QuestionQUESTION: Howard - I'm still trying to figure out why the injectors
are not firing on my XJ6. With the key in the 'on' position,
should I have power to the resistor pack? I don't seem to
have any voltage reading at the resistor pack on the main
feed wires as shown in your wiring diagram. I've pulled the
wiring plug out and checked for voltage on both of the fee
wires (1 to each bank), and nothing. If I apply 12v to one
of the injector wires coming out of the plug, should I be
able to get the noid light to illuminate?
ANSWER: Hi Peter,
You said "my wiring diagram". Did you download a copy of my diagram? If so why are you putting 12v to an injector? The injectors are powered by the resistor pack NOT 12v. I don't what damage to the ECU that you may do by feeding 12v back into the ECU. If you have the diagram it is clear that the main relay powers the resistor pack and the main relay it what powers almost everything. The main relay is on the firewall in the engine compartment.
Howard
---------- FOLLOW-UP ----------
QUESTION: Thanks Howard, I am using the wiring diagram from your site. I have already
replaced both relays on the firewall with new units, that didn't help, haven't
replaced he diode pack. So back to my original question - should I see power at
the resistor pack with the key turned on?
ANSWER: Peter, You should have power on the Brown w/slate trace wire in the Ignition position. To confirm what is happening you should use the diagram and test with a test light at the sockets of the relays and don't replace anything until you find where the power is stopped.
For example, remove the air filter can, so you can reach in the airflow meter and turn the key on. Reach in the front of the airflow meter and push the flap door open. If you hear the fuel pump start pumping fuel through the system (it is noisy) then by the diagram you know for sure there is power on the Brown w/Slate trace wire. Which is the power for the resistor pack. If the injector wire does not have power on it at that time then you know to go to the resistor pack (mounted low on the right front fender panel under the hood.) Then test the connector there.
Don't replace the resistor pack unless you have power in and none out.
Howard
---------- FOLLOW-UP ----------
QUESTION: OK, I tried the air-flap test, and don't hear the pump running
at all, which confirms what I saw at the resistor pack - no
voltage on the Brown/slate wire. Suggestions as to what to
check next? Thanks for the help.
AnswerNext step is to confirm all powers "IN".
There are 4 relays lined up on the firewall under the hood. The larger metal relay is the starter relay and the next is a black plastic relay which is the "Main" relay, next is the "Fuel Pump" relay also black plastic and the last is what looks like a red plastic relay but it is the "Diodes".
Unplug the main relay from it's socket and take a test light and check for power in the socket at pin number 30 (brown wire) Look at the bottom of the relay for the pin numbers next to each pin so you know which socket to probe. That socket must be hot all the time. Then probe the socket where pin 86 was, (white wire) and that should be hot in the "IGN" position. Now connect your test light clip to a power source and probe the socket where pin number 85 was and that should be a good ground. If all that is correct make up a short jumper wire with male flat spade terminals on each end and plug one end into socket number 30 and the other end into socket number 87. Now test any injector wire for power on one of the terminals.
If you will follow along in your wiring diagram you will see the procedure for testing that circuit.
Howard
