L31 into an '86 Regal Limited V8
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Should probably plug it though.I have almost finished the fuse box. The fuse box was completely separated from the harness to make the modifications simpler. The fuse box now has six relays: the original starter and fuel pump relays, two relays that will energized the HOT/RUN loads of the original Vortec engine (the relay will be picked up from the Nova coil wire), and two fan relays.
Here are some parts for the modifications:
1) the terminals for the relays and fuse are Delphi Metri-pack 280 series; the part numbers are based on the wire size; here is a typical part number I order from Mouser 12110845-L
2) the relays are OMRON series G8W and G8V rated at 35 amps. For the fan relays I used relays with a resistor to suppress voltage spike since the relays are picked up be the computer. I used the previously installed relay for the fuel pump, I noted it does not have a resistor.
I soldered the terminals but you have to be careful not o make them too fat because the retaining clip will not slide back in.
Here are some parts for the modifications:
1) the terminals for the relays and fuse are Delphi Metri-pack 280 series; the part numbers are based on the wire size; here is a typical part number I order from Mouser 12110845-L
2) the relays are OMRON series G8W and G8V rated at 35 amps. For the fan relays I used relays with a resistor to suppress voltage spike since the relays are picked up be the computer. I used the previously installed relay for the fuel pump, I noted it does not have a resistor.
I soldered the terminals but you have to be careful not o make them too fat because the retaining clip will not slide back in.
RUDE DOG said:
This is exactly what I want to do, keep the harness and fuse & relay box STOCK. I hadn't planned on touching it at all, don't want to.
But now I'm wondering if keeping them stock is even possible.
I don't know how to rewire a fuse & relay box and have no desire to.
ATL Regal said:
I think your best and cheapest option is to get an aftermarket harness. I believe the cheapest is from Howell:
http://howellefi.com/gm-vortec-products ... 3-4-5.html
[/quote]
Is keeping the underhood fuse & relay box stock possible???[/quote]
I don't think so. There has to be some modifications. For instance, the L31 underhood fuse box has fuses for heated seats. I don't have heated seats in my Nova and I doubt you have heated seats in your Regal so you would have to remove those wires. I modified those circuits to provide power to my new electric fans-- I had to add relays to the relay box since the L31 has a clutch fan.
Essentially, I have two relay and fuses boxes:
Nova original fuse box- everything this fuse box supplies is original to the car-- horn, taillights, brake lights, radio, etc.
L31 fuse box- this supplies everything I added with the engine swap-- fuel pump, computer, electric fans, etc.
The L31 fuse box requires only two interfaces with the original electrical system: 1) it needs +12V from the battery [computer gets power at all times] and 2) it needs +12V during START and RUN [loads such as fuel pump and electric fans]. That's it, no other interface with the original wiring harness is required to get the engine running. Some additional wires from the L31 harness may be required to get your instruments to work (tach, speedometer).
I suppose you could go through each load in the L31 and see if it is function you intend to use. For instance the L31 has a horn relay (which I converted to another function) as does your Regal fuse box. You would have to find the four wires going to the Regal horn relay and move them to the L31 horn relay. The L31 underhood fuse box does not contain all the circuits your Regal fuse box does (radio, lights, etc.) so you have to keep the Regal fuse box anyway or severely modify the L31 fuse box.
Rather than trying to integrate the two fuse boxes, it is much simplier to envision them as two separate devices. The stand-alone wiring harnesses (like the one in my previous post) adds a fuel pump relay and appropriate fuses, they are just not put in a box.
Is keeping the underhood fuse & relay box stock possible???[/quote]
I don't think so. There has to be some modifications. For instance, the L31 underhood fuse box has fuses for heated seats. I don't have heated seats in my Nova and I doubt you have heated seats in your Regal so you would have to remove those wires. I modified those circuits to provide power to my new electric fans-- I had to add relays to the relay box since the L31 has a clutch fan.
