Coil Resistor

[Kacers]

There is apparently a resistor between the coil and the ECU on my friend's '95 D1. Only his rig doesn't have one and I think this may be his firing issues.

Anyone have a PN for this and/or know what size this is and whether or not the absence of this would cause starting issues?

I checked the Manual and can't find it in there but don't have access to an electrical diagram (schematic) to check this. Maybe someone who does could check???

TIA,

AndrewT

 

[92rrrandall]

The signal going from the neg ignition coil terminal to the ECU is the most important input in the system. There is exacly one pulse of fuel for every pulse from the coil. This is the case for all Bosch or Lucas MPI fuel systems from day one.

The ECU only needs a signal from the coil so it is easier to use a resistor to step the current down to process the signal. The ECU then takes the signal and shapes it to suit the injector's circuit and engine load. The resistor is 6800ohms. You can probably check to see if it is present by connecting an ohm meter from the neg coil terminal to terminal 39 in the EFI harness. Should measure 6800ohms. can't image why it wouldn't be present. If this wire is not present and have the resistor in it then not even one drop of fuel will be injected into the engine.

Randall

 

[Kacers]

Very informative Randall. Thx for posting. I got access to the RaveCD for his D1 and was able to see the 6.8KOhm resistor you reference in the schematic there.

We put an injector test light in the harness and saw the injectors firing during cranking so I would think the line between the coil and ECU is good as the ECU is enabling the injectors. The resistor must be within the wiring harness and not near the connection to the coil so I assumed it was missing.

One question on coil wiring. The wire between the dizzy and the coil is red/blue (blue is actually labeled U for Ultramarine). It enters first into the Ignition Module and then exits the ignition module as two white wires that go to the coil. Actually, one of these is white w/black stripe and one is solid white. RaveCD only labels these as R/U (red/ultramarine) and I can't tell how that relates to the two wires going to coil.

For the two wires leaving the ignition module and going to the coil, I think the white w/black strip goes to the - terminal on the coil and the solid white wire goes to the + terminal on the coil. Can anyone confirm this?

AndrewT

 

[92rrrandall]

All Range Rover/Discovery/Defender with distributor have white wire with black stripe going to the neg term on ig coil. Solid white wire goes to positive coil term. It is very easy to test if the ig system is working. Just put your timing strobe lite on a spark plug cable and see if it flashes while you crank the engine with the starter. You can also just put a test lite on the neg terminal of the ig coil. Again the test lite should flash while cranking. Not a 100% test of the system, but can quickly isolate the problem if there is no flash.

Randall

 

[Kacers]

Once again - Thank You!

AndrewT