Stumped....85 XJS Won't start
#1
Stumped....85 XJS Won't start
I am not sure where to go from here.... Car will not start unless I spray starting fluid into the air cleaner. Then it starts for maybe a second until the fluid is gone.
I got this car about 3 years ago after it sat for a couple years. I charged up the battery and drove it home. Ran fine then. Now the car has been sitting for another 3 years and won't start. I did drain the fuel and add new gas to it. Even cleaned out the filter and both sides of the injector rail. I am getting fuel up to the rail because it used the pump to help clean out the lines.
I turned on the ignition and opened the throttle, did not hear any clicking from the injectors. Cleaned all the connections to the amplifier, still nothing although I wouldn't know,what the clicking sounded like if it bit me....
With the ignition on, I pulled one injector plug and had voltage on both sides. In fact all injectors have power on both sides.
Read that it was the harness so I pulled the AC pump, cruse and a few other small parts. After looking at the harness, I didn't see anything grounded, broken etc. unplugged all the injector plugs and tested the harness again and this time only one side lite up. As soon as I connect an injector and it doesn't matter which one, I once again get power to both sides....
I did run an Ohm meter across the unplugged injector and it showing ohms but wouldnt read a number... Same results on all injectors...
Any suggestions?..
I got this car about 3 years ago after it sat for a couple years. I charged up the battery and drove it home. Ran fine then. Now the car has been sitting for another 3 years and won't start. I did drain the fuel and add new gas to it. Even cleaned out the filter and both sides of the injector rail. I am getting fuel up to the rail because it used the pump to help clean out the lines.
I turned on the ignition and opened the throttle, did not hear any clicking from the injectors. Cleaned all the connections to the amplifier, still nothing although I wouldn't know,what the clicking sounded like if it bit me....
With the ignition on, I pulled one injector plug and had voltage on both sides. In fact all injectors have power on both sides.
Read that it was the harness so I pulled the AC pump, cruse and a few other small parts. After looking at the harness, I didn't see anything grounded, broken etc. unplugged all the injector plugs and tested the harness again and this time only one side lite up. As soon as I connect an injector and it doesn't matter which one, I once again get power to both sides....
I did run an Ohm meter across the unplugged injector and it showing ohms but wouldnt read a number... Same results on all injectors...
Any suggestions?..
#2
#4
Guess I should have re-read your first post, sorry about that.
Because you have power on both sides of all the injectors, I think you might be correct in assuming the harness is the culprit. Unfortunately, most of the problems with these old harnesses is not visible unless you open up the looms and then you'll see exposed wires.
Thats where I'd put my money!
Because you have power on both sides of all the injectors, I think you might be correct in assuming the harness is the culprit. Unfortunately, most of the problems with these old harnesses is not visible unless you open up the looms and then you'll see exposed wires.
Thats where I'd put my money!
#5
#6
If you would post photos that would be great...thanks. I will give the harness a closer look to see if I can see anything in the wires. Funny part is that if all the injectors are unplugged, each plug only lights on one side but as soon as I connect any injector, they all light up on both sides....
#7
Join Date: Mar 2008
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OK, good start. At least you know the voltage supply end of things is fundamentally working.
If you back-probe an injector connector while it's still on the injector you should get voltage on both wires. When cranking and running one of the wires goes to ground as commanded by ECU to actually operate the injector. this is such a short duration event than you might not even pick it up with meter but a noid light would blink, if you have one
Read that it was the harness so I pulled the AC pump, cruse and a few other small parts. After looking at the harness, I didn't see anything grounded, broken etc. unplugged all the injector plugs and tested the harness again and this time only one side lite up.
I suspect a problem in the voltage supply side of the harness. The voltage supply is two wires off the "main relay" which branch to four wires well downstream.These are the pink/black wires in the injector harness. You may have to open up the harness to check them. If needed you can reduce the redundancy of the pink/black wires.
As soon as I connect an injector and it doesn't matter which one, I once again get power to both sides....
I'm not sure what to make of that. I'll have to mull. But begin by verifying that all the pink/black wires in the injector harness have 12v (or prevaling battery voltage) with the key "on"
Cheers
DD
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#8
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When you've verified the voltage supply is good thru the whole injector harness you can then start looking for a problem on the "trigger" side of things. The ECU commands the injectors to ground by input from a wire at the ignition amp (square-ish black box on left inlect manifold). So...take a good look at the amplifier wires. I can't remember which one is the trigger wire to the ECU but look all of them
Cheers
DD
Cheers
DD
#10
Here is the latest....
Bought a nod light kit and with everything back together I turn over the key and hit the throttle and the noid light blinks brightly. I did try both sides and the both blinked. So it seems like the harness is fine???
Still no start...
It turns over and almost seems like it wants to start but doesn't unless I hit it with starting fluid and again for only for a second. I did just put in 2 gallons of premium gas just in case it was out. I will try draining out a little more gas just in case there is some old gas still in there.
Not sure where to go from here.
Bought a nod light kit and with everything back together I turn over the key and hit the throttle and the noid light blinks brightly. I did try both sides and the both blinked. So it seems like the harness is fine???
Still no start...
It turns over and almost seems like it wants to start but doesn't unless I hit it with starting fluid and again for only for a second. I did just put in 2 gallons of premium gas just in case it was out. I will try draining out a little more gas just in case there is some old gas still in there.
Not sure where to go from here.
