Hi all,

I have a non start issue on my 1984 US-spec XJ6. It hasn't been started up for around nine months.

I HAVE spark from the coil to the distributor, but NO spark at the plugs - there is nothing visually wrong with the cap or leads.

There was initially a little corrosion where the rotor meets the contacts but I cleaned it up and it looks fine. (I checked the resistance at the terminals on the pickup module and it's reading 3.3 Ohms.)
Internally, nothing looks burnt. I am wondering if there's a likely area of failure or if I should look at replacing the cap and leads first, followed by the whole unit?

Any help would be appreciated - these cars make pleasant viewing as yard art but I really would like to drive it !

 

Let's begin with something really easy:

The big wire from the coil to the center of the distributor cap......remove it. Any corrosions on the ends, or the sockets?

If so, clean and re-try starting. Report back

Cheers
DD

 

Well, that (and cleaning the other contacts again) does seem to have worked because I have spark !

But, it still won't start so there seems to be another problem. I went through the various checklists and tested the various components as follows:

checked voltage at both + and - sides of coil, and checked for voltage drop on cranking, it dropped from 11.7 to around 8v, so concluded the amp is working.

checked fuel pressure. pump is audibly working, and loosening clamp at the fuel rail causes fuel to spray out, so pressure is ok.

I took a connector off one of the injectors and tested voltage with key to "on". there is voltage at both terminals on the connector. I'm not sure if that means they're working properly, or are just not firing.

am I looking at an ECU problem?

 

Oh,oh?


1. voltage drop at the coil doesn't necessarily mean the amp is working. More likely that the starter or it's connections are drawing off a lot of volts that are needed to fire other stuff. Ignition, injectors, fuel pump, etc.


2. Are the plugs sparking? Each and every one each time? the rotor has a contact that matches the button in the center of the inside of the distributor cap. If no contact there, the spark plugs get zip!!


3. My tool kit includes a short length of coat hanger wire. It is bent back at one end. I insert a strip of emery cloth. I use it to clean the inside of the spark plug wire ends, coil wire ends and coil and distributor towers. Lots of corrosion found at times!!


Carl

 

my '84 was asleep for 15 months in a storage unit, all it needed was fresh gasoline and it has been starting every day for the last 2 weeks. (the battery maintainer kept working all 15 months, so the battery was saved and fully charged when I opened the storage unit).

Was your car starting before the 9 month sleep ?

 

thanks for the help
1. ah, so it may yet be the amp..
2. I'm going to test them all now. I assume though if some were sparking but others not, that it would be an audible struggle, i.e. the engine spluttering? it's turns over smoothly and feels like no ignition whatsoever. if that makes sense..
3. I was using a screwdriver with cloth, but I think I need to replace the cap and leads, they look old to me and aren't expensive anyway.

It was allegedly starting then, although I didn't own it then so only have the POs word for it. He said it may have to be "coaxed", although how you coax a fuel injected car I don't know ...

 

Coaxed aka persuaded in one way or another. Ether injection being popular.


Jose has a point. Modern fuels don't have long lives. primed with fresh fuel, they might run the car, sorta. but fire it cold, not so much.


FI cars need the same elements, compression, ie air, fuel and spark, each in the right amount and at the right time.


Push starts no longer available. That's how I used to get my tired 37 Ford V8 going in winter to go to class.


Carl

 

I have experience fiddling with carb'ed cars to get them going, but not FI so it's new to me that way. currently checking all the plugs, gaps, etc.

If only I'd learned all this stuff years ago ...

 

if the coil-to-distributor high-tension cable check does not change anything, just put a couple gallons of fresh fuel in the left tank, (the tanks dash switch pressed IN), and then check the Cold Start Injector by removing it and holding it while someone cranks the engine, a spurt of fuel should come out. Easy pulling it or you'll tear the paper gasket.

also try priming the fuel system before attempting to crank the engine, it is a routine I always do and it starts the engine on the first turn of the switch:

place the shifter in first Gear (1), turn and hold the ignition switch for 3 seconds, then back to OFF. Repeat a second time and a third time. Everytime you do this, you can hear the fuel pump priming-pressurizing the FI. Can you hear the pump when you do this? (it sounds like "hammmmm").

I never believe anything that a seller tells me. Especially stories about mileage and other tall tales. So it looks like you have to start from scratch until you get it to start, and it will. But if you have spark, then it is a fuel issue. Check the Cold Start Injector.

 

Well, you've proven that you do have fuel delivery but pressure is not known. It's probably Ok...but you need 36 psi while cranking.





Good that you have voltage to the injectors but they don't operate unless grounded....which is the job of the ECU.

Easy step/check: Do the injectors click while cranking? If they click, the ECU is 'firing' them and they should squirt fuel....if there's enough pressure

If no click, post back.

Cheers
DD

 

removing the hose at the Fuel Pressure Regulator or Fuel Rail does not prove the cold Start Injector (CSI) is working.

the two times I've have a no-start condition no matter what I did, it turned out to be the CSI. I am not saying THAT is the problem, but it is one check that he should confirm.

 

thankyou for the assistance (and patience), I will check that.

the first thing I'm going to do this morning is go through the CSI checklist, I have it disconnected ready to test ...

 

Good to do on general principles but a faulty CSI is unlikely to cause a flat-out no start situation....unless perhaps you're in a sub-freezing climate. The CSI gives a quick spurt of raw fuel to aid in cold starts, that's all. It doesn't even operate at all if the coolant temp is above 90ºF degrees or so. Even without a CSI the regular injectors (if operational!) are still fueling the cylinders and the engine should run.


I went for months with an inoperative CSI and the only thing I noticed was longer cranking was needed on cold mornings.


Cheers
DD

 

Interesting! I had the opposite experience. Go figure!

Cheers
DD

 

Seems that if the engine needs a bit more fuel to fire, a prime with either either or gas would solve that.


Carefully, of course.


And, if it doesn't fire when primed, go elsewhere.


Off to the relay redo and the missing 1/4 drive 3/8 socket!!!


Carl

 

There is audible clicking, barely so - like a sparking sound. Not sure how loud it should be but that's the best comparison I can come up with. I may disconnect the starter and try again to to get a better listen.

I am starting to think the injectors are just bunged up with old rust and particles: I have bills from the previous owner for having the fuel tanks restored several times on this car and I've read it's not an uncommon issue. If I can ascertain the injectors are working I will separate the fuel feeds and see if there is dirt in there.

again, thanks for your patience!

update:
Injectors are spraying fuel. I took one out and reconnected it to confirm. This thing should start!

 

With some more cleaning and checking, and the addition of some ether spray, the motor briefly kicked into life - which I'm regarding as something of a success. going to take a break and see if it will fire up with more consistency.

thanks for the all the invaluable help, to everyone who responded.

 

all this is weird because the 1984 model year is one of the most reliable years for the XJ-6.

here's something to check: the two wires the connect to the Coolant Temp Sensor.

 

weird too because this engine was rebuilt 14,000km ago. those wires you mention aren't the best but they aren't broken, the insulation is cracked a bit.

would I be right in thinking that fuel pressure regulator failure would result in too much fuel, rather than too little? I think I am looking at a fuelling issue, now I know it can start with the ether.

(Also, while cleaning the plugs I managed to damage one of the threads so until I repair that it can only run on 5 cylinders ...)

 

Yeah, but sooner or later the years take a toll.....




Great idea.

Cheers
DD