QuestionQUESTION: Hello, My 86 xj6 yesterday I tested everything and ended up pulling the injectors because they were not firing.When i use a voltmeter on each injector connector and 1 side meter shows about 12 volts and the other side is between 3-4 on all 6 injector connectors.Is the voltage correct and should it be different.I went thru the XJ6 wont start and the fuel pump checklist 3 times and everything seems to be correct except the injectors were not firing.Today my friend came over and tried to help but no strange enough the fuel pump works when i bypass the circuit or open the AFM valve but not when i have the key to the ON position.
ANSWER: Hi Rick,
You can't test the injector signal that way. The fact that you see 12v on one side is an indication the all the resistors are connected and are powered but it does not test each resistor because a resistor must be grounded by a load to be tested other than by using a low ohm scale ohm meter across the resistor. The correct way to test is to use a "Noid" light (available at most auto parts stored) Get the one for Lucas or Bosch. A simple test is to place your finger on an injector and spin the engine, you should feel it "Click". If you get no Noid light flash you need to check for an ignition signal to the ECU (check the single bullet connector on top of the coolant rail about half way down the engine) and check for spark at the plugs.
Confirm that you have power and ground at the ECU plug.
As for the fuel pump circuit it operates the fuel pump by turning the key to the "On" position and opening the air flow meter flap. If it works in some other way you for sure have a wiring problem or relay problem. (The fuel pump relay is one of the black relays on the fire wall, the other black relay is the main relay)
You need a wiring diagram to work on this system. If you don't have one let me know and I will put one up on my web site for you to copy.
Howard
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wire with brown stripe
QUESTION: Hello, I bought a Noid light and have flashing light with injectors and cold start connector as well.But still my fuel pump does not turn on when I turn the key to the on position.Only when i jump it or open the afm then do I hear it come on.
I have a wire with a brown stripe on it in the frint right area some of the wires go to my coil and some look like they go around the front of the engine down to my alternator and one goes to a sensor on the right side of the engine.I seem to be getting 7 volts from it with key in on position.I took pics because Im colorblind but 2 people told me the wire has a brown stripe either the main color is light or dirty white or light green.I cant seem to find anything with the diagrams from the book as to where this wire should be connected it only looks about 16 inches long and my guess is the starter solenoid but it is only a guess.Also the bullet connector wire was damaged and i put in a replacement wire but i do not know how to test for power and ground at the ECU it just has a connector that it connects too and i can see and of the wire, maybe i can cut through he rubber and find the wires i need to check.
I have taken pictures and show the wire that is not connected.
ANSWER: Rick, if the noid light flashes then that proves the power is there and the ECU is triggering the injectors. That is what a noid light checks. As for the cold start injector, it does NOT flash! It opens when the key is in the start position (If the thermal time switch is cold and only for a few seconds)
You must not be reading what I am telling you. The fuel pump ONLY runs when the KEY is on and the air flow meter door is OPENED. If you just turn the key on the fuel pump will NOT run.
Your photo shows a plug that looks like the plug going to the injector resistor pack. If that is what it is someone has been rewiring as the color codes don't match.
Why are you testing voltage on wires that you don't know what they are for?
You have an injector pulse (the noid light proves that) check for spark at the plugs and you say the pump runs when you open the flap. These are the first things needed for the engine to run.
Do this, Pull a spark plug and put it on the plug wire and lay it on the head and spin the engine over. If you see a good blue spark (not in the bright sun light).
Put the plug back in if you have spark.
Confirm that you have a Noid light flash on each of the six injector plugs.
With the key on, open the air flow meter flap and listen for the fuel running through the fuel rail.
Check the battey voltage (12+v) Now take another known good battery and connect it to the good charged battery that is in the car as a jumper battery as though you are starting a car with a dead battery.
Now take a can of starter fluid and have someone try to start the engine as you spray a little starter fluid in the intake.
If you do all this and the engine does not start then you need to do a compression test and check the ignition timing.
Howard
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QUESTION: Hello, again I went outside to get everything ready to be tested and just checked the spark plugs and the car was running incorrectly some how.
he has my plugs connected this way my 1 plug is connected to 6 on distributor as per book.His firing order seems 180 out or something.
1 is on 6, 2 is on 5, 3 is on 4, 4 is on 3, 5 is on 2 and 6 is on 1--first number order off block second number being where he has it hooked up to distributor cap at.The numbers off distributor I am getting out of the book and counting 1 off engine block at back and 6 near fan(front of engine)...I am so confused right now, and not sure how the car ran for 2 years like that.It does explain why it was harder to start after the mechanic did the work last time also it tended to get hotter faster and was a tad bit sluggish.I have now changed the firing order to what my book says on page 72 of my Haynes manual.I am going to get starting fluid and a gapping tool to check the gap on the plugs and then let you know answers to previous questions.Thanks I guess will have to paypal you when this is done..Thanks
AnswerOn a Jaguar #1 is at the back and #6 is at the front. But it does not matter you can call the front cylinder #1 if you like as long as the firing order is correct 1,5,3,6,2,4. And you confirm that the cylinder you want to call #1 is on the TDC of the compression stroke.
Howard
