Please, I need help!!! I have a 1985 XJ6 that was running perfect, and at the last engine turn off, the car would not start back up. I have done every test I can think of, to find out what went wrong and EVERYTHING is in working order!!! The issue I did find was that the injectors are not firing.
The ECU has 12v in on pin #10, the mass air flow meter has 12v in, the resistor pack has 12v in on both red/brown wires, the ECU is receiving ignition coil pulse signal, the injector wires have 12v power on both pins (checked both pins individually to ground) the injectors are receiving fire pulse in proper correlation to engine, (injector pulse point every 3rd ignition point (pulse, skip, skip, pulse, skip, skip, pulse).
I have replaced the ECU, mass air flow meter, Resistor pack, diode pack, main relay, fuel pump relay, starter relay, cold start relay, swapped out one injector (I put a “T” connector on the fuel line at the “in” side of the fuel rail, connected it to the injector and plugged in the injector plug from cylinder 4, then 5 then 6). I have cleaned every ground I could find, checked the fuse behind the battery, which as 12v “in”, the three fuses under the ECU, all of which have 12v “in”. I have cleaned the wire loom harness connectors (the ones next to the battery) cleaned the ECU connector plug, the mass air flow meter plug, the throttle potentiometer plug, all the sensors on the water rail, all the injector plugs, cold start injector plug, the resistor pack plug. I have checked the internal resistances of the resistor pack which read 60 ohms from red wire to yellow wires +/- 5 ohms, 115 ohms resistance between all yellow wires +/- 2 ohms, the injectors all have about 35 ohms resistance +/- 1.5 ohms. The injectors actual pulse signal only registered 1.2 volts average (I connected a volt meter to the injector plug between the two pins). But in all, the injectors still will not fire. Is there something I am forgetting, something I’m not looking at or something I have missed?

ANY help will be helpful!!!

BTW...I did check the ignition system (this was the very first thing i did), all the plugs have a whitish blue spark....which stung like a F***ing hornet... and the engine will run if I spray fuel directly into it with a squirt bottle, and runs rather smooth this way, so by this i know there’s nothing wrong with the ignition system.

 

Are you sure you've found, checked, and cleaned *all* the ground wires under the bolt at the end of the water rail? There should be about a half dozen black wires. The whole F.I. system grounds there.


Cheers
DD

 

yes, there is a braid strap grounding the water rail to the head through the intake manifold plus two more with it, 3 thick wires and 2 thin wires on the same bolt that attaches the water rail to the intake manifold.

Just to humor myself, I went and tested one of the injectors from my old 95 XJ6 (just because it had the same pin connector) and it fired; it was very week but it shot fuel right out, now I really don’t understand what’s wrong. Is there a way that the car could simultaneously fry six factory original Lucas injectors at the same time without frying anything else??? And a same type test injector(just newer) for a total of 7 injectors , but a newer model bosh injector will work?. BTW... I checked the ohm resistance on the bosh injector and the injector had about 165 ohms.

 

Also the braid strap had about 1.2 ohm of resistance

 

It looks like you having so much fun! In these cases I fully recommend that you start from the begging... step by step... from the battery to the spark-plug and from the gas tank to the injector. It will be a very STUPID thing. I'm sure you will find it! Don't forget anything,,, you must think as a child otherwise you go to fast (because you know too much) and you are going to miss this small wrong detail.


PS: Did you check the crash-inertia switch? I know is stupid to ask... but... I only ask.


I send you lots of positive energy.

 

Are you asking if this is possible?

Or are you saying that you DO have fried injectors and you're asking how it might have happened?

Either way, I'm stumped....at least for the moment!

Cheers
DD

 

You might drop a line to David Faircloth at:

Jaguar Fuel Injector Service


He's a great guy and might be able to help WRT what it takes to fry an injector


Cheers
DD

 

I feel like a complete idiot, as I found out what the what the problem was. First thing, the injector that I used to test fire (so I didn’t have to pull the injectors on the car) though came off an XJ6, that was a running car, just turned into a parts car(when the engine went) was locked up, I pulled the rest of the injectors and found 2 that fired (from the parts car), then actually pulled cylinder 5 & 6 injectors from the non-parts XJ to swap and test, and found that all both injectors were firing. And because when I pulled the fuel rail to pull the injectors I unfortunately destroyed all the injector fuel lines, so I set up a test fix to test just cylinder 5 & 6, this temporary set-up include a glass, sight flow-strainer because i have any more hose connectors, and what I saw going through it was massive ammout of water. Turns out the last time I was getting gas, what I got was 1.5 Gallons of water and 6.5 Gallons of gas for the left hand tank alone.

