the ignition switch in run/crank position. Must be hot in crank or no start, if hot in accessory engine will continue to run.
3. Don't do that, pin X1 52 is a critical wire. This wire energizes the starter relay when a valid crank signal is received from the BCM. In most cases the output is 12v and the other side of the trigger is ground. The ECM receives feedback from the starter relay through this wire and if it is not valid shuts off noid, your engine will not run. 2009 OS should be able to flash out the starter check, in 2007 it cannot be flashed out and a 100 ohm resistor must be used between this wire and ground. Then use whatever button/switch/relay you want to energize the starter solenoid.
4. Most E38's I worked with run a Fuel Pump Control Module which controls fuel pressure. Flash out the FPCM and use a Corvette fuel filter/regulator if your desired pressure is 58 psi. Use the fuel control wire from the E38 to trigger a fuel pump relay.
5. I've run with and without MAF, it's a toss up for me. With a MAF things seem more stable, idle, cold start; but speed density seems to have a little better response.
HPT or EFI Live is a good investment with a project like yours and the retunes are free.
05-10-2011, 08:40 AM
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Thanks for the help. The book for the 2009 implala have the the LS4 V8 on one diagram and the LZ4 V6 on the next. The only difference I see in the pinouts is the number of injector and ignition signal drivers.
On the starter, if I leave wire X1 52 hooked up to the ECU can I splice into that wire and energize it with 12 volts? This way I can use the stock underhood fuse block and wiring. The ECU will still have the feedback loop for starter activity but I will still flash out the starter.
Fuel pump seems easy enough. Flash it out and run it manually. I already have a lot of $$$ invested in a full -08 AN fuel system with a Paxton Regulator and Pump.
I think I am just going to bite the bullet and get HP Tuners Pro as I am going to need the capability to tune with the wideband. Plus most folks are quoting me around 300 for a tune and HP tuners is only 650.
On the starter, if I leave wire X1 52 hooked up to the ECU can I splice into that wire and energize it with 12 volts? This way I can use the stock underhood fuse block and wiring. The ECU will still have the feedback loop for starter activity but I will still flash out the starter.
Fuel pump seems easy enough. Flash it out and run it manually. I already have a lot of $$$ invested in a full -08 AN fuel system with a Paxton Regulator and Pump.
I think I am just going to bite the bullet and get HP Tuners Pro as I am going to need the capability to tune with the wideband. Plus most folks are quoting me around 300 for a tune and HP tuners is only 650.
05-10-2011, 10:41 PM
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If you run the fuse block leave X1 52 alone, leave the starter relay in place and you will be fine. If you try and feed it power without a valid BCM crank signal the ECU will shut off noid thinking the VTD is being bypassed.
04-25-2012, 06:00 PM
#5
Bringing this back. What is DLC in the communications chain? Is that the OBD2 connector?
I have the E38 ECM to the TCM and that is all I have except for the OBD2 connector. How does that hook up in the scheme of things?
I have the E38 ECM to the TCM and that is all I have except for the OBD2 connector. How does that hook up in the scheme of things?
04-25-2012, 07:18 PM
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Thank You. I am using the engine harness out of a 2009 Escalade going into a 1965 Buick Skylark. One more question. Then does a 120 ohm resister bridge the Tan/ Tan Black wires at the OBD2 connector?
Last edited by 1989GTA; 04-25-2012 at 07:24 PM.
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11-10-2017, 10:37 AM
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I have an 07 lh6 with e38 ecu. I had to use a 120ohm resistor with my swap. All I have is the ecu, no tcm. I would recommend homing out he two can data lines. If you read 60 your good, if not then add the 120 ohm resistor.
Hptuners can now disable the starter enable check stuff. So no need to run any additional wires now.
I know this is an old thread but I got rid of the truck fuse panel and trying to get this ecu to turn on. I have battery power at pin 20, the red and white wire. I also have 12v switched power at pins 19 and 47, the pink wires. I am gonna double check the computer isn't actually on but the engine runs, but I don't hear any of the same noises that the engine made before. It's really weird.
Hptuners can now disable the starter enable check stuff. So no need to run any additional wires now.
I know this is an old thread but I got rid of the truck fuse panel and trying to get this ecu to turn on. I have battery power at pin 20, the red and white wire. I also have 12v switched power at pins 19 and 47, the pink wires. I am gonna double check the computer isn't actually on but the engine runs, but I don't hear any of the same noises that the engine made before. It's really weird.
11-10-2017, 11:54 AM
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Okay, I feel silly but here it goes. I ohmes out my two can data lines at my obd2 port and had 2 ohms. So I checked my wiring where I had installed my resistor and found that the two wires had made contact through the one side of my resistor.
My ecu is powered up with the way I wired it.
My ecu is powered up with the way I wired it.
04-14-2019, 06:14 PM
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Ls swap 2011 Silverado 5.3 with 6l80e with e38ecu into a 74 Chevy nova First of all I took the engine apart to delete the DOD and put an ls9 cam with springs and lifters, 3 bolt cam sprocket, new valley cover.. I did my own stand alone harness.. put everything back together but when I tried firing it up it cranks but no spark.... I have power on my injectors and coils... I can hear the fuel pump prime... I unplugged one of my spark plug wires an plug in spare spark plug to check spark, didn't get anything...... I was reading about some resistors and 12v to the crank, I am not aware of that.... or what can my problem be?
04-14-2019, 09:38 PM
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The vats have been deleted.... I was just thinking... since I deleted the DOD, maybe the guy that flashed my ecu didn't remove the variable timing. Can that cause it not to fire... I checked the crank sensor and I have the 5v and grond.
04-14-2019, 10:12 PM
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Did it have VVT? That's different from DOD.
04-15-2019, 08:44 AM
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I can tell you, sometimes it needs reflashed to delete the vats for some reason. I traced an issue that I resolved by just flashing it again. Hptuners has an option to bypass the 12v to crank. If you got rid of your bcm, you need to install the resistor. The best way to know if this all works is having a scan tool and attempting to communicate with the computer. Next, I would confirm your ecu is indeed turning on. One issue I had was, I have it power but there was 1 wire that needed powered that I missed. Are you able to confirm these things?
06-15-2019, 11:57 PM
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NNBS Escalade cluster help. I did ls swap out of a 2011 5.3 Silverado onto a 74 Chevy nova with 6l80e trans. I have the bcm out of the same donor car and recently bought a nnbs escalde cluster to try and make it work.... does anyone know what wires on the bcm need to bee hook up to make the cluster work?