Essentially, I have two relay and fuses boxes:
Nova original fuse box- everything this fuse box supplies is original to the car-- horn, taillights, brake lights, radio, etc.
L31 fuse box- this supplies everything I added with the engine swap-- fuel pump, computer, electric fans, etc.
The L31 fuse box requires only two interfaces with the original electrical system: 1) it needs +12V from the battery [computer gets power at all times] and 2) it needs +12V during START and RUN [loads such as fuel pump and electric fans]. That's it, no other interface with the original wiring harness is required to get the engine running. Some additional wires from the L31 harness may be required to get your instruments to work (tach, speedometer).
I suppose you could go through each load in the L31 and see if it is function you intend to use. For instance the L31 has a horn relay (which I converted to another function) as does your Regal fuse box. You would have to find the four wires going to the Regal horn relay and move them to the L31 horn relay. The L31 underhood fuse box does not contain all the circuits your Regal fuse box does (radio, lights, etc.) so you have to keep the Regal fuse box anyway or severely modify the L31 fuse box.
Rather than trying to integrate the two fuse boxes, it is much simplier to envision them as two separate devices. The stand-alone wiring harnesses (like the one in my previous post) adds a fuel pump relay and appropriate fuses, they are just not put in a box.
nova_rookie said:
Ok, this gives me a better idea of what I want to do.
1. My L31 didn't have heated seats, I don't know if it has a relay for it.
But even if it did, couldn't I leave it alone and just not use those wires?
2. The part about having 2 fuse & relay boxes (Regal's original under the dash on the firewall behind the parking brake, and the L31's underhood fuse block, right?) is what I'm trying to achieve.
From what I understand, this is what I need:
L31:
1. +12V from battery
2. +12V during Start & Run
a. +12V to fuel pump during Start & Run
b.
3. Signals for Tach, water temp, oil pressure, & VSS from trans to come from their respective sensors > through the L31's underhood fuse block > then through the fire either INTO the Regal's fuse box or bypass it > then to the dash (Dakota Digital)
Regal:
1. Leave it be as much as possible since it will only be controlling things like wipers, lights, horn, radio, maybe a/c, maybe cruise control.
Sound about right?
From what I understand, this is what I need:
L31:
1. +12V from battery
2. +12V during Start & Run
a. +12V to fuel pump during Start & Run
b.
3. Signals for Tach, water temp, oil pressure, & VSS from trans to come from their respective sensors > through the L31's underhood fuse block > then through the fire either INTO the Regal's fuse box or bypass it > then to the dash (Dakota Digital)
Regal:
1. Leave it be as much as possible since it will only be controlling things like wipers, lights, horn, radio, maybe a/c, maybe cruise control.
Sound about right?
Yes, you are on the right track. Go back to the diagram I posted on Feb 13. Using the numbering system from above:
1) +12V from the battery is shown on the left hand side of the diagram, note the battery supplies PCM directly, orange wire ckt 440; the other ckt shown DLC ckt 840 is to the connector where they hook up the device when they inspect your vehicle
2) +12V during Start & Run. You need a fair amount of amperage so you dont want to get this from your Regal harness, instead you want the Regal system to send a signal that the ignition switch is in Start & Run. Look at the top most relay labeled PCM RLY. The Regal signal (most likely the +12V to the original coil) is attached to 86 of the relay. When the signal comes from Regal to 86 the circuit is complete to ground through 85. This energizes a coil in the relay which closes the contacts and the circuit is closed between 30 and 87, current is then made available to the loads downstream of 87. The reason that the relay is desirable is that the load on the Regal harness is less than 1 amp (current from 86 to 85) whereas the current through 30 and 87 is limited by the rating of the relay, typically 30 to 40 amps. In actuality, I found about 60 amps were needed so I used two relays and broke up the loads between them.
a) for the fuel pump, the signal to energize the pump comes from the computer, for my vehicle it is a dark green wire coming from computer connector 4, pin 1. The relay works the same as described above.
As for the instruments, the wires do not run through either fuse box, the wires run directly from the sensor or computer to the gauge.
1) run the tach wire in the L31 directly to the gauge
2) water temp- the Dakota digital system probably came with its own sensor (or told you what to buy). You will need to install the sensor and run a wire from the sensor to your gauge.
3) oil press- same as water temp, use sensor supplied by Dakota digital; the L31 has two oil pressure sensors-- one for the gauge and the second keeps the fuel pump running after the engine starts. I will provide a diagram to show you that circuit.
3) VSS run from computer to your gauge, again does not go through either fuse box; you need to ensure that the computer signal is compatible with Dakota digital, should be
If you took the cruise control unit off the L31, then you will want disconnect all the Regal wiring and use the L31 computer to operate the L31 cruise control module. You will have to run the wire from the L31 system to your old Regal cruise control switch.
I also used the L31 crank start circuit. I'll provide a diagram for that circuit, too.
Mike
L31:
1. +12V from battery
2. +12V during Start & Run
a. +12V to fuel pump during Start & Run
b.
3. Signals for Tach, water temp, oil pressure, & VSS from trans to come from their respective sensors > through the L31's underhood fuse block > then through the fire either INTO the Regal's fuse box or bypass it > then to the dash (Dakota Digital)
Regal:
1. Leave it be as much as possible since it will only be controlling things like wipers, lights, horn, radio, maybe a/c, maybe cruise control.
Sound about right?
Yes, you are on the right track. Go back to the diagram I posted on Feb 13. Using the numbering system from above:
1) +12V from the battery is shown on the left hand side of the diagram, note the battery supplies PCM directly, orange wire ckt 440; the other ckt shown DLC ckt 840 is to the connector where they hook up the device when they inspect your vehicle
2) +12V during Start & Run. You need a fair amount of amperage so you dont want to get this from your Regal harness, instead you want the Regal system to send a signal that the ignition switch is in Start & Run. Look at the top most relay labeled PCM RLY. The Regal signal (most likely the +12V to the original coil) is attached to 86 of the relay. When the signal comes from Regal to 86 the circuit is complete to ground through 85. This energizes a coil in the relay which closes the contacts and the circuit is closed between 30 and 87, current is then made available to the loads downstream of 87. The reason that the relay is desirable is that the load on the Regal harness is less than 1 amp (current from 86 to 85) whereas the current through 30 and 87 is limited by the rating of the relay, typically 30 to 40 amps. In actuality, I found about 60 amps were needed so I used two relays and broke up the loads between them.
a) for the fuel pump, the signal to energize the pump comes from the computer, for my vehicle it is a dark green wire coming from computer connector 4, pin 1. The relay works the same as described above.
As for the instruments, the wires do not run through either fuse box, the wires run directly from the sensor or computer to the gauge.
1) run the tach wire in the L31 directly to the gauge
2) water temp- the Dakota digital system probably came with its own sensor (or told you what to buy). You will need to install the sensor and run a wire from the sensor to your gauge.
3) oil press- same as water temp, use sensor supplied by Dakota digital; the L31 has two oil pressure sensors-- one for the gauge and the second keeps the fuel pump running after the engine starts. I will provide a diagram to show you that circuit.
3) VSS run from computer to your gauge, again does not go through either fuse box; you need to ensure that the computer signal is compatible with Dakota digital, should be
If you took the cruise control unit off the L31, then you will want disconnect all the Regal wiring and use the L31 computer to operate the L31 cruise control module. You will have to run the wire from the L31 system to your old Regal cruise control switch.
I also used the L31 crank start circuit. I'll provide a diagram for that circuit, too.
Mike
I'm 95% sure of this. The headers have to go up from under the car with the oil filter and starter removed... at least it was easiest this way on mine, and I did 1 side at a time, jacking the car way up in the air... a little nerve racking really.ATL Regal said:
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