 

unfortunately the water with a good bit of sludge did foul out the injectors so i will have to pull and clean them all. Any ideas on how i might do this without damaging the injectors? The last time i did this, I set them up-side-down in an old coffee can with a 50/50 mix of coleman fuel and marvel mystery oil for about 3 days. It seemed to work because the spray pattern went from about a 5 degree skeet, to about a 45 degree spray. But that engine was on its last legs to start with, later that month I ended up pulling the head only to find the head was pretty well shot (I ended up dropping in a rebuilt engine that turned out was not rebuilt properly, thus it was also pretty well shoot and never ran).

 

To Debbiesidera, yes i did check the crash-inertia switch and i think its working correctly, one thing i noticed is that when tripped, it kills the fuel pump and the fuel injectors; i saw this when i tripped it to replace the driver side tank, the fuel pump and the engine stopped at the same time, when i pulled the fuel line at the fuel rail to use the pump to remove the fuel from the tank (i prefer not getting gas all over the place when at all possible...half of the time i still end up getting a gas-bath), there was still good pressure on the fuel rail. On my other XJ6 tripping the crash-inertia switch only killed the pump allowing the engine to use the fuel in the system to deplete the pressure. Both of my XJ6s are 85-MY, one built in september of 84 the other, october 84.

[i have for the time being, turned the one manufactured in september into a parts car, though if i get my hands on another XK6 4.2L or a 5.3L v12 engine, its going right back on the road because its body is in perfect shape, the one manufactured in october needs a whole set of all the horizontal trunk panels, the vertical ones have no rust damage (how that worked out i have no clue) and a new driver floorboard, same issue as with the trunk...LOL]

 

Don't beat yourself up too badly. I went through a similar "snipe hunt" recently. After many hours and a cloud of profanity, the problem came down to bad gas. It is simple, but something you don't think about immediately. Especially when it is running, and then just stops.

Anyway, there is a service on E-bay, and I believe it is the same guy mentioned by Doug - you send your injectors in, they are cleaned, rebuilt, and checked for proper spray pattern, and then returned to you. It is posted at 115 bucks. I would think that is a good option.

 

I went and pulled all the injectors did what cleaning i could and then tested them, there still fouled up pretty badly internally with not a good spray pattern, so im just going to send them off to have them professionally cleaned and/or rebuilt, along with the spare set so i have a working spare set.

Thanks to all!

 

so i got the engine back up and running....5 out of 6 cylinders anyway...need to do further tests on cylinder # 5, good spark, nice fuel, but no fire and overall the engine is lacking in some performance.

Anyone come across an issue where the whole dash cluster stopped working? no tach, speed-o, water temp, oil pressure, voltage, fuel level and trip-computer. Though they never worked when i got the car, i know the previous owner was in the middle of restoring the interior (all new seats, carpet, headliner... the whole lot, the only three items not replaced were the dashboard, dash-top, (the black part) and the rear platform thingie under the rear wind shield), and unplugged A LOT of wire-plugs in the center console, i have re-plugged all the wires i could, but know i've got to be missing a couple I can't see or find.

 

I am having a near identical no start condition with my 1985 4.2 XJ6. All the testing you did, I also did, and with the same values registered.

In your experience now do you believe that the injectors having been serviced professionally sorted the no start condition in your jaguar? I am at my wits end with this turn over, but no start condition. Any other advice would be greatly regarded.

Cheers

 

Update and reply
With my car the primary problem was water in the gas tank, enough water to were the fuel pump only cycled water in the fuel system. the secondary problem which was caused by the crud in the bottom of the tank at the gas station was fouled injectors. What i did instead of sending them off to get rebuilt (will do later though, pending a different project), was connect the fuel line to the injectors in reverse and "run" the injectors on a modified system, which contained the entire injection system setup on a workbench (no engine required) with the spark pulse generated through a spare distributor attached to a drill. I was able to set this up because i had at my disposal a second, complete fuel and ignition system.

After getting the engine back up and running, about a week later, i found out why cylinder #5 was not firing, at some point in time before i bought the car, i'm thinking the exhaust side of the head over-heated changing the spring resistance in the exhaust valve springs allowing them to "float" at low engine speeds (i cross checked the spring resistance to a rebuilt head i had gotten for my parts Xj to try and fix up that engine, i could barely open any valves by hand on the rebuilt head but could completely compress both springs on Cylinder #5 which just so happened to be the worst.) About a week after i got the engine running somewhat properly it broke and dropped cylinder #5's exhaust valve, destroying cylinder #5's piston, connecting rod and head surface, and locking the motor up against the connecting rod after about three seconds.