#11
New update:
I decided to pull the front injector on the passenger side... I removed the round metal tube covering the injector bolts and then removed the injector. I tested the plug with the noid light and it light up nicely but when I plugged in the injector and cranked it over no fuel came out. Possibly clogged fuel injectors? I will do some research to see how to remove the injector from the rubber tube then see if I can somehow clean the injectors..... Hope I don't have to buy new ones.....
I decided to pull the front injector on the passenger side... I removed the round metal tube covering the injector bolts and then removed the injector. I tested the plug with the noid light and it light up nicely but when I plugged in the injector and cranked it over no fuel came out. Possibly clogged fuel injectors? I will do some research to see how to remove the injector from the rubber tube then see if I can somehow clean the injectors..... Hope I don't have to buy new ones.....
#12
Power on both sides of the injector is normal. You are reading voltage at an open circuit. There is only a ground when the ECM applies it. When there is a ground you will not see power on both sides of the injector. This is basic electrical theory. It can be confusing if you are not really comfortable with electrical.
The pulsing noid light proves you do not have a wiring issue at the injector(s) you tested. Test all 12 to make sure. If no fuel sprays out then you either have 12 injectors that are blocked(or stuck) or no fuel pressure. The most likely cause is lack of fuel pressure. If it is really stuck injectors you can try applying 12 volts to them manually. That can sometimes free them up. Have you connected a fuel pressure gauge and measured the pressure? Just because the pump does not mean you have fuel pressure. Also you need volume too. If you have not replaced your injectors hoses now is a good time to do so. You could remove the fuel line at the rail and crank the car. See if it fills a jar rather quickly. This won't show pressure but can tell you if you are at least getting fuel to the rail.
The pulsing noid light proves you do not have a wiring issue at the injector(s) you tested. Test all 12 to make sure. If no fuel sprays out then you either have 12 injectors that are blocked(or stuck) or no fuel pressure. The most likely cause is lack of fuel pressure. If it is really stuck injectors you can try applying 12 volts to them manually. That can sometimes free them up. Have you connected a fuel pressure gauge and measured the pressure? Just because the pump does not mean you have fuel pressure. Also you need volume too. If you have not replaced your injectors hoses now is a good time to do so. You could remove the fuel line at the rail and crank the car. See if it fills a jar rather quickly. This won't show pressure but can tell you if you are at least getting fuel to the rail.
#13
Thanks guys for all your suggestions...
Today I reconnected the fuel rail but left the injectors out of the engine so I could try a few things. Turned on the key and heard the fuel running into the fuel rail, applied 12v to the injector and it sprayed. Tryed to go to the second injector and nothing. Turned the key off then on, heard the fuel again and the second injector sprayed when applying 12v. When I did this to each injector they all sprayed but I hard to turn off the key then back on. While I had the plugs off all injectors, I tested each injector plug with the noid light and each one lit up only when I turned the throttle plate.
Also noticed that the moment switch under the throttle cable had broken so I now need one of those.... All the test above were done with that switch out of the carand the wires disconnected.... This switch was okay before as it broke while trying to unplug the injector....
Tried to take the fuel pressure using my gauge but couldn't find the valve to connect it to... Do I need a different gauge or some sort of adapter?
Today I reconnected the fuel rail but left the injectors out of the engine so I could try a few things. Turned on the key and heard the fuel running into the fuel rail, applied 12v to the injector and it sprayed. Tryed to go to the second injector and nothing. Turned the key off then on, heard the fuel again and the second injector sprayed when applying 12v. When I did this to each injector they all sprayed but I hard to turn off the key then back on. While I had the plugs off all injectors, I tested each injector plug with the noid light and each one lit up only when I turned the throttle plate.
Also noticed that the moment switch under the throttle cable had broken so I now need one of those.... All the test above were done with that switch out of the carand the wires disconnected.... This switch was okay before as it broke while trying to unplug the injector....
Tried to take the fuel pressure using my gauge but couldn't find the valve to connect it to... Do I need a different gauge or some sort of adapter?
#14
didnt read through the full thread but from your first post i can say this. if the injectors dont click, and its an audible, tactile click, then your injectors are siezed. have them rebuilt, buy new, or buy N.O.S.
check to make sure your getting voltage to them though. the injectors click in pulses. the ECU applies this pulse. simply applying 12 volts to the injector will allow it to spray once without returning to the magnetic rest position.
check to make sure your getting voltage to them though. the injectors click in pulses. the ECU applies this pulse. simply applying 12 volts to the injector will allow it to spray once without returning to the magnetic rest position.
#15
#16
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No Schrader valve.
On the left side of the fuel rail is a rubber/metal fuel pipe....it attaches towards the rear of the rail. Cut open the rubber portion and "tee" in your fuel pressure gauge.
Of course you'll have to replace the hose when you're all done. No big deal....just cut the old hose away from the meal ends and push new (fuel injection grade) hose on
Cheers
DD
On the left side of the fuel rail is a rubber/metal fuel pipe....it attaches towards the rear of the rail. Cut open the rubber portion and "tee" in your fuel pressure gauge.
Of course you'll have to replace the hose when you're all done. No big deal....just cut the old hose away from the meal ends and push new (fuel injection grade) hose on
Cheers
DD
#17
There is no test port. You can either buy a master fuel gauge test kit and use it as import car techs do or as Doug said cut the fuel line and use a tee. You disconnect a fuel line and via the kit's fittings tee in the gauge. Only domestic and asian imports give you a fuel pressure tap.
This place make tees with Schrader ports you can install and leave in place. The Race Place Home Page
Others have remove the fuel rail and had a port welded in.
This place make tees with Schrader ports you can install and leave in place. The Race Place Home Page
Others have remove the fuel rail and had a port welded in.
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