Guys.

I contacted the Volo Chip guys to check if I can connect to my 1994 Disco 1 the chip and they requested me the pinout of the OBD 1 connector in order to check if it can be done. Have googled, but got nothing. Anyone can help?

Thanks!

 

I assume you need the ECM plug pin out? I also assume you are running the original ECM, is that all correct? If yes then here ya go...

After you unplug the connection and when you remove the rubber boot from the wires simply slide it off the plug and down the wires a few inches. Do not remove the boot. Once the boot is out of the way look closely at the back of the plug and you will see numbers on the left side of the plug. These are the pin numbers...

Pins 1 to 13 Left to Right
1
Red/Green
Idle bypass valve - circuit 1
2
Brown/Orange
Power feed to the fuel injection main relay
3
Yellow
Throttle position sensor output/reference - see also 20 and 25
4
Black
Oxygen sensors (ground) and to the relay that powers their heater coils
5
Grey/Black
Tune resistor (through VIN LA451517 only)
6
Yellow
Road speed input
7
Green/Blue
Coolant temperature sensor (input) - see also 25
8
Purple/Yellow
Windshield defroster input, if fitted
9
White/Light Green
Diagnostic connector output
10
Black/Yellow
"Check Engine" lamp
11
Yellow/White
Right bank of injectors - cylinders 2, 4, 6 and 8
12
Blue/Red
Main relay "request"
13
Yellow/Blue
Left bank of injectors - cylinders 1, 3, 5 and 7

Pins 14 to 27 Left to Right
14
Black
Ground
15
Brown
"Battery" supply
16
Blue/Purple
Fuel pump relay "request"
17
Grey/Yellow
Purge control valve output
18
White/Pink
Diagnostic connector output
19
White/Grey
"Ignition" supply
20
Red
Throttle position sensor (input) - see also 3 and 25
21
Yellow/Black
Air conditioning thermostat input, if fitted
22
Blue/Red
Air flow sensor (input) - see also 25
23
Blue
Signal from the LH oxygen sensor
24
Blue
Signal from the RH oxygen sensor
25
Red/Black
Ground side of coolant, fuel, airflow & throttle-position sensors
26
Green/White
Idle bypass valve - circuit 1
27
Black/Grey
Ground

Pins 28 to 40 Left to Right
28
Blue/Grey
Idle bypass valve - circuit 2
29
Orange
Idle bypass valve - circuit 2
30
Black
Fault display data
31
Black/Green
Diagnostic connector request input
32
Grey/White
Fuel temperature sensor (input) - see also 25
33
Black/Grey
Air conditioning compressor clutch relay, if fitted
34
Orange/Black
Transmission gear switch signal
35
Blue/Green
Air flow sensor (input) - see also 25
36
Black/Green
Air conditioning condenser fan output, if fitted
37
(Not Used)

38
Brown/Black
Fault display data
39
White/Black
Engine speed signal cable (harness includes 6.8k ohm resistor)
40
Black
Ground

I do hope this helps you out. The main chip in the ECM is an EPROM... it is reprogramable or you can simply switch it out for a remapped one. May I ask why you are doing this?

 

Cosmo,

Do you know if the EPROM is soldered in or if it just pushes in

Larry

Not that I'll be replacing my EPROM or remapping my truck, because I like it the way it is, but, I'm just wondering.

 

'94 was the year they stopped soldering them in. For NAS Disco's they were all removable and programable. As far as I am aware Rover / Lucas stopped soldering the chips in place when they switched from the 14CU to the next generation ECM.

Honestly, the remap with th 3.9 in this truck is far more effort than it is worth. Now, if you squeezed that 3.9 V8 into a MG, Triumph, TVR etc... then it would be worth it.

 

Thanks for the pinout...

Well.... Actually I need the pinout of the OBD1 connector. The Volo chip remaps the ecu every time you start the engine.

What I am trying to do is to get more MPG.

Thanks!

 

I'm assuming you've done the basics?

-new plugs
-new air filter
-new fuel filter
-(if it's a 95) new cap and rotor
-new plug wires
-premium fuel
-proper air pressure in your tires
-drive line operating as smooth as possible

so, they are making an obd2 piece work for your obd1 truck?

the obd2 trucks do not have a distributor. they have a crank fired ignition. I don't think they'll be able to make this piece work.

 

I'll try to find that for ya... it's up under the glove box.

If they lean out the fuel map in mid-range rpm's you'll simply lose power. Maybe try ignition tune up first? If fuel economy is your goal this may not be the right vehicle...

Your Disco came programmed with a mean air/fuel mix of about 14.7 :1 during normal revs (closed loop). This ratio does change somewhat of course when you floor it or let off the skinny pedal. You could go up to 16:1 but I guess it would be like driving an underpowered RV.

Please let us know if you have this done.

 

I figured I'd just throw this out there. If you're serious about EFI mods... start here. http://www.microsquirt.info/index.htm

Megasquirt and Microsquirt are good options...

 

Daydreaming is good..... I just realized I already gave you what you are looking for. Read the pinout for the ECM more closely.

pins 9, 18, 31, 38

Also, so you know the only way to reprogram the chip (remap) is to remove the chip or replace it. the Data link plug is a one way (output) deal as far as air:fuel mix settings.

 

I will be looking into megsquirt/microsquirt with my upcoming supercharger